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Sun, X., Anderson, L. G., Dessirier, B., Geibel, M. C., Mörth, C.-M. & Humborg, C. (2024). Large-Scale Summertime Variability of Carbonate Chemistry Across the East Siberian Sea: Primary Production Versus Ikaite Dissolution. Journal of Geophysical Research - Oceans, 129(1), Article ID e2023JC020600.
Open this publication in new window or tab >>Large-Scale Summertime Variability of Carbonate Chemistry Across the East Siberian Sea: Primary Production Versus Ikaite Dissolution
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2024 (English)In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 129, no 1, article id e2023JC020600Article in journal (Refereed) Published
Abstract [en]

Sea-ice dynamics can affect carbon cycling in polar oceans, with sea-ice ikaite acting as a potentially important carbon pump. However, there is no large-scale direct field evidence to support this. Here we used a unique data set that combined continuous measurements of atmospheric and water CO2 concentrations with water chemistry data collected over 1,200 km along the East Siberian Sea, the widest Arctic shelf sea. Our results reveal large spatial heterogeneity of sea-ice ikaite contents, which directly interact with carbonate chemistry in the water column. Our findings demonstrate that the CO2 drawdown by sea-ice ikaite dissolution could be as important as that by primary production. We suggest that the role of ikaite in regulating the seasonal carbon cycle on a regional scale could be more important than we previously thought. Effects of the warmer climate on sea ice loss might also play a role in the ikaite inventory.

Keywords
ikaite dissolution, East Siberian Sea, CO2 uptake, sea ice melting, carbonate chemistry
National Category
Environmental Sciences
Identifiers
urn:nbn:se:su:diva-225440 (URN)10.1029/2023JC020600 (DOI)001135623800001 ()
Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-01-16Bibliographically approved
Hossain, M., Bhattacharya, P., Frape, S. K., Ahmed, K. M., Jacks, G., Hasan, M. A., . . . Mörth, C.-M. (2023). A potential source of low-manganese, arsenic-safe drinking water from Intermediate Deep Aquifers (IDA), Bangladesh. Groundwater for Sustainable Development, 21, Article ID 100906.
Open this publication in new window or tab >>A potential source of low-manganese, arsenic-safe drinking water from Intermediate Deep Aquifers (IDA), Bangladesh
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2023 (English)In: Groundwater for Sustainable Development, E-ISSN 2352-801X, Vol. 21, article id 100906Article in journal (Refereed) Published
Abstract [en]

Elevated manganese (Mn) concentration in many drinking water tubewells in Bangladesh has made access to safe drinking water more critical despite providing arsenic (As) safe water to millions of people after decades of efforts to achieve latter. This study evaluates the potential of the Intermediate Deep Aquifer (IDA) in the Matlab area of Bangladesh as a source of As-safe and low-Mn groundwater. Based on observations from depth-specific piezometer nests, drinking water tubewells were installed at a targeted depth of 120 m in the Matlab region, an As-hot spot in the country. Water chemistry analysis of 243 Intermediate Deep Tubewells (IDTW) provided promising results which support the strategy of exploiting the IDA as a safe source for drinking water tubewells. Arsenic, manganese and other trace elements, along with the major ions, were analyzed by high-precision ICP-OES and ion chromatography. The Bangladesh drinking water standard for As (50 μg/L) was exceeded only in 3 wells (1%) while 99% (n = 240) of the wells were found to be safe. More than 91% (n = 222) were within the WHO guideline value of 10 μg/L. For Mn, 89% (n = 217) of the wells showed the concentration within or below the former WHO guideline value of 0.4 mg/L with a mean and median value of 0.18 and 0.07 mg/L respectively. Similar high permeability sand units at this depth range, if available could be targeted by the local tubewell drillers for tapping water at half the cost of deep tubewell installation, which will be quite encouraging for the local community, considering their affordability for installation of As-safe and low-Mn drinking water tubewells. This study's results could also be important for other relevant stakeholders, including the policy makers, implementing agencies and the water sector development partners, as well as water supply projects elsewhere in the world with similar hydrogeological settings.

