Increasing
habitat destruction and ecosystem alteration either by physical (e.g., landfills,
sedimentation), chemical (e.g., pollution) or biological means (e.g., the introduction
of non-indigenous species) constitutes the most widespread, frequently irreversible,
human impact on the coastal zone.
Poorly planned coastal urban and industrial development – including the indiscriminate exploitation of coastal resources and the development of recreational, harbour and aquaculture facilities – has considerably changed the natural coastline and reduced the areas previously covered by dunes, wetlands and mangroves. These ecosystems, and the wildlife inhabiting them, suffer all over the world. In many places fisheries are affected as a result, as fish spawning and nursery grounds are degraded. Sewage and various chemical compounds released into the marine environment may significantly affect members of ecosystems: in extreme cases, this may lead to the destruction of whole ecosystems. The chemical compounds of pre-eminent contemporary concern are: nutrients; substances disrupting endocrine functions; a group of substances classified as persistent organic pollutants (POPs); petroleum hydrocarbons (largely from major accidental oil spills at sea); and, in a few cases, metallic compounds, such as those of mercury, cadmium, tin and copper.
[…]Natural marine and coastal ecosystems represent tangible economic goods
and provide valuable services, such as the treatment and assimilation of wastes,
protection from storms, food production, raw materials, recreational amenities,
genetic resources, and employment opportunities. The global value of the goods
and services provided by marine and coastal ecosystems is roughly double of
value of those provided by terrestrial ecosystems, and is comparable with the
level of global GDP.
| GESAMP71:1 |