Poster abstracts 2023

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Monitoring in Aquaculture is Win-Win-Win-Win
Anders Tengberg1, Inger Graves1, Jarle Heltne1, Reidun Dalland1

As European aquaculture is changing from small family run businesses to large industrial companies the requirements for efficient automatized remotely controlled operations has increased and so has the demands from governments to minimize the environmental impact. Efficient production requires constant monitoring with sensors and cameras in and around the facilities and high speed data connections to shore. This poster gives examples of monitoring at aquaculture sites and how the EuroSea project has contributed to this with two buoy platforms that serves multiple purposes: for Fish Production that becomes more efficient, For the Environment that is less impacted, For the Fish that has better living conditions and for Science that benefits from the data to improve prediction models for e.g. heat waves, oxygen deficit, jelly fish ”invasions” and toxic algae blooms.

1Aanderaa-Xylem, Bergen, Norway

Can artificial reefs help the declining cod populations in the Baltic Sea?
Josefine Larsson1, Helena L Filipsson2, Hampus Söderberg3, Hannes Kindeberg3, Anders Tengberg4,5, Karl Ljung2 , Anders Persson2

The cod in the Baltic Sea is a highly threatened species and despite a fishing ban in 2019 no recovery of the stocks has been shown. It is mainly large individuals that are missing from the populations, and predation from seals and cormorants is identified as part of the problem. Increasing the opportunity for cod to hide from predators has been shown to have a positive effect on the growth and recovery of local populations. Hanö Bay (SW Baltic Sea) is one of the Baltic cod’s most important areas with good opportunities for foraging, proximity to spawning grounds in the Bornholm Deep, and inhabits moderate populations of grey seals. In February 2023, 15 artificial reefs were deployed in the inner Hanö Bay at 20 m and 10 m water depth. During the spring video surveys of the artificial reef structures, complemented with underwater surveys were conducted, showing positive results of cod inhabiting the reefs. The project is a cooperation between academia, the public sector, and local entrepreneurs and is part of the Strategic Research- and Innovation collaboration between Lund University and Marint centrum, Simrishamn municipality. The intention of the collaboration is to addressing current environmental issues and societal challenges in the southern Baltic Sea and promote sustainable development in the Hanö Bay region through research, education, collaboration, and innovation.

1Marint centrum, Simrishamn, Sweden
2Lund University, Lund, Sweden
3Hanö torskrevsförening, Sölvesborg, Sweden
4Aanderaa-Xylem, Bergen, Norway
5University of Gothenburg, Gothenburg, Sweden

Intraspecific variation in egg size and its role for coping with thermal variation
Francesca Leggieri1, O. Nordahl, H. Berggren, P. Tibblin

Aquatic ectotherms are threatened by climate change. Understanding how organisms can adapt to, and cope with, increasing temperatures is crucial to mitigate the consequences of climate change. Recent research suggests that the early life-stage is especially vulnerable to a warmer climate, necessitating investigations into the causes of variation in thermal performance. Comparisons among species and populations highlight the significance of egg size in determining early life-stage thermal performance. The oxygen-limitation hypothesis posits that smaller eggs, with more efficient oxygen diffusion due to a higher volume-surface ratio, outperforms larger eggs in oxygen-poor warm water. However, this assumption has rarely tested within populations. In this study, we incubated fertilized eggs from 22 female pike at four temperatures until hatching to assess how egg size influences hatching success. We found that larger eggs had the highest success in cold water whereas smaller eggs were equally good, or better, in higher temperatures. This constitutive rare evidence of that intraspecific variation in egg size adhere to the oxygen-limitation hypothesis and suggest that fitness advantages associated with larger eggs may change in the future climate.

