Change search
Refine search result
1 - 25 of 25
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Amid, C.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Olstedt, M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gunnarsson, Jonas S.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Le Lan, H.
    Tran Thi Minh, H.
    Van den Brink, P. J.
    Hellström, M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Additive effects of the herbicide glyphosate and elevated temperature on the branched coral Acropora formosa in Nha Trang, Vietnam2018In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, no 14, p. 13360-13372Article in journal (Refereed)
    Abstract [en]

    The combined effects of the herbicide glyphosate and elevated temperature were studied on the tropical staghorn coral Acropora formosa, in Nha Trang bay, Vietnam. The corals were collected from two different reefs, one close to a polluted fish farm and one in a marine-protected area (MPA). In the laboratory, branches of the corals were exposed to the herbicide glyphosate at ambient (28 degrees C) and at 3 degrees C elevated water temperatures (31 degrees C). Effects of herbicide and elevated temperature were studied on coral bleaching using photography and digital image analysis (new colorimetric method developed here based on grayscale), chlorophyll a analysis, and symbiotic dinoflagellate (Symbiodinium, referred to as zooxanthellae) counts. All corals from the MPA started to bleach in the laboratory before they were exposed to the treatments, indicating that they were very sensitive, as opposed to the corals collected from the more polluted site, which were more tolerant and showed no bleaching response to temperature increase or herbicide alone. However, the combined exposure to the stressors resulted in significant loss of color, proportional to loss in chlorophyll a and zooxanthellae. The difference in sensitivity of the corals collected from the polluted site versus the MPA site could be explained by different symbiont types: the resilient type C3u and the stress-sensitive types C21 and C23, respectively. The additive effect of elevated temperatures and herbicides adds further weight to the notion that the bleaching of coral reefs is accelerated in the presence of multiple stressors. These results suggest that the corals in Nha Trang bay have adapted to the ongoing pollution to become more tolerant to anthropogenic stressors, and that multiple stressors hamper this resilience. The loss of color and decrease of chlorophyll a suggest that bleaching is related to concentration of chloro-pigments. The colorimetric method could be further fine-tuned and used as a precise, non-intrusive tool for monitoring coral bleaching in situ.

  • 2.
    Faxneld, Suzanne
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hellström, Micaela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Symbiodinium spp. composition in nearshore and offshore Porites lutea and Galaxea fascicularis in northern VietnamManuscript (preprint) (Other academic)
  • 3.
    Faxneld, Suzanne
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Jörgensen, Tove L.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Effects of elevated water temperature, reduced salinity and nutrient enrichment on the metabolism of the coral Turbinaria mesenterina2010In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 88, no 4, p. 482-487Article in journal (Refereed)
    Abstract [en]

    Water quality is declining in many coastal areas, which has caused coral degradation worldwide. In addition, reduced water quality may aggravate the impacts of seawater temperature. In this study the effects of increased temperature (31 degrees C), nitrate enrichment (+5 mu M NO3-), low salinity (20) and combinations of these stressors were investigated compared to ambient water (25 degrees C, 30, 0.3 mu M NO3-) on the metabolism and survival of the coral Turbinaria mesenterina from the Tonkin Gulf, Vietnam. The results showed that all specimens exposed to a combination of all three stressors (i.e. high temperature + high nitrate + low salinity) died after 24 h exposure, while those that had been exposed to high nitrate + low salinity at ambient temperature did not show any effects on the metabolism or survival. Furthermore, corals exposed to low salinity + high temperature displayed a decrease in gross primary production/respiration (GP/R) ratio and the mortality rate was 50%. In addition, all corals exposed to increased temperature, alone or in combination with another stressor, displayed a GP/R-24h ratio below 1.0, suggesting that they depend on stored energy to cover their metabolic requirements. The results showed that corals may tolerate short-term exposure to stressors such as low salinity + high nitrate concentration in ambient temperature, while additional increased temperature lead to rapid mortality, hence suggesting a synergistic effect. Thus, the effect of climate change might be more severe in nearshore coastal areas where corals already are exposed to several disturbances.

