Marine reinforcements

The ocean is in poor health. Its immune system is buckling under the strain. The fight against pollution, one of the main ailments sapping the health of our seas, is becoming a European research priority. In this fight, researchers are also finding some strong allies in the form of marine organisms themselves.

Monitoring toxic phytoplankton at the Centre Ifremer laboratory at Nantes. © Ifremer/Olivier Barbaroux Monitoring toxic phytoplankton at the Centre Ifremer laboratory at Nantes. © Ifremer/Olivier Barbaroux

Biomonitoring undertaken by Mytilos project Researchers. © IEO & Ifremer Biomonitoring undertaken by Mytilos project Researchers. © IEO & Ifremer

In the Philippines, teams from the Dekonta company (CZ) are working on bioremediation solutions following the oil spill which struck the coasts around the Guimaras Straight in 2006. © Jakub Kanta In the Philippines, teams from the Dekonta company (CZ) are working on bioremediation solutions following the oil spill which struck the coasts around the Guimaras Straight in 2006.
© Jakub Kanta

Pollution from the Prestige: oil slick reaching Punta Rocundo in Galicia (ES) 2002 and Erika in France in 1999. © Cedre Pollution from the Prestige: oil slick reaching Punta Rocundo in Galicia (ES) 2002 and Erika in France in 1999.
© Cedre

Sooner or later, nearly all terrestrial pollution ends up tipped into the sea. Despite its huge size and self-purifying properties, the ocean is unable to absorb this incessant stream of pollution of every kind deriving from human activity. For Christophe Rousseau, deputy director of Cèdre(1), “marine pollution is such a vast phenomenon that a uniform response is impossible. At Cèdre, we concern ourselves solely with accidental pollution, most of it from shipping. Even taken on its own, this problem area involves a multitude of technological constraints. The task is less vast, however, than for the chronic pollution caused by land-based human activities. This is infinitely greater and more varied than that caused by ships.” From this brief overview one thing is clear: each pollution has its own particular solution and each source of contamination its own specific action! In achieving this tangle of research objectives, a little help from nature can be very welcome.

From sentinel mussels …

Take a cage, a handful of mussels, an anchoring system... and you have a coastal water pollution surveillance station. The simplest solutions are at times the most effective. The designers of the Mytilos project, launched in 2004, clearly understood this in choosing active biomonitoring for developing a network to control chemical contaminants. The project has a budget of more than € 1.5 million, including € 800 000 from the Interreg III B Medocc programme, financed by the ERDF(2). The objective of Mytilos is precisely to use active biomonitoring, a simple and inexpensive technology, for pollution surveillance in the western Mediterranean. “We are severely lacking in homogeneous information on the state of contamination of this fragile sea, the waters of which are renewed very little owing to its semi-enclosed structure,” explains Charlotte Blottière, project coordinator at Toulon Var Technologies, which is organising the Mytilos network with scientific coordination by Ifremer. “The states that had responsibility in this area did indeed regularly monitor water quality. But each used its own monitoring  methodology, defined at national level, which of course made it impossible to compare results at trans-regional level.”

Biomonitoring consists of using living organisms, in this case mussels, to assess the level of chemical contamination of a particular environment. Mussels have been selected as sensors because they are constantly filtering sea water in the search for the plankton on which they feed. Physiologically they are perfect bio-accumulators, as they concentrate the different substances contained in the oceans – which makes them remarkable tools for measuring chemical contamination! “Using mussels as biosensors for pollution measuring was suggested in the 1970s, but the first trials used species taken directly from the environment. This approach posed a number of problems, such as assessing the original contamination, comparing results from different species, or the fact that mussels were always naturally available on those parts of the coast where pollution was to be monitored,” Charlotte Blottière explains. “To alleviate these gaps, Mytilos favours active biomonitoring. After locating the sites by GPS, experts place the artificial stations of mussels themselves, thanks to caging, a system of baskets and anchorings. All the specimens are of the same species (Mytilus galloprovincialis) and come from the same reference batch, which makes it possible to precisely assess the original contamination.” At the end of 2007, an initial snapshot of contamination levels in the western Mediterranean basin was presented by the Mytilos network’s initiators. Even if the results do not diverge fundamentally from those obtained previously by national studies, this system marks the start of cooperation and a standardisation of pollution monitoring methods at trans-regional level. Mytimed, a similar project, was also launched in 2006 to extend the existing network to the eastern Mediterranean.

… to oil-eating bacteria

Marine pollution immediately conjures up images of oil slicks. But whilst the spilling of crude oil into the sea represents a serious danger to the environment, these contaminants have the one advantage of being biodegradable. This is because certain bacteria strains that are naturally present in the marine environment use oil as a source of carbon and hence of energy. The speed of this process varies according to the type of crude oil, bacteria and ecosystem. But communities that depend on the sea for their livelihood cannot sit and wait for nature to act. A little help is sometimes necessary to speed up biodegradation. “These organisms exist naturally in most of the environments which are polluted by crude oil. By optimising temperature, oxygen concentration and nutrient levels, we can create ideal conditions for bacteria to proliferate, which has the effect of speeding up biodegradation,” says Petra Zackova, chief laboratory researcher in the Remediation and Environment department at Dekonta, a Czech company specializing in pollution prevention and absorption. Ms Zackova has been delegated to the Philippines via the Community Mechanism for Civil Protection to advise the local authorities on different forms of bioremediation for tackling the oil slick which has been fouling the coasts around Guimaras Straight since August 2006. With its many mangroves and coral reefs, this region contains a biodiversity that is unique in the world and provides a livelihood to a whole community of small-scale fishermen.

“Initially we took soil and water samples at different sites to confirm the existence of native bacteria and to determine their ability to break down oil. The laboratory test results showed that, with the addition of appropriate catalysts, local microflora could be used. For example, in one month, the aquatic bacteria that had been stimulated in this way had broken down around 90% of the hydrocarbons,” Petra Zackova continues. “We are now working on isolating these bacterial strains, to make sure their use does not represent any danger to the environment. Certain of these organisms could, for example, give off toxins that are damaging to the overall target ecosystem.” Bioremediation is not a miracle solution, and the intention is to use it only to complement existing mechanical and chemical methods of combating oil spills. But it does remind us of the incredible potential of the oceans, hardly 1% of the biodiversity of which has been recorded until now.

Julie Van Rossom

  1. Centre of Documentation, Research and Experimentation on Accidental Water Pollution, a French organisation that is a world reference in its area.
  2. Interreg III B Western Mediterranean Méditerranée occidentale (Medocc) is a programme to promote European cross-border cooperation. It is supported by the European Regional Development Fund.


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