Oil pollution and plankton dynamics 1. Controlled ecosystem experiments during the 1980 spring bloom in lindåspollene, Norway

Removal and Biodegradation of Phenanthrene, Fluoranthene and Pyrene by the Marine Algae Rhodomonas baltica Enriched from North Atlantic Coasts

This study is focused on the removal, accumulation and degradation of three environmental ubiquitous polycyclic aromatic hydrocarbons (PAHs), phenanthrene (PHE), fluoranthene (FLA) and pyrene (PYR), by the marine alga Rhodomonas baltica enriched from the English Channel. After separation, purification and culture in several phases, R. baltica was exposed to PAH concentrations that are frequently encountered in the field in several anthropized environments. The results showed that R. baltica can grow under PAH stress, efficiently remove up to 70% of these compounds from the medium by 216 h of culture and selectively bioaccumulate PAHs by their hydrophobicity. Between PHE, FLA and PYR, phenanthrene was the compound with higher degradation rates throughout incubation. The equilibrium partitioning theoretical approach showed that physico-chemical partitioning, rather than active bioconcentration, was the major factor governing the bioaccumulation, outlying a potential application in decontamination processes for this species.

Fingerprinting petroleum hydrocarbons in plankton and surface sediments during the spring and early summer blooms in the Galician coast (NW Spain) after the Prestige oil spill

Plankton samples (20-350 microm and >350 microm) collected at three transects along the Galician coast (NW Spain) were analysed for individual aliphatic and aromatic hydrocarbons by GC-MS. Sample collection was performed in April-July 2003, after the Prestige oil spill (November 2002), to determine whether the hydrocarbons released into the water column as a consequence of the spill were accumulated by the planktonic communities during the subsequent spring and early summer blooms. Surface sediments were also collected to assess the presence of the spilled oil, removed from the water column by downward particle transport. Plankton concentrations of PAHs (Sigma14 parent components) were in the range of 25-898 ng g(-1)dw, the highest values being close to coastal urban areas. However, the individual distributions were highly dominated by alkyl naphthalenes and phenanthrenes, paralleling those in the water dissolved fraction. The detailed study of petrogenic molecular markers (e.g. steranes and triterpanes, and methyl phenanthrenes and dibenzothiophenes) showed the occurrence of background petrogenic pollution but not related with the Prestige oil, with the possible exception of the station off Costa da Morte in May 2003, heavily oiled after the accident. The dominant northerly wind conditions during the spring and early summer 2003, which prevented the arrival of fresh oil spilled from the wreck, together with the heavy nature of the fuel oil, which was barely dispersed in seawater, and the large variability of planktonic cycles, could be the factors hiding the acute accumulation of the spilled hydrocarbons. Then, with the above exception, the concentrations of PAHs found in the collected samples, mostly deriving from chronic pollution, can be considered as the reference values for the region.