1Linnaeus University Centre for Ecology and Evolution in Microbial model Systems (EEMiS), Kalmar, Sweden

Traits of habitat-forming algae promote mesophotic ecosystem resilience under environmental change
Heidi Burdett1, Sofie Voerman2, Beau Marsh2, Ricardo Bahia3, Guilherme Pereira-Filho4, Thomas Yee5, Ana Clara Becker4, Gilberto Amado-Filho3, Arvydas Ruseckas6, Graham Turnbull6, Ifor Samuel6

The euphotic-mesophotic transition is characterized by large environmental changes, which can significantly alter ecosystem engineer functioning and the structure of their associated communities. Benthic mesophotic communities can be highly biodiverse, but the drivers of biodiversity change across the euphotic-mesophotic transition remain unclear. Here, we investigated macrofaunal biodiversity change in free-living red coralline algal habitats around the Fernando de Noronha archipelago, Brazil, from euphotic to mesophotic depths (13-86 m). These habitats, known as rhodolith or maerl beds, are global biodiversity hotspots. We found a gradient of macrofaunal biodiversity decline with depth; distinct euphotic/mesophotic shifts were not evident. Macrofaunal biodiversity was negatively associated with water depth and some rhodolith host taxa, and positively associated with rhodolith thallus diameter. The gradient in ecosystem niche provision may be in part driven by coralline algae’s superior capacity for mesophotic light acclimation – a process we have experimentally defined. Taxa with low total abundance were most responsive to driver change and therefore may be highly sensitive to global change trajectories. However, dispersion among communities (i.e. beta-diversity) was highest at the deepest depths and the major taxa exhibited limited depth specificity. This suggests that mesophotic rhodolith beds could act as a long-term depth refugium, providing an ecological buffer against the significant biodiversity threats experienced by their shallow-water counterparts.

1Umeå Marine Sciences Centre & Department of Ecology and Environmental Science, Umeå University, Sweden
2Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt University, UK
3Botanical Garden Research Institute of Rio de Janeiro, Brazil
4Laboratório de Ecologia e Conservação Marinha, Universidade Federal de São Paulo, Brazil
5Department of Statistics, University of Auckland, New Zealand
6School of Physics and Astronomy, University of St Andrews, UK

Extensive prokaryotic maintenance respiration in the sea influenced by osmoregulation
Johan Wikner1,2, Kevin Vikström1

Understanding the ability of the ocean to assimilate and release CO2 and its regulation is a grand challenge in aquatic science. Microbial respiration is the major process consuming oxygen and releasing CO2 in the biosphere. The relative energy demand from growth of biomass or maintenance activities determines the regulation of respiration with impact on how the development of hypoxia and CO2 emissions is controlled. This coupling is furthermore crucial for understanding the life history and associated ecological interactions of microorganisms. However, the knowledge of rate and regulating factors of maintenance respiration in the biosphere is limited. In this study, we demonstrated significant relationships in marine field samples where the prokaryotic specific growth rate predicts cell-specific respiration, in accordance with theory from culture models, over a 10- fold salinity range. This enables the first reported direct estimates of maintenance respiration in nature to show a 6-fold variation between 0.12-0.62 fmol O2 cell-1 d-1, comprising 29-72% of prokaryotic specific respiration. The lowest maintenance respiration occurred at salinity close to physiological osmolarity, suggesting osmoregulation as one of the more energy-consuming maintenance activities. A conservative global estimate of maintenance respiration accounted for 66% of the total prokaryotic respiration in the ocean´s mixed layer. This means that maintenance activities dominate the use of the energy generated by prokaryotic respiration in the sea, where osmoregulation is one significant energy consumer. Consequently, maintenance respiration and its regulation must be included in ecological and biogeochemical models to accurately project and manage the development of hypoxia and CO2 emissions from the ocean.

1Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
2Umeå Marine Sciences Centre, Umeå University, Hörnefors, Sweden

Habitat specific and whole ecosystem basal production in shallow coastal ecosystems influenced by riverine inflow
Jenny Ask1, Pia Bartels1, Pär Byström1, Reiner Giesler1, Jan Karlsson1, and Agneta Andersson1

Rivers transport large amounts of terrestrial organic matter (OM) to the ocean every year, but there are still large gaps regarding its effects on the marine environment. To investigate spatial and temporal differences in the effects of terrestrial OM, we sampled in a spatial gradient along the river plume in the Öre estuary, northern Baltic Sea, and sampled three times between May and August in 2015. An additional reference station without the influence of terrestrial OM were also included. We measured primary production and bacterial production in benthic and pelagic habitats and estimated their relative contribution to whole-system basal production. We found variability in basal production (the combined primary and bacterial production in benthic and pelagic habitats) in space and time and across habitats, with overall higher production in the benthic habitat compared to the pelagic in June and August. In May however, when temperatures were low and riverine inflow high, the distribution between benthic and pelagic production was more similar. In addition, the total basal production was lower in May than in June and August, especially at the reference station. Data from June and August also indicate that the riverine input had a negative impact on benthic primary production, likely via light extinction caused by the colored terrestrial OM. Indeed, the station closest to the river mouth had the lowest rates of both benthic primary production and total basal production on both dates. Primary production was consistently higher than bacterial production except at the station closest to the river mouth where they were more equal. Our results suggest that climate change predictions of increasing inputs of terrestrial OM to shallow coastal ecosystems may affect basal production by decreasing both benthic primary production as well as total basal production, which will have implications for higher trophic levels in coastal food webs.

