| 1. |
- Motiei, Asa, 1980-, et al.
(författare)
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Ecotoxicological Assessment Of Suspended Solids : The Importance Of Biofilm And Particle Aggregation
- 2021
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 280
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Tidskriftsartikel (refereegranskat)abstract
- Assessment of microplastic impacts in biota is challenging due to the complex behavior of the test particles and their interactions with other particulates, including microorganisms, in the environment. To disentangle responses to microplastic exposure from those to other suspended solids, both microplastic and natural particles must be present in the test system. We evaluated how microplastic, non-plastic particles, and biofilms interacted in their effects on survivorship using acute toxicity assay with Daphnia magna. The animals were exposed to microplastic and kaolin at different concentrations of suspended solids (SS; 10, 100, and 1000 mg/L) with a varying microplastic contribution (%MP; 0 to 80%) and biofilm (presence/absence) associated with the solids. Also, we examined how these exposure parameters (SS, %MP, and Biofilm) affected aggregate formation that was analyzed using particle size distribution data. Under the exposure conditions, Daphnia mortality was primarily driven by SS concentration but ameliorated by both microplastic and biofilm. The ameliorating effects were related to increased particle aggregation in the presence of biofilm and high %MP. In addition, a weak yet significant positive effect of the biofilm on the survivorship was observed, presumably, due to microbial food supply to the daphniids in the exposure system; the bacteria were utilized at the absence of other food. Therefore, the effects of both natural and anthropogenic particulates depend on the particle behavior and aggregation in the water governed by microbial communities and physicochemical properties of the particles, which must be taken into account in the hazard assessment of plastic litter.
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| 2. |
- Ogonowski, Martin, 1980-, et al.
(författare)
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A weight and temperature dependent model of respiration in Praunus flexuosus (Crustacea, Mysidacea)
- 2012
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 34:7, s. 642-645
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Tidskriftsartikel (refereegranskat)abstract
- The mysid shrimp Praunus flexuosus is common in littoral habitats in the Baltic Sea and other marine areas, but its bioenergetic characteristics have not been studied. We present the first model of its routine respiration rate as a function of size and a natural temperature range. The model explained 87% of the variance in respiration, indicating that it could be useful in a larger modeling framework. Specific respiration rates and temperature dependence were consistent with previous reports for this and other littoral mysids at low-to-moderate temperatures. Respiration at higher temperatures was lower, indicating that previous reports may have been biased by residual SDA (specific dynamic action) effects. Increased respiration due to SDA was detectable over a longer period than previously reported, ∼30 h.
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| 3. |
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| 4. |
- Ogonowski, Martin, 1980-, et al.
(författare)
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Status and vertical size distributions of a pelagic mysid community in the northern Baltic proper
- 2012
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Ingår i: Boreal environment research. - 1239-6095 .- 1797-2469. ; 18:1, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- We report on abundance, biomass, trophic position and vertical size distribution of pelagic mysids (Mysis mixta, Mysis relicta/salemaai, Neomysis integer) in a coastal Baltic Proper area. As compared with the situation in this area in the 1980s, the formerly dominating M. mixta has declined and the total mysid biomass decreased by 50%. Neomysis integer now constitutes the bulk of the mysids. Stable isotopes indicate that they feed on a lower trophic level than Mysis spp., and M. relicta appears more carnivorous than M. mixta. For N. integer, size increases with depth and decreases with in situ light. This was not found for Mysis spp., probably due to their narrow size span and smaller sample size than for N. integer. In N. integer, in situ light explained the size variation with depth better than temperature, indicating that this variation is a response to predation rather than size-related thermal preference.
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| 5. |
- Ogonowski, Martin, 1980-
(författare)
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Studies on Baltic Sea mysids
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mysid shrimps (Mysidacea, Crustacea) are efficient zooplanktivores in both marine and freshwater systems as well as lipid rich prey for many species of fish. Although some efforts have been made to study the role of mysids in the Baltic Sea, very few studies have been carried out in recent time and there are still knowledge gaps regarding various aspects of mysid ecology. This thesis aims to explore some of these gaps by covering a mixture of topics. Using multifrequency hydroacoustics we explored the possibility to separate mysids from fish echoes and successfully established a promising and effective method for obtaining mysid abundance/biomass estimates (paper I). An investigation of the current mysid community in a coastal area of the northern Baltic proper (paper II) demonstrated that the formerly dominant, pelagic mysid Mysis mixta had decreased substantially (~50%) in favor for phytoplanktivorous, juvenile Neomysis integer and Mysis relicta sp. By examining different aspects of mysid behavior, we studied the vertical size distribution of mysids in the field and found that size increased with depth/declining light, irrespective of temperature; indicating that their vertical size distribution primarily is a response to predation (paper II). In paper III, a combination of ecological and genetic markers was used to investigate intraspecific differences in migratory tendency. Both marker types indicated that some part of the Mysis salemaai population is sedentary on the bottom and that this strategy is a phenotypically plastic but persistent trait, analogous to the partial migrations seen in many birds and fishes. In paper IV a temperature and weight specific respiration model was developed for the littoral Praunus flexuosus. Routine respiration was moreover elevated by post-prandial effects (specific dynamic action) for longer times than previously suggested. Consequently, ignoring such effects could significantly bias respiration measurements.
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