Hope may be in sight for the Deepwater Horizon clean up operation as Spanish researchers show the rapid recovery of wild mussel populations following a similarly disastrous oil spill. 

In November 2002, the tanker Prestige split in two, disgorging over 60 000 tonnes of oil into the Atlantic Ocean. The Galician coastline, Europe's largest producer of mussels, was one of the worst affected areas. Miren Cajaraville led a team at the University of the Basque Country, Leioa, to assess the impact of the spill on the reproductive capabilities of wild mussel populations. 

Mussels are commonly used as a gauge of marine pollution levels as they are inactive and do not move to feed, so accumulate high levels of contaminants from their environment. Cajaraville monitored the levels of a protein that control the development of sex cells in females along with other indicators of abnormality, such as premature cell death and abnormal reproductive organ development to determine the effect of the oil-contaminated waters on the mussels. 

Shortly after the spill a number of deviations from the norm were observed, says Cajaraville, including a significant reduction in the size of the reproductive organs. But, as the small organs still contained mature sex cells, it is uncertain in this case whether size really does matter. 

Gordon Watson, an expert on reproduction in marine invertebrates from the University of Portsmouth in the UK highlights the complexity involved in 'teasing apart the impact of oil from any underlying influences, including other pollutants already present.' But Cajaraville says that the data shows a very clear effect caused by the oil spill: 'Our conclusion is that there are transient effects one year after the oil spill, and it seems that the mussels were able to cope and adapt.' 

This could be good news for similar invertebrate species affected by oil leaked from the Deepwater Horizon rig in the Gulf of Mexico. Mike Moore, an environmental pathologist at Plymouth Marine Laboratory in the UK comments that the method developed by Cajarville's group could be 'readily transferred to monitoring the current oil disaster,' and adds that he wouldn't be surprised to see further work using these methods to monitor the recovery of other invertebrates affected by the Deepwater Horizon spill. 

Fran Burgoyne 

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