  • 4.
    Faxneld, Suzanne
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lund Jörgensen, Tove
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nguyen, Ngai D.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Differences in physiological response to increased seawater temperature in nearshore and offshore corals in northern Vietnam2011In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 71, no 3, p. 225-233Article in journal (Refereed)
    Abstract [en]

    Effects of elevated seawater temperature show high spatial heterogeneity and variation within and among coral species. The objective of this study was to investigate how two coral species, Porites lutea and Galaxea fascicularis, from two high latitude reefs differently exposed to chronic disturbance, respond to elevated seawater temperatures. Corals were collected from reefs nearshore (i.e. subjected to high sediment load, higher chlorophyll α concentrations, turbidity etc.) and offshore (i.e. less exposed). The corals were exposed in the lab to gradually increasing temperatures (25.5–33.5 °C) for 72 h after which they were allowed to recover to ambient temperature (25.5 °C) for 24 h. Production and respiration were measured after 24, 48, 72 and 96 h. The results show that P. lutea from nearshore reefs suffered an initial decrease in gross primary production/respiration (GP/R) ratio after 24 h, after only a moderate temperature increase (+2 °C, from 25.5 to 27.5 °C), while there was no difference in GP/R ratio between heat-exposed and controls the other days, indicating that the chronic disturbance in the nearshore reef had no effect on their thermotolerance. Furthermore, P. lutea from the offshore reef showed a decrease in GP/R ratio both after 24 h and 72 h (33.5 °C) of exposure.

    In comparison, G. fascicularis showed a decrease in GP/R ratio after 48 h, 72 h and 96 h of exposure for the nearshore corals. Also, after 72 h these corals had withdrawn their polyps. There were no differences between heat-treated and controls for the offshore G. fascicularis. This implies that the chronically disturbed G. fascicularis had lower thermotolerance when exposed to a temperature increase.

    This study, hence, shows that the response of corals to elevated seawater temperature varies with species and environmental background history.

  • 5.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Elfwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Löf, Marie
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Davenport, Julia
    Davenport, John
    The effect of thermal stress on protein composition in dogwhelks (Nucella lapillus) under normoxic and hyperoxic conditions2007In: Comparative Biochemistry and Physiology A, ISSN 1095-6433, E-ISSN 1531-4332, Vol. 148, no 4, p. 869-875Article in journal (Refereed)
    Abstract [en]

    In this laboratory study, dogwhelks (Nucella lapillus) were collected from the intertidal zone and exposed to 16 °C (ambient), 26.5 °C and 30 °C under normal and hyperoxic conditions respectively. It was shown that there was no thermally induced mortality at 26.5 °C, but that the mortality rate was 40–50% in 30 °C. This mortality rate was reduced to 10% if extra oxygen was provided, indicating that oxygen supply was setting the limit for whole organism thermal tolerance. Tissue samples were then analysed for protein features using two-dimensional gel electrophoresis, and both up and down regulation of proteins were visualised by silver staining and crosswise comparisons of gels from control vs. treated animals. The results clearly show that the protein profiles from dogwhelks exposed to increased water temperatures differ from those of the control, but that increased oxygen availability alleviates these differences thus increasing the similarity between heat-shocked and control animal protein pattern. This implies a more stable protein metabolism and might explain the increased survival of heat-shocked individuals when extra oxygen is supplied.

  • 6.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Isabell, Stenson
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hellström, Micaela
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Shared Environments Create Conflicts Between Sea Cage Aquculture and Coral Reefs in VietnamManuscript (preprint) (Other academic)
  • 7.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hellström, Micaela
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Spatial correlation and potential conflicts between sea cage farms and coral reefs in South East Asia2015In: Aquaculture, ISSN 0044-8486, E-ISSN 1873-5622, Vol. 448, p. 418-426Article in journal (Refereed)
    Abstract [en]

    In the South China and Java Seas, cage farming is a recent regional activity, which since the year 2000 has experienced an annual growth of 29%. The region holds the highest diversity of marine life, which is partly or completely dependent on coral reefs. The increasingly growing coastal human population in the area relies on ecosystem goods and services provided by the reefs that are threatened by anthropogenic activities. Sea cage farming is one of the stressors negatively impacting coral reefs by being point sources of nutrients and other effluents. To date no systematic information is available on the physical location of marine farms in relation to the coral reefs. Little is known about the distance where impact from the farms can be detected on nearby coral reefs. The present survey aimed to fill this gap by assessing to what extent marine cage farms in South East Asia are placed in the vicinity of the reefs and at which distance stress indicators from the farms are observed. We used Google Earth satellite images to investigate the extension and spatial distribution of sea cage aquaculture in relation to the presence of coral reefs. The stress indicators were locally assessed in Central Vietnam by recording turf algal overgrowth, coral mortality, live coral and branching coral cover at increasing distances from the farms. We found that 90% of sea cage farms throughout the region clustered closer than 5 km from coral reefs and 50% of them closer than 1 km from reefs. In Taiwan, 71% of the cages were located within 100m from a reef. This pattern is nonrandom and could not be explained by the natural distribution of coral reefs; only 5% of the Vietnamese coast harbors coral reefs, and sea cage farms are present in these areas only. This indicates that the farms require similar conditions as the reefs including clear and shallow waters and protection against storms and wave action. We found that turf algal overgrowth decreased at 287 m +/- 54 m, dead coral at 1446m +/- 154 m, live coral cover increased at 566 +/- 221 m and branching corals increased at 867 m +/- 140 m from the cage farms. We conclude that proximity to coral reefs should be considered when planning future developments of sea cage aquaculture, and recommend that distances of at least 1.5 km should be kept. Statement of relevance: Consider coral reefs when planning sea cage aquaculture site.

