Oceanography and ecosystem dynamics

¶ … Threats to Ecosystem: Cause and Solution

There are various threats to the marine ecosystem. Three of the most common are:

(a) Pollution from point and nonpoint sources; (b) Overexploitation of marine stocks that can deplete marine animals; and (c) Global climactic and oceanographic events that contribute to sea level rise, coastal erosion, storm, and intensified sea temperature

Pollution

Pollution, as threat to the marine system, stems from point and non-point sources. A major source is plastic where plastic impacts the marine system by as much as 90-95% in some areas. Some areas of the ocean are completed y saturated by plastic (forming into piles called 'gyres'), and often mistaken for food by marine animals such as turtles, small feeders, and sea birds. A large percent of them have plastic in their guts causing their digestive systems to be blocked with the stuff and for them to starve. Plastic also acts as carrier for other pollutants extending the damage to marine life by killing and destructing much of the marine ecosystem.

Noise is another pollutant, since underground animals rely on sound for distance. Man, however, by increased use of the sea is changing the underwater sound environment leaving certain animals, such as whales, stranded.

Other sources of pollution include climate change that makes the oceans more acidic; eutrophicaiton where chemical nutrients are being absorbed into the oceans resulting in tremendous parts of the ocean putrefying; industrial pollution from factories and mining sources serves as toxic food for marine animals (and, in turn, to humans); whilst pharmaceutical pollution harms reproduction and mortality of marine animals.

Remedies include monitoring ocean pollution that includes plastic (and general pollution), pharmaceutical contamination, discouraging eutrophicaiton, and decreasing sonar levels. (Save Our Seas Foundation)

2. Overexploitation of marine stocks

Overexploitation or over fishing may lead to resource depletion and with endangered and threatened species disappearing from our life.

Humans exploit more than 400 marine species -- far more than on land and far more than they need to - and modern fishing techniques have exacerbated tendency to over fish. The problem is so bad that the UN Food and Agriculture Organization (FAO) estimates that over 25% of the world's fish stocks are incompletely depleted and that as high as 50% are totally depleted (The State of World Fisheries and Aquaculture (SOFIA)). In fact, about 90% of the world's predatory fish are virtually non-existent (ibid).

Over fishing has direct and indirect effects, with direct effects reducing and wiping out the number and size of huge populations of marine animals, whilst indirect effects can lead to suffocation and trapping of marine animals by, for instance, nets that are left on the ocean floor. Another indirect effects includes tropic cascading effects where the sea marine level is dislodged with predators removed resulting in cascading effects throughout the marine ecosystem.

3.Global climactic and oceanographic events

Not only does increase of temperature level effect marine life, but acidification, caused by climate changes, also impedes organisms in various ways, not least to build their shells, whilst changes in cloud cover and sea ice affect the light supply to the ocean.