1Umeå Marine Sciences Centre, Umeå University, Sweden

Effects of fluctuating temperatures on phytoplankton are modulated by light and nutrient availability
Anna Lena Heinrichs1, Johanna Exner2, Helmut Hillebrand1, Apostolos-Manuel Koussoroplis3,4, Maren Striebel1

Global warming and predicted intensified temperature fluctuations make it necessary to consider fluctuations as a standard in scientific research. Based on the principle of Jensens’ inequality, effects of variable conditions (i.e., temperature variability) deviate from those under constant conditions on organisms’ responses. As phytoplankton perform in a nonlinear way to temperature, responses under to variable temperature differ from those to constant temperatures. In addition to temperature, phytoplankton performance is significantly affected by nutrient availability and light . Recent studies have examined the influence of nutrients and light on thermal performance, but the impact of thermal fluctuations under different nutrient and light conditions remains unclear. We exposed the green alga Scenedesmus armatus to gradients of light intensity and nutrient concentrations (nitrogen and phosphorus) and investigated the effect of three temperature fluctuation scenarios (same frequency and amplitude, but fluctuations around different means). We compared the obtained results with outcomes m easured under constant temperature conditions at the different combinations of nutrient and light supply. Our findings demonstrate an effect of resource availability under constant temperatures and that phytoplankton’s ability to adapt to fluctuating tempe ratures increases with increasing light intensities. This suggests that understanding the connection between temperature and resource availability will be crucial in explaining future phytoplankton communities and biogeochemical processes.

1Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Schleusenstrasse 1, 26382, Wilhelmshaven, Germany
2Centre for Ecology and Evolution in Microbial Model Systems EEMiS, Linnaeus University, Kalmar, Sweden
3Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Genome et Environnement (LMGE), Clermont Ferrand, France
4Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany

Contrasting organic pollutant and heavy metal trends in juvenile herring during a growth season
John M. Taylor1,2, Marcus Sundbom2,3, Agnes ML Karlson1,2,4

The Baltic Sea has historically been plagued with a high input of persistent organic pollutants (POPs) and heavy metals such as mercury. Although recent decades have seen a decrease in the input of POPs, extensive legacy concentrations of these compounds still exist in the environment with potentially detrimental effects for both the organisms living in the Baltic and those that consume them (i.e. humans). For mercury, climate change is increase precipitation and exacerbate Baltic brownification potentially leading to an increase input of Hg to the food web and heightened biomagnification. Baltic herring (Clupea harengus membras), an economically important species due to consumption by humans, have been extensively studied and analyzed for the presence of POPs and heavy metals for decades. Although a long history of contaminant data exits for herring, previous research has focused on adult fish which feeds partly on benthos and not juvenile young-of-year (YOY) individuals which feed only form the pelagic food web. In this study, YOY herring were captured from the coastal Baltic Sea throughout the summer, when growth rate is high, and analysed for dioxins, dioxin-like polychlorinated biphenyls (PCBs), and mercury. Results showed that POPs were unexpectedly highest in the smallest individuals and decreased over the growing season as fish grew larger indicating growth dilution. An opposite trend was however seen in Hg where the lowest levels were seen in the smaller fish and concentrations increased with fish size. Potential reasons for this contrasting pattern are discussed. This study is one of the first to investigate contaminant concentrations in juvenile herring and the results will add to the knowledge of Baltic contaminant cycling and to the origins of contaminants in young coastal fishes.

