Bioaccumulation of metals in calanoid copepods by oral intake

Abstract

We demonstrated that oral intake of water by two calanoid copepods, Pseudodiaptomus annandalei and Eurytemora affinis takes place and has implications for their ecotoxicology. In the first experiment, copepods were exposed to a dyed medium, which allowed us to visually examine the possibility of water uptake by the copepod. We observed that both copepod species were taking in water orally and evacuated dye at different speeds. This exposure left concentrated dye in the guts of the copepods indicating adsorption into the gut epithelium. This was further demonstrated by exposing both copepod species independently to dissolved metals (Cd,17 µg/L; Cu,13.8 µg/L; Ni, 29.3 µg/L) and to dietary metals (Cd,18.8 µg/g; Cu, 35.3 µg/g; Ni, 32.5 µg/g). The results showed that although the concentration of dissolved metals they were exposed to were lower than those of the dietary metals, nevertheless, uptake of metals by both copepod species from the dissolved phase alone was substantially higher than from dietary exposure. This provides clear evidence to support our hypothesis that higher metal body burden observed in copepods exposed to dissolved metals than in those exposed to dietary metals is an implication of oral intake of water. P . annandalei showed higher excretion rate of metals when exposed to dissolved metals than E . affinis . However, the excretion rate of metals from both copepod species exposed to dietary metal was similar. We conclude here that both copepod species take in water orally. Our study further showed that metal uptake depends on the exposure routes and the uptake and excretion rates are dependent on the type of metals, amounts and the species.

Partitioning of heavy metals in different environmental and biotic components in the coastal waters of the Straits of Malacca, Peninsular Malaysia

“…A significantly higher (p<0.05) concentration of heavy metals in Juru waters, copepods and sediments compared to those in Gula estuary might be attributed to industrialization and urbanization along the Juru coastal area. Wang and Fisher (1998) and Kadiene et al (2019) found that copepods can completely assimilate ingested trace elements Metal concentrations in estuarine waters fluct -1 Fig. 3 Comparison of Cd, Cu, Pb, and Zn concentrations (μg g ) in sediment throughout the study period in Juru and Gula estuaries.…”

“…The nMDS showed distinct separation of two study sites in terms of metals contents in copepods and sediments, indicating that high metal contents in sediments would be available to copepods and would ffect the health of marine food chain. Fang et al (2006) and Kadiene et al (2019) reported that copepods have high capacity of accumulating and bioconcentrating trace metals and can be used as an effective biological indicator for assessing and monitoring metal contamination in marine environment. In addition, Wang and Fisher (1998) also noted higher fraction of metals found in copepods' soft tissues compared to those obtained from water indicating higher uptake rate of metals through ingestion oted that heavy metals were highly persistent in sediment and biological compartments, such as copepods, making them suitable markers for environmental health monitoring.…”

Ocean Acidification-Mediated Food Chain Transfer of Polonium between Primary Producers and Consumers

“…Studies have reported that copepods create feeding currents and selectively ingest food particles [ 87 , 88 , 89 ]. Kadiene et al [ 20 ] demonstrated that metal uptake in copepods from the dissolved phase was significantly higher than metals from their diet.…”

“…One of the overarching effects of OA on phytoplankton communities is that phytoplankton will likely alter the chemical speciation of trace metals [ 4 , 17 , 18 , 19 , 20 ]. Phytoplankton concentrate metals and transuranic elements from surrounding waters [ 21 , 22 , 23 , 24 , 25 ].…”

Susceptibility of the Non-Targeted Crustacean Eurytemora affinis to the Endocrine Disruptor Tebufenozide: A Transcriptomic Approach

“…They provide essential ecosystem services by supporting the maintenance of fish of economic importance. They are thus suitable model organisms for ecotoxicology and genomics studies [2,4,5] due to their primordial position in the trophic chain, copepod ubiquity, diversity, and capacity to transfer pollutants to higher trophic levels [6][7][8][9][10][11][12].…”