Keywords
Intermediate deep aquifers (IDA), Arsenic, Manganese, IDTW, Groundwater, Drinking water supply
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:su:diva-216803 (URN)10.1016/j.gsd.2023.100906 (DOI)000955241900001 ()2-s2.0-85150891671 (Scopus ID)
Available from: 2023-04-28 Created: 2023-04-28 Last updated: 2023-04-28Bibliographically approved
Ehnvall, B., agren, A. M., Nilsson, M. B., Ratcliffe, J. L., Noumonvi, K. f., Peichl, M., . . . Oquist, M. G. (2023). Catchment characteristics control boreal mire nutrient regime and vegetation patterns over  ∼5000 years of landscape development. Science of the Total Environment, 895, Article ID 165132.
Open this publication in new window or tab >>Catchment characteristics control boreal mire nutrient regime and vegetation patterns over  ∼5000 years of landscape development
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2023 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 895, article id 165132Article in journal (Refereed) Published
Abstract [en]

Vegetation holds the key to many properties that make natural mires unique, such as surface microtopography, high biodiversity values, effective carbon sequestration and regulation of water and nutrient fluxes across the landscape. Despite this, landscape controls behind mire vegetation patterns have previously been poorly described at large spatial scales, which limits the understanding of basic drivers underpinning mire ecosystem services. We studied catchment controls on mire nutrient regimes and vegetation patterns using a geographically constrained natural mire chronosequence along the isostatically rising coastline in Northern Sweden. By comparing mires of different ages, we can partition vegetation patterns caused by long-term mire succession (<5000 years) and present-day vegetation responses to catchment eco-hydrological settings. We used the remote sensing based normalized difference vegetation index (NDVI) to describe mire vegetation and combined peat physicochemical measures with catchment properties to identify the most important factors that determine mire NDVI. We found strong evidence that mire NDVI depends on nutrient inputs from the catchment area or underlying mineral soil, especially concerning phosphorus and potassium concentrations. Steep mire and catchment slopes, dry conditions and large catchment areas relative to mire areas were associated with higher NDVI. We also found long-term successional patterns, with lower NDVI in older mires. Importantly, the NDVI should be used to describe mire vegetation patterns in open mires if the focus is on surface vegetation, since the canopy cover in tree-covered mires completely dominated the NDVI signal. With our study approach, we can quantitatively describe the connection between landscape properties and mire nutrient regime. Our results confirm that mire vegetation responds to the upslope catchment area, but importantly, also suggest that mire and catchment aging can override the role of catchment influence. This effect was clear across mires of all ages, but was strongest in younger mires.

Keywords
Catchment support, Chronosequence, NDVI, Landscape ecology, Holocene
National Category
Physical Geography Ecology
Identifiers
urn:nbn:se:su:diva-221283 (URN)10.1016/j.scitotenv.2023.165132 (DOI)001037832700001 ()37379918 (PubMedID)2-s2.0-85163869847 (Scopus ID)
Available from: 2023-09-22 Created: 2023-09-22 Last updated: 2023-09-22Bibliographically approved
Hirst, C., Andersson, P. S., Mörth, C.-M., Murphy, M. J., Schmitt, M., Kooijman, E., . . . Porcelli, D. (2023). Iron isotopes reveal seasonal variations in the mechanisms for iron-bearing particle and colloid formation in the Lena River catchment, NE Siberia. Geochimica et Cosmochimica Acta, 363, 77-93
Open this publication in new window or tab >>Iron isotopes reveal seasonal variations in the mechanisms for iron-bearing particle and colloid formation in the Lena River catchment, NE Siberia
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2023 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 363, p. 77-93Article in journal (Refereed) Published
Abstract [en]

Large Arctic rivers are an important source of iron (Fe) to the Arctic Ocean, though seasonal variations in the terrestrial source and supply of Fe to the ocean are unknown. To constrain the seasonal variability, we present Fe concentrations and isotopic compositions (δ56Fe) for particulate (>0.22 µm) and colloidal (<0.22 µm–1 kDa) Fe from the Lena River, NE Russia. Samples were collected every month during winter baseflow (September 2012–March 2013) and every 2–3 days before, during and after river ice break-up (May 2015).