  • 8.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Stenson, Isabell
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hellström, Micaela
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tedengren, Micael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Causes and consequences of spatial links between sea cage aquaculture and coral reefs in VietnamManuscript (preprint) (Other academic)
  • 9.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Stenson, Isabell
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hellström, Micaela
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Causes and consequences of spatial links between sea cage aquaculture and coral reefs in Vietnam2017In: Aquaculture, ISSN 0044-8486, E-ISSN 1873-5622, Vol. 481, p. 245-254Article in journal (Refereed)
    Abstract [en]

    A majority of the sea cage farms in South East Asia are located close to coral reefs. This causes a conflict between conservation and food production since sea cage aquaculture has a number of negative impacts on coral reefs. The aim of this investigation was to assess the drivers causing the sea cage farmers to place their farms close to reefs and to examine some potential farming effects in detail i.e. usage of coral reef fish for grow out farming and feed. For some 3500 Vietnamese fish and lobster farms, we measured; the distance to the closest coastal city (proxy for infrastructure access), satellite derived Chl a (proxy for water quality), wind fetch, and the adjacent coastal slope and elevation. We also performed 159 semi-structured interviews with fish and lobster cage farmers from three regions in Vietnam. The interviews revealed that the choice of farming site is mainly determined by access to infrastructure, wind and wave shelter, and water quality. Although the farmers used coral reef services, e.g. coral reef derived seedlings, they were in general not aware of coral reef presence or did not find it important for selection of site. Both coral reefs and sea cage farms were found close to steep rocky coasts, which are favorable for corals, and provide sufficient depth for sea cages. Sea cages were always found on the leeward side of the coast where the wind fetch is low enough for the floating farms and their inhabitants. Most of the farms were located within 20 km from a coastal city confirming the importance of access to infrastructure. With few exceptions, sea cage farms were located in areas with good water quality, where also coral reefs are present. The study showed that several of the coral associated species groups farmed were dependent on wild caught seedlings and that 22% of the feed used at farms was trashfish of coral reef associated species. We consider the spatial correlation between sea cage farms and coral reefs as circumstantial and suggest that shared environmental preferences explain the farm distribution pattern, rather than access to ecosystem services provided by the nearby reef itself. We found no evidence that it is necessary for sea cage farms to be located near coral reefs and strongly recommend that sea cages are moved further away from coral reefs, but to areas still providing clear water, shelter and access to infrastructure.

  • 10.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Stenson, Isabell
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Nitz Pettersson, Mika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Warshan, Denis
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nguyen-Kim, H.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Antibiotic use in Vietnamese fish and lobster sea cage farms; implications for coral reefs and human health2018In: Aquaculture, ISSN 0044-8486, E-ISSN 1873-5622, Vol. 495, p. 366-375Article in journal (Refereed)
    Abstract [en]

    Several papers have reported on the development of antibiotic resistance and implications for human medicine but fewer deal with environmental impacts of antibiotic use. Marine sea cage aquaculture in SE Asia is often established close to coral reef ecosystems. Large amounts of antibiotics are used in the cultivation of fish and lobster and hence released directly into the environment. This study investigates the antibiotic practices in sea cage farms producing fish and spiny lobster in Vietnam, mainly for the domestic market. There are approximately 3500 sea cage farms in Vietnam and we performed semi-structured interviews with 109 sea cage farmers asking them if they use antibiotics and if so; what sort/when/how often/how much. We found that the Vietnamese cage farmers are using antibiotics in an unstructured way, which seems to have little or no effect on the survival of the stock, or profit of the farm. The fact that the farmers live at their farm and use the sea next to the cages both for fishing and collecting filter-feeding bivalves for direct consumption, as well as a toilet, poses an additional risk for the spreading of human antibiotic resistant pathogens. Thirteen different antibiotics were found in the study. Eighty-two percentage of the lobster farmers and 28% of the fishfarmers used antibiotics. The average amounts used were over 5 kg per produced ton of lobster and about 0.6 kg per ton of fish, which is much higher than in other studies. Several antibiotic substances listed as critical and highly important for human medicine by WHO were used prophylactically and routinely with little control and enforcement of regulations. We tested and detected antibiotic resistance to Tetracycline, Vancomycin and Rifampicin in the coral associated bacteria Bacillus niabensis as far as 660m from fish farms with resistance decreasing with distance from the cage farms. The antibiotics are likely to have negative effects on the coral-symbiont relationship adding further risks to an already stressed environment.

