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"Blomqvist, Mats"
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Long‐term recovery and food web response of benthic macrofauna following cessation of bottom trawling in a marine protected area
by
Sköld, Mattias
,
Bradshaw, Clare
,
Börjesson, Patrik
in
Abundance
,
Agricultural and Veterinary Sciences
,
Andra lantbruksrelaterade vetenskaper
2025
The understanding of the depletion of species and communities and recovery following the reduction of pressures is fundamental in conservation biology. The impact of bottom trawl fisheries on benthic communities has been well studied, but there are few studies of the long‐term recovery after the cessation of bottom trawling. Here we followed the recovery of the benthic macrofaunal community over 12 years in a large (426 km2) no‐take zone (NTZ) area in the south Kattegat after demersal trawling was stopped and compared it to a nearby area where trawling continued. Using multivariate analyses, we found shifts in the community composition. Two species of burrowing brittle stars, Amphiura filiformis and Amphiura chiajei, dominated abundance and biomass and decreased in the closed area (abundance effect size A. filiformis 48%; A. chiajei 45%). In parallel, there was an increase in benthivore flatfish. Stomach contents of the dominating flatfishes matched the availability of benthic prey taxa, and brittle stars were the staple food. Food web effects thus appear to override the decrease in mortality of the dominant macrofauna caused by the cessation of trawling in the NTZ. The recovery response in the species community in the NTZ correlated with the pattern in community composition along a chronic bottom trawling intensity gradient in the same area. This indicates that the recovery of the benthic community is not random but follows a successional pattern that can also be observed in chronic states of disturbance from bottom trawling. This is important information from the perspective of management efforts to restore marine ecosystems from the impact of bottom trawl fisheries, as it indicates that reduced effort may lead to predictable recovery. The study is unique in covering how the benthic community has responded to a long‐term fishing closure in one of Europe's largest strictly marine protected areas. We find the recovery of species and strong links to the food web in the response to protection.
Journal Article
Scale-dependent influence of environmental variables on species distribution: a case study on five coastal benthic species in the Baltic Sea
by
Nyström Sandman, Antonia
,
Kautsky, Hans
,
Wikström, Sofia A.
in
animals
,
Aquatic plants
,
Baltic Sea
2013
Statistical modelling can be used to relate biological survey data to environmental factors, thereby providing a basis for predictive mapping of species or communities. Although environmental variables vary and influence biota at different scales, models are often fitted without discussion of how scale dependency influences the results. In this study, we analysed the relative importance of environmental factors for the distribution of aquatic species as a function of extent, using data on the cover of five common benthic species (four macrophytes and one animal), from 1731 sites along the Swedish Baltic Sea coast. We modelled the cover and distribution of the five species in relation to salinity, depth, slope, wave exposure and substrate in scale steps from 25 to 1500 km, and analysed the relative contribution of the environmental variables to each species model. The average total deviance explained by the models was generally quite high, and decreased with increasing scale for all macrophyte species, while it increased for the animal, the Baltic Sea blue mussel Mytilus edulis. The relative contribution of different environmental variables changed with scale, and responses also differed between species. The average contribution of salinity increased for all species when moving from local to Baltic Sea scale, and for the Baltic Sea blue mussel it was the single most important factor at the Baltic Sea scale. The average contribution of depth decreased with increasing scale for all species. However, regardless of scale, depth was the most important environmental factor to explain the distribution of all but one of the investigated macrophyte species. This shows that fine scale predictor variables can be of major importance also for species distribution models covering large areas.
