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  • 1.
    Ahlgren, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Changes in size distribution of lakes in the Nadym catchment, northern Russia2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Because of climate change and resource development there is an ongoing increase in the attention directed towards high latitude areas. Over the last years, warming in the Arctic has accelerated quickly. The warming climate can possibly lead to thawing of ground ice, which in turn leads to alterations of the cryosphere. This can have a huge influence on the terrestrial hydrology of the Arctic and, more specifically, on the presence and distribution of lakes in arctic regions since both are coupled to subsurface ice. In this thesis data from remote sensing were used to look at the change in the size distribution of lakes for the Nadym catchment in northern Russia. The aim was to find out if there has been an increase or decrease in the number of lakes in the area over the past years. Results suggest that there were 229 lakes less (representing a 4% decrease) in 2007–2009 compared to 1987, indicating that lakes are slowly disappearing. Also, the total lake surface area decreased with 5%. Almost half of the lakes that disappeared (49%) can be found among the smallest lakes ranging between 10–20 ha. In the entire catchment this size class was also found to be the class with by far the highest number of lakes.

  • 2.
    Ahlqvist, Ola
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Context Sensitive Transformation of Geographic Information2000Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This research is concerned with theoretical and methodological aspects of geographic information transformation between different user contexts. In this dissertation I present theories and methodological approaches that enable a context sensititve use and reuse of geographic data in geographic information systems.

    A primary motive for the reported research is that the patrons interested in answering environmental questions have increased in number and been diversified during the last 10-15 years. The interest from international, national and regional authorities together with multinational and national corporations embrace a range of spatial and temporal scales from global to local, and from many-year/-decade perspectives to real time applications. These differences in spatial and temporal detail will be expressed as rather different questions towards existing data. It is expected that geographic information systems will be able to integrate a large number of diverse data to answer current and future geographic questions and support spatial decision processes. However, there are still important deficiencies in contemporary theories and methods for geographic information integration

    Literature studies and preliminary experiments suggested that any transformation between different users’ contexts would change either the thematic, spatial or temporal detail, and the result would include some amount of semantic uncertainty. Consequently, the reported experiments are separated into studies of change in either spatial or thematic detail. The scope concerned with thematic detatil searched for approaches to represent indiscernibility between categories, and the scope concerned with spatial detail studied semantic effects caused by changing spatial granularity.

    The findings make several contributions to the current knowledge about transforming geographic information between users’ contexts. When changing the categorical resolution of a geographic dataset, it is possible to represent cases of indiscernibility using novel methods of rough classification described in the thesis. The use of rough classification methods together with manual landscape interpretations made it possible to evaluate semantic uncertainty in geographic data. Such evaluations of spatially aggregated geographic data sets show both predictable and non-predictable effects. and these effects may vary for different environmental variables.

    Development of methods that integrate crisp, fuzzy and rough data enables spatial decision support systems to consider various aspects of semantic uncertainty. By explicitly representing crisp, fuzzy and rough relations between datasets, a deeper semantic meaning is given to geographic databasses. The explicit representation of semantic relations is called a Geographic Concept Topology and is held as a viable tool for context transformation and full integration of geographic datasets.

  • 3.
    Andersson, Erik
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Enqvist, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Tengö, Maria
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Stewardship in Urban Landscapes2017In: The Science and Practice of Landscape Stewardship / [ed] Claudia Bieling, Tobias Plieninger, Cambridge University Press, 2017, p. 219-221Chapter in book (Refereed)
  • 4. Andersson, Hans
    et al.
    Widgren, MatsStockholm University, Faculty of Social Sciences, Department of Human Geography.
    Kan man leva på en ödegård? Huvudgårdar, landbotorp och odlingssystem under medeltid i Lägerbobygden, Östergötland2016Collection (editor) (Refereed)
    Abstract [en]

    Is it possible to survive on a deserted farm: Manors, tenants and farming systems during the Middle Ages in the Lägerbo area, Östergötland. 

    This study approaches the late medieval farm desertion from a landscape perspective. It focuses on the area of a former medieval estate in southern Östergötland, Sweden. Based on a retrogressive analysis of cadastral maps and historical records the medieval settlement is reconstructed. In this process three formerly unknown deserted farms were identified, with abandoned field systems and building remains.  The volume provides the archaeological documentation of field systems and settlements at these sites. These data provide the background for investigating the shifting social and ecological circumstances that once made it possible for tenant families to survive on these farms. During the height of the manorial system the small farms were specialised units in a redistributive system. In the late 14th century the estate and all tenant farms were donated to the convents of Vadstena and Vreta.  Rents were no longer paid in labour but in butter.  In the fifteenth century several farms were abandoned and turned into meadows under the surviving farms. The new tenurial relations prevented the recolonization of the farms. The study is the result of an interdisciplinary project involving medieval archaeology, historical geography, palynology and medieval history.

  • 5.
    Aronsson, Johanna
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Användning av tredimensionell geologisk modellering i hydrogeologiska utredningar: En fallstudie inför anläggandet av ett akviferlager i Brunkebergsåsen i Stockholm2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Akviferlager är en form av geoenergi där solenergi lagrad i grundvattnet används för att värma och kyla byggnader. Inför anläggandet av ett akviferlager är det viktigt med grundläggande geologiska och hydrogeologiska utredningar för att säkerställa funktion och kapacitet hos akviferlagret, samt minimera eventuell miljöpåverkan. I denna studie utvecklas en tredimensionell geologisk modell för att öka kunskapen om rullstensåsens geologiska uppbyggnad samt bedöma hur geologin kan komma att påverka det planerade akviferlagret. För att undersöka vilken påverkan manuella justeringar och tolkningar av geologin har, togs två geologiska modeller fram för jämförelse. Utifrån de geologiska modellerna uppskattades effektiv hydraulisk konduktivitet för åsen, d.v.s. sammanlagd konduktivitet för hela akviferens mäktighet, samt transporttid mellan akviferlagrets brunnspoler. Studien visar att akviferen består av sammanhängande jordlager med hög hydraulisk konduktivitet. Beroende på tolkningar och justeringar i modelleringsprocessen visar de två olika modellerna på skillnader vad gäller jordlagrens utbredning och mäktighet. Detta medför skillnader i effektiv hydraulisk konduktivitet mellan modellerna, vilket resulterar i relativt stora skillnader vad gäller transporttider mellan brunnspolerna. Tredimensionella geologiska modeller bedöms bidra till förbättrade hydrogeologiska utredningar då det är ett enkelt och effektivt sätt att bygga upp ett områdes geologi för översikt, tolkning och vidare studier i form av exempelvis grundvattenmodellering.

