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dos Anjos, T. B., Abel, S., Lindehoff, E., Bradshaw, C. & Sobek, A. (2023). Assessing the effects of a mixture of hydrophobic contaminants on the algae Rhodomonas salina using the chemical activity concept. Aquatic Toxicology, 265, Article ID 106742.
Open this publication in new window or tab >>Assessing the effects of a mixture of hydrophobic contaminants on the algae Rhodomonas salina using the chemical activity concept
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2023 (English)In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 265, article id 106742Article in journal (Refereed) Published
Abstract [en]

The production and release of chemicals from human activities are on the rise. Understanding how the aquatic environment is affected by the presence of an unknown number of chemicals is lacking. We employed the chemical activity concept to assess the combined effects of hydrophobic organic contaminants on the phyto-plankton species Rodomonas salina. Chemical activity is additive, and refers to the relative saturation of a chemical in the studied matrix. The growth of R. salina was affected by chemical activity, following a chemical activity-response curve, resulting in an Ea50 value of 0.078, which falls within the baseline toxicity range observed in earlier studies. The chlorophyll a content exhibited both increases and decreases with rising chemical activity, with the increase possibly linked to an antioxidant mechanism. Yet, growth inhibition provided more sensitive and robust responses compared to photosynthesis-related endpoints; all measured endpoints correlated with increased chemical activity. Growth inhibition is an ecologically relevant endpoint and integrates ther-modynamic principles such as membrane disruption. Our study utilized passive dosing, enabling us to control exposure and determine activities in both the medium and the algae. The concept of chemical activity and our results can be extended to other neutral chemical groups as effects of chemical activity remain independent of the mixture composition.

Keywords
Chemical activity, Algae toxicity test, Polycyclic aromatic hydrocarbons, Mixture toxicity, Passive dosing, Exposure confirmation
National Category
Biological Sciences Basic Medicine
Identifiers
urn:nbn:se:su:diva-224641 (URN)10.1016/j.aquatox.2023.106742 (DOI)001113530200001 ()37977012 (PubMedID)2-s2.0-85177769467 (Scopus ID)
Available from: 2023-12-19 Created: 2023-12-19 Last updated: 2023-12-19Bibliographically approved
Corell, H., Bradshaw, C. & Sköld, M. (2023). Sediment suspended by bottom trawling can reduce reproductive success in a broadcast spawning fish. Estuarine, Coastal and Shelf Science, 282, Article ID 108232.
Open this publication in new window or tab >>Sediment suspended by bottom trawling can reduce reproductive success in a broadcast spawning fish
2023 (English)In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 282, article id 108232Article in journal (Refereed) Published
Abstract [en]

Suspended sediment adheres to pelagic fish eggs, affecting their buoyancy. In the stratified southern Baltic Sea, eggs of the Eastern cod depend on neutral buoyancy in the “reproductive volume” (RV) (approx. >11 salinity and >2 ml O2/L) for successful hatching. With increased suspended sediment concentrations (SSC), eggs risk sinking out of the RV into deeper, unfavourable conditions. Bottom trawling, which increases SSC, has been intense around the Eastern cod spawning ground. We modelled the transport of sediment suspended from trawling at this spawning ground to estimate the degree to which eggs could be affected by increased SSC. SSC >1 mg/L above background levels was found 3 km away, one trawl track subjecting a water volume equivalent to 0.01% of the RV to this excess SSC for >12 h. At this excess SSC, it would take c. 6 d for an egg to sink out into unfavourable conditions; insufficient time for it to become a larva. Extrapolating to real bottom trawling intensities in the area of the RV where suspension is highest showed that a water volume equivalent to half the RV experiences excess turbidity of >1 mg/L for c. 24 h during a year. However, fishing effort is heterogeneous; spatio-temporal overlap between trawling and the RV will enhance the duration and/or frequency of turbidity in the spawning area, affecting a higher fraction of the eggs than the model predicts. We conclude that bottom trawling at this spawning ground could decrease cod's reproductive success through increased SSC. Such effects are likely in populations of other fish with pelagic eggs that spawn at trawling grounds.

