Environmental Engineering Reference
In-Depth Information
10
PLASTICS IN THE OCEANS
Over 70% of the Earth's surface is covered with water, mostly bodies of salt
water that together constitute the global ocean system. The few percent of
fresh water on Earth is trapped within the arctic ice mass, in groundwater,
or in rivers and lakes. The oceans support a variety of marine life ranging in
size from the tiny nano-planktons to the giant whales. This intricate ocean
ecosystem also supports life on land. Life on terra is only possible because of
the numerous ecosystem services (benefits humans receive from ecosystems)
provided by the oceans (Beaumont et al., 2008). These include carbon
regulation (half the primary photosynthetic production harnessing solar
energy, occurs in oceans), acting as a sink for acidic and carbonic gases
produced on land, nutrient cycling, climate regulation, and provision of
seafood. The ocean plankton produces over half the oxygen in the
atmosphere and nearly 15% of the world's protein is from seafood. The global
catch of fisheries is approximately 90 million tons per year (Roney, 2012)
and the fishery serves as a perennial source of renewable food. Overfishing
and general mismanagement of the resource, however, have resulted in more
than half the global fish stocks being already fully exploited. Having a
healthy, vibrant, functional ocean system is critical to sustainability of life on
land.
But the health of world's oceans has already been seriously compromised
and is rapidly deteriorating. Gradual acidification of oceans from burning
of fossil fuel on land, climate change-driven increase in the average water
temperatures, eutrophication in areas where nutritive pollutants
contaminate the waters, and drastic changes in native ocean communities
due to exotic invasive species, are all growing stresses on the ocean ecology.
The pollution load on the oceans from chemicals, oils, and fertilizers has
increased dramatically over the recent decades (Islam and Tanaka, 2004).
A recent addition to this burgeoning list of ocean stressors is the influx of
plastic waste into the oceans (Copello and Quintana, 2003; Derraik, 2002;
Moore, 2008; Moore et al., 2001; Moret-Ferguson et al., 2010). The waste
ranges from large plastic objects (for instance building debris from the
Japanese tsunami) to the invisible plastic microparticles dispersed in
seawater and in beach sand, worldwide (Saido, 2014).
Search WWH ::




Custom Search