Copepod Production in Warm, Oil Polluted Environment: A Laboratory Investigation of Temora stylifera (Dana, 1849) Adapted to the Gulf of Guinea
Abstract Recent studies suggests that sea surface warming, evidently caused by greenhouse gas emissions, magnifies the toxicity of petroleum hydrocarbons on marine copepods. We assessed this understanding using Temora stylifera, a calanoid copepod common in the Atlantic Ocean and its surrounding waters, as a case study. The copepod was exposed to moderate (0.2 μg.l-1) and high levels (2.0 μg.l-1) of pyrene under three warming scenarios: (i) a no warming control at 28 °C, the surface temperature of the Gulf of Guinea during stable hydrographic period, (ii) moderate warming (+2 °C) and (iii) severe warming (+4 °C) above the control. Food ingestion rate of the copepod increased with warming without significant effect from the pollutant. Feacal pellet production rate (FP) increased by about 86% when the animal was exposed to moderate warming and pyrene at the same time, signifying reduced assimilation of food ingested in these conditions. Lowest FP (3.5 ± 1.1 copepod-1.day-1) indicating increased food assimilation occurred when the stressors were presented either alone or together. Egg production rate and efficiency of the copepod were impacted by only warming, decreasing by ≈60% under both warming scenarios, consistent with previous observations. Mortality rate increased by ≈ 40 % when pyrene pollution was elevated from nought to the highest level. It did not change significantly with temperature, suggesting warming did not exacerbate the lethal effect of pyrene to T. stylifera. These results are contrary to observations on other copepods and highlight the unique responses of Temora to sea surface warming and petroleum pollution.