1Department of Ecology, Environment and Plant Science, Stockholm University
2Bolin Centre for Climate Research, Stockholm University
3Department of Environmental Science, Stockholm University
4Baltic Sea Centre, Stockholm University

Structure, function and diversity of microbial community in coastal northern Baltic Sea
Li Zhao1,2, Brugel, S.1,2, Paczkowska, J.1, Eriksson, K.1,2, Zhao, W.1, Wang, X-R.1, Andersson, A.1,2

Increased precipitation in northern Europe associated with climate change will flush more terrestrial dissolved organic matter (tDOM) to the sea, the influence on the plankton inhabiting coastal areas is still poorly known. This study aims to understand the composition and diversity bacterioplankton communities in the subarctic land-sea transitional zone of the northern Baltic Sea and their responses to environmental factors such as dissolved organic carbon, salinity, temperature, and nutrient availability. we used surface water metagenomic sequencing datasets to construct metagenome-assembled genomes (MAGs) from 86 river-estuary-coast water samples in northern Baltic Sea. In total, 1145 de-replicated MAGs with completeness ≥ 50% and contamination ≤ 10% were obtained, among which, 66 (758 MAGs) have a completeness ≥70%. These MAGs together span 1143 bacterial and 2 archaeal species, a subset of which are from underrepresented genus-level lineages in public databases. They are dominated by phyla Proteobacteria (36%), Bacteroidota (26%), and Actinobacteriota (24%). Temporal variations in physicochemical variables, such as temperature and nutrient availability, have a greater impact on the bacterial communities than spatial differences in the ecosystem. The seasonal shift in the relative abundance of these bacterial classes suggests that environmental factors and ecological processes drive changes in the abundance of different bacterial classes over time. Our findings improve the understanding of the factors shaping bacterioplankton community composition and diversity in northern coastal areas, such as in the northern Baltic Sea.

1Department of Ecology and Environmental Science, Umeå University, SE-901 87 Sweden
2Umeå Marine Sciences Centre, Umeå University, SE-905 71 Hörnefors, Sweden

Microbial plankton diversity in the Baltic Sea area: geographic changes in seasonal succession and modeling efforts
Krzysztof T. Jurdzinski1, Meike A.C. Latz1,2, Anders Torstensson3, Sonia Brugel4,5, Mikael Hedblom3, Markus Lindh3, Jenny Lycken3, Agneta Andersson4,5, Bengt Karlson3, Anders F. Andersson1

Bacteria and protists (unicellular eukaryotes) are crucial organisms in the Baltic Sea area surface waters. They play key roles in nutrient cycles, anoxic zone formation, and food webs, including being responsible for the majority of primary production. We leveraged the first DNA metabarcoding dataset which includes year-round sampling across the entire length of the Swedish coastline, to analyze at large the spatiotemporal changes in microbial communities across the broad environmental gradients of the Baltic Sea. We investigated the relative abundance of major microbial taxa, as well as the dissimilarity of bacterial and protist communities (beta-diversity). These analyses showed not only differences in the geographic distribution of microbial taxa but also distinct regional succession patterns, driven by different key organisms. Alpha-diversity was indicative of the seasonal succession patterns and connected to major events such as cyanobacteria and eukaryotic phytoplankton blooms. We plan to build a machine-learning model predicting the impact of climate change and altered nutrient input on the investigated We plan to benchmark the model on a newly obtained metabarcoding dataset with wide geographic and seasonal coverage but from a different time than the original dataset. We hope that these analyses will enhance the understanding of and possibilities to monitor processes shaping the microbial communities in the Baltic Sea and their future changes.

1KTH Royal Institute of Technology, Department of Gene Technology, Science for Life Laboratory, Stockholm, Sweden
2University of Copenhagen, Department of Plant and Environmental Sciences, Frederiksberg C, Denmark
3Swedish Meteorological and Hydrological Institute, Oceanographic Services, Västra Frölunda, Sweden
4Umeå University, Department of Ecology and Environmental Sciences, Umeå, Sweden
5Umeå Marine Sciences Centre, Umeå University, SE-905 71, Hörnefors, Sweden

To detect or not detect: The importance of sampling frequency for meaningful phytoplankton monitoring
Jakob Walve1, Helena Höglander1, and Elizaveta Mattsson1

The Swedish national marine monitoring of hydrography, pelagic biology and chemistry include only few stations sampled at high-frequency, i.e. 20-25 times per year. We used high-frequency phytoplankton data (weekly in spring, bi-weekly in summer) from the Landsort Deep station BY31 in the Baltic Sea to simulate the effects of monthly sampling (12 times per year), a sampling interval commonly used in pelagic monitoring. We find that monthly data impose large limitations in the confidence of certain analyses, such as phytoplankton bloom timing, bloom magnitude and species composition. In the future, novel methods may complement the traditional monitoring, however, these methods often have limited back-ward compatibility relative to existing data and it will take many years before the new time-series can be evaluated.

1Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University

Who are the waterborne pathogens of the future? – Opportunistic bacterial persistence to predation, organic matter, and iron
Karolina Eriksson1,2, Jon Ahlinder3, Johanna Thelaus4, David Sundell4, Agneta Andersson1,2

Climate-induced changes in coastal ecosystems, including intensified nutrient loads and increased water browning, can lead to ecosystem imbalances and establishment of bacterial opportunists. Changes even risk to disrupt the balance between autotrophic and phagotrophic primary producers. Phagotrophic protozoan predation drives the evolution of defense mechanisms in bacteria, resulting in predation resistant bacteria able to cause disease, many of them found within Gammaproteobacteria. Surprisingly, it is unknown where these opportunists exist and how they respond to their surroundings, which hinder our ability to understand the risk of emerging diseases. In this study, we identified opportunistic bacteria in a bay in the northern Baltic Sea by their response to changing conditions, including eutrophication, water browning, and varying iron levels using partial and full-length 16S ribosomal RNA gene sequencing. Pseudomonadales and Enterobacteriales exhibited rapid resource utilization skills under eutrophic-like conditions, while Betaproteobacteriales contributed to the degradation of complex humic substances in brownification-like conditions. Gammaproteobacteria were generally resilient to large increases in iron and watercolor. Notably, whereas other bacterial groups declined, an uncultivated species of the genera Chromulinavorax and the opportunistic pathogen Pseudomonas aeruginosa were especially persistent to increasing iron concentrations, likely linked to the same mechanism that enables survival in protozoan predators. Several uncultured species were identified together with intracellular pathogens for their shared positive correlation to iron content. These species were all present in the future climate scenarios of eutrophication and brownification. This study provides insights into the selection dynamics of opportunistic and pathogenic bacteria in aquatic ecosystems. To gain a deeper understanding of ecosystem controls on bacteria and the stability of aquatic environments in a changing climate, future research should untangle the biogeochemical factors controlling these organisms.

1Department of Ecology and Environmental Sciences, Faculty of Science and Technology, Umeå University, Sweden
2Umeå Marine Sciences Centre, Umeå University, 905 71 Hörnefors, Sweden
Department of Tree Breeding, Skogforsk, Sävar, SE-91821, Sweden
4Division of CBRN Defence and Security, Swedish Defence Research Agency (FOI), Sweden

When you kick out your guest: a hybrid analytical – agent-based modelling approach to understand coral bleaching dynamics
Adriano Bonforti1, Libby E.1, Ohlsson F.1, Kamenos N.A.1

Symbioses are prevalent across many biomes and can be critical to the biodiversity, productivity, and survival of some of the most charismatic ecosystems on earth. Sometimes these symbiotic interactions break down, which can lead to widespread death of both symbiont and host. However, evidence is emerging that they may enhance individual and community fitness via holobiont acclimation and adaptation. To understand disruption of endosymbiosis we use tropical coral reefs as a model system. We focus on coral bleaching, i.e. the stress-driven expulsion of the algal endosymbionts that provide corals with their photosynthetic capabilities. Nevertheless, our results and approach may have broad applicability across other systems where host-symbiont interactions are dynamic, including lichens and human gut microbiomes. While a wide range of empirical data on coral reef bleaching are available, novel mathematical approaches are needed to make a major advance in understanding. Model development is carried out in a multidisciplinary fashion at the interface between empirical marine biology, advanced mathematical techniques (e.g., symmetry analysis), and agent-based modelling to construct biologically relevant models of both population and evolutionary dynamics. We use an agent-based model (ABM) informed by empirical results in the literature to gain insights into coral endosymbiotic dynamics and build a biophysically informed mathematical model for analytical exploration. We base our initial ABM on widely accepted models by the coral community and extend the existing models to include the coral’s response to thermal stress. We implement symbiont population dynamics both in coral and in the water column and make predictions to be tested both with a differential equations model and in a laboratory experiment involving real corals.

