Publications
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Schultze, Sabrina; Langva, Hilde Kleppe; Wei, Jing; Chatzigeorgiou, Marios; Rundberget, Thomas & Hessen, Dag Olav
[Show all 9 contributors for this article]
(2024).
Do DOM quality and origin affect the uptake and accumulation of a lipid-soluble contaminant in a filter feeding ascidian species (Ciona) that can target small particle size classes?
Aquatic Toxicology.
ISSN 0166-445X.
273.
doi:
10.1016/j.aquatox.2024.107026.
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The widely reported increase of terrestrial dissolved organic matter (terrDOM) in northern latitude coastal areas (“coastal darkening”) can impact contaminant dynamics in affected systems. One potential impact is based on differences in chemical adsorption processes of the molecularly larger terrDOM compared to marine DOM (marDOM) that leads to increased emulsification of lipophilic contaminants with terrDOM. Filter feeders filter large amounts of water and DOM daily and thus are directly exposed to associated contaminants through both respiration and feeding activity. Thus, increased exposure to terrDOM could potentially lead to an increase in bioaccumulation of lipid soluble contaminants in filter feeders. To assess the effect of DOM on bioaccumulation in filter feeders, we exposed the mucous based filter feeding ascidian Ciona intestinalis (formerly known as Ciona intestinalis Type B), to the lipophilic veterinary drug teflubenzuron (log KOW: 5.39) in combination with four DOM treatments: TerrDOM, marDOM, a mix of the two called mixDOM, and seawater without DOM addition. The exposure lasted for 15 days, after which the individuals in all DOM treatments showed a trend towards higher bioaccumulation of Teflubenzuron than those in the seawater control. However, there was considerable overlap in posterior distributions. Against our expectations, marDOM resulted in the highest bioaccumulation factor (BAF), followed by mixDOM, with terrDOM resulting in the lowest BAF except for seawater (kinetic BAF L/kg median, 2.5 %–97.5 % percentile marDOM 94, 74–118; mixDOM 82, 63–104; terrDOM 79; 61-99; seawater 61, 44–79). All BAFs were below the level of concern according to the EU REACH regulation (BAF < 2000 L / kg) and, therefore, likely not environmentally problematic in the examined context. However, the results show that DOM can act as a dietary vector; thus, different combinations of contaminants, DOM, and filter feeding organisms should be tested further.
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Schultze, Sabrina; Andersen, Tom; Knudtzon, Nina; Ruus, Anders; Rundberget, Jan T. & Brooks, Steven J.
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(2023).
Do DOM quality and origin affect the uptake and accumulation of lipid-soluble contaminants in coastal filter feeders? An experimental simulation of teflubenzuron exposure to blue mussels.
Aquatic Toxicology.
ISSN 0166-445X.
263.
doi:
10.1016/j.aquatox.2023.106696.
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The increased export of terrestrial dissolved organic matter (terrDOM) to coastal marine ecosystems may affect local filter feeders and the local food web via the altered uptake of organic material and associated contaminants. To compare terrDOM to marine DOM (marDOM) as contaminant vectors to coastal biota, we exposed blue mussels (Mytilus sp.) to the different DOM types in combination with teflubenzuron, a widely applied lipophilic aquaculture medicine targeting salmon lice (Lepeophtheirus salmonis). A 16-day exposure of the blue mussels to DOM and teflubenzuron was followed by a depuration phase of 20 days without teflubenzuron. We calculated teflubenzuron adsorption rates and bioaccumulation factors (BAF) using a Bayesian model, expecting teflubenzuron uptake to be greater with terrDOM than marDOM due to the higher prevalence of large amphipathic humic acids in terrDOM. Humic acids have strong absorption properties and are able to envelope lipophilic molecules. Thus, humic acids can function as an efficient contaminant vector when taken up by filter feeders. Although there were varying degrees of overlap, the mussels tended to accumulate higher amounts of teflubenzuron in the DOM treatments than in the seawater control (bioaccumulation factor [BAF] in seawater: median 106 L/kg; 2.5 %–97.5 % percentile: 69–160 L/kg). Contrary to expectations, mussels exposed to marDOM showed a trend toward more bioaccumulation of teflubenzuron than those exposed to terrDOM (BAF marine 144 L/kg; 102–221 L/kg versus BAF terrestrial: 121 L/kg; 82–186 L/kg). The highest teflubenzuron accumulation was observed with the 50:50 mixture of marDOM and terrDOM (BAF mix: 165 L/kg; 117–244 L/kg). The slight difference in DOM-type accumulation rates observed in this experiment—especially the accumulation rate of terrDOM compared to that of the seawater-only treatment type—was not considered environmentally relevant. Further studies are necessary to see if the observed trends transfer to complex environmental systems.
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Schultze, Sabrina; Andersen, Tom; Hessen, Dag Olav; Ruus, Anders; Borgå, Katrine & Poste, Amanda
(2022).
Land-cover, climate and fjord morphology drive differences in organic matter and nutrient dynamics in two contrasting northern river-fjord systems.
Estuarine, Coastal and Shelf Science.
ISSN 0272-7714.
270.
doi:
10.1016/j.ecss.2022.107831.