National Category
Ecology
Research subject
Marine Biology
Identifiers
urn:nbn:se:su:diva-222904 (URN)10.1016/j.ecss.2023.108232 (DOI)001017172600001 ()
Funder
Swedish Research Council Formas, 2017-00866
Available from: 2023-10-17 Created: 2023-10-17 Last updated: 2024-01-02Bibliographically approved
Beauchard, O., Bradshaw, C., Bolam, S., Tiano, J., Garcia, C., De Borger, E., . . . Sciberras, M. (2023). Trawling-induced change in benthic effect trait composition – A multiple case study. Frontiers in Marine Science, 10, Article ID 1303909.
Open this publication in new window or tab >>Trawling-induced change in benthic effect trait composition – A multiple case study
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2023 (English)In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 10, article id 1303909Article in journal (Refereed) Published
Abstract [en]

Introduction: The importance of the response-effect trait dichotomy in marine benthic ecology has garnered recent attention. Response traits, characterising species responses to environmental variations, have been a dominant focus in the development of ecological indicators for ecosystem health assessment. In contrast, effect traits, expressing effects of organism activities on the ecosystem, still do not benefit from an equal interest in spite of the complementary facet that they provide to complete our understanding of functional diversity and ecosystem vulnerability. In this study, we explore the consequences of disturbance by bottom trawl fisheries on benthic effect trait composition.

Methods: To this end, we used different contexts of environmental and trawling conditions from thirteen case studies in European waters and apply the same analytical procedure to derive a gradient that solely account for trawling-induced disturbance (Partial RLQ analysis).

Results: Bottom trawling was found to be a selective force of benthic effect trait composition in a majority of case studies. In general, tube-dwelling species were more typical of low trawling frequencies, whereas deep burrowing species were more resistant at high trawling frequencies. Although we report significantly deleterious effects of trawling on benthic ecosystem functions, the effect trait pattern along the gradient was never related to life span, a key response trait generally assumed to express recoverability following disturbance. Furthermore, we show that trends in species multi-functionality and community functional diversity can be negative or positive along the trawling intensity gradient.

Discussion: We discuss the relevance of these results in light of recent developments in the framework of response and effect trait dichotomy, and provide guidelines of trait data analysis in the context of trawl fisheries impact on the sea floor. Our findings emphasize the importance of fundamental concepts from functional ecology in this context and represent a first step toward an assessment of trawling effect more oriented on benthos-mediated biogeochemical processes.

Keywords
benthic invertebrate, effect trait, ecosystem function, bottom trawling, vulnerability, functional niche breadth, functional diversity
National Category
Ecology
Identifiers
urn:nbn:se:su:diva-225772 (URN)10.3389/fmars.2023.1303909 (DOI)001136472400001 ()2-s2.0-85181652988 (Scopus ID)
Available from: 2024-01-22 Created: 2024-01-22 Last updated: 2024-01-22Bibliographically approved
Liénart, C., Cirtwill, A. R., Hedgespeth, M. L. & Bradshaw, C. (2022). A sprinkling of gold dust: Pine pollen as a carbon source in Baltic Sea coastal food webs. Limnology and Oceanography, 67(1), 53-65
Open this publication in new window or tab >>A sprinkling of gold dust: Pine pollen as a carbon source in Baltic Sea coastal food webs
2022 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 67, no 1, p. 53-65Article in journal (Refereed) Published
Abstract [en]