  • 6.
    Backman, Jan
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Frank, Martin
    Sangiorgi, F
    Brinkhuis, Henk
    Sluijs, Appy
    Stickly, Catherine
    Gattacecca, Jerome
    Age/depth relationships for the ACEX sedimentary section recovered from the Lomonosov Ridge2007Conference paper (Other (popular science, discussion, etc.))
  • 7.
    Barliaev, Aleftin
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Paleogeography and shore displacement of Eastern Gotland between 9.5 and 2.8 ka cal BP2017Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Located in the middle part of the Baltic, the island of Gotland underwent major environmental changes, associated with different stages of the development of the basin during the Holocene, and therefore represents a promising location for shore-displacement studies. This thesis is focused on a palaeohydrological evolution of the Lina Mire, central eastern part of Gotland, in the Middle Holocene and aims to reconstruct the timing and environment of the Littorina transgression. The research is based on a multi-proxy approach and carried out, applying lithostratigraphical, biostratigraphical (diatom analysis) and geochemical methods (XRF, organic and carbonate content) along with radiocarbon dating. The initiation of the Littorina transgression was constrained at 8.5 ka cal BP, however, probably proceeded by a hiatus. A two-folded pattern oft he maximum sub-phases is suggested. Acquired results fit well with previous studies on areas with the similar rate of apparent land uplift, suggesting an average rate of 2 mm/yr for the last 2.8 ka.

  • 8. Bignert, Anders
    Biological aspects and statistical methods to improve assessments in environmental monitoring2003Doctoral thesis, comprehensive summary (Other academic)
  • 9.
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Borrning efter interstadiala sediment vid Ultevisplatån, Norrbotten2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study is to find datable interstadial sediments in the core area of the LateWeicheslian ice sheet extent. Based on geomorphological evidence, three coring sites wereidentified close to the Ultevis plateau in Norrbotten, northern Sweden. Sediment coring wascarried out in two pre-Late Weichselian stream channels and in a sediment basin. Stratigraphyfrom one of the sites, a 100 meter wide meltwater channel, was chosen for further analysis. Thestudied core was 5,93 m long and ended in a lower till unit. The core contained silt and sandbelow an upper till unit, indicating presence of interstadial sediments in the stratigraphy. Thecore was subsampled for luminescence dating. Two samples from above the upper till unit andtwo samples from below this unit were chosen for initial luminescence measurements onfeldspar. These preliminary measurements indicate a significant difference in paleodosebetween the upper samples and the lower. The upper samples displayed relatively highpaleodoses, possibly representing pre-Late Weichselian ages. This could imply presence of twointerstadials in the stratigraphy. The lower samples exhibited significantly higher paleodosesthan the upper ones, possibly indicating early-Weichselian or even Saalian ages for the lowersamples.

  • 10.
    Björkvald, Louise
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Geokemi.
    Hydrogeochemistry of Fe and Mn in small boreal catchments2007Licentiate thesis, monograph (Other academic)
    Abstract [en]

    It is suggested that the overall understanding of the general hydrogeochemistry of a region is best understood from a landscape perspective. If so, this can provide useful information when planning monitoring programmes and influence of human activity. In this thesis the influence of landscape properties on iron (Fe) and manganese (Mn) is investigated.

    Iron and manganese are abundant in the Earth’s crust but occur in relatively low concentrations in most aquatic systems, due to the low solubility of their thermodynamically stable oxidation states (Fe(III) and (Mn(IV)). The hydrogeochemistry of iron and manganese is important, since their naturally occurring oxyhydroxides exhibit a strong adsorption affinity for trace elements. Moreover, the redox transformations of iron and manganese occur at pH and Eh (redox potential) boundaries found in natural waters.

    We investigated the hydrogeochemistry of iron and manganese in a boreal stream network of 15 streams, located in Västerbotten, Sweden. Water samples were collected on a frequent basis during 2004 and 2005, from 15 sub-catchments of the Krycklan catchment (67 km2). Total (unfiltered) and dissolved (<0.4µm) concentrations of iron and manganese were used to investigate the influence of landscape types (i.e. percentage cover of wetlands and forest) on the spatial and temporal variations of these elements.

    We found that iron correlates significantly with percentage of wetland and also with dissolved organic carbon (DOC). For manganese we did not observe a significant correlation with wetlands, which indicates that this element is less dependent on organic matter in comparison to iron. In particular, the correlation of the Fe/Al ratio to wetlands was highly significant (r2=0.92, p<0.01). However, principal component analyses indicate that iron, during peak discharge at spring flood, is not correlated with wetlands. During this period iron instead correlates with soil variables (i.e. silt) which highlights the importance of particulates during high discharge events.

    Since the naturally occurring oxyhydroxides have a strong adsorption affinity for other trace elements it is of great importance to further increase the knowledge of how these elements interact with iron and manganese in relation to the landscape composition. Further analyses of relations between trace metals (e.g. Cd, Co, Cr, Cu, Pb), and iron and manganese, but also between trace metals and landscape composition, will highlight the importance of studying the hydrogeochemistry from a landscape perspective.

  • 11.
    Borén, Thomas
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Meeting-places of Transformation: Urban Identity, Spatial Representations and Local Politics in St Petersburg, Russia2005Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This study develops a model for understanding spatial change and the construction of space as a meeting-place, and then employs it in order to show an otherwise little-known picture of (sub-)urban Russia and its transformation from Soviet times to today. The model is based on time-geographic ideas of time-space as a limited resource in which forces of various kinds struggle for access and form space in interaction with each other. Drawing on cultural semiotics and the concepts of lifeworld and system, the study highlights the social side of these space-forming forces. Based on a long-term fieldwork (participant observation) in Ligovo/Uritsk, a high-rise residential district developed around 1970 and situated on the outskirts of Sankt-Peterburg (St Petersburg), the empirical material concerns processes of urban identity, spatial representations and local politics. The study explicates three codes used to form the image of the city that all relate to its pre-Revolutionary history, two textual strategies of juxtaposition in creating the genius loci of a place, and a discussion of what I call Soviet "stiff landscape" in relation to Soviet mental and ordinary maps of the urban landscape. Moreover, the study shows that the newly implemented self-governing municipalities have not realised their potential as political actors in forming local space, which raises questions on the democratisation of urban space. Finally, the study argues that the model that guides the research is a tool that facilitates the application of the world-view of time-geography and the epistemology of the landscape of courses in concrete research. The study ends with an attempt to generalise spatial change in four types.

  • 12.
    Bäckström, Alexander
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    A new digital bathymetric model of Lake Vättern, Southern Sweden2018Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
  • 13.
    Bäckström, Alexander
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Sediment classification from backscatter analysis of multibeam data from Lake Vättern2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 14. Christian, Marcussen
    et al.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Marin geovetenskap.
    Lomonosov Ridge off Greenland (LOMROG) 20072007In: EOS Transactions: American Geophysical Union, v. 88(52), 2007, p. Abstract OS41C-03Conference paper (Other academic)
  • 15.
    Crimella, Daniele
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Exploring future land system change in Central and Eastern Africa2017Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The Central and Eastern African region is confronted with increasing socio-economic demands and global change pressures which could in the near future threaten the sustainability of its land system. Significant land use and cover (or land system) change would critically impact nature and people both locally and globally. Yet, its action is comparatively less studied than for other parts of the world, highlighting the need to have improved information on plausible future land system change in this region.

