Data/hora: 10/06/2024 14:25:05

Provedor de dados: 	5	
País: 	France	
Título: 	Dynamics of an estuarine ecosystem - The Chesapeake Bay experience: Statistical approaches and water quality patterns	
Autores: 	Alden, Rw.	
Data: 	1997	
Ano: 	1997	
Palavras-chave: 	Water quality; Monitoring; Statistics; Trends; Flow.	
Resumo: 	A long-term water quality monitoring program has been established in the Virginian waters of the Chesapeake Bay. To date, over eight years of data have been analyzed to characterize spatio-temporal patterns and long-term trends in water quality. Complementary multivariate statistical procedures were employed to define spatial and seasonal patterns, while a series of non-parametric trend analyses were used for determining overall, site-specific, and season-specific long-term trends for water quality variables in the tributaries and mainstem of the Bay. Particular attention was focused on determining the effect of river flow on the trends, because flow rates in some of the tributaries have changed dramatically since the beginning of the monitoring program. Many of the water quality variables from the tributaries displayed strong relationships to flow. Trends for increasing nutrients could be attributed to flow effects in certain tributary regions, while in others ''potential trends'' for improvement in water quality were obscured by flow. Nonetheless, point source controls in the tidal fresh region of the James River apparently produced decreasing nutrient trends which persisted for the flow-corrected data. Water quality conditions in the mainstem of the lower Bay were not as greatly affected by flow. The up-bay segments displayed trends for decreasing inorganic nitrogen and ammonium, while the down-bay regions were characterized by declining trends for phosphorus. Total organic carbon and suspended solids displayed increasing trends throughout the Virginian waters of the Bay. Chlorophyll and bottom dissolved oxygen concentrations displayed no significant long-term trends, but both variables showed potential trends in the flow-corrected data sets. The ecological and management implications of major findings are discussed.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/00093/20461/18133.pdf	
Editor: 	Gauthier-Villars	
Relação: 	http://archimer.ifremer.fr/doc/00093/20461/	
Formato: 	application/pdf	
Fonte: 	Oceanologica Acta (0399-1784) (Gauthier-Villars), 1997 , Vol. 20 , N. 1 , P. 55-69