Allochthonous subsidies to marine ecosystems have mainly focused on biogeochemical cycles, but there has also been recent interest in how terrestrial carbon (C) influences marine food webs. In the Baltic Sea, pine (Pinus sylvestris) pollen is found in large amounts in shallow bays in early summer. Pollen is a significant C-source in freshwater ecosystems and may also be important in coastal food webs. We examined the consumption of pollen and autochthonous resources by benthic invertebrates in shallow bays of the Baltic Sea. We used stable isotopes to estimate diets and reconstructed consumer-resource networks (food webs) for grazers and particulate organic matter (POM)-feeders to compare how these different guilds used pollen. We found that P. sylvestris pollen was consumed in small amounts by a variety of animals and in some cases made up a sizeable proportion of invertebrates' diets. However, invertebrates generally depended less on pollen than other resources. The degree of pollen consumption was related to feeding traits, with generalist invertebrate grazers consuming more pollen (> 10% of diet) than the more specialist POM-feeders (< 5% of diet contributed by pollen). POM-feeders may consume additional microbially-degraded pollen which was not identifiable in our model. We suggest that pollen is a small but substantial allochthonous C-source in shallow bay food webs of the Baltic Sea, with the potential to affect the dynamics of these ecosystems. 

National Category
Biological Sciences
Identifiers
urn:nbn:se:su:diva-200018 (URN)10.1002/lno.11974 (DOI)000717970400001 ()
Available from: 2021-12-22 Created: 2021-12-22 Last updated: 2022-01-25Bibliographically approved
Bradshaw, C. (2022). Are There Ecosystem-Relevant Endpoints for Measuring Radiation Impacts?. In: Michael D. Wood; Carmel E. Mothersill; Gohar Tsakanova; Tom Cresswell; Gayle E. Woloschak (Ed.), Biomarkers of Radiation in the Environment: Robust Tools for Risk Assessment. Paper presented at NATO Advanced Research Workshop on 'Biomarkers of Radiation in the Environment: Robust Tools for Risk Assessment (BRITE)’, (pp. 223-243). Dordrecht: Springer
Open this publication in new window or tab >>Are There Ecosystem-Relevant Endpoints for Measuring Radiation Impacts?
2022 (English)In: Biomarkers of Radiation in the Environment: Robust Tools for Risk Assessment / [ed] Michael D. Wood; Carmel E. Mothersill; Gohar Tsakanova; Tom Cresswell; Gayle E. Woloschak, Dordrecht: Springer, 2022, p. 223-243Conference paper, Published paper (Refereed)
Abstract [en]

Ecosystem-level effects of stress are the net result of the direct effects of the stressor and indirect effects caused by altered interactions between organisms and between biotic and abiotic components of the environment. Measuring impacts of any single stressor at the ecosystem level means acknowledging, and accounting for, a number of simultaneously acting processes.

It is therefore highly unlikely that there are radiation-specific responses at an ecosystem level. In the field, ecosystem-level responses will be the net result of the effects of the various radionuclides, other contaminants, environmental conditions and species interactions. However, this does not mean that we should not attempt to measure ecosystem-level endpoints, but in order to pinpoint the relative contribution of radiation in this multi-factorial situation, robust sampling and statistics and a sound ecological foundation is required.

What, then, are ecosystem-relevant endpoints? They include those that describe ecosystem structure and function and sometimes also the services an ecosystem provides to humans. Quantifying ecosystem effects may thus include measuring species composition, abundance, biodiversity, food web complexity and connectivity, habitat complexity (ie. aspects of ecosystem structure) and production, decomposition, pollination, functional or trait diversity (ie. ecosystem function). Many of these may also be used to estimate impacts on ecosystem services (e.g., provision of food, carbon storage). Many are by necessity proxy measures which we assume reflect the state of the ecosystem, since overall ecosystem condition is very hard to quantify. However, in risk assessment these proxies are sometimes combined into general measures of ‘ecological status’ and in ecosystem science, various metrics are used as integrative measures of the vulnerability or resilience of the ecosystem.

In this paper, I give an overview of the ways we can address and measure ecosystem-relevant and ecosystem-level endpoints in science and risk assessment, including community structure and function, ecological traits, ecosystem processes, ecological network metrics, ecological integrity and ecosystem services. I draw on examples from ecosystem science, stress ecology, ecotoxicology and environmental impact and risk assessment and discuss how these can inform assessment of radiation impacts.