    This work synthesised a set of underlying drivers and proximate causes of land system change in the region through a metastudy, to than conduct a scenario analysis based on identified critical uncertainties, exploring future change in this land system.

    Multiple social and biophysical underlying drivers emerged as acting on proximate causes through chains of causation, driving change in cropland, forest, infrastructure, urban, and dryland areas. Two identified critical uncertainties, global versus local economic system orientation and fragmented versus integrated regional governance, defined four plausible scenarios exploring different land system change.

    The findings of this work contribute to the understanding of plausible future change in this understudied land system, and provide the base for complementary land system research. Additionally, reported conclusions could inform policy or practice processes aimed at steering the future of this land system at a critical juncture.

  • 16.
    Demina, Ludmila
    et al.
    P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences.
    Holm, Nils
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Galkin, Sergey
    P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences.
    Lein, Alla
    P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences.
    Concentration function of deep-sea vent benthic organisms2010In: Cahiers de Biologie Marine, Vol. 51, p. 369-373Article in journal (Refereed)
  • 17.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    The National Geosphere Laboratory2012Other (Other (popular science, discussion, etc.))
  • 18.
    Edvinsson, Johan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Thermokarst lake expansion and infilling rates in the Tavvavuomapeat plateau complex, northern Sweden2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The permafrost region has recently experienced an increased attention, due to projected climatechange and resource development. In permafrost landscapes, thermokarst lakes are commonfeatures. These water-filled collapse features form when ice-rich ground thaws. Thermokarstlakes are dynamic and change naturally in size due to erosion and/or infilling of fen vegetationalong lake shorelines. When they are formed, thermokarst lakes emit large amounts of carbon inform of the greenhouse gases methane (CH4) and carbon dioxide (CO2). Quantifying rates ofthermokarst lake expansion and infilling of fen vegetation by cardinal direction can help ourunderstanding of thermokarst lake dynamics. This study quantifies rates and extent ofthermokarst lake expansion and infilling of fen vegetation by cardinal direction for the timeperiods 1963-1975 and 1975-2003, in Tavvavuoma peat plateau complex, northern Sweden.This is done using the ArcGIS extension Digital Shoreline Analysis System (DSAS). The rateswere less than 0.1 m/yr, and lake expansion was greater than infilling between 1963 and 1975.For the 1975-2003 period, infilling of fen vegetation was greater than lake expansion. Thedirectional patterns for expansion and infilling of fen vegetation could potentially explained beby wind direction for different seasons, but the patterns are far from uniform in all lakes,indicating that local properties like lake depth, lake size and shape and the surrounding peatdepth and permafrost depth and temperature also might affect the activity in the lakes.

  • 19.
    Edwards, Nathalie
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Telegrafberget & Ällmora träsk - ett potentiellt naturreservat på Brevikshalvön, Tyresö kommun2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Within the Regional Development Plan of the Stockholm area, certain lands are to be included and reserved for the sake of natural, cultural and recreational values. In Tyresö municipality, south of Stockholm, lies Telegrafberget and Ällmora träsk, an area located on the peninsula of Brevik. There is a proposition to establish this area as a nature reserve. This is mainly due to the recreational value as a leisure area, where people walk their dogs, pick mushrooms and berries, rock climb etc. But it also has ecological values of certain characters, such as an intact hydrographic basin, a pine forest with several 300 year old trees, including biotope typical fauna, and a landscape containing both a rather high hill and a fault line-formed lake. In addition, the area has an exciting history, where archaeological finds show that there has been people around the area since the Stone Age. This in turn can have a pedagogical value. There are already a number of nature reserves on the peninsula, each with its own specific character. To complement these with the proposed area would mean an additional width in the versatile network of protected nature in the relatively small area that forms the peninsula. It would thus be of great value, not only for the inhabitants of Tyresö, but also for other locals of Stockholm, and fully in line with the government mandate that declares the importance of closeness to nature.

  • 20. Ehrenfreund, Pascale
    et al.
    Spaans, Marco
    Holm, Nils G.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    The evolution of organic matter in space2011In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 369, no 1936, p. 538-554Article in journal (Refereed)
    Abstract [en]

    Carbon, and molecules made from it, have already been observed in the early Universe. During cosmic time, many galaxies undergo intense periods of star formation, during which heavy elements like carbon, oxygen, nitrogen, silicon and iron are produced. Also, many complex molecules, from carbon monoxide to polycyclic aromatic hydrocarbons, are detected in these systems, like they are for our own Galaxy. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly high number of molecules that are used in contemporary biochemistry on the Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites and interplanetary dust particles. Large quantities of extra-terrestrial material were delivered via comets and asteroids to young planetary surfaces during the heavy bombardment phase. Monitoring the formation and evolution of organic matter in space is crucial in order to determine the prebiotic reservoirs available to the early Earth. It is equally important to reveal abiotic routes to prebiotic molecules in the Earth environments. Materials from both carbon sources (extra-terrestrial and endogenous) may have contributed to biochemical pathways on the Earth leading to life’s origin. The research avenues discussed also guide us to extend our knowledge to other habitable worlds.

  • 21.
    Enqvist, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Stewardship in an urban world: Civic engagement and human–nature relations in the Anthropocene2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Never before have humans wielded a greater ability to alter and disrupt planetary processes. Our impact is becoming so noticeable that a new geological epoch has been proposed – the Anthropocene – in which Earth systems might no longer maintain the stable and predictable conditions of the past 12 millennia. This is particularly evident in the rapid expansion of urban areas, where a majority of humans now live and where environmental changes such as rising temperatures and habitat loss are happening faster than elsewhere.  In light of this, questions have been raised about what a more responsible relationship between humans and the rest of the planet might look like. Scholars in sustainability science employ the concept of ‘stewardship’ in searching for an answer; however, with multiple different applications and definitions, there is a need to better understand what stewardship is or what novelty it might add to sustainability research. This thesis investigates stewardship empirically through two case studies of civic engagement for protecting nature in cities – Bengaluru, India and New York City, USA. Further, the thesis also proposes a conceptual framework for how to understand stewardship as a relation between humans and the rest of nature, based on three dimensions: care, knowledge and agency. This investigation into stewardship in the urban context uses a social–ecological systems approach to guide the use of mixed theory and methods from social and natural sciences. The thesis is organized in five papers. Paper I reviews defining challenges in managing urban social–ecological systems and proposes that these can more effectively be addressed by collaborative networks where public, civic, other actors contribute unique skills and abilities. Paper II and Paper III study water resource governance in Bengaluru, a city that has become dependent on external sources while its own water bodies become degraded and depleted.Paper II analyzes how locally based ‘lake groups’ are able to affect change through co-management arrangements, reversing decades of centralization and neglect of lakes’ role in Bengaluru’s water supply.Paper III uses social–ecological network analysis to analyze how patterns in lake groups’ engagements and collaborations show better fit with ecological connectivity of lakes.Paper IV employs sense of place methods to explore how personal bonds to a site shapes motivation and goals in waterfront stewardship in New York City. Finally,Paper V reviews literature on stewardship and proposes a conceptual framework to understand and relate different uses and underlying epistemological approaches in the field. In summary, this thesis presents an empirically grounded contribution to how stewardship can be understood as a human–nature relation emergent from a deep sense ofcare and responsibility, knowledge and learning about how to understand social–ecological dynamics, and theagency and skills needed to influence these dynamics in a way that benefits a greater community of humans as others. Here, the care dimension is particularly important as an underappreciated aspect of social–ecological relations, and asset for addressing spatial and temporal misalignment between management institutions and ecosystem. This thesis shows that care for nature does not erode just because green spaces are degraded by human activities – which may be crucial for promoting stewardship in the Anthropocene.

