1998 Year of the Ocean Ocean Living Resources 



The various land-based sources of pollution affect marine biodiversity in many ways. Soil 

 erosion and contamination from pesticides and fertilizers all degrade ocean habitats. Chemical 

 pollution also can cause physiological effects such as increased mortality rates, decreased 

 growth, impaired reproduction, genetic mutations, tumors, disease, or endocrine disruption. 

 Pollution can cause physical as well as chemical harm to ocean organisms and their habitats, for 

 instance, by smothering ocean bottom communities, blocking pathways, entangling animals, or 

 by changing the level of light availability for photosynthesis. Eutrophication, the process of 

 organic enrichment, results from excess nutrients from runoff (particularly nitrogen in the coastal 

 zone). Eutrophication can cause harmful or noxious algal growth, shifts in food chains, oxygen 

 depletion (anoxia), and other undesirable effects on marine ecosystems. Finally, pollution is 

 believed to contribute to the observed increase in the occurrence of blooms of unicellular marine 

 algae, which can cause mass mortalities in a variety of marine organisms and cause illness and 

 even death in humans who consume contaminated seafood.'' 



Alterations of Physical Habitat 



The health of living marine resources is dependent upon the integrity of their habitat. No 

 organism can live in isolation; all are dependent upon the health and biodiversity of the 

 surrounding ecosystem, which provides the necessary ingredients of life. However, human 

 activities can change, degrade, or destroy these habitats and the biodiversity associated with 

 them. Habitat degradation is an important factor in the decline of many species, salmon being the 

 prime example. Moreover, as world population increases, so do demands on the coastal 

 environment. According to the United Nations, more than half of the world's population lives 

 within 60 km of the shoreline and this could rise to 75 percent by the year 2020. 



Coastal zones contain the planet's most productive marine ecosystems, providing habitats 

 and essential spawning and nursery areas for the major portion of the commercially and 

 recreationally important fisheries. Coastal habitats (mangrove swamps, estuaries, wetlands, 

 seagrass beds, coral reefs, etc.) are fragile, biologically productive, and susceptible to 

 degradation through human activities. In addition, the living marine resources in coastal wetlands 

 often serve as efficient filters for land-based contaminants, and coral reefs and wetlands buffer 

 storm surges and help retard coastal erosion. It is here, where the shore meets the sea, and where 

 people are most inclined to build, manufacture, and recreate, that the most susceptible and 

 diverse aspects of marine life exist. 



In the United States and worldwide, coastal salt marshes have been destroyed by dredging 

 and filling, mangroves have been removed for shrimp aquaculture, coastal development has 

 altered natural patterns of erosion and sedimentation, and mining and dredging have directly 

 altered habitats for marine species. The effects of development are not limited to the shoreline. 

 As noted above, trawl-fishing operations are a major cause of underwater habitat destruction. 

 Similarly, activities such as unsustainable forestry, mining, the diversion of water for agriculture. 



^For a more comprehensive discussion of marine pollution, please see the Year of the Ocean Marine Environmental Quality 

 Discussion Paper. 



C-20 