  • 11.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Stenson, Isabell
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nitz Pettersson, Mika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Warshan, Denis
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nguyen-Kim, Hanh
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Antibiotic use on Vietnamese fish and lobster sea cage farms and implications for the coral reef environment and human healthManuscript (preprint) (Other academic)
  • 12.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    von Schreeb, Kristina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Charisiadou, Stefania
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jiddawi, Narriman S.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mtwana Nordlund, Lina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Habitat preference for seaweed farming - A case study from Zanzibar, Tanzania2018In: Ocean and Coastal Management, ISSN 0964-5691, E-ISSN 1873-524X, Vol. 154, p. 186-195Article in journal (Refereed)
    Abstract [en]

    Global marine seaweed aquaculture is growing rapidly. In Zanzibar, Tanzania, seaweed farming, primarily conducted by women, is the main coastal aquaculture activity. Many types of aquaculture are linked to a specific ecosystem (e.g. shrimp-mangrove), and understanding if such a coupling exists for seaweed farming important for further development. A prerequisite to understand if farming affects coastal habitats is the need to know where, and on which habitat, the farms are located. In this study, we investigated the habitat preferences of seaweed farmers by interviews, field observations and satellite imagery analysis. We found that the majority of the farms were distributed in a narrow corridor (380-600 m from shore) along the coast where water depth (x) over bar = 2 m) and tidal regime (+/- 2 m) allow for a suitable environment for both the algae and the farmers. Within this corridor, thus defined by depth, the water is deep enough for the algae not to be overexposed to sunlight but also sufficiently shallow for the women to access and work on the farms at low tide. The farmers accordingly expressed depth as the major limiting factor when choosing the site for their farms, and the preferred habitat type was seagrass beds. Most farms (92%) were partly located on seagrass meadows, but also other habitats, such as sand. The total area of the studied seaweed farms was 65.6 ha, with 39% of this being seagrass meadow, which is significantly more than the seagrass cover in the farming corridor. The farms also covered 43% sand; however, the interviews indicate that a substantial part of the sandy areas was, in fact, also recently covered by seagrasses. Our findings are relevant for improved management, conservation, and marine spatial planning, as we show where and on which habitats seaweed farms are preferably located. This information can be used to further investigate the ecological impact on the habitats and their associated fauna and in order to provide more effective management actions. Furthermore, this is much-needed baseline information for investigating the increased production of seaweed, i.e. if the habitat has any effect on the algae growth.

  • 13.
    Hedberg, Nils
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    von Schreeb, Kristina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Charisiadou, Stefania
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Jiddawi, Narriman
    Tedengren, Micael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mtwana Nordlund, Lina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Habitat preference for seaweed farming – a case study from Zanzibar, TanzaniaManuscript (preprint) (Other academic)
  • 14.
    Hellström, Micaela
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gross, Susanna
    Hedberg, Nils
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Faxneld, Suzanne
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Cuong, C. T.
    Nguyen Ngai, D.
    Huong, Le Lan
    Grahn, M.
    Benzie, J.A.H.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Symbiodinium spp. diversity in a single host species, Galaxea fascicularis, Vietnam: Impact of environmental factors, host traits, and diversity hot spotsManuscript (preprint) (Other academic)
    Abstract [en]

    We determined the distribution of zooxanthellate ITS2 types within one broadcast spawning coral species,

    Galaxea fascicularis with horizontal symbiont uptake, in both inshore and offshore reef habitats over a 3200 km range along the coast of Vietnam, covering 11 degrees of latitude. Host traits (mtDNA genotype) and environmental factors (visibility, sea surface temperatures and Chlorophyll a derived from satellite data, regional measures of coral species diversity and distance from land (inshore/offshore)) were measured to test whether symbiont type distribution was determined by host characteristics or by environmental factors. The G. fascicularis and their associated symbionts were not genetically coupled to each other but to environmental factors The host displayed an inshore-offshore zonation, with higher diversity offshore. The D1a symbiont exhibited an inshore- offshore zonation. In contrast; the 5 different C symbiont types showed a latitudinal distribution gradient, which shifted in dominance north to south. We found regional differences in symbiont type; these were related to environmental differences and not to genetic characteristics in the coral G. fascicularis.