  • 22.
    Enqvist, Johan
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Campbell, Lindsay K.
    Stedman, Richard C.
    Svendsen, Erika M.
    Pathways to urban environmental stewardship: Sense of place and civic engagement for urban waterfrontsManuscript (preprint) (Other academic)
    Abstract [en]

    Participation of local residents is considered beneficial for urban environmental stewardship, but the understanding of how urban stewards relate to the places they work with is poorly developed. This study of civic groups working to steward urban waterfronts challenges the notion that stronger attachment drives deeper commitment to stewardship. The study looks at three types of groups doing stewardship work on waterfronts and water bodies in New York City: community groups, environmental groups and recreational groups. Using interviews and Likert scale surveys (n=31), we assessed stewardship activities, place attachment and place meanings that members associate with site that each group works with. Our findings show that community group members are more attached to the sites they work with than members of environmental or recreational groups, but environmental groups report the greatest effort put into stewardship work. Further, we show that place meanings reveal different categories of groups based on how they currently view the site (as a place of work, a place of home, or a place of use), and what they want to achieve for it in their stewardship work: some groups work to restore what the place was previously, others work to protect what it currently is, while a few work to create a new identity for their place. These findings demonstrate how pathways to stewardship differ and are not dependent on strong place attachment; however, they can generate fundamentally different outcomes depending on what place meanings stewardship seeks to protect.

  • 23.
    Enqvist, Johan
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Tengö, Maria
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Bodin, Örjan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Enhancing social–ecological fit from the bottom up: Urban lake networks and grassroots innovatorsManuscript (preprint) (Other academic)
    Abstract [en]

    Urban environmental governance is often hampered by social institutions being poorly aligned with fragmented ecosystems. Bottom-up approaches have been argued to address this problem of social-ecological fit, but there is a lack of empirical understanding of how local initiatives might emerge and spread in a way that enhances fit. We study a system of hydrologically interconnected lakes in Bengaluru, which public authorities have largely failed to protect resulting in many degraded lakes and undermined societal and ecological benefits that the system of lakes provides. Local residents have, largely in response to these failures, formed lake groups and convinced municipal actors to recognize them as partners that share management responsibilities for certain lakes. These initiatives have inspired others to follow suit and work with lakes elsewhere in the city, hence triggering the question whether local lake groups in this way contribute to a better social–ecological fit at a broader landscape scale. This study mixes quantitative social–ecological network analysis with interviews to analyze fit and describe the processes by which lake management can be shaped to match ecosystem structure. Results show that certain key lake groups – enabled by supportive municipal officers – have successfully innovated how lakes are managed, acknowledging their place in and dependence on the broader network of interconnected lakes. In the wake of this, a new generation of collaborative lake groups is emerging, where lakes are often managed more holistically by recognizing them to be part of the larger network of lakes. The analysis identifies key lake groups that are instrumental to shaping the spread of the bottom-up driven initiatives in ways that aligns with the interconnected nature of the lake system. This is a process that relies on acknowledgement and support from public authorities, but is primarily driven by local actors. By describing this process of innovation and diffusion, the study contributes important lessons on how to enhance fit between governance arrangements and the ecosystem on which cities depend.

  • 24.
    Enqvist, Johan
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    West, Simon
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Haider, L. Jamila
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Masterson, Vanessa
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Svedin, Uno
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Tengö, Maria
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Stewardship as a boundary object for sustainability research in the Anthropocene: Linking care, knowledge and agencyManuscript (preprint) (Other academic)
  • 25.
    Eriksson, Pia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Modeling the effect of activelayer deepening on stocks ofsoil organic carbon in thePechora River Basin2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study investigates how the estimated thickening of the active layer will affectthe soil organic carbon in permafrost soils. The focus lies on estimating how muchof the upper permafrost soil organic carbon will be affected by the active layerdeepening due to global warming, on what timescale the deepening will take placeand if the estimated changes differ depending on the extent of permafrost in theregion. A model made in a Geographic Information System (GIS) combines datasetsfrom The Northern Circumpolar Soil Carbon Database, field data of soil organiccarbon content (SOCC) in different permafrost soil horizons in the Usa basin anddata of recent and future active layer depth from a spatially distributed permafrostdynamics model in the Pechora River Basin. The model shows that in 1980, 75% ofthe available 0–100 cm Gelisol soil organic carbon mass (SOCM) has affected byseasonal thawing. In 2050 the proportion is increased to 86% and by 2090 almostthe whole study area has an active layer deeper than 1 meter (98%). This indicatesan increase from approximately 0.64% to 0.84% of the total 1–100 cm SOCM in thenorthern permafrost region. The change is more gradual in the isolated and thesporadic permafrost zones and more abrupt in the continuous and discontinuous regions.

  • 26.
    Eriksson, Sandra
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ekosystemtjänster vid dagvattenhantering: En jämförelse av öppna dagvattenlösningar i urban miljö2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Stormwater is a valuable resource but with climate change and changed precipitation it may cause problems in urban environments. With increasing urbanisation more land becomes exploited which can not naturally manage stormwater and solve the problems. The purpose with this study is to demonstrate the importance of green infrastructure to manage stormwater. The stormwater systems this study includes are different forms of green infrastructure; green areas, swales, ponds and wetlands. They manage stormwater, have different pros and cons and are various good at meeting the selected ecosystem services; balancing stormwater peaks, sewage treatment and groundwater recharge. Wetlands stand out as the best at meeting the ecosystem services balancing stormwater peaks and sewage treatment. Green areas are best with groundwater recharge. These areas can naturally manage stormwater and that is a strong reason to preserve and/or restore them during exploitation.