1Department of Ecology and Environmental Sciences, Umeå University, Sweden.

A blast from the past: incorporating historical symbiotic dynamics into long-term coral thermal resilience
Lourdes Martínez-García1, Burdett, H.L.1, Capo E.1, Kamenos N.A.1

Marine ecosystems are threatened by the increasing anthropogenic climate change worldwide. Coral reefs are especially vulnerable to such pressures and can have profound responses to rising ocean temperatures. One response is the expulsion of symbiotic energy-providing microalgae by the coral host; a process called coral bleaching. Yet, maintenance of this mutualistic symbiosis is essential for the survival of shallow-water coral reefs. However, it is unclear if such symbiotic breakdowns have been present across long time periods, and whether alternative symbiotic interactions have been the key factor to coral survival through historical climatic changes. Here, we use corals from the Indo-Pacific Ocean as models of historical and modern natural ecosystems to reveal ecological and molecular changes within the coral holobiont (animal and associated microbiota) across time. To this aim, we will first employ a 1-year time series of experimental sampling, simulating concurrent thermal pressures, to identify if the natural symbiotic community compositions from living Acropora and Porites corals are fully deposited and preserved in their skeleton. Secondly, we will recover varying amounts of coral holobiont DNA from Porites lutea coral skeletal cores sampled at different locations in Mayotte, France. Using ancient DNA metagenomics, we will compare the community composition of historical microbiota to their modern conspecifics, and evaluate their metabolic potential during historical bleaching and non-bleaching events, to describe spatiotemporal symbiotic dynamics. Finally, we will experimentally investigate the expression patterns of heat-tolerant associated genes in Acropora and Porites in response to increasing heat stress and evaluate possible similarities between historical and modern in hospite genetic variation. This study will extend the understanding of heat tolerance in coral-microalgal symbiotic associations, which is key for future management and potential recovery of coral reefs.

1Department of Ecology and Environmental Sciences, Umeå University, Sweden

Land-sea continuum: long-term fate of terrestrial organic carbon in coastal environments of the Baltic Sea
Alexandra Rouillard1,2,3, Cristian Gudasz2,3, Jan Karlsson2,3, Nick Kamenos1,3

Nature-based solutions to climate change are recognised as a mechanism for drawing down carbon from the atmosphere. Together with geoengineering, this natural solution is required for reduction of anthropogenic carbon dioxide (CO2) concentrations in the atmosphere which are contributing to global warming. At the land-sea interface and continental shelf, sequestration and storage of carbon by marine ecosystems and sediments is a globally significant process that locks away carbon for hundreds to thousands of years. Importantly, the presence of both sequestration and efficient burial is required for marine systems to be effective nature-based solutions. For the subarctic, there is emerging evidence that at millennial time scales, ca. 50% of organic carbon buried in shallow-water marine sediments may be organic material derived from terrestrial and inland water systems via riverine discharge. The source and type of the organic material entering the oceans will also determine the role marine sediment stores play in climate regulation and sensitivity to disturbance. In particular, sources of terrestrial organic material supplying carbon not easily degraded by chemical and microbial processes likely endow coastal sediments with better capacity to act as a nature-based solution to climate change. We seek to better understand organic carbon (OC) processing along the land-sea continuum by: 1) determining the riverine supply of OC from differing terrestrial land uses, 2) its fate in coastal sediments, and 3) detecting marine hotspots of organic carbon burial, as well as the carbon donor sources and pathways. These advances will be made by quantifying and determining the source (terrestrial vs. marine) and stability of OC transported to and buried in coastal sediments of the Baltic Sea along gradients of riverine discharge with contrasting land-use.

