photographist

“Coastal ecosystems are highly diverse, both in their nature or function, but very vulnerable to human activities that are being developed increasingly with the population and coastal tourism. To protect them we must know what will affect them. Ecosystems are composed from the high tide to low tide marks in zones. In these zones, the zonation of algae, fixed organisms, occurs in distinct belts. There is the Fucus serratus belt, then the Ascophyllum nodosum, etc. Everywhere we find the same algal zonation, with variations of species. With each algal canopy are associated algal and animal species that live together. When the canopy is removed, it disrupts all these species and it upsets the food chain and surrounding ecology . I work on the impact of commercial harvesting of seaweed.

At the base of the food chain, the algae are eaten by grazing snails, periwinkles, and smaller organisms which will then be eaten in turn. If we remove algae, there is a loss of these grazers and higher organisms. The harvesting of other algae and higher temperatures favour the appearance of green algae on the available substrata - their growth increases with the onset of nitrates in the water. Green algae are opportunistic algae that often develop at the expense of other algae; they compete with the algae that would have settled if there had been no loss of the canopy. They often succeed because they are more resistant and have a faster growth than other algae. They are currently being studied for use as a biofuel.”

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