  • 27.
    Erlandsson, Rasmus
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Långtida markanvändningsförändringar i jordbruket på Ingmarsö2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Traditionellt skötta jordbrukslandskap hyser några av Sveriges mest artrika naturtyper, i huvudsak öppna gräsmarker till vilka en stor del av Sveriges hotade kärlväxter är knutna. Jordbrukets utveckling sedan 1800-talets slut har lett till kraftig minskning av gräsmarker och sämre kvalitet hos de kvarvarande. Skärgårdsjordbruket har små möjligheter till storskalighet och har inte haft samma effektiviseringstryck på sig som jordbruk på fastlandet. Det kan alltså tänkas ha behållit äldre tiders småskalighet – i de fall det fortfarande bedrivs – och därmed stora naturvärden. Studien är en jämförelse mellan jordbrukets utveckling i skärgården och på fastlandet, baserat på GIS-analys av historiska kartdata kompletterat med fältstudier och intervjuer. Undersökningsområdena omfattar Ingmarsö i Stockholms skärgård och Myra, norr om Norrtälje. Arbetet omfattar också en GIS-baserad hävdanalys där gräsmarker klassats utifrån historisk markanvändning. Resultatet är tänkt att vara ett hjälpmedel i restaureringsprojekt genom att ringa in marker med potentiellt höga naturvärden. Reslutatet visar att skärgårdsjordbruket gått tillbaka men behållit sin småskalighet och förblivit aktivt. Till skillnad från det undersökta fastlandsjordbruket som så gott som upphörde innan 1950-talet. Hypotesen att skärgårdsjordbruket skulle vara mindre påverkat av jordbrukets allmäna utveckling bekräftas alltså, men då studien inte bygger på replikat går det inte att dra några generella slutsater. Ett flertal tänkbara förklaringar finns, bland annat skärgårdsbondens bredare försörjningsbas med möjlighet till fiske och intäkter från sommargäster. Hävdanalysen ringar in ett flertal områden som kan vara intressanta föremål för restaurering, men inventeringar krävs för att utvärdera analysmetoden.

  • 28.
    Flodin, Charlotte
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Equity in rural water resource development and management: A case study of Kilombero Valley, Tanzania, and the investments delivered by a participatory and demand-driven NGO2015Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    The demand-driven and participatory approach to water resource development and management in Tanzania has been both praised and criticized; some see progress where others see increased inequalities. This study focuses on one progressive, demand-driven NGO which has a participatory approach to water resource development and management. This NGO, MSABI, is active in Kilombero Valley in southern Tanzania, and can be considered successful as it manages to keep 91 % of its water points functional, whilst the national average for pump functionality is just above 50 %.

    To study the performance of MSABI from a user perspective, it was decided that two sites in Kilombero Valley should be investigated in terms of users’ views on water access and quality. The identification of sites is based on population density and landcover change, so that the issues of scale and urban bias, as well as changes in the landscape affecting hydrological processes, are accounted for. In total, 29 interviews were conducted (October to November 2014), 15 at the Ifakara study site, the more densely populated location, and 14 at the Mchombe Ward study site. The interviews were semi-structured, using a participatory approach, focusing on users’ perspectives on water sources and the access to and quality of those water sources in dry and rainy seasons. The information gathered was used to construct definitions for water access and quality. These definitions, as well as the two locations and categorization of participants according to socio-economic status, were then used to sort and analyse the collected material.

    The results show that MSABI does not manage to make water accessible in an equitable way because of its demand-driven and participatory approach to water resource development and management. However, MSABI offers the only improved water source at the Mchombe Ward study site, except for one improved open well. MSABI manages to counter urban-bias better than any of the other water resource development and management facilitators encountered at the two study sites. The seasons influence water access, especially at the more peripheral locations, where improved water sources are less common and, as open water sources, are more prone to drought and contamination. When participants in Ifakara seasonally migrate for farming, during 4-5 months per year, the majority’s access to improved water sources is lost. At the distant seasonal fields, open water sources are more common and few report that they treat the unsafe water. The migration to peripheral farmlands coincides with the rainy season, causing open water sources to have their lowest water quality when seasonal migrants utilize them. This underlines the importance of securing safe water supply for people at remote locations, and the important role MSABI plays as water resource developer at those locations.

    In conclusion, if the current demand-driven and participatory approach to water resource development and management is to be retained, regardless of the heavy criticism it has received with regards to equity, this study suggests that the practices of MSABI should be spread further based on MSABI’s ability to increase safe water access at remote locations. Another recommendation is to further look into the effects of seasonal migration on access to safe water. The effect seasonal migration has on water access in Kilombero could exist in other areas in Tanzania or in other countries. The aspect of seasonal migration might show that water access statistics are misleading, as the seasonal water consumption in remote locations risks being omitted in official statistics. 

  • 29.
    Fones- Sundell, Melinda
    et al.
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Saywell, Darren
    Reporting back on Establishing water and food equity2012In: World Water Week in Stockholm, 2012: Water and food security: Overarching conclusions, Stockholm: Stockholm International Water Institute , 2012, p. 18-20Conference paper (Other academic)
  • 30. Forsberg, Rene
    et al.
    Skourup, H
    Kenyon, S.C.
    Laxon, S.W.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Marin geovetenskap.
    New Arctic Gravity Field Grids with Applications for Oceanography and Bathymetry2007In: EOS Transactions: American Geophysical Union, v. 88(52), 2007, p. Abstract OS43A-0991Conference paper (Other academic)
  • 31.
    Forselius, Ellen
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    The Good, The Bad and The Seascape: Possible Effects of Climate Change in Tropical People and Ecosystems in the Western Indian Ocean Using a Gender Perspective2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The tropical seascape is herein defined as a landscape made up of five ecosystems: coastal terrestrial forests, mangrove forests, seagrass beds, coral reefs and the deep sea. Previous studies have shown that men and women use the tropical seascape in different ways. If the seascape was to change as a result of anthropogenic climate change, then men and women could potentially be affected differently by those changes. The seascape is particularly vulnerable to the predicted rise in sea-level and ocean warming, but the coastal terrestrial forests and mangrove forests are in addition vulnerable to the increased storms and hurricanes a warmer climate is predicted to lead to. While men and women utilizes these ecosystems in many different ways, this study found, based on the literature reviewed, that in a worst-case scenario all parts of the seascape could potentially be destroyed and none of the activities performed there today could be performed in the future. The deep sea would not be destroyed, but the fish living there would move to higher latitudes and deeper waters, effectively ending the fishing practices in the tropical waters. To save the tropical seascape anthropogenic climate change would have to stop on a global scale, since the problem cannot be solved on a local or regional level.

  • 32.
    Galafassi, Diego
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Transformational knowledge practices in social-ecological systems2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Climate change and poverty alleviation are examples of interconnected challenges propelling changes across environmental, social, cultural and political spheres. Interconnected challenges are characterized by multiple causality, feedback loops, non-linear dynamics. Transformations, as fundamental reconfigurations of social-ecological relations, are increasingly proposed as a strategy for tackling interconnected challenges. Transformations seem to require a move towards diverse, integrated, imaginative, anticipatory, dynamic forms of knowledge making. Although new forms of knowledge creation are indeed emerging in sustainability science and practice, this area of studies is yet to yield a coherent research framework for analyzing the contribution of these practices to transformations in social-ecological systems. The central aim of this thesis is to a) provide a theoretical framework and b) to explore and assess feasibility and effectiveness of concrete knowledge practices that could help governance actors to move towards forms of deliberate transformations in the face of interconnected challenges. Two empirical research papers based on a case-study in Coastal Kenya are presented. In these papers we approached the interconnected challenges of social-ecological trade-offs by engaging multiple knowledge practices (ranging from dialogue, to narrative scenarios, participatory modelling and ecological modelling) to create a space for imagination and deliberation amongst governance actors and scientists. Assessment of this process was performed with a mixed methods research design, including interviews, surveys, and participant observation. Results suggest that overall, these knowledge practices supported: a) development of systemic and collaborative mindsets (Paper 1); b) revision of core assumptions (Paper 1); c) the identification of key cross-scale tradeoffs that were previously not considered by governance actors (Paper 2). These results highlight the potential of these knowledge practices in fostering knowledge relevant for re-imagination and reconfiguration of social-ecological systems. I conclude by proposing that transformational knowledge practices present at least four key elements in that they are: plural and coproduced, affect change across scales, involve multiple ways of knowing and foster imagination. 