Iron in particles have isotope ratios lower than crustal values during winter (e.g., δ56FePart = −0.37 ± 0.16‰), and crustal-like values during river ice break-up and spring flood (e.g., δ56FePart = 0.07 ± 0.08‰), indicating a change in the source of particulate Fe between winter and spring flood. Low isotope values are indicative of mineral dissolution, transport of reduced Fe in sub-oxic, ice-covered sub-permafrost groundwaters and near-quantitative precipitation of Fe as particles. Crustal-like isotopic compositions result from the increased supply of detrital particles from riverbank and soil erosion during river ice break-up and flooding. Iron colloids (<0.22 μm) have δ56Fe values that are comparable to or lower than crustal values during winter (e.g., δ56FeCol = −0.08 ± 0.05‰) but similar to or higher than crustal values during spring flood (e.g., δ56FeCol = +0.24 ± 0.11‰). Low δ56Fe ratios for colloidal Fe during winter are consistent with precipitation from isotopically light Fe(II)aq transported in sub-permafrost groundwaters. Higher colloidal δ56Fe ratios during the spring flood indicate that these colloids are supplied from surface soils, where Fe is fractionated via oxidation or organic carbon complexation, similar to during summer. Approximately half of the annual colloidal Fe flux occurs during spring flood while most of the remaining colloidal Fe is supplied during summer months. The total amount of colloidal Fe transported during winter was relatively low. The seasonal variation in colloidal Fe isotope values may be a useful tool to trace the source of colloidal Fe to the Arctic Ocean and monitor future changes in the sources and supply of Fe from the permafrost landscape to the Lena River basin.

Keywords
Climate change, Iron, Isotopes, Permafrost, River, Seasonality
National Category
Geochemistry
Identifiers
urn:nbn:se:su:diva-223033 (URN)10.1016/j.gca.2023.09.016 (DOI)001129055300001 ()2-s2.0-85173324912 (Scopus ID)
Available from: 2023-10-19 Created: 2023-10-19 Last updated: 2024-01-12Bibliographically approved
Fischer, S., Jarsjö, J., Rosqvist, G. & Mörth, C.-M. (2022). Catchment-scale microbial sulfate reduction (MSR) of acid mine drainage (AMD) revealed by sulfur isotopes. Environmental Pollution, 292, Part B, Article ID 118478.
Open this publication in new window or tab >>Catchment-scale microbial sulfate reduction (MSR) of acid mine drainage (AMD) revealed by sulfur isotopes
2022 (English)In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 292, Part B, article id 118478Article in journal (Refereed) Published
Abstract [en]

Laboratory experiments and point observations, for instance in wetlands, have shown evidence that microbial sulfate reduction (MSR) can lower sulfate and toxic metal concentrations in acid mine drainage (AMD). We here hypothesize that MSR can impact the fate of AMD in entire catchments. To test this, we developed a sulfur isotope fractionation and mass-balance method, and applied it at multiple locations in the catchment of an abandoned copper mine (Nautanen, northern Sweden). Results showed that MSR caused considerable, catchment-scale immobilization of sulfur corresponding to a retention of 27 ± 15% under unfrozen conditions in the summer season, with local values ranging between 13 ± 10% and 53 ± 18%. Present evidence of extensive MSR in Nautanen, together with previous evidence of local MSR occurring under many different conditions, suggest that field-scale MSR is most likely important also at other AMD sites, where retention of AMD may be enhanced through nature-based solutions. More generally, the developed isotope fractionation analysis scheme provides a relatively simple tool for quantification of spatio-temporal trends in MSR, answering to the emerging need of pollution control from cumulative anthropogenic pressures in the landscape, where strategies taking advantage of MSR can provide viable options.

Keywords
Bacterial sulfate reduction (BSR), Metal retention, Nature-based solution, Mine waste, End-member mixing model, Rayleigh equation
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-202007 (URN)10.1016/j.envpol.2021.118478 (DOI)000744239800008 ()34752789 (PubMedID)
Available from: 2022-02-14 Created: 2022-02-14 Last updated: 2022-08-22Bibliographically approved
Fischer, S., Mörth, C.-M., Rosqvist, G., Chalov, S. R., Efimov, V. & Jarsjö, J. (2022). Microbial Sulfate Reduction (MSR) as a Nature-Based Solution (NBS) to Mine Drainage: Contrasting Spatiotemporal Conditions in Northern Europe. Water resources research, 58(4), Article ID e2021WR031777.
Open this publication in new window or tab >>Microbial Sulfate Reduction (MSR) as a Nature-Based Solution (NBS) to Mine Drainage: Contrasting Spatiotemporal Conditions in Northern Europe
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2022 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 58, no 4, article id e2021WR031777Article in journal (Refereed) Published
Abstract [en]