Place, publisher, year, edition, pages
Dordrecht: Springer, 2022
Series
NATO Science for Peace and Security Series A: Chemistry and Biology (NAPSA), ISSN 1874-6489, E-ISSN 1874-6527
National Category
Biological Sciences Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-209806 (URN)10.1007/978-94-024-2101-9_14 (DOI)2-s2.0-85127871808 (Scopus ID)978-94-024-2100-2 (ISBN)978-94-024-2101-9 (ISBN)
Conference
NATO Advanced Research Workshop on 'Biomarkers of Radiation in the Environment: Robust Tools for Risk Assessment (BRITE)’,
Available from: 2022-10-07 Created: 2022-10-07 Last updated: 2022-10-07Bibliographically approved
Holmerin, I., Svensson, F., Hirawake, T., Ishimaru, T., Ito, Y., Kanda, J., . . . Bradshaw, C. (2022). Benthic food web structures as an explanation for prolonged ecological half-life of Cs-137 in flatfish species in the Fukushima coastal area. Journal of Environmental Radioactivity, 246, Article ID 106844.
Open this publication in new window or tab >>Benthic food web structures as an explanation for prolonged ecological half-life of Cs-137 in flatfish species in the Fukushima coastal area
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2022 (English)In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 246, article id 106844Article in journal (Refereed) Published
Abstract [en]

After the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP), Japan, in March 2011, Cs-137 in demersal fish had, between 2011 and 2015, a prolonged ecological half-life when compared to pelagic fish. Using stable isotope mixing models combined with gut content analysis and Cs-137 activity concentrations, this study investigated the hypothesis that an unexplored food web structure could be a contributing factor explaining the ecological half-life of Cs-137 in benthic flatfish. Benthic invertebrates and demersal fish species sampled in 2015 still showed Cs-137 activity concentrations higher than pre-accident. The mixing models of stable N and C isotopes and gut content analysis identified deposit, suspension and filter feeders to be the main flatfish food items in the benthos. There was a significant correlation between Cs-137 activity concentrations in specific flatfish species and benthos, and between Cs-137 activity concentrations in benthos and surface sediment. The results of this study partially explained the Cs-137 activity concentrations found in the analysed demersal fish, suggesting that the benthos can be a continuous source of Cs-137 for the demersal fish during this period of time. Extending monitoring programmes to include invertebrates that are not food species for humans would greatly improve our ability to understand the role of trophic transfer pathways and take appropriate management actions.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-204560 (URN)10.1016/j.jenvrad.2022.106844 (DOI)000775887200003 ()35202906 (PubMedID)2-s2.0-85125482874 (Scopus ID)
Available from: 2022-05-10 Created: 2022-05-10 Last updated: 2022-06-15Bibliographically approved
Morys, C., Brüchert, V. & Bradshaw, C. (2021). Impacts of bottom trawling on benthic biogeochemistry in muddy sediments: Removal of surface sediment using an experimental field study. Marine Environmental Research, 169, Article ID 105384.
Open this publication in new window or tab >>Impacts of bottom trawling on benthic biogeochemistry in muddy sediments: Removal of surface sediment using an experimental field study
2021 (English)In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 169, article id 105384Article in journal (Refereed) Published
Abstract [en]

Experimental benthic dredging was conducted in an unfished, muddy area in the Baltic Proper to mimic the impact of trawling by removing surface sediment, with a focus on benthic biogeochemical processes. Sediment cores were taken on the track and compared to undisturbed controls. Benthic fluxes were immediately affected and an upward shift in pore water DIC profiles was detected. The time needed for the sediment to readjust to a new biogeochemical state seemed to be nutrient-specific. Sediment properties (profiles of chlorophyll, organic carbon and water content) were found to change significantly. Macrofauna was removed completely by the dredge pointing out the potential loss of highly valuable functions that are associated with them. In the Baltic Sea, in areas which were previously the most heavily fished, the frequency of trawling may have left little time for readjustment and potentially kept the seabed in a permanent state of transient biogeochemical cycling.

