THIS ARTICLE IS republished from The Conversation under a Creative Commons license.
An oil tanker carrying jet fuel was recently hit by a cargo ship while at anchor 13 miles off the east coast of England. This set off a series of large explosions and a huge plume of black smoke, while a still unknown quantity of jet fuel has spilled into the sea.
We’re marine ecologists at the University of Hull, the city nearest the incident. We know this coast and these seas very well. While it’s too early to say exactly what the consequences will be, we do know that this spill puts at risk one of Britain’s most important stretches of coastline—both for conservation and for commercial fishing.
The collision occurred in the Holderness offshore marine protected area, a region of coarse sandy seabed that supports lots of different species. These include the ocean quahog, an edible clam known to live for over 500 years. The area also acts as a nursery for fish like lemon sole, plaice, and European sprat.
This area overlaps with those designated to protect harbor porpoises and the nearby Humber Estuary and its mud flats, sand dunes, and marshes where thousands of birds spend the winters alongside other important species, such as lampreys and gray seals.
The UK’s largest mainland breeding seabird colony is found just north of the collision site, along the Flamborough and Filey coast. More than 250,000 birds nest there every year, including impressive numbers of guillemots and razorbills. It also hosts species of conservation concern like gannets, kittiwakes, and puffins.
Seabirds return to Flamborough for the start of nesting season in March.
Photograpg: Ifetayo Stewart/ Getty Images
To the south are other protected coastlines and an important breeding site for grey seals. The Wash, where four rivers empty into the same large square-shaped estuary, is found 70 kilometers to the south, in the general direction of drift from the tanker collision. The area has large salt marshes and is another important site for over-wintering birds.
The spill has taken place in a productive fishing area that supports the largest crustacean fishery in Europe, with about £15 million of live lobster landed annually. The mix of coarse sand and cobbles on the seabed provides ideal nursery ground for lobsters as they can create burrows under perfectly-sized stones.
How This May Affect Life in and Around the Sea
Given the ecological and commercial importance of the region, people are right to be worried by the possible effects of spilled aviation fuel, air pollution, and deposition of contaminated soot from the smoke plume. While it is too early to comment on the potential severity of the fuel spill, the nature of the contaminant and the environmental conditions allow us to make some assumptions.
Jet fuel is thinner than crude oil and spreads rapidly to form a film on the surface of the water. It is unlikely that the fuel spilled would lead to heavy oiling of birds or the formation of tar balls and smothering of the sea bed by oily material, as can happen after crude oil spills.
Conditions at the spill site are highly dynamic. There is therefore a good chance the fuel will mix into the seawater below, breaking up the surface slick, potentially exposing the seabed to contaminants. Strong currents, wave action, and relatively coarse sediment help oxygen to mix into the water and sediments, which helps the fuel to degrade more quickly.
In calmer areas areas, particularly where there is lots of sediment suspended in the water (such as within the Humber estuary and parts of the Wash), there may be potential for contaminants to adhere to fine particles in suspension and subsequently sink to the seabed. Fuel will likely take longer to degrade in organic-rich, fine-grained, and poorly oxygenated sediment within the estuary than in offshore areas.
Mud flats in the Humber estuary at low tide.
Photograph: Neil Mitchell/ Getty Images
While the conditions at sea favor degradation, jet fuel is highly toxic and will likely impact species in the water ranging from tiny plankton at the base of the food chain, up to the predatory birds, seals, porpoise, and dolphins at its top.
Animals at the surface and those that regularly break through it to feed or breathe will be especially affected by direct contact with the surface slick. Though seals breed between late October and December, there are still seals at the nearby breeding sites, potentially including young seals.
Even if we do not see high levels of mortality, the incident could not have come at a much worse time for birds as they prepare for breeding season. Adults birds challenged by toxic fuel over the short term may suffer reduced reproductive fitness, although it’s difficult to say for sure at the moment.
It will be some time before we really get the full picture. We still don’t know how much fuel was spilled, its chemical composition and toxicity, how it behaved once it hit the sea, where it will end up, and how long it will last. All these factors will be important if we are to understand how this incident will affect the environment.