  • 33.
    Georges, Carolin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dendroklimatologisk analys av lokalklimat vid Grövelsjön i Dalafjällen2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Climate on earth is getting warmer, which effects earth’s energy balance and so forth the ocean and atmospheric circulation.  In many sub-polar regions on the northern hemisphere changes due to warming of the climate can be observed. Some examples that already have been observed are shifts in tree line, towards higher altitudes and latitudes, increased ablation of Swedish glaciers and melting of the permafrost on the Siberian tundra. In Sweden climate change scenarios tell us that it will become warmer and that a higher amount of precipitation in form of rain will be an effect from this. To study climate changes in Sweden, transition zones are useful in order to observe changes in distribution of species and animal populations. This study uses tree rings from Scots Pine (Pinus sylvestris L.) that grow at the tree line in Grövelsjön that is part of the mountains in Dalarna County. By measuring the width of the tree rings, a chronology that is representative for July temperature is made over this area. The method is called dendroclimatology and has generally been used to reconstruct past climate for the last 1000 years.  The results of this study show that the tree ring chronology don’t show a clear increase in temperature for the last century, which could have been expected from an area like this. But the result also show that when instrumentally measured temperature were plotted month by month, the only month with significant up going trend in temperature in this area is April. A temperature change in April does not leave a signal in the tree rings because it is too cold for them to grow that early in the season.

  • 34.
    Halldén, Tom
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Förändringar i västra Yoldiahavets vattenmiljö under trettioett år: En studie av fossil från ostracoder, mollusker och foraminiferer från Myssjaren, östra Mellansverige2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I denna studie undersöks hur vattenmiljön förändrades i ett område av västra Yoldiahavet, idag sjön Myssjaren i östra Mellansverige. Syftet med undersökningen har varit att återskapa hur vattnets salthalt förändrades i området genom att studera förekomsten av fossil från saltvattenkrävande bentisk kalkskalsfauna i lera från perioden.

    Fossil hittades från sju år, 10 395-10 388 lervarvsår BP, av den 31 år långa period, 10 410-10 379 lervarvsår BP, som har undersökts. Utifrån fossilförekomsten kunde det konstateras att vattnet var bräckt under dessa sju år. Eftersom att fossil inte hittades från tidigare och senare perioder Därför är det möjligt att vattnet var bräckt både före och efter denna period.

    Det som begränsade de undersökta arternas utbredning i området var halten suspenderat sediment i vattnet. Det var en konsekvens av att mycket sediment transporterades till området i och med att området befann sig mellan två större utlopp av glacialt smältvatten.

    Därför har denna studie, förutom att konstatera att vattnet var bräckt under den undersökta perioden, även visat en succession av arter i Yoldiahavet.

    I studien identifieras också en 4 år lång kallperiod som varade mellan 10 393-10 389 lervarvsår BP. Vid 10 387 lervarvsår BP börjar iskanten att avancera, troligen som ett resultat av denna kallperiod, vilket slutligen leder till att de undersökta arterna upphör att förekomma i leran.

  • 35.
    Halldén, Tom Halldén
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Measuring coastal erosion along the coast of Ystad municipality using PSInSAR and SBAS2017Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    In this study the use of two radar interferometry methods, PSInSAR and SBAS, were tested as tools for measuring coastal erosion. If successful it would have allowed for measuring coastal erosion as a function of material lost. The study area used was Ystad municipality, in southern Sweden.

    Radar data for the study was provided by the ESA, the European space agency, from their ERS-2 and ENVISAT satellites, spanning the period 1998-2005.

    Unfortunately, even after many different configurations of settings were tested, the results indicated that both methods are very unsuited for use in rural areas such as Ystad, whether for measuring coastal erosion or otherwise. Both methods had severe problems achieving significant coverage after low coherence areas were masked out, and PSInSAR suffered from several anomalies. This is likely due to the highly vegetated nature of the landscape, which results in low coherence through temporal decorrelation.

    Of the two methods SBAS showed the most promise, but not nearly enough to be considereduseful.

    It is, based on the scientific literature, possible that simpler interferometry methods might have been more useful. This, and other possible ways to improve the results is something that this study discusses at length.

  • 36.
    Hamzo, Bachir
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Habitatmodellering som hjälpmedel i naturvårdsplanering: - exempel mindre flugsnappare (Ficedula parva)2010Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Loss of biological diversity is today a major global concern. One of the main reasons for this is loss and fragmentation of species habitat due to changes caused by humans. Therefore it is important to consider the impact on biological diversity early in physical planning. This report uses a method that could assist the prediction of effects on biological diversity during stages of physical planning, such as environmental impact assessment (EIA) and strategic environmental assessment (SEA). By modeling in Geographic Information Systems (GIS) using logistic regression, connections between observations of Red-breasted Flycatcher (Ficedula parva) and various environmental variables where made. The aim was to establish the preferred habitat type for the Red-breasted Flycatcher and thereby help biodiversity consideration in physical planning and conservation. Connections were confirmed between the Red- breasted Flycatcher and the variables old deciduous forests and edge zones around water areas and wetlands. This most likely means that the species prefers old deciduous swamp forests. In order to get more conclusive results, better variable data as well as improved observations are required. The study shows that with the required improvements this method has potential to be a useful tool for conservation planing.

  • 37.
    Han, Guoyi
    Clark University, Graduate School of Geography.
    Understanding regional dynamics of vulnerability: a historical approach to the flood problem in China2011Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Throughout its long history, China is among the world's most flood-prone and consequently the most experienced countries in coping with floods. This is a dissertation about developing a historical approach for understanding regional dynamic change of vulnerability to flood hazards in the Chinese context, and providing an analytic base for the country's shift of its flood management strategy from the current predominant and prevalent flood control approach to a broader and more comprehensive risk management paradigm. The dissertation asks two central questions: (1) How can the changing vulnerability situation be better understood and analyzed so that the insights gained are most relevant for policy and practice? (2) What are the plausible pathways and key options for managing future flood risks in China in the context of rapid socioeconomic transition and climate change? By developing an analytical framework and a case study in the Dongting Lake area of China, and by outlining three fundamental dilemmas and three plausible pathways for managing future flood risk in China, the dissertation concludes that China needs a new flood management strategy--one that centers on vulnerability reduction and resilience building and one that embraces and internalizes variability and uncertainty in decision making. While a resilience strategy embodies a wide range of opportunities for long-term sustainable flood risk prevention and mitigation, the dissertation argues further that China faces major dilemmas in managing its future flood risks. Trade-offs between economic development and flood vulnerability reduction and between cooperation and tensions across diverse actors and scales cannot be escaped.

