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Organic Matter
Published in Michael J. Kennish, Ecology of Estuaries Physical and Chemical Aspects, 2019
Marine benthic invertebrates are subdivided into three categories on the basis of size, namely micro-, meio-, and macrofauna. Benthic microfauna consist of animals smaller than 0.1 mm in size, while meiobenthic organisms range in size from 0.1 to 0.5 mm. Macrofauna include benthic invertebrates greater than or equal to 0.5 mm. Protozoans comprise the benthic microfauna; these unicellular organisms, which live aerobically or anaerobically in sediments, feed heavily on bacteria. The meiobenthos are differentiated into temporary and permanent members. Temporary members of the meiobenthos (e.g., macrobenthic larvae) spend only their larval stages among the meiobenthos, in contrast to the Rotifera, Gastro-tricha, Nematoda, Archiannelida, Tardigrada, Copepoda, Ostracoda, Mystacocarida, Tur-bellaria, Acariña, Gnathostomulida, and some specialized membranes of the Hydrozoa, Nemertina, Bryozoa, Gastropoda, Aplacophora, Holothuroidea, Tunicata, Priapulida, Po-lychaeta, Oligochaeta, and Sipunculida, which are permanent members. The meiofauna utilize a wide diversity of habitats, living as interstitial, burrowing, or epibenthic organisms.173 Nematodes dominate the meiofauna in terms of absolute numbers. Some are selective deposit feeders, and others nonselective deposit feeders, epigrowth feeders, and carnivores. Free-living estuarine nematodes have been deemed useful indicators of the environmental quality of estuarine sediments.174 In general, bacteria and benthic algae probably represent the most important food sources of the meiobenthos. Among the macrobenthos, crustaceans, polychaetes, and molluscs commonly dominate in estuaries. Suspension-feeding macrofauna, which primarily feed on phytoplankton, have greater production rates than deposit-feeding species that consume detritus and benthic algae.17
Toxicity and biomarkers of micro-plastic in aquatic environment: a review
Published in Biomarkers, 2021
Kamrul Hassan Suman, Md Niamul Haque, Md Jamal Uddin, Most Shirina Begum, Mahmudul Hasan Sikder
Lower-density MPs like polyethylene (PE) and polypropylene (PP) usually remain at the sea surface and thus easily taken by filter or suspension-feeders while high-density MPs such as PS and PVC sink and aggregate into sediments becoming bioavailable to benthic feeders or deposit-feeders (Browne et al. 2007, Wright et al. 2013b, Chubarenko et al. 2016). Positively charged MPs were found in higher consistency and causes higher toxicological costs than negatively charged MPs to microalgae (Casado et al. 2013, Nolte et al. 2017). The adsorption of MPs could encourage reactive oxygen species production- positively charged PS beads resulted in a higher rate of reactive oxygen species than the negatively charged beads (Liu et al. 2020). Properties of MPs also influences the adsorption of particles. For example, the toxicity of doxycycline and procainamide were increased by PE while uninterrupted the copper toxicity (Davarpanah and Guilhermino 2015, Prata et al.2018).
Biodynamics and adverse effects of CuO nanoparticles and CuCl2 in the oligochaete T. tubifex: Cu form influence biodynamics in water, but not sediment
Published in Nanotoxicology, 2021
In sediment exposures, limited effects were detected for both 65Cu treatments. Our findings indicate a slight decrease in fecal matter production (a proxy for ingestion) as a result of exposure to 65CuO NPs, though the results were not statistically significant. However, previous studies have reported effects of Cu and other metals in sediment on feeding (ingestion rate) and burrowing activity of T. tubifex (Pasteris et al. 2003; Mendez-Fernandez, De Jonge, and Bervoets 2014; Thit et al. 2020). Sediment-associated CuO NPs have been reported to decrease the ingestion rate of L. variegatus (Ramskov et al. 2015) and the burrowing activity of Nereis diversicolor (Buffet et al. 2013). The main focus of the present study was to characterize the biodynamics of 65CuCl2 and 65CuO NPs in T. tubifex. Thus, the limited adverse effects observed for either 65Cu treatment in the present study may be a result of the very short exposure time required to obtain unidirectional influx (4 h). In addition, the low exposure concentration used in the 7-day bioaccumulation experiments (40 µg g−1 dw sediment) is considerably lower than the 28-day LC50-value of 327 µg Cu g−1 dw sediment published by Roman et al. 2007. Furthermore, long-term effects may be particularly important concerning sediment-associated CuO NPs. For example, a study with the freshwater snail Bellamya aeruginosa exposed to sediment-associated CuO NPs indicated that these particles cause oxidative stress and subsequent lipid peroxidation after 14 days of exposure when the oxidative defense was overwhelmed (Ma, Gong, and Tian 2017). In addition, CuO NPs have been suggested to cause delayed effects in deposit-feeders, for example, the polychaete Capitella teleta and the freshwater snail Potamopyrgus antipodarum, as no acute mortality was observed during sediment exposures, but substantially delayed mortality was observed during subsequent elimination in both studies (Pang et al. 2013; Dai et al. 2015).
The first evidence of microplastic uptake in natural freshwater mussel, Unio stevenianus from Karasu River, Turkey
Published in Biomarkers, 2022
MPs are taken up by many invertebrates, as the items are the size of plankton (Browne et al. 2008). The uptake of MPs by invertebrates with a variety of feeding methods such as filter feeders (mussels, barnacles), deposit feeders (lugworms) and detritivores (sea cucumbers, amphipods) have been well documented (Browne et al. 2008, Graham and Thompson 2009, Thompson et al. 2009). Furthermore, it has been reported that among the negative effects of ingested MPs on aquatic organisms are damage to the digestive system, decreased nutrition, growth inhibition and decreased reproduction (Sussarellu et al. 2016, Suman et al. 2021). Several experimental documents have asserted that MPs may migrate from the intestinal cavity to the circulatory system, enter cells and cause adverse effects in the tissues and cells of mussels (von Moos et al. 2012). Morover, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), and dichlorodiphenyltrichloroethane (DDT) from persistent organic pollutants have been found to be carried by plastic items in water column (Mato et al. 2001, Rios et al. 2007, Heskett et al. 2012). Mussels with large geographic distribution are very useful as ideal biological indicators for monitoring microplastic pollution, due to being filter feeders, benthic organisms and important species within intertidal ecosystems (Bricker et al. 2014, Beyer et al. 2017). Goldberg (1975) reported that mussels were one of the first animals used to monitor the water quality, as they met the necessary criteria for a bioindicator species. In addition to being a filter feeder and having wide geographical distribution, mussels are preferred in such studies due to sedentary, long-lived, regionally abundant, easy of sampling, have sufficient tissue mass for analysis, have high tolerance to chemical pollutants and physical changes, accumulation toxins, heavy metals and other particles in their shells and organs (Naimo 1995, Huang et al. 2007, Khan et al. 2018, Premalatha et al. 2020).