Journal Article
A General-Purpose Biotic Index to Measure Changes in Benthic Habitat Quality across Several Pressure Gradients
by
Bernard, Guillaume
,
Grall, Jacques
,
Van Hoey, Gert
in
Anthropogenic factors
,
Bathyal-benthic zone
,
Benthic fauna
2021
Realistic assessments of the ecological status of benthic habitats, as requested by European directives such as the Water Framework Directive and the European Marine Strategy Framework Directive, require biotic indices capable of detecting anthropogenic impact without having preliminary knowledge of the occurring pressures. In this context, a new general-purpose biotic index (GPBI) based on the deviation of benthic macrofauna community composition and structure from a valid reference (i.e., good ecological status) is proposed. GPBI is based on the assumption that as a site becomes impacted by a pressure, the most sensitive species are the first to disappear, and that stronger impacts lead to more important losses. Thus, it explicitly uses the within-species loss of individuals in the tested station in comparison to one or several reference stations as the basis of ecological status assessment. In this study, GPBI is successfully used in four case studies considering the impact of diversified pressures on benthic fauna: (1) maerl extraction in the northern Bay of Biscay, (2–3) dredging and trawling in the North Sea, and (4) hypoxic events at the seafloor in the Gullmarfjord. Our results show that GPBI was able to efficiently detect the impact of the different physical disturbances as well as that of hypoxia and that it performs better than commonly used pressure-specific indices (M-AMBI and TDI). Signal detection theory was used to propose a sound good/moderate ecological quality status boundary, and recommendations for future monitoring are also provided based on the reported performance of GPBI.
Journal Article
Effects of chronic bottom trawling on soft-seafloor macrofauna in the Kattegat
by
Bastardie, Francois
,
Agrenius, Stefan
,
Jonsson, Patrik
in
Amphiura filiformis
,
amphiura-filiformis echinodermata
,
communities
2018
Impact studies of chronic bottom trawling aiming to reveal long-term effects on benthic organisms are often hampered by the lack of comparable untrawled conditions and the difficulty in assessing the spatial distribution of trawling intensity. We sampled soft-seafloor macrofauna over a precise trawling gradient in the Kattegat using hourly vessel monitoring systems and logbooks. The gradient included the establishment of a marine protected area (MPA), where trawling intensity declined sharply to zero. Our results show shifts in the macrofauna assemblage and non-linear responses, with decreases in the number and diversity of species at low to medium trawling intensities. The benthic community was dominated by burrowing brittle stars, of which one species, Amphiura chiajei, increased in abundance from low to medium trawling intensities. We interpret this positive response to increasing trawling intensities as a consequence of reduction in predation by benthivorous flatfish and Norway lobster Nephrops norvegicus, which are significant catches of the fishery. The response was supported by a corresponding trend towards lower abundance of the dominating brittle stars following enforcement of the MPA and presumably an increase in benthivore density and predation pressure within the MPA. We conclude that chronic bottom trawling reduces diversity and may boost the abundances of species resistant to bottom trawling. The results emphasize the need to consider food web effects when assessing the impact of bottom trawling.
Journal Article
Cover of coastal vegetation as an indicator of eutrophication along environmental gradients
by
Carstensen, Jacob
,
Krause-Jensen, Dorte
,
Wikström, Sofia A.
in
Aquatic plants
,
Baltic Sea
,
Biodiversity
2016
Coastal vegetation communities are important for primary production, biodiversity, coastal protection, carbon and nutrient cycling which, in combination with their sensitivity to eutrophication, render them potential indicators of environmental status for environmental policies like the EU Water and Marine Strategy Framework Directives. We evaluated one potential indicator for coastal vegetation, the cumulative cover at depths where the vegetation is light limited, by investigating its response to eutrophication along gradients in natural conditions. We used a large data set covering the Swedish coastline, spanning broad gradients in nutrient level, water clarity, seabed substrate, physical exposure and climate in addition to a salinity gradient from 0.5 to 30.5. Macroalgal cover increased significantly along gradients of declining nutrient concentration and increasing water clarity when we had accounted for diver effects, spatio-temporal sampling variability, salinity gradients, wave exposure and latitude. The developed empirical model explained 79% of the variation in algal cover across 130 areas. Based on this, we identified macroalgal cover as a promising indicator across the Baltic Sea, Kattegat and Skagerrak. A parallel analysis of soft-substrate macrophytes similarly identified significant increases in cover with decreasing concentrations of total nitrogen and increasing salinity, but the resulting empirical model explained only 52% of the variation in cover, probably due to the spatially more variable nature of soft-substrate vegetation. The identified general responses of vegetation cover to gradients of eutrophication across wide ranges in environmental settings may be useful for monitoring and management of marine vegetation in areas with strong environmental gradients.
Journal Article
Substantial changes in the depth distributions of benthic invertebrates in the eastern Kattegat since the 1880s
by
Rolandsson, Johan
,
Josefson, Alf B.
