Epidemics in the Marine System
Humans influence marine ecosystems in many ways. Direct anthropogenic impacts on marine resources include the removal of organisms such as corals, fish, and mammals and the destruction of habitat, for example, by off-shore drilling for oil, experimental detonation of weapons, use of poisons and explosives to stun and kill fish, incidental release of toxics, run-off of nutrients, and impacts of fishing gear on the sea floor habitat. Increased anthropogenic impacts on the ecosystem may trigger indirect effects such as elevated incidents of disease. For example, release of nutrients from farms or sewage plants can raise nutrient concentrations in coastal areas and tidal backwaters to an extent that fosters blooms of algae and growth of microbes. In the presence of sufficiently high concentrations of excreta, some zoospores, such as Pfiesteria piscicida, are induced to become toxic. The toxics may not only affect the behavior of fish, for example by making them lethargic, but can directly injure their skin, inducing hemorrhaging and bleeding, and impacting their salt balance.
KeywordsExplosive Drilling Sewage Microbe Fishing
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