An emerging solution in mine waste remediation is the use of biological processes, such as microbial sulfate reduction (MSR), to immobilize metals, reducing their bioavailability and buffering the pH of acid mine drainage. Apart from laboratory tests and local observations of natural MSR in, for example, single wetlands, little is known about spatiotemporal characteristics of freshwater MSR from multiple locations within entire hydrological catchments. We here applied an isotopic fractionation (δ34S values in SO42−) and a Monte Carlo-based mixing analysis scheme to detect MSR and its variation across two major mining regions (Imetjoki, Sweden and Khibiny, Russia) in the Arctic part of Europe under different seasonal conditions. Results indicate a range of catchment-scale MSR values in the Arctic of ∼5%–20% where the low end of the range was associated with the non-vegetated, mountainous terrain of the Khibiny catchment, having low levels of dissolved organic carbon (DOC). The high end of the range was related to vegetated conditions provided by the Imetjoki catchment that also contains wetlands, lakes, and local aquifers. These prolong hydrological residence times and support MSR hot spots reaching values of ∼40%. The present results additionally show evidence of MSR persistence over different seasons, indicating large potential, even under relatively cold conditions, of using MSR as part of nature-based solutions to mitigate adverse impacts of (acid) mine drainage. The results call for more detailed investigations regarding potential field-scale correlations between MSR and individual landscape and hydroclimatic characteristics, which, for example, can be supported by the isotopic fractionation and mixing scheme utilized here.

Keywords
bacterial sulfate reduction (BSR), sulfur-reducing bacteria (SRB), catchment-scale, acid mine drainage (AMD), Arctic hydrology, end-member mixing model
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-204509 (URN)10.1029/2021WR031777 (DOI)000786346100001 ()
Available from: 2022-05-08 Created: 2022-05-08 Last updated: 2022-08-22Bibliographically approved
Jilbert, T., Cowie, G., Lintumäki, L., Jokinen, S., Asmala, E., Sun, X., . . . Humborg, C. (2021). Anthropogenic Inputs of Terrestrial Organic Matter Influence Carbon Loading and Methanogenesis in Coastal Baltic Sea Sediments. Frontiers in Earth Science, 9, Article ID 716416.
Open this publication in new window or tab >>Anthropogenic Inputs of Terrestrial Organic Matter Influence Carbon Loading and Methanogenesis in Coastal Baltic Sea Sediments
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2021 (English)In: Frontiers in Earth Science, E-ISSN 2296-6463, Vol. 9, article id 716416Article in journal (Refereed) Published
Abstract [en]

Coastal regions globally have experienced widespread anthropogenic eutrophication in recent decades. Loading of autochthonous carbon to coastal sediments enhances the demand for electron acceptors for microbial remineralization, often leading to rearrangement of the sediment diagenetic zonation and potentially enhancing fluxes of methane and hydrogen sulfide from the seafloor. However, the role of anthropogenic inputs of terrestrial organic matter (OMterr.) in modulating diagenesis in coastal sediments is often overlooked, despite being of potential importance in regions of land-use and industrial change. Here we present a dated 4-m sediment and porewater geochemistry record from a eutrophic coastal location in the northern Baltic Sea, to investigate sources of recent carbon loading and their impact on modern diagenetic processes. Based on an end-member mixing model of sediment N/C ratios, we observe that a significant fraction of the late-20th century carbon loading at this location was contributed by OMterr.. Furthermore, analysis of lignin in this material shows depleted ratios of syringyl/vanillyl (S/V) and cinnamyl/vanillyl (C/V) phenols, indicative of enhanced inputs of woody gymnosperm tissue likely from forest industries. The rapid loading of organic matter from combined terrestrial and autochthonous sources during the late 20th century has stimulated methanogenesis in the sediment column, and shoaled the sulfate-methane transition zone (SMTZ) to a depth of 5–20 cm. Optical parameters of colored dissolved organic matter confirm that OMterr. is actively degrading in the methanogenic layer, implying a role for this material in diagenetic processes. Porewater CH4, SO42− δ13C-DIC, and ∑S2− data suggest that the modern SMTZ is a broad zone in which organoclastic sulfate reduction, methanogenesis and anaerobic oxidation of methane (AOM) co-occur. However, fluxes of CH4 and SO42− show that rates of these processes are similar to other marine locations with a comparably shallow SMTZ. We suggest that the shallow depth of the modern SMTZ is the principal reason for high observed diffusive and ebullitive methane fluxes from sediments in this area. Our results highlight that anthropogenic activities lead to multiple pathways of carbon loading to coastal sediments, and that forest industry impacts on sedimentation in the northern Baltic Sea may be more widespread than previously acknowledged.