1Umeå Marine Sciences Centre, Umeå University, Sweden
2Climate Impacts Research Centre, Umeå University, Sweden
3Department of Ecology and Environmental Sciences, Umeå University, Sweden

Use of Aliivibrio fischeri to detect microtoxicity in Baltic Sea sediments
Christine Gallampois1, Katarzyna Arturi2, Martin Krauss3, Timo Hamers4, Mats Tysklind1, and Marja Lamoree5

Human activities have introduced an unprecedented array of chemicals into aquatic environments, such as pesticides, heavy metals, pharmaceuticals, industrial pollutants, and countless other synthetic substances. These anthropogenic chemicals are often introduced into water bodies through runoff, industrial discharges, and sewage systems, eventually settling in sediments. Sediments are a complex matrix where natural and man-made chemicals co-exist. They contain thousands of chemicals, accumulated over decades, able to cause harmful damages on aquatic life but also on human health. Assessing the sediments toxicity is an important task. This may be addressed by the use of bioassays. They are great tools to detect different type of biological effects and enable the focus on the locations where the highest responses to the assay are detected, but do not allow the identification of the responsible chemical(s) for these observed effects. Aliivibrio fischeri is a marine bacterium possessing bioluminescence properties, as the result of a respiration by product. When exposed to toxic compounds, the respiratory process is disturbed causing a decrease of light. In the bioassay, response to toxicity is observed as a reduction of the bioluminescence. Sixty-two sediments samples were collected in the Baltic Sea (open sea, and in the proximity or not of industrial activities) and subjected to chemical analyses by LC-MS in positive and negative modes. Microtoxicity assay with the Aliivibrio fischeri. bacteria were performed and showed concentrations that can inhibit 20% of the maximum light from 2.81 to 144.3 mg of sediment/mL in the assay, with 9 samples for which no inhibition of light was observed and thus considered non-toxic towards this bacterium. Our aim is to show that Aliivibrio fischeri a a great tool for fast detection of toxicity within different sediments and can help in the selection of the location(s) where efforts need to be made for chemical identification.

1Department of Chemistry, Umeå University, KBC Building, 901 87 Umeå, Sweden
2Department of Environmental Chemistry, EAWAG, Überlandstr. 133, 8600 Dübendorf, Switzerland
3Department of Effect-Directed Analysis, UFZ, Permoserstr. 15, 04318 Leipzig, Germany
4Environmental Health & Toxicology, Vrije Universiteit Amsterdam, De Boelelan 1081, 1081 HV Amsterdam, The Netherlands
5Chemistry for environment & Health, Vrije Universiteit Amsterdam, De Boelelan 1081, 1081 HV Amsterdam, The Netherlands

Emissions from shipping affect marine plankton communitiesreduced growth, impaired reproduction and altered biodiversity
Jenny Egardt1, Christina Jönander1, Ida-Maja Hassellöv2, Ingela Dahllöf1

The Swedish governments goods transport strategy is under evaluation but it has been suggested by the previous government that goods transport should be decreased on roads in favor of railways and sea transport. An increase in shipping could lead to increased environmental impact on our oceans as a result of the several different emissions associated with ships. In 2020, the International Maritime Organization (IMO) reduced the allowed sulphur content in marine fuels to decrease emission to air. As a result of this, ships were equipped with scrubbers to clean the exhaust which allowed for the continued use of heavy fuel oils while still complying with the new regulation. The scrubber wash water, which contain sulphur, metals and organic substances like polyaromatic hydrocarbons (PAHs), is continuously generated and discharged at sea. When exposed to scrubber wash water, marine zooplankton communities showed increased mortality, decreased egg production with up to 60 % reduction in hatching frequency as well as decreased biodiversity at the lowest tested concentration. Another ship emission, bilge water, originates from onboard maintenance. It consists of fuel residues, hydraulic oils, metals, detergents etc. and as it accumulates it need to be released. Discharge is allowed en route if compliant with IMO regulations, which states that the oil content should be below 15 ppm (MARPOL (73/78) Annex I). The brackish-water diatom, Nitzschia sp. experienced reduced growth when exposed to bilge water from different vessels. Composition of bilge water varies a lot between ships which was reflected in the growth pattern, which displayed both low growth reduction and total growth inhibition at the lowest tested concentration. The continued release of these, and other ship related emissions like grey water and antifouling compounds, create a chemical cocktail along the shipping lanes in our oceans. With increased shipping, we can expect an increase in these continuous emissions which reduces the oceans dilution capacity and threatens the life of marine organisms. As shipping lanes pass through our archipelagoes and near shore areas, which are home to some of the more sensitive ecosystems, the consequence of continued and increased emissions could be severe.

1Department of Biological and Environmental Sciences, University of Gothenburg
2Mechanics and Maritime Sciences, Chalmers