Plankton stress responses from PAH exposure and nutrient enrichment

Abstract

The hypothesis that the nature and force of PAH stress responses from plankton systems are coupled to the nutrient status of that system was tested in a mesocosm experiment. Four treatments were applied consisting of control (Cn), pyrene exposed (Py), nutrient spiked (Nu), and nutrient spiked and pyrene exposed (NuPy) groups in replicate bags (n = 3) representing plankton communities including bacteria, phytoplankton and zooplankton. Regardless of nutrient status, all the Py mesocosms were affected directly with decreases in chlorophyll a concentrations to 20% of control values on Day 1. Primary production was also significantly lower (< 50%) than Cn communities in both Py and NuPy communities after the first pyrene exposure. Indirect effects were observed as increased bacterial activity due to nutrient release from algal death, thereby channelling growth to another trophic level. With time the plankton system became top-down controlled, dominated by zooplankton, which was also the trophic group experiencing the longest lasting effect on structure. The occurrence of late effects in the zooplankton communities were seen in all treatments, but the magnitude of the effects was dependent on the nutrient status, most probably because of a larger trophic transfer of the contaminant. To improve our understanding of contaminant effects on food webs in natural communities, it is imperative that interactions between trophic levels in relation to abiotic factors are investigated.

Effects of Macondo Oil on Phytoplankton from Grand Isle, Louisiana

“…The extent of inhibitory effects depends very much on the composition of the oil. Analogous studies have examined the effects on natural phytoplankton communities of crude oil [28][29][30][31][32][33][34], pyrene [35], and fuel oil [23,29,36,37]. The results of those studies have been generally consistent with the studies on individual species.…”

The chronic effects of oil pollution on marine phytoplankton in a subtropical bay, China

“…The inhibition of high WAF concentrations was related to the toxicities of hydrocarbon, especially PAHs (Fleeger et al 2003). The biological and chemical composition of phytoplankton would be changed at the high concentration contamination (Fiala and Delille 1999;Shi et al 2001;Hjorth 2008). The toxicity of oil WAF worked by the decrease of CO 2 and nutrients absorption (Koshikawa et al 2007;Sargian et al 2007), inhibition of photosynthesis and respiration (Singh and Kumar 1991;Aksmann and Tukaj 2008;Stepaniyan 2008), damage of cell structure and membrane system (Sikkema et al 1995), interference of antioxidation defending system operation (Aksmann and Tukaj 2008;, and blockage of nuclear acid and protein synthesis (Bopp and Lettieri 2007).…”

PAHs reduce DNA synthesis and delay cell division in the widespread primary producer Prochlorococcus

“…Prochlorococcus DNA synthesis could be delayed or interrupted as a result of exposition to UV radiation or phosphorous and light deprivation (Vaulot et al, 1995, Kolowrat et al, 2010. Previous studies describe the decrease of Prochlorococcus growth rates and even cell mortality in the presence of determinate concentrations of PAHs (Echeveste et al, 2010a(Echeveste et al, , 2011Hjort et al, 2008;Gilde and Pinckney, 2012). The presence of PAHs in the ocean may involve an effect on DNA synthesis and cell division of Prochlorococcus as was observed in other organisms (e.g.…”