  • 15.
    Lilja, Carl
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Prevodnik, Andreas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gardeström, Johanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Elfwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bollner, Tomas
    Regional differences in mRNA responses in blue mussels within the Baltic proper2008In: Comparative Biochemistry and Physiology - Part C: Toxicology & Pharmacology, ISSN 1532-0456, E-ISSN 1878-1659, Vol. 148, no 2, p. 101-106Article in journal (Refereed)
    Abstract [en]

    Mussels (Mytilus sp.) from two regions along the permanent salinity gradient within the Baltic proper were exposed to copper (35 ppb) or petrol (0.3 mL/L) for 10 days and analyzed for mRNA expressions in gill tissue. Expression of mRNAs for the heat shock proteins HSP70 and HSP90 was significantly induced by copper, but not by petrol. For the metallothioneins MT10 and MT20, regional differences in mRNA expressions could be seen. In mussels from the northern Baltic proper, MT20 expression increased 2.8 and 3.4 times, after exposure to copper and petrol, respectively. In contrast, no change could be seen in MT20 expression for mussels from the southern Baltic proper. MT10 showed a peculiar expression not previously described. For some mussels, no expression at all was detected, some showed a weak expression and for some individuals a strong expression could be seen. For the mussels from the southern Baltic proper, the number of individuals with a strong expression of MT10 increased from 1 out of 18 (control), to 7 and 8, after exposure to copper and petrol, respectively. The results clearly show that responses vary between different regions within the Baltic proper, which emphasises the importance to study interactions between contaminants, populations and regions. 

  • 16. Mena, F.
    et al.
    Azzopardi, M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Pfennig, S.
    Ruepert, C.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Castillo, L. E.
    Gunnarsson, Jonas S.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Use of cholinesterase activity as a biomarker of pesticide exposure used on Costa Rican banana plantations in the native tropical fish Astyanax aeneus (Gunther, 1860)2014In: Journal of environmental biology, ISSN 0254-8704, Vol. 35, no 1 (SI), p. 35-42Article in journal (Refereed)
    Abstract [en]

    In Costa Rica, thousands of tones of agricultural pesticides have been used for decades and their use is continuously increasing due to intensive and expanding production of coffee, pineapple, rice, ornamental plants and bananas. The objective of this study was to evaluate whether choline esterase (ChE) activity could be used as a biomarker of exposure to pesticides in the Costa Rican native fish Astyanax aeneus (characidae). Three methods used in order to evaluate the ChE biomarker were as follows: Laboratory studies where A. aeneus was exposed to organophosphate pesticide (ethoprophos); In situ 48 hr exposure assessment using caging experiments with fish exposed upstream and downstream of banana plantations and ChE activity estimation of in fish captured directly at sites with different degrees of pesticide exposure. Results from the laboratory studies showed that ChE activity in both brain and muscle tissue was significantly lower in fish exposed to ethoprophos than in controls. Fish from the caging experiments showed no difference in ChE activity neither in brain nor in muscle tissue between the four tested sites and was attributed to the short duration of the exposure. A significant difference in ChE activity was determined in muscle of fish captured from Laguna Madre de Dios compared to fish from Canal Batan. Although our laboratory results revealed that ChE activity in A. aeneus was highly responsive to ethoprophos, results from field experiments were less conclusive and showed that the captured fish showed large variability in ChE activity and that more research is needed before ChE activity can be used as reliable biomarker of pesticide exposure.