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Climate and land-use changes are leading to impacts on individual ecosystems as well as shifts in transfer dynamics between interconnected systems. At the land-ocean interface, changes in riverine inputs of organic matter (OM) and nutrients have the potential to lead to shifts in coastal carbon and nutrient cycling with consequences for ecosystem structure and function. In this study, we assess OM and nutrient dynamics for two contrasting Norwegian river-to-fjord systems: a boreal system with a forested catchment draining into a narrow fjord (‘narrow boreal system’), and a subarctic system where lowland forests and mountainous regions drain into a broad fjord (‘broad subarctic system’). We characterized seasonal organic carbon and nutrient concentrations and DOM absorption properties for samples collected along transects from river to outer fjord during 2015/2016. While differences in catchment properties drove contrasts in river chemistry between the two study rivers, fjord morphology and hydrodynamics as well as dissolved organic carbon (DOC) and nutrient concentrations in marine receiving waters predicted water-chemistry patterns along the transect. The narrow boreal system, with high riverine DOC and nutrient concentrations, was structured mainly by a horizontal salinity gradient from river to outer fjord, with limited impact of seasonality. In contrast, the broad subarctic system tended to be dominated by vertical salinity stratification, with strong between-date differences in surface water salinity linked to seasonality in river discharge. These dynamics were also reflected in the strong horizontal gradients in DOC, nutrients and DOM properties in the narrow boreal system, in contrast to the broad subarctic system, where strong seasonality paired with a lack of strong contrast between riverine and marine concentrations of DOC and most nutrients led to an uncoupling between salinity and other water chemistry variables. In the narrow boreal system, terrestrial OM dominated both the particulate and dissolved OM pools, while OM in the broad subarctic system was derived primarily from marine phytoplankton. Non-linear declines in NO3 + NO2 were observed consistently in the boreal system and during the productive spring season in the subarctic system, suggesting biological uptake and a potentially important role of these rivers as sources of bioavailable N to coastal ecosystems. The results from these two case studies highlight the complex and interacting effects of catchment land-cover, river water chemistry and discharge, fjord morphometry and hydrodynamics in structuring the transport, fate and potential impacts of terrestrially-derived nutrients and organic matter in northern coastal environments.
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McGovern, Maeve; Evenset, Anita; Borgå, Katrine; Wit, Heleen de; Braaten, Hans Fredrik Veiteberg & Hessen, Dag Olav
[Show all 9 contributors for this article]
(2019).
Implications of Coastal Darkening for Contaminant Transport, Bioavailability, and Trophic Transfer in Northern Coastal Waters.
Environmental Science and Technology.
ISSN 0013-936X.
53(13),
p. 7180–7182.
doi:
10.1021/acs.est.9b03093.
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The increased transport of terrestrially derived organic material (tOM) from catchments to rivers and lakes is leading to browning of northern freshwaters.(1) Although the same environmental drivers can be expected to lead to widespread increases in tOM and subsequent darkening in adjacent coastal systems,(2) this has received considerably less attention, and long-term monitoring data for detecting these changes are scarce. This is despite expectations that darkening is likely to have a range of implications for coastal biogeochemistry and food-web ecology.
tOM is accompanied by other catchment-derived materials including contaminants, inorganic particles, and nutrients. Together, these terrestrial inputs can affect cycling and food-web accumulation of contaminants, in particular, methyl mercury (MeHg) and persistent organic pollutants (POPs). Because of the human and ecosystem health risks associated with these contaminants, and to ensure informed policy decisions, there is a need for a better understanding of the drivers of darkening and their direct and indirect impacts on the transport, bioavailability, and trophic transfer of contaminants in northern coastal waters.
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Schultze, Sabrina; Langva, Hilde K.; Knudtzon, Nina Cathrine; Chatzigeorgiou, Marios; Rundberget, Jan Thomas & Brooks, Steven
[Show all 11 contributors for this article]
(2023).
Increases in Terrestrial Dissolved Organic Matter Will Not Increase Feeding Related Uptake of a common Lipid Soluble Contaminant In coastal Filter Feeders.
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Schultze, Sabrina; Poste, Amanda; Ruus, Anders; Hessen, Dag Olav; Andersen, Tom & Borgå, Katrine
(2017).
Do high levels of terrestrial DOM uptake lead to higher contaminant concentration and changes in energy allocation and growth? A study on three marine lower food web taxa.
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Schultze, Sabrina
(2024).
From the land to the sea: Dynamics and ecotoxicological implications of rising levels of terrestrially derived organic matter entering river and fjord systems.
Universitetet i Oslo.
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My thesis is about how an increase of terrestrial dissolved organic matter (terrDOM) – thus all organic matter (OM) originating from the land (eg. plant detritus) that is breaking down into very small particles and entering different waterbodies– affects contaminant uptake in organisms that filter water for food. This is very relevant, because, in recent years, more and more “browning” of waterways was observed, which is due to more of the darkly coloured terrDOM entering waterbodies. My focus was specifically on the ecotoxicological implications of this trend. For this, I first analyzed DOM dynamics in two fjord systems with either high or low DOM concentrations (addressing the question: what can be found in nature?), before running two experiments with two different filter-feeders to see, whether they take up more of a lipophilic contaminant when exposed to terrDOM compared to marine DOM (eg. phytoplankton), a mix, or only seawater. I expected terrDOM to lead to the highest accumulation of the contaminant since it is known that lipophilic contaminants can absorb well to terrDOM. However, in my experiments, it seemed like accumulation was higher in the DOM types containing marine DOM, although all types of DOM lead to higher accumulations than only seawater.
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Published
Sep. 29, 2016 3:47 PM
- Last modified
Jan. 24, 2025 1:27 PM
