Biochemical responses of earthworm Eisenia fetida exposed to cadmium-contaminated soil with long duration

The biochemical responses of the earthworms, Eisenia fetida, exposed to a series of Cd concentrations (0.00, 1.25, 2.50, 5.00 and 10.00 mg Cd2+ kg−1 soil) for up to 8 weeks were investigated, aiming to evaluate the sublethal effects of Cd with long exposure and to explore the potential for applying these responses as biomarkers to indicate the Cd-contaminated soil. The following biochemical parameters were determined: cytochrome P450 (CYP) contents and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-s-transferase (GST). Cadmium concentrations in all earthworms were apparently accumulated in 4 weeks, and showed minor changes in weeks 6–8 compared to the first 4 weeks. CYP presented a significant elevation in 2–4 weeks and a decline in 6–8 weeks in each treated group. The activities of SOD and CAT showed an obvious increase with exposure of 6–8 weeks while their levels were not affected in 4 weeks in each treated group. GST activity revealed significant activation starting from week 4. This study confirmed the significance of applying a suite of biomarkers rather than a selective choice to assess the impact of pollutants on organisms. It also indicated that the observed effects were more dependent upon exposure duration than dose.

Biochemical responses to ocean acidification contrast between tropical corals with high and low abundances at volcanic carbon dioxide seeps

At two natural volcanic seeps in Papua New Guinea, the partial pressure of carbon dioxide (pCO2) in the seawater is consistent with projections for 2100. Here, the cover of massive scleractinian corals Porites spp. is twice as high at elevated compared with ambient pCO2, while that of branching corals such as Acropora millepora is greater than twofold reduced. To assess the underlying mechanisms for such community shifts under long-term exposure to elevated pCO2, biochemical parameters related to tissue biomass, energy storage, pigmentation, cell protection, and cell damage were compared between Porites spp. and A. millepora from control (mean pHtotal = 8.1, pCO2 = 323 µatm) and CO2 seep sites (mean pHtotal = 7.8, pCO2 = 803 µatm) each at two reefs. In Porites spp., only one of the biochemical parameters investigated (the ratio of photoprotective to light-harvesting pigments) responded to pCO2, while tissue biomass, total lipids, total proteins, and some pigments differed between the two reefs, possibly reflecting differences in food availability. Furthermore, some fatty acids showed pCO2 –reef interactions. In A. millepora, most pigments investigated were reduced at elevated pCO2, while other parameters (e.g. tissue biomass, total proteins, total lipids, protein carbonyls, some fatty acids and pigments) differed between reefs or showed pCO2–reef interactions. Tissue biomass, total lipids, and cell-protective capacities were distinctly higher in Porites spp. than in A. millepora, indicating higher resistance to environmental stress in massive Porites. However, our data suggest that important biochemical measures remain relatively unaffected in these two coral species in response to elevated pCO2 up to 800 µatm, with most responses being smaller than differences between species and locations, and also when compared with responses to other environmental stressors such as ocean warming.