  • 38.
    Hanslik, Daniela
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Late Quaternary Biostratigraphy and Paleoceanography of the central Arctic Ocean2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The central Arctic Ocean is one of the least explored deep sea regions and long biostratigraphic sediment records are sparse. The main focus of this thesis is the Arctic Ocean foraminiferal record and its application to reconstruct paleoceanographic variations and summer sea ice cover changes between late Quaternary interglacial periods. One of the studied cores was retrieved from the central Lomonosov Ridge Intra Basin. This core contains a relatively high-resolution biostratigraphic record spanning Marine Isotope Stages (MIS) 1–3, although with a hiatus encompassing the Last Glacial Maximum. Radiocarbon age calibrations in this core show a decreasing trend of high marine reservoir ages of about 1400 years during the last deglaciation to 700 years in the late Holocene. The cores from the Lomonosov Ridge off Greenland and the Morris Jesup Rise contain preserved calcareous microfossils further back in time than most previously studied central Arctic Ocean cores. The calcium content estimated by X-ray fluorescence scanning of these cores shows a distinct pattern of calcium rich intervals coinciding with peaks in foraminiferal abundance in the sediment record of MIS 1–7. The calcium peaks originate from material accumulated during interglacials, primarily through detrital carbonate and dolomite input from the decaying North American ice sheet and secondarily from biogenic material. Intervals of calcareous benthic foraminifera are found in pre MIS 7 sediments on both the southern Lomonosov Ridge and Morris Jesup Rise. Their assemblage composition and stable carbon isotope data suggest increased primary production and decreased summer sea ice cover compared to the Holocene central Arctic Ocean. This is also suggested for an interval of high abundance of the subpolar planktic foraminifera Turborotalita quinqueloba on the southern Lomonosov Ridge with a proposed MIS 11 age.

  • 39.
    Hell, Benjamin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Mapping bathymetry: From measurement to applications2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Surface elevation is likely the most fundamental property of our planet. In contrast to land topography, bathymetry, its underwater equivalent, remains uncertain in many parts of the World ocean. Bathymetry is relevant for a wide range of research topics and for a variety of societal needs. Examples, where knowing the exact water depth or the morphology of the seafloor is vital include marine geology, physical oceanography, the propagation of tsunamis and documenting marine habitats. Decisions made at administrative level based on bathymetric data include safety of maritime navigation, spatial planning along the coast, environmental protection and the exploration of the marine resources.

    This thesis covers different aspects of ocean mapping from the collection of echo sounding data to the application of Digital Bathymetric Models (DBMs) in Quaternary marine geology and physical oceanography. Methods related to DBM compilation are developed, namely a flexible handling and storage solution for heterogeneous sounding data and a method for the interpolation of such data onto a regular lattice. The use of bathymetric data is analyzed in detail for the Baltic Sea. With the wide range of applications found, the needs of the users are varying. However, most applications would benefit from better depth data than what is presently available. Based on glaciogenic landforms found in the Arctic Ocean seafloor morphology, a possible scenario for Quaternary Arctic Ocean glaciation is developed. Our findings suggest large ice shelves around parts of the Arctic Ocean during Marine Isotope Stage 6, 130–200 ka. Steered by bathymetry, deep water from the Amerasian Basin of the Arctic Ocean flows over the central Lomonosov Ridge into the Eurasian Basin. This water mass is traced on its continuing way towards Greenland and the Fram Strait. At the Morris Jesup Rise, bathymetry plays an important role in the partial re-circulation of the water into the Amerasian Basin.

  • 40.
    Hell, Benjamin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Broman, Barry
    SMHI, Rossby Centre.
    Jakobsson, Lars
    Sjöfartsverket.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Magnusson, Åke
    Sjöfartsverket.
    Wiberg, Patrik
    The use of bathymetric data in society and science: A review from the Baltic SeaArticle in journal (Refereed)
    Abstract [en]

    Bathymetry, the underwater topography, is a fundamental property of oceans, seas and lakes. As such it is important for a wide range of applications, like physical oceanography, marine geology, geophysics and biology or the administration of marine resources. The exact requirements users may have regarding bathymetric data are, however, unclear. Here, the results of a questionnaire survey and a literature review are presented, concerning the use of Baltic Sea bathymetric data in research and for societal needs. It is demonstrated that there is a great need for detailed bathymetric data, which cannot be satisfied by the digital bathymetric models publicly available, despite of the abundance of high quality bathymetric data that are produced for safety of navigation purposes. Our study shows that DBMs based on such data could substantially improve the base data for administrative decision making as well as the possibilities for marine research in the Baltic Sea.

  • 41.
    Hell, Benjamin
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    A Data Model and Processing Environment for Ocean-Wide Bathymetric Data Compilations2008In: The international hydrographic review, ISSN 0020-6946, Vol. 9, no 1, p. 23-33Article in journal (Refereed)
  • 42. Hibbert, F. D.
    et al.
    Wastegård, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Gwynn, R.
    Austin, W. E. N.
    Identification of a MIS 6 age (c. 180 ka) Icelandic tephra within NE Atlantic sediments: a new potential chronostratigraphic marker2014In: Gas Generation and Migration in Deep Geological Radioactive Waste Repositories / [ed] R. P. Shaw, London: The Geological Society Publishing House, 2014, Vol. 398, p. 65-80Chapter in book (Refereed)
    Abstract [en]

    The incidence of volcanic ash (tephra) within marine sediments serves as a useful stratigraphic marker and tool for correlation. In addition, where an independent age estimate exists, tephra layers can provide a means of dating the sediments themselves. Here we present a geochemically characterized, size sorted tephra layer within Marine Isotope Stage (MIS) 6, most likely resulting from primary air-fall from an Icelandic volcanic source. This tephra layer is tentatively correlated to the Kerlingarfjoll volcanic system using major element geochemistry. The ash layer has an interpolated age of 181 +/- 6 ka based on the age model for MD04-2822. We briefly review the occurrence of silicic tephra in the North Atlantic region from MIS 7 to MIS 5e inclusive and find potential correlatives to the MD04-2822 MIS 6 ash layer in the Norway Basin and Irminger Sea.

