Biology 1B Ecology Lecture 11 Page 1 Assigned readings 8th Edition pp 1260 1263 7th Edition pp 1224 1229 San Francisco Bay Outline of Lecture 11 A B C D San Francisco Bay Biological Resources of Bay Physical influences on habitats Current problems A San Francisco Bay Estuary a point at which the river meets the sea with a mixture of saline and freshwater conditions tidal mud flats and salt marshes and a characteristic and unique fauna Population change pre 1769 10 20 000 native Americans after 1848 San Francisco grew from 400 to 25 000 Legacy of gold mining activities still affects the Bay Professor Resh Spring 2010 Biology 1B Ecology Lecture 11 Page 2 Assigned readings 8th Edition pp 1260 1263 7th Edition pp 1224 1229 San Francisco Bay B Biological Resources of Bay 1 Commercial fisheries decline of salmon sturgeon and striped bass began about 1900 only herring and anchovies fished commercially today 2 Dungeness crab in 1880 commercial fisheries left Bay 1960 off shore fishing collapsed Increased ocean temperature predation by hatcheryreared salmon and pollution caused decline 3 Introduced species oyster drill and shipworm 20 out of 42 Suisun marsh fish are introduced Success of introduced species resulted from lack of a diverse natural fauna and opportunistic traits Professor Resh Spring 2010 Biology 1B Ecology Lecture 11 Page 3 Assigned readings 8th Edition pp 1260 1263 7th Edition pp 1224 1229 San Francisco Bay B Physical influences on habitats 1 hydraulic mining 2 land reclamation 1400 km2 of freshwater marsh 800 km2 salt marsh reclaimed with 125 km2 remaining today 3 water diversion pre 1850 34 km3 year now 40 removed for local consumption 24 for Southern California Biological response lost of migratory fish loss of ability to dilute contaminants C Current problems agricultural wastewater domestic and industrial wastes 1 San Francisco Bay problems are not unique but problems are less obvious because urbanization is directly on estuary mouth water quality has improved and most changes occurred long ago 2 What is the effect on further reductions on inflow D San Francisco Bay is a model of grassroots environmental activism E San Francisco Bay is an important case history of anthropogenic change Discuss other examples with your study group Professor Resh Spring 2010
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