Keywords
terrestrial organic matter, forestry, lignin, diagenesis, methane, blue carbon, baltic sea
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-199464 (URN)10.3389/feart.2021.716416 (DOI)000717755600001 ()
Available from: 2021-12-16 Created: 2021-12-16 Last updated: 2023-08-28Bibliographically approved
Kahma, T., Karlson, A. M. L., Liénart, C., Mörth, C.-M., Humborg, C., Norkko, A. & Rodil, I. F. (2021). Food-web comparisons between two shallow vegetated habitat types in the Baltic Sea. Marine Environmental Research, 169, Article ID 105402.
Open this publication in new window or tab >>Food-web comparisons between two shallow vegetated habitat types in the Baltic Sea
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2021 (English)In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 169, article id 105402Article in journal (Refereed) Published
Abstract [en]

Coastal vegetated habitats maintain highly diverse communities, where the contribution of macrophyte production is significant for macroinvertebrate primary consumers. In the brackish-waters of the Baltic Sea, the taxonomical diversity of different macrophytes includes both marine and limnic species. To study the basal food-web differences of two key vegetated habitat types, either dominated by a perennial brown macroalgae (Fucus vesiculosus) or by angiosperm plants, 13C and 15N compositions of different primary producers and macroinvertebrate consumers were examined, and their diets were estimated by Bayesian mixing models. Carbon isotope diversity of primary producers was high especially in the hard-bottom Fucus-dominated habitats, which was also reflected in a larger consumer isotope niche. However, consumer isotope niche among sites was similar within the same habitat type. Our models indicated that the perennial macrophyte dietary median contribution was about 25% for deposit feeders and omnivores in both habitat types, while epigrazers preferred filamentous algae (30–60%). The niche positions of the abundant clams L. balthica, M. arenaria and C. glaucum differed between the two habitats, but they showed only small (<10% units) differences in their macrophyte dietary contributions. The isotopic compositions of the dominating primary producer assemblage reflected significantly in the isotope niche structure of the associated primary consumers.

Keywords
Coastal ecosystem, Benthic macrofauna, Food sources, Stable isotopes, Macrophytes, Baltic sea
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-196503 (URN)10.1016/j.marenvres.2021.105402 (DOI)000672848900005 ()34246890 (PubMedID)
Available from: 2021-09-14 Created: 2021-09-14 Last updated: 2022-02-25Bibliographically approved
Rocher-Ros, G., Harms, T. K., Sponseller, R. A., Väisänen, M., Mörth, C.-M. & Giesler, R. (2021). Metabolism overrides photo-oxidation inCO(2)dynamics of Arctic permafrost streams. Limnology and Oceanography, 66(S1), S169-S181
Open this publication in new window or tab >>Metabolism overrides photo-oxidation inCO(2)dynamics of Arctic permafrost streams
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2021 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 66, no S1, p. S169-S181Article in journal (Refereed) Published
Abstract [en]

