|Benthos Overview Why should the benthos be monitored ?|
A natural and human origin
Marine biocoenoses on the continental shelf are subject to modifications of natural origin (climate changes) and to numerous disturbances due to human activities, either directly (dragging fishing gear, aggregate extraction, shellfish farming) or resulting from chronic pollutions (urban, industrial or agricultural waste disposal) or accidental input (oil spills, introduction of exogenous species).
Disturbances to benthic species can occur through different mechanisms affecting the water mass or the sea floor.
A local evaluation difficult to carry out
The causes of disturbance to benthic species and the mechanisms involved are often numerous in the same area. For that reason, it is often difficult in a local survey to estimate and distinguish the part linked to “natural” variability from the part due to human activities.
Follow-up and comprehension of the evolutions
Long-term benthic monitoring is essential, in order to estimate the changes observed in space and time. The perception of various modifications, between the different biocenosis and the different selected points, helps to improve our hypotheses. However, more specific surveys will be necessary in order to fully understand the modification involved and to assess the respective contributions of the different causes.