Eutrophication:
- Over the past century, a wide range of human activities--the intensification of agriculture, waste disposal, coastal development, and fossil fuel use--has substantially increased the discharge of nitrogen, phosphorus, and other nutrients into the environment
- the increased nutrient content of the water causes algal blooms, once the algae die, they fall to the bottom of the ocean and are decomposed. Their decomposition leads to the use of dissolved oxygen, leaving the ocean with a hypoxic zone (area with no dissolved oxygen)
- Hypoxia changes the energy flow of marine systems, altering the dynamics of the food chain; the increased prevalence of N and P in aquatic ecosystems boots the primary productivity, which means that there is an explosion in the base of the aquatic food web.
- The algal blooms that can occur as a result are linked to both red and brown tides, which can result in human shellfish poisonings, fish kills, and the deaths of marine mammals.
- Studies have shown that it can lead to smaller reproductive organs, and females, once exposed to the lowered oxygen levels tended to produce less eggs.
- Some fish are even rendered unconscious due to the lack of oxygen and cannot escape the dead zone.
- Can be good for invasive species (e.g. comb jellies taking over the black sea)
The EPA has pinpointed two main approaches to solving the problem of nutrient enrichment, reducing nitrogen loss from land and to increase denitrification
1) reducing nitrogen loss-
- applying nitrogen fertilizer at not more than recommended rates
- implementing alternative cropping systems
- improving manure management
- point source nitrogen pollution, applying tertiary water treatment could reduce the nitrogen output from sewage treatment plants
2) denitrification
- riperial buffers
- WETLANDS
RAMSAR CONVENTION:- The Convention on Wetlands is an intergovernmental treaty adopted on 2 February 1971 in the Iranian city of Ramsar, on the southern shore of the Caspian Sea
- Ramsar is the first of the modern global intergovernmental treaties on the conservation and sustainable use of natural resources
- The Ramsar List of Wetlands of International Importance now includes over 1,675 sites
- The nation with the highest number of sites is the United Kingdom at 164
- the nation with the greatest area of listed wetlands is Canada with over 130,000 km²
- Presently there are 156 contracting parties, up from 119 in 2000 and from 18 initial signatory nations in 1971
- There is a standing committee, a scientific review panel and a secretariat. The headquarters is located in Gland, Switzerland shared with the IUCN.