Global warming is enhancing the mobilization of organic carbon (C) from Arctic soils into streams, where it can be mineralized to CO(2)and released to the atmosphere. Abiotic photo-oxidation might drive C mineralization, but this process has not been quantitatively integrated with biological processes that also influence CO(2)dynamics in aquatic ecosystems. We measured CO(2)concentrations and the isotopic composition of dissolved inorganic C (delta C-13(DIC)) at diel resolution in two Arctic streams, and coupled this with whole-system metabolism estimates to assess the effect of biotic and abiotic processes on stream C dynamics. CO(2)concentrations consistently decreased from night to day, a pattern counter to the hypothesis that photo-oxidation is the dominant source of CO2. Instead, the observed decrease in CO(2)during daytime was explained by photosynthetic rates, which were strongly correlated with diurnal changes in delta(13)C(DIC)values. However, on days when modeled photosynthetic rates were near zero, there was still a significant diel change in delta(13)C(DIC)values, suggesting that metabolic estimates are partly masked by O(2)consumption from photo-oxidation. Our results suggest that 6-12 mmol CO2-C m(-2)d(-1)may be generated from photo-oxidation, a range that corresponds well to previous laboratory measurements. Moreover, ecosystem respiration rates were 10 times greater than published photo-oxidation rates for these Arctic streams, and accounted for 33-80% of total CO(2)evasion. Our results suggest that metabolic activity is the dominant process for CO(2)production in Arctic streams. Thus, future aquatic CO(2)emissions may depend on how biotic processes respond to the ongoing environmental change.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-184385 (URN)10.1002/lno.11564 (DOI)000551565700001 ()
Available from: 2020-10-06 Created: 2020-10-06 Last updated: 2022-02-25Bibliographically approved
Bradshaw, C., Jakobsson, M., Brüchert, V., Bonaglia, S., Mörth, C.-M., Muchowski, J., . . . Sköld, M. (2021). Physical Disturbance by Bottom Trawling Suspends Particulate Matter and Alters Biogeochemical Processes on and Near the Seafloor. Frontiers in Marine Science, 8, Article ID 683331.
Open this publication in new window or tab >>Physical Disturbance by Bottom Trawling Suspends Particulate Matter and Alters Biogeochemical Processes on and Near the Seafloor
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2021 (English)In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 8, article id 683331Article in journal (Refereed) Published
Abstract [en]

Bottom trawling is known to affect benthic faunal communities but its effects on sediment suspension and seabed biogeochemistry are less well described. In addition, few studies have been carried out in the Baltic Sea, despite decades of trawling in this unique brackish environment and the frequent occurrence of trawling in areas where hypoxia and low and variable salinity already act as ecosystem stressors. We measured the physical and biogeochemical impacts of an otter trawl on a muddy Baltic seabed. Multibeam bathymetry revealed a 36 m-wide trawl track, comprising parallel furrows and sediment piles caused by the trawl doors and shallower grooves from the groundgear, that displaced 1,000 m3 (500 t) sediment and suspended 9.5 t sediment per km of track. The trawl doors had less effect than the rest of the gear in terms of total sediment mass but per m2 the doors had 5× the displacement and 2× the suspension effect, due to their greater penetration and hydrodynamic drag. The suspended sediment spread >1 km away over the following 3–4 days, creating a 5–10 m thick layer of turbid bottom water. Turbidity reached 4.3 NTU (7 mgDW L–1), 550 m from the track, 20 h post-trawling. Particulate Al, Ti, Fe, P, and Mn were correlated with the spatio-temporal pattern of suspension. There was a pulse of dissolved N, P, and Mn to a height of 10 m above the seabed within a few hundred meters of the track, 2 h post-trawling. Dissolved methane concentrations were elevated in the water for at least 20 h. Sediment biogeochemistry in the door track was still perturbed after 48 h, with a decreased oxygen penetration depth and nutrient and oxygen fluxes across the sediment-water interface. These results clearly show the physical effects of bottom trawling, both on seabed topography (on the scale of km and years) and on sediment and particle suspension (on the scale of km and days-weeks). Alterations to biogeochemical processes suggest that, where bottom trawling is frequent, sediment biogeochemistry may not have time to recover between disturbance events and elevated turbidity may persist, even outside the trawled area.

Keywords
otter trawl, sediment suspension, turbidity, biogeochemistry, disturbance, nutrients, oxygen, multibeam echo-sounding
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-200955 (URN)10.3389/fmars.2021.683331 (DOI)000729031300001 ()
Available from: 2022-01-14 Created: 2022-01-14 Last updated: 2022-01-14Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0541-0781

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