Keywords
Baltic sea, Benthos, Environmental impact, Disturbance, macrofauna, Nutrient fluxes, Organic and dissolved inorganic carbon, Chlorophyll, water content
National Category
Biological Sciences
Identifiers
urn:nbn:se:su:diva-197351 (URN)10.1016/j.marenvres.2021.105384 (DOI)000675833400005 ()34233256 (PubMedID)
Available from: 2021-09-30 Created: 2021-09-30 Last updated: 2022-02-25Bibliographically approved
Bruce, P., Bradshaw, C., Ohlsson, Y., Sobek, A. & Christiernsson, A. (2021). Inconsistencies in How Environmental Risk Is Evaluated in Sweden for Dumping Dredged Sediment at Sea. Frontiers in Marine Science, 8, Article ID 755443.
Open this publication in new window or tab >>Inconsistencies in How Environmental Risk Is Evaluated in Sweden for Dumping Dredged Sediment at Sea
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2021 (English)In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 8, article id 755443Article in journal (Refereed) Published
Abstract [en]

Millions of tons of dredged sediment are dumped at sea annually. International conventions limit dumping when there is a risk of adverse ecological effects, for example if the sediment is contaminated. However, the perception of risk differs substantially among stakeholders and in Sweden there is a lack of guidelines for how to address such risk. In the current study, we examined exemptions to the Swedish ban on dumping at sea, to explore the extent of dumping and how ecological aspects were considered in the evaluation of risks. We analyzed data from all cases granted exemption by county administrative boards and all court cases considering exemption to the ban from the beginning of 2015 to June 2020. We found that while dumping is the least common alternative management method for dredged sediment in total number of cases (98/792), dumping is the main method in terms of volume (30.8/38.2 million m3). When considering exemptions, the courts mainly evaluated the risk of exposure to contaminants and resuspended sediment for the environment adjacent to the dumpsite. The risks from contaminants were characterized based on various lines of reasoning, mainly relying on reference values not based on a scientific correlation to environmental risk. We argue that the evaluations were not in line with current regulations and international conventions as they insufficiently accounted for the ecotoxicological risk of the dumped sediment. These issues are potentially similar in other Baltic Sea countries, where there is a similar dependency on binary chemical limit values.

Keywords
sediment, contaminant, risk assessment, risk evaluation, risk management, regulation, sea dumping
National Category
Environmental Sciences
Research subject
Marine Ecotoxicology
Identifiers
urn:nbn:se:su:diva-195035 (URN)10.3389/fmars.2021.755443 (DOI)000716142000001 ()
Available from: 2021-08-02 Created: 2021-08-02 Last updated: 2021-12-09Bibliographically 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
Bruce, P., Sobek, A., Ohlsson, Y. & Bradshaw, C. (2021). Risk assessments of contaminated sediments from the perspective of weight of evidence strategies – a Swedish case study. Human and Ecological Risk Assessment, 27(5), 1366-1387
Open this publication in new window or tab >>Risk assessments of contaminated sediments from the perspective of weight of evidence strategies – a Swedish case study
2021 (English)In: Human and Ecological Risk Assessment, ISSN 1080-7039, E-ISSN 1549-7860, Vol. 27, no 5, p. 1366-1387Article in journal (Refereed) Published
Abstract [en]

Several countries currently lack common recommendations specific to Ecological Risk Assessment (ERA) of contaminated sediments and stakeholders report inconsistencies between currently used approaches. The objective of this study was to provide an increased understanding of how ERAs of contaminated sediments are conducted in comparison to established guidelines. For this, we use Sweden as a case study and compare seven ERAs with four internationally established strategies. Our results indicate that contaminant concentrations receive a comparatively high weight, despite a lack of appropriate benchmarks; toxicity measurements are uncommon, while routine in established strategies; and the integration and interpretation of results lack transparency. We identify three areas that may help improve the practice of ERAs: a common approach to benchmarks, recommendations for how to assess toxic effects, and a common approach for integrating and interpreting results.

Keywords
Ecological risk assessment, weight of evidence, contaminated sediment, management, guidelines
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-186880 (URN)10.1080/10807039.2020.1848414 (DOI)000592023200001 ()
Available from: 2020-11-25 Created: 2020-11-25 Last updated: 2022-02-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8421-2750

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