,
Loo, Lars‐Ove
in
Benthic environment
,
Benthic fauna
,
bottom communities
2018
Bottom trawling and eutrophication are well known for their impacts on the marine benthic environment in the last decades. Evaluating the effects of these pressures is often restricted to contemporary benthic data, limiting the potential to observe change from an earlier (preimpact) state. In this study, we compared benthic species records from 1884 to 1886 by CGJ Petersen with recent data to investigate how benthic invertebrate species in the eastern Kattegat have changed since preimpact time. The study shows that species turnover between old and recent times was high, ca. 50%, and the species richness in the investigation area was either unchanged or higher in recent times, suggesting no net loss of species. Elements of metacommunity structure analysis of datasets from the 1880s, 1990s, and 2000s revealed a clear change in the depth distribution structure since the 1880s. The system changed from a Quasi‐nested/Random pattern unrelated to depth in the 1880s with many species depth ranges over a major part of the studied depth interval, to a Clementsian pattern in recent times strongly positively correlated with depth. Around 30% of the 117 species recorded both in old and in recent times, including most trawling‐sensitive species, that is large, semiemergent species, showed a decrease in maximal depth of occurrence from the deeper zone fished today to the shallower unfished zone, with on average 20 m. Concurrently, the species category remaining in the fished zone was dominated by species less sensitive to bottom trawling like infauna polychaetes and small‐sized Peracarida crustaceans, most likely with short longevity. The depth interval and magnitude of the changes in depth distribution and the changes in species composition indicate impacts from bottom trawling rather than eutrophication. Furthermore, the high similarity of results from the recent datasets 10 years apart suggests chronic impact keeping the system in an altered state. Because impacts of several threats to marine benthic habitats in recent times in eastern Kattegat are water depth dependent, we ask the question whether benthic invertebrate species depth distributions have changed since preimpact times in the late 1800s. EMS analyses suggest dramatic change in depth distribution structure in the eastern Kattegat from a quasi‐nested/random structure with great overlaps between species distributions in the 1880s, to Clementsian patterns in the 1990s and 2000s strongly correlated with water depth. These results suggest that some factor(s) has reinforced the influence of water depth on species distributions in the Kattegat since hypothetically pristine times and underpin suggestions that chronic fishing disturbance has changed benthic community structure over wide areas of the shelf seas using a temporal reference.
Journal Article
Trawling-induced change in benthic effect trait composition – A multiple case study
by
Sciberras, Marija
,
Smith, Christopher J.
,
Beauchard, Olivier
in
Analytical methods
,
benthic invertebrate
,
Benthos
2023
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. To this end, we use 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). 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. 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 context of trawl fisheries impact on the sea floor.
Journal Article
Exploring caregivers’ experiences of Kangaroo Mother Care in Bangladesh: A descriptive qualitative study
2023
Kangaroo Mother Care (KMC) is an evidence-based intervention recommended by the World Health Organization (WHO) to reduce preterm mortality and morbidity. The aim of this study was to explore caregivers' experiences of providing KMC in hospital settings and after continuation at home in Bangladesh in order to assess enablers and barriers to optimal implementation.
Interviews with fifteen caregivers were conducted using an interview guide with semi-structured questions in August 2019 and March 2020. Convenience sampling was used to select hospitals and participants for the study. The inclusion criteria were being a caregiver currently performing KMC in the hospital or having been discharged one week earlier from the KMC ward. The interviews were audio recorded, transcribed verbatim, and translated. The data were analyzed using thematic analysis with an inductive approach.
Three themes were identified as regards the caregivers' experiences of providing KMC: conducive conditions, an empowering process, and suboptimal implementation. The results showed that there are supporting circumstances for caregivers performing KMC in Bangladesh, including social support structures and positive attitudes to the method of care. It also appeared that the caregivers felt strengthened in their roles as caregivers by learning and performing KMC. However, the implementation of KMC was suboptimal due to late initiation of KMC, difficulties with keeping the baby skin-to-skin, and pain after cesarean section hampering skin-to-skin practice.
The social and cultural conditions for the caregivers to perform KMC as well as the empowerment the parents felt in their roles as caregivers when performing KMC are facilitating factors for this method of care. Initial separation and late initiation of KMC, as well as disregard for the mothers' needs for care and support, were barriers to optimal practice leading to missed opportunities. These facilitators and barriers need to be addressed in order to succeed in scaling up the national KMC program.
Journal Article
Microbial lipid production from crude glycerol and hemicellulosic hydrolysate with oleaginous yeasts
by
Sandgren, Mats
,
Blomqvist, Johanna
,
Passoth, Volkmar
in
Biodiesel fuels
,
Biofuels
,
Bioreactors
2021
Background Crude glycerol (CG) and hemicellulose hydrolysate (HH) are low—value side-products of biodiesel transesterification and pulp—and paper industry or lignocellulosic ethanol production, respectively, which can be converted to microbial lipids by oleaginous yeasts. This study aimed to test the ability of oleaginous yeasts to utilise CG and HH and mixtures of them as carbon source. Results Eleven out of 27 tested strains of oleaginous yeast species were able to grow in plate tests on CG as sole carbon source. Among them, only one ascomycetous strain, belonging to Lipomyces starkeyi, was identified, the other 10 strains were Rhodotorula spec. When yeasts were cultivated in mixed CG/ HH medium, we observed an activation of glycerol conversion in the Rhodotorula strains, but not in L. starkeyi. Two strains—Rhodotorula toruloides CBS 14 and Rhodotorula glutinis CBS 3044 were further tested in controlled fermentations in bioreactors in different mixtures of CG and HH. The highest measured average biomass and lipid concentration were achieved with R. toruloides in 10% HH medium mixed with 55 g/L CG—19.4 g/L and 10.6 g/L, respectively, with a lipid yield of 0.25 g lipids per consumed g of carbon source. Fatty acid composition was similar to other R. toruloides strains and comparable to that of vegetable oils. Conclusions There were big strain differences in the ability to convert CG to lipids, as only few of the tested strains were able to grow. Lipid production rates and yields showed that mixing GC and HH have a stimulating effect on lipid accumulation in R. toruloides and R. glutinis resulting in shortened fermentation time to reach maximum lipid concentration, which provides a new perspective on converting these low-value compounds to microbial lipids.
Journal Article
Oleaginous yeasts respond differently to carbon sources present in lignocellulose hydrolysate
by
Brandenburg, Jule
,
Sandgren, Mats
,
Blomqvist, Johanna
in
Accumulation
,
Acetic acid
,
Alternative fuels
2021
Background Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By unravelling the diversity of lipid accumulation physiology in different oleaginous yeasts grown on the various carbon sources present in lignocellulose hydrolysate (LH), new targets for optimisation of lipid accumulation can be identified. Monitoring lipid formation over time is essential for understanding lipid accumulation physiology. This study investigated lipid accumulation in a variety of oleaginous ascomycetous and basidiomycetous strains grown in glucose and xylose and followed lipid formation kinetics of selected strains in wheat straw hydrolysate (WSH). Results Twenty-nine oleaginous yeast strains were tested for their ability to utilise glucose and xylose, the main sugars present in WSH. Evaluation of sugar consumption and lipid accumulation revealed marked differences in xylose utilisation capacity between the yeast strains, even between those belonging to the same species. Five different promising strains, belonging to the species Lipomyces starkeyi, Rhodotorula glutinis, Rhodotorula babjevae and Rhodotorula toruloides, were grown on undiluted wheat straw hydrolysate and lipid accumulation was followed over time, using Fourier transform-infrared (FTIR) spectroscopy. All five strains were able to grow on undiluted WSH and to accumulate lipids, but to different extents and with different productivities. R. babjevae DVBPG 8058 was the best-performing strain, accumulating 64.8% of cell dry weight (CDW) as lipids. It reached a culture density of 28 g/L CDW in batch cultivation, resulting in a lipid content of 18.1 g/L and yield of 0.24 g lipids per g carbon source. This strain formed lipids from the major carbon sources in hydrolysate, glucose, acetate and xylose. R. glutinis CBS 2367 also consumed these carbon sources, but when assimilating xylose it consumed intracellular lipids simultaneously. Rhodotorula strains contained a higher proportion of polyunsaturated fatty acids than the two tested Lipomyces starkeyi strains. Conclusions There is considerable metabolic diversity among oleaginous yeasts, even between closely related species and strains, especially when converting xylose to biomass and lipids. Monitoring the kinetics of lipid accumulation and identifying the molecular basis of this diversity are keys to selecting suitable strains for high lipid production from lignocellulose.
Journal Article