Analysis of the feeding ecology of the sea anemone Bunodosoma zamponii: populations under differential anthropogenic pressures

The feeding ecology of two populations of the sea anemone Bunodosoma zamponii Schama and Solé-Cava, 2012 living under different anthropogenic pressures in the coast of Mar del Plata (Buenos Aires, Argentina) was studied. One population was located in Las Delicias (LD, an impacted site adjacent to a wastewater treatment plant) and another in Punta Cantera (PC, the reference site). Both populations of sea anemones were monitored for two years and their trophic ecology was analyzed. The mytilid Brachidontes rodriguezii (d'Orbigny, 1842) was the main item found throughout all seasons. Prey diversity was highest in PC during autumn and lowest during winter for both sites. Prey abundance was lower in LD during autumn and summer. Additionally, prey items were larger in PC during autumn, winter and summer. Item capture probability in autumn was significantly lower in LD. Altogether, the results indicate that the diet of B. zamponii differed significantly between sites and such differences varied throughout the year. Most of the differences occurred during autumn and winter, which corresponds with a greater concentration of organochlorine pesticides, chlorpyrifos and polychlorinated biphenyls in anemones from LD registered in previous studies. Overall, this study provides significant knowledge on the feeding ecology of Bunodosoma zamponii that complements the existing information and will provide meaningful insight into the current status of this anemone’s populations.

Occurrence of polychlorinated biphenyls (PCBs) in the sea anemone Bunodosoma zamponii, sediments and seawater from the southwestern Atlantic

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulable organic compounds. The occurrence of PCBs was assessed in two populations of the intertidal sea anemone Bunodosoma zamponii living under different anthropogenic strains. One location was in vicinity to a wastewater plant (Las Delicias, LD), and the other was a preserved location chosen as a reference site (Punta Cantera, PC). Anemone populations were sampled 4 times (spring, summer, autumn and winter) throughout a year, in addition to seawater and sediment from those areas. PCB loadings ranged from 2.89 to 79.41 ng L^-1 in seawater samples and from 0.07 to 6.61 ng g^-1 dry weight in sediment samples. Total PCB levels ranged from 0.22 to 14.94 and 2.79 to 24.69 ng g^-1 wet weight in anemones from PC and LD, respectively. PCBs concentrations in anemones from LD were significantly greater than PC during spring, summer and winter. The congeners 18 and 44 prevailed in seawater samples, 44 and 52 in sediment and 18 and 132+153 in anemones. Redundancy analysis integrated PCB levels from all matrixes and bolstered contrast between sampling sites. Seasonality was also a relevant factor since during winter PCB loading was greater in sediment and anemone samples, coincident with the rainiest season. Disparity between sites could be due to LD's proximity to the wastewater plant, effect of littoral drift direction and/or asymmetries in anemones physiological condition.