  • 17.
    Nguyen, Thanh Tam
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Nong Lam University, Vietnam.
    Berg, Håkan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Laureus, Jenny
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Van Nguyen, Cong
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Effects of Sequential Applications of Bassa 50EC (Fenobucarb) and Vitashield 40EC (Chlorpyrifos ethyl) on Acetylcholinesterase Activity in Climbing Perch (Anabas testudineus) Cultured in Rice Fields in the Mekong Delta, Vietnam2016In: Bulletin of Environmental Contamination and Toxicology, ISSN 0007-4861, E-ISSN 1432-0800, Vol. 97, no 1, p. 98-104Article in journal (Refereed)
    Abstract [en]

    This study assesses the effects of sequential applications of the insecticides Bassa 50EC (fenobucarb-F) and Vitashield 40EC (chlorpyrifos ethyl-CPF), sprayed at concentrations used by rice farmers in the Mekong Delta, on the brain acetylcholinesterase (AChE) in climbing perch fingerlings. After spraying the pesticides on the rice fields, the water concentrations of both insecticides decreased below the detection levels within three days. The sequential applications caused significant inhibition on the brain AChE activity in the exposed fish. The inhibition by F was quicker, but less prolonged, than for CPF. The inhibition levels caused by the sequential applications were lower than those caused by only CPF and by a mixture of CPF and F. The results indicate that sequential applications of pesticides could have a negative impact on aquatic organisms and fish yields, with implication for the aquatic biodiversity, local people’s livelihood and the aquaculture industry in the Mekong Delta.

  • 18.
    Prevodnik, Andreas
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Gardeström, Johanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lilja, Karl
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Elfwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    McDonagh, B
    Petrovic, N
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sheenan, D
    Bollner, T
    Oxidative stress in response to xenobiotics in the blue mussel Mytilus edulis L.: Evidence for variation along a natural salinity gradient of the Baltic Sea2007In: Aquatic Toxicology, Vol. 82, no 1, p. 63-71Article in journal (Refereed)
  • 19.
    Sanderson Bellamy, Angelina
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Svensson, Ola
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    van den Brink, Paul
    Wageningen University, Department of Aquatic Ecology and Water Quality Management.
    Gunnarsson, Jonas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, MIchael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Insect diversity on high-input, low-input and organic banana farmsIn: Agricultural and Forest Entomology, ISSN 1461-9555, E-ISSN 1461-9563Article in journal (Refereed)
    Abstract [en]

    High intensity of pesticide use in banana production is problematic not only for human health and the surrounding environment, but can threaten the provision of ecosystem services on which farm productivity depends. This research investigates the effects of varying pesticide-use intensities on on-farm insect diversity, using three different types of farm management systems: high pesticide input conventional system, reduced pesticide input conventional system and organic system. Insect sampling was done using pitfall and yellow bowl traps, left for a 24-hour period at 2 locations inside the banana farm, at the edge of the farm, and in adjacent forest. Species were classified to family level and then morphospecies. Insect species community composition and diversity were compared using multivariate statistics with ordination analysis and Monte Carlo permutation testing, and revealed that each of the management systems were significantly different from each other for both trap types. Insect diversity decreased as production management increased its pesticide use. Reduced insect diversity resulted in fewer functional groups and fewer insect families assuming different functions essential to ecosystem health. Organic farms had similar species composition on the farm compared to adjacent forest sites, whereas species composition increasingly differed between farm and forest sites as pesticide-use intensity increased. We conclude that while organic production has minimal impact on insect biodiversity, even small reductions in pesticide-use intensity can have a significantly positive impact on on-farm insect biodiversity and functional roles supported.

  • 20. Sanderson Bellamy, Angelina
    et al.
    Svensson, Ola
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    van den Brink, Paul J.
    Gunnarsson, Jonas
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Insect community composition and functional roles along a tropical agricultural production gradient2018In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, no 14, p. 13426-13438Article in journal (Refereed)
    Abstract [en]

    High intensity agricultural production systems are problematic not only for human health and the surrounding environment, but can threaten the provision of ecosystem services on which farm productivity depends. This research investigates the effects of management practices in Costa Rica on on-farm insect diversity, using three different types of banana farm management systems: high-input conventional system, low-input conventional system, and organic system. Insect sampling was done using pitfall and yellow bowl traps, left for a 24-h period at two locations inside the banana farm, at the edge of the farm, and in adjacent forest. All 39,091 individual insects were classified to family level and then morphospecies. Insect species community composition and diversity were compared using multivariate statistics with ordination analysis and Monte Carlo permutation testing, and revealed that each of the management systems were significantly different from each other for both trap types. Insect diversity decreased as management intensity increased. Reduced insect diversity resulted in fewer functional groups and fewer insect families assuming different functions essential to ecosystem health. Organic farms had similar species composition on the farm compared to adjacent forest sites, whereas species composition increasingly differed between farm and forest sites as management intensity increased. We conclude that while organic production has minimal impact on insect biodiversity, even small reductions in management intensity can have a significantly positive impact on on-farm insect biodiversity and functional roles supported.