  • 43. Hicks, Kevin
    et al.
    Kuylenstierna, Johan
    Owen, Anne
    Dentener, Frank
    Seip, Hans-Martin
    Rodhe, Henning
    Stockholm University, Faculty of Science, Department of Meteorology.
    Soil sensitivity to acidification in Asia: Status and prospects2008In: Ambio, Vol. 37, no 4, p. 295-303Article in journal (Refereed)
    Abstract [en]

    Exceedance of steady-state critical loads for soil acidification is consistently found in southern China and parts of SE Asia, but there is no evidence of impacts outside of China. This study describes a methodology for calculating the time to effects for soils sensitive to acidic deposition in Asia under potential future sulfur (S), nitrogen (N), and calcium (Ca) emission scenarios. The calculations are matched to data availability in Asia to produce regional-scale maps that provide estimates of the time (y) it will take for soil base saturation to reach a critical limit of 20% in response to acidic inputs. The results show that sensitive soil types in areas of South, Southeast, and East Asia, including parts of southern China, Burma, Hainan, Laos, Thailand, Vietnam, and the Western Ghats of India, may acidify to a significant degree on a 0–50 y timescale, depending on individual site management and abiotic and biotic characteristics. To make a clearer assessment of risk, site-specific data are required for soil chemistry and deposition (especially base cation deposition); S and N retention in soils and ecosystems; and biomass harvesting and weathering rates from sites across Asia representative of different soil and vegetation types and management regimes. National and regional assessments of soils using the simple methods described in this paper can provide an appreciation of the time dimension of soil acidification–related impacts and should be useful in planning further studies and, possibly, implementing measures to reduce risks of acidification

  • 44.
    Hock, Regine
    et al.
    University of Alaska Fairbanks.
    de Woul, Mattias
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Radic, Valentina
    University of British Columbia.
    Dyurgerov, Mark
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Mountain glaciers and ice caps around Antarctica make a large sea-level rise contribution2009In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 36, no L07501Article in journal (Refereed)
    Abstract [en]

    The Intergovernmental Panel on Climate Change (IPCC) estimates that the sum of all contributions to sea‐level rise for the period 1961–2004 was 1.1 ± 0.5 mm a−1, leaving 0.7 ± 0.7 of the 1.8 ± 0.5 mm a−1 observed sea‐level rise unexplained. Here, we compute the global surface mass balance of all mountain glaciers and ice caps (MG&IC), and find that part of this much‐discussed gap can be attributed to a larger contribution than previously assumed from mass loss of MG&IC, especially those around the Antarctic Peninsula. We estimate global surface mass loss of all MG&IC as 0.79 ± 0.34 mm a−1 sea‐level equivalent (SLE) compared to IPCC's 0.50 ± 0.18 mm a−1. The Antarctic MG&IC contributed 28% of the global estimate due to exceptional warming around the Antarctic Peninsula and high sensitivities to temperature similar to those we find in Iceland, Patagonia and Alaska.

  • 45.
    Holm, Nils
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. geokemi.
    Abiotic synthesis underneath the ocean floor2008In: XV International Conference on the Origin of Life: Book of Abstracts, 2008, p. 19-20Conference paper (Other (popular science, discussion, etc.))
  • 46.
    Holm, Nils
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. geokemi.
    Mineral-fluid interaction at convergent margins: the initiation of genetic information?2008In: International Workshop on Geobiology, 2008, p. 3-3Conference paper (Other (popular science, discussion, etc.))
  • 47.
    Holm, Nils
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Oceanic lithosphere, Mg(II), Na(I), PPi and life's origin2012In: Serpentine days: 3rd edition / [ed] M. Andreani, A.-L. Auzende, I. Daniel, A. Delacour, Deep Carbon Observatory , 2012Conference paper (Other academic)
    Abstract [en]

    Life may have started in connection with early plate tectonic processes coupled to alkaline hydrothermal activity. Pyrophosphate (PPi) and Na+ transport may have preceded ATP and H+ transport through primitive membranes in association with the dominant geochemistry of the Earth at the time of the origin and early evolution of life. A hydrothermal environment in which Na+ is abundant and H+ is rare exists in sediment-starved subduction zones, like the Mariana forearc in the W Pacific Ocean. It is considered to mimic the Archean Earth (Pons et al., 2011). There, the forearc pore fluids have a pH up to 12.6 and a Na+-concentration of 0.7 mol/kg seawater. PPi could have been formed during early subduction of oceanic lithosphere by dehydration of protonated orthophosphates.  A key to PPi formation in these geological environments is a low local activity of water. Magnesium, on the other hand, is a common element on Earth, particularly in oceanic crust and the upper mantle (as well as on the other terrestrial planets) and plays a special role in biochemistry due to its ability to coordinate six oxygen atoms efficiently in its first coordination shell. Such oxygen atoms may be part of one or two charged oxyanions, which means that Mg2+can, for instance, tie together two different phosphate groups that are located at distance from each other in a macromolecule, and in this way be responsible for the folding of large molecules like RNA. This property of Mg2+ also helps the stabilization of diphosphate and triphosphate groups of nucleotides, as well as promoting the condensation of orthophosphate to oligophosphates, like PPi and trimetaphosphate. According to the ‘RNA World’ hypothesis the first enzymes – the ribozymes – consisted of RNA, which depended on Mg2+ for its self-cleavage (Gilbert, 1986). Mg2+ is also present in all DNA and RNA activation processes. The central role of Mg2+ in the function of ribozymes and its ‘archaic’ position in ribosomes (the protein making machinery in all cells), and the fact that magnesium generally has coordination properties different from other cations, suggests that the inorganic chemistry of magnesium, together with that of sodium and phosphate, had a key position in the first chemical processes leading to the origin and early evolution of life.

  • 48.
    Holm, Nils
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. geokemi.
    Phosphorylation underneath the ocean floor?2008In: Geochimica et Cosmochimica Acta, 2008Conference paper (Other (popular science, discussion, etc.))
  • 49.
    Holm, Nils
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    THE POTENTIAL OF ABIOTIC ORGANIC SYNTHESIS IN ALKALINE ENVIRONMENTS OF SUBDUCTION ZONES2010Conference paper (Other academic)
    Abstract [en]

    Reduced carbon and nitrogen precursor compounds may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Once the reduced carbon and nitrogen compounds have been formed the synthesis of hydrogen cyanide is, in principle, possible [1]. HCN is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form the HCN, which is then available for further organic reactions. Since the released fluids will rise through hydrated ultramafic mantle rocks of the lower part of the overriding plate, they will experience a strong pH increase. The reason for this increase is that the serpentinization of ferromagnesian minerals in ultramafic rocks in contact with the water leads to the formation of the secondary magnesium hydroxide mineral brucite, which causes high pH. The high pH may promote abiotic formation of carbohydrates like pentose sugars, particularly ribose, as well as nucleosides and even nucleotides, since pyrophosphate is stable under alkaline conditions at low water-rocks ratios [2]. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic organic reactions on terrestrial planets, provided that some type of plate tectonics occurs.

  • 50.
    Holm, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Neubeck, Anna
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Reduction of nitrogen compounds i oceanic basemet and its implications for HCN formation and abiotic organic synthesis2009In: Geochemical Transactions, ISSN 1467-4866, E-ISSN 1467-4866, Vol. 10, no 9Article in journal (Refereed)
    Abstract [en]

    Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.

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