Oily Times

This side of the Exxon Valdez event, there is a certain deadly rhythm and predictability to the story of major oils spills.

First comes the realization that something major has happened. Then comes the panic, as governments and companies try to address something that is so huge that it is technically, in terms of spreading into the wider environment, mainly unstoppable. (This is the stage where booms are seen to be deployed, dispersants sprayed and there is ‘burning off’ of oil.) The agencies and the industries need to try and do something (and they need to be seen to be doing something) but still the black-tide pushes onwards.

Then come the pictures of the stricken wildlife – birds being usually the most obvious first victims (but sadly not the only ones). Interviews with the concerned members of local communities, the fishermen, the wildlife rangers, the representatives of the tourism industries follow. Next we hear promises of compensation – payments promised to cover the costs of the ‘clean-up’ and the economic losses to the local community.

All of this is worthy and I don’t mean to denigrate mitigatory actions taken to protect wildlife and fisheries. However, given the vast quantities of oil flowing into the sea, what chances have booms and dispersants to make much of an impact? There will certainly be questions about how the expectations used in the relevant risk assessments match up to the awful realities now being witnessed. There is already talk of blame. Some will name companies; others will focus on how emergency responses worked out. Many will also hopefully recall that oil spills, like climate change and the greenhouse effects, are part of the modern ‘carbon cycle’; a product of the dependency of our societies on fossil fuels. Indeed, oil spills provide a more public view of these costs compared to the mainly invisible devastation being slowly but surely wrought by climate change. As the tragedy in the Gulf of Mexico unfolds slowly unfolds in coming weeks, it will hopefully help remind us that there is a high price to pay for oil-based energy and that the price may be getting greater.     

Cetaceans are vulnerable to oil and, sadly, the Gulf of Mexico is rich in wildlife including some 19 species of cetaceans. Once-upon-a-time it was suggested that cetaceans were too intelligent to swim into slicks. Regrettably this is not true and the extent of vast slicks may in practice give them little choice anyway. Crude oils are made up of many hundreds of different hydrocarbons. The more volatile ones evaporate most quickly. Typically they are also the more toxic ones. Cetaceans and other wildlife may be poisoned by breathing these fumes. Seabirds and furry mammals use their plumage and pelage for insulation. When they encounter oil, they tend to be fouled by it. This removes their insulation and they try to clean themselves and in doing so ingest oil which causes internal damage. (Even small quantities of ingested oil can kill.)

In the case of cetaceans, insulation is provided by blubber, so they do not become fouled by oil in the same way as these other animals, although the baleen plates of the filter feeding whales might be impacted in this manner, potentially also leading to oil ingestion.

Gaining evidence that highly mobile marine species have been impacted by events out at sea has always been very difficult. This may have lead to impacts on cetaceans of oils spills being under-reported and under-appreciated. Animals that die at sea or which have their health chronically compromised may never be witnessed. Even if dead cetacean bodies wash ashore during a spill, this is not necessarily evidence that they were killed by the spill. The best evidence of the vulnerability of cetaceans comes from the Exxon Valdez event where it could be shown that known individuals from a group of orcas disappeared. Even this evidence is disputed, but there is really no reason to hope that the cetaceans are not as vulnerable as other wildlife to the toxic effects of oil-derived hydrocarbons on their health and survival, and then there will be the indirect impacts on this, especially the loss of their prey, invertebrates, fish and squid. Again such things are very difficult to document and we, at WDCS, shall be watching intently the monitoring efforts that will follow this latest tragic spill.

We clearly need to think very carefully about future oil and gas extraction and use. The Californian governor is reported to have responded to the Gulf of Mexcio spill by closing his coastline to further exploration. It will be interesting to see if this holds and if others follow.

Marine ecosystems are being stressed by many factors, including industrial development, over-fishing, climate change, the introduction of loud noise and numerous others. Oil spills are perhaps the most visible and notorious form of pollution but they are also far from the only problem. But they do serve as a reminder of the vulnerability of our seas and their precious inhabitants; a major oil spill cannot stay 'out of sight and out of mind'!