  • 21.
    Sanderson Bellamy, Angelina
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Svensson, Ola
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    van den Brink, Paul J.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    What is in a label? Rainforest-Alliance certified banana production versus non-certified conventional banana production2016In: Global Ecology and Conservation, ISSN 2351-9894, Vol. 7, p. 39-48Article in journal (Refereed)
    Abstract [en]

    Export banana production in Latin America is pesticide intensive, receiving much negative publicity regarding human health problems and environmental degradation. The Rainforest Alliance (RA) certification scheme was established to certify farms that met a number of social, occupation health and environmental standards set by RA and their certifying body, the Sustainable Agriculture Network (SAN). This study was one of the first, independent studies of the environmental impact of some of the principles set by RA and SAN. The study focuses on insect and bird diversity as an indicator of ecosystem health. Five RA certified farms, six non-RA certified farms, and five organic certified farms were sampled. The data was analyzed with RDA multivariate analyses and Monte Carlo permutation tests. The results showed that RA certified farms had less insect diversity compared to non-RA certified farms and that both farm types had less insect diversity than organic farms. There was little difference between RA and non-RA certified farms with regards bird community composition. Thus, organic farming conserves biodiversity, while alternative environmental labels (e.g. a Rainforest alliance seal) may not have any visible positive effect on in-farm biodiversity. This study points to the need for improvements in SAN certification standards to achieve improved environmental conditions.

  • 22.
    Sanderson Bellamy, Angelina
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Svensson, Ola
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    van den Brink, Paul
    Wageningen University, Department of Aquatic Ecology and Water Quality Management.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    What’s in a label? Rainforest-Alliance certified banana production versus non-certified conventional banana production:  Manuscript (preprint) (Other academic)
    Abstract [en]

    Export banana production in Central and South America, Costa Rica included, is a very pesticide intensive crop, receiving a lot of negative publicity with regards human exposure to pesticides and environmental degradation. In the 1990s, the Rainforest Alliance (RA) certification scheme was established to certify banana producing farms that met a number of social, occupation health and environmental standards set by RA together with their certifying body, the Sustainable Agriculture Network (SAN). The RA seal is meant to convey that bananas were produced using the Best management practices that, among other things, ensures a lower impact on the environment. This study is one of the first, independent scientific studies of the environmental impact of some of the principals set by RA and SAN. The study focuses on insect and bird diversity as an indicator of ecosystem health, and uses yellow bowl traps, pitfall traps and bird survey with audio recording point counts. Five RA certified farms, six non-RA certified farms, and five organic certified farms were sampled; five replicates of each type of insect trap were taken from inside, 30m inside, the edge and adjacent forest areas and 2 replicates were taken of audio bird recordings at inside, edge and forest sites. The data was analyzed with RDA multivariate analyses andMonte carlopermutation tests. The results showed that RA certified farms had less insect diversity when compared to non-RA certified farms and that both farm types had less insect diversity than organic farms, and that there was little difference between RA and non-RA certified farms with regards bird community composition. This study only addressed a few of the principles set forth in the certification standards and that further research needs to be done to investigate the effects of changes made as the result of other principles included in the SAN standards.

  • 23.
    Svensson, Ola
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sanderson Bellamy, Angelina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    van den Brink, Paul
    Wageningen University, Department of Aquatic Ecology and Water Quality Management.
    Gunnarsson, Jonas
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Assessing the ecological impact of banana farms on water quality using aquatic macroinvertebrate community compositionIn: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026Article in journal (Refereed)
    Abstract [en]

    In Costa Rica considerable effort goes to conservation and protection of biodiversity while at the same time agricultural pesticide use is among the highest in the world. Several protected areas, some being wetlands or marine reserves, are situated downstream agricultural areas where large-scale banana farms constitute a major land use, with an average of 57 pesticide applications per year. The banana industry is increasingly aware of the need to reduce their negative environmental impact, but few ecological field studies have been made to evaluate the efficiency of proposed mitigation strategies. This study evaluated if benthic macroinvertebrate community structure is sensitive enough to detect environmental impact of banana farming, and thereby usable to measure improvements in pesticide management practices. Aquatic invertebrate samples were collected at 13 sites between March and April 2007, using kick-net sampling. Samples were taken both up- and downstream banana farms in fast flowing streams, with mostly cobbles for substrate in runs and riffles. The changes in community composition were measured at the family level using ordination methods. Additionally, the Biological Monitoring Working Party (BMWP) score system was applied along with a number of community composition descriptors. In total, 2890 specimens were collected, belonging to 14 orders and 49 families or taxa. The results support the hypothesis that surface waters immediately up- and downstream large-scale banana farms have different macroinvertebrate community compositions, with fewer sensitive taxa according to the BMWP-score values at the downstream sites. Rapid assessment using macroinvertebrate community composition thus appears to be a possible means to detect negative impact from chemical-intense agriculture. As the method is moderately time-consuming, low-cost and highly ecologically relevant it could become a useful complement to chemical analysis of pesticide residues in environmental risk assessment.

