1. Marine Estuaries What are they? - Positive - Negative  Where are they located?  What is their importance?  What are the biological characteristics of an estuary?  Environmental Importance of estuaries.  Field Studies: - Ireland. - Mexico.

2. What is an estuary? Estuaries are semi-enclosed areas where fresh water and seawater mix. Can be either positive or negative: 1. Positive = A river continuously flows into an area where it is met by seawater. 2. Negative = The river that used to feed an area of land has dried up. The water is therefore fed by seawater, and over an extended period of time, may become entirely saline.

3. Location of Estuaries Estuaries can be found along any ocean, but vary in name and structure.

4. Importance of Estuaries Estuaries act as distinct communities and can be generally divided into the following: 1. Open Water 2. Mudflats 3. Salt Marshes 4. Mangrove Forests 5. Seagrass and Oyster Beds

5. Biological Characteristics of Estuaries Typically inhabited by fewer species than rocky shores.

6. Environmental Aspects of Estuaries Estuaries are one of the environments most affected by humans.

7. Field Study # 1: Ireland Fall 2001. Mainly studied

8. About 76% of urban waste water in Ireland is discharged to freshwaters and estuaries, while the rest is discharged to coastal waters

9. Habitat loss - estuaries Estuaries in Ireland are extremely important for wildfowl, such as the Brent Goose, and wading birds. They support large numbers of these birds in winter. Estuaries also provide essential feeding grounds for waders that need to refuel as they travel between their northern breeding grounds and wintering areas in southern Europe and West Africa. But many of our important estuaries are threatened. Land claim, industrial development, pollution, disturbance from recreation and the possibility of tidal barrages all threaten these birds havens. All of these threats could mean fewer feeding areas available for birds at a stage in their journeys. If these estuaries disappear, fewer birds will survive the winter and their migration journeys.

11. http://www.oblue.utvinternet.com/ob _irelands4.html

12. The Owenboy River, one of the many tranquil river estuaries that flow into Cork Harbour.

13. Field Study # 2: Rocky Point, Mexico