  • 24.
    Svensson, Ola
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sanderson Bellamy, Angelina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Cardiff University, UK.
    Van den Brink, Paul J.
    Tedengren, Michael
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gunnarsson, Jonas S.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Assessing the ecological impact of banana farms on water quality using aquatic macroinvertebrate community composition2018In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, no 14, p. 13373-13381Article in journal (Refereed)
    Abstract [en]

    In Costa Rica, considerable effort goes to conservation and protection of biodiversity, while at the same time agricultural pesticide use is among the highest in the world. Several protected areas, some being wetlands or marine reserves, are situated downstream large-scale banana farms, with an average of 57 pesticide applications per year. The banana industry is increasingly aware of the need to reduce their negative environmental impact, but few ecological field studies have been made to evaluate the efficiency of proposed mitigation strategies. This study compared the composition of benthic macroinvertebrate communities up- and downstream effluent water from banana farms in order to assess whether benthic invertebrate community structure can be used to detect environmental impact of banana fanning, and thereby usable to assess improvements in management practises. Aquatic invertebrate samples were collected at 13 sites, using kick-net sampling. both up- and downstream banana farms in fast flowing streams in the Caribbean zone of Costa Rica. In total, 2888 invertebrate specimens were collected, belonging to 15 orders and 48 families or taxa. The change in community composition was analysed using multivariate statistics. Additionally, a biodiversity index and the Biological Monitoring Working Party (BMWP) score system was applied along with a number of community composition descriptors. Multivariate analyses indicated that surface waters immediately up- and downstream large-scale banana farms have different macroinvertebrate community compositions with the most evident differences being higher dominance by a single taxa and a much higher total abundance, mostly of that same taxon. Assessment of macroinvertebrate community composition thus appears to be a viable approach to detect negative impact from chemical-intensive agriculture and could become an effective means to monitor the efficacy of changes/proposed improvements in fanning practises in Costa Rica and similar systems.

  • 25.
    Tedengren, Michael
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Olsson, Björne
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Reimer, O
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Brown, D.C.
    Bradley, B.P.
    Heat pretreatment increase cadmium resistance and HSP 70 levels in Baltic Sea mussels2000In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 48, no 1, p. 1-12Article in journal (Refereed)
    Abstract [en]

    The effects of heat treatment and cadmium exposure on the synthesis of a major stress inducible protein (hsp 70) and on the metabolism of the blue mussel Mytilus edulis L. from the Baltic Sea, were studied in a laboratory experiment. The mussels were kept in sea water of ambient salinity (6.3‰) and temperature (4°C). The effects of cadmium (20 μg l−1), measured as changes in physiological rates (oxygen consumption, ammonia excretion, clearance rates and scope for growth) and hsp 70 expression were studied at 4°C and in combination with a rapid rise in temperature to 20°C. Relatively low levels of hsp 70 were detected but the negative effect was reflected in a reduction of scope for growth of the exposed mussels compared to controls. This effect was more pronounced at 20°C. Mussels not exposed to cadmium in the first experiment were used in a second set of experiments. Heat shocked mussels were allowed to reacclimatise to 4°C for 5 days and then, along with the mussels already at 4°C, exposed to cadmium (20 μg l−1). The results clearly indicated that the mussels exposed to 20°C in the first experiment more rapidly induced synthesis of hsp 70 after cadmium exposure in the second experiment. Also the reacclimatised mussels exposed to heat shock but not to cadmium in the first experiment, induced some hsp 70 in the second experiment. This suggests that the rate of induction of heat shock or stress proteins in Baltic mussels is slower than what has been described for mussels from more marine environments. The mussels kept at 4°C throughout the experiment and exposed to cadmium showed low levels of hsp 70, again indicating a low rate of induction. The increasing levels of hsp 70 correlated well with a maintained level of physiological fitness, in terms of scope for growth, although the mussels showed increasing body burdens of cadmium.

1 - 25 of 25
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf