Herbicide and Insecticide Loadings from the Susquehanna River to the Northern Chesapeake Bay

ABSTRACT Vibrio cholerae is autochthonous to natural waters and can pose a health risk when it is consumed via untreated water or contaminated shellfish. The correlation between the occurrence of V. cholerae in Chesapeake Bay and environmental factors was investigated over a 3-year period. Water and plankton samples were collected monthly from five shore sampling sites in northern Chesapeake Bay (January 1998 to February 2000) and from research cruise stations on a north-south transect (summers of 1999 and 2000). Enrichment was used to detect culturable V. cholerae, and 21.1% (n = 427) of the samples were positive. As determined by serology tests, the isolates, did not belong to serogroup O1 or O139 associated with cholera epidemics. A direct fluorescent-antibody assay was used to detect V. cholerae O1, and 23.8% (n = 412) of the samples were positive. V. cholerae was more frequently detected during the warmer months and in northern Chesapeake Bay, where the salinity is lower. Statistical models successfully predicted the presence of V. cholerae as a function of water temperature and salinity. Temperatures above 19°C and salinities between 2 and 14 ppt yielded at least a fourfold increase in the number of detectable V. cholerae. The results suggest that salinity variation in Chesapeake Bay or other parameters associated with Susquehanna River inflow contribute to the variability in the occurrence of V. cholerae and that salinity is a useful indicator. Under scenarios of global climate change, increased climate variability, accompanied by higher stream flow rates and warmer temperatures, could favor conditions that increase the occurrence of V. cholerae in Chesapeake Bay.

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Responses of Upper Chesapeake Bay to variations in discharge of the Susquehanna River

Deep Sea Research Part B Oceanographic Literature Review ◽

10.1016/0198-0254(87)90009-4 ◽

1987 ◽

Vol 34 (9) ◽

pp. 730

Keyword(s):

Chesapeake Bay ◽

Susquehanna River

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Particle-borne radionuclides as tracers for sediment in the Susquehanna River and Chesapeake Bay

Estuarine Coastal and Shelf Science ◽

10.1016/0272-7714(89)90033-4 ◽

1989 ◽

Vol 29 (4) ◽

pp. 341-360 ◽

Cited By ~ 16

Author(s):

Joseph F. Donoghue ◽

Owen P. Bricker ◽

Curtis R. Olsen

Keyword(s):

Chesapeake Bay ◽

Susquehanna River

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Particulate Carbon:Nitrogen Relations in Northern Chesapeake Bay

Journal of the Fisheries Research Board of Canada ◽

10.1139/f71-132 ◽

1971 ◽

Vol 28 (6) ◽

pp. 911-918 ◽

Cited By ~ 17

Author(s):

David A. Flemer ◽

Robert B. Biggs

Keyword(s):

Chesapeake Bay ◽

Net Primary Production ◽

C:N Ratio ◽

Particulate Material ◽

Late Winter ◽

Suspended Material ◽

Particulate Carbon ◽

Susquehanna River ◽

Low Salinity ◽

Thaw Period

The Susquehanna River annually supplies about 8.4 × 104 and 4.7 × 103 metric tons of particulate carbon (PC) and nitrogen (PN), respectively, to upper Chesapeake Bay. In the upper bay, the concentration of PN usually ranges between 0.10 and 0.30 mg liter−1 and is occasionally greater than 0.50 mg liter−1. In the lower study area, the concentration of PN stabilizes near 0.10 mg liter−1. Maximum values of the carbon:nitrogen (C:N) ratio (atomic basis) occurred in the upper bay, and highest values were associated with the late-winter thaw period of the Susquehanna River. C:N ratios of 20–30 were usual most of the year in the low salinity region, and often greater than 30 during times of maximum river discharge. In the lower study area, the ratio approached 15 throughout most of the year. In general, the reduction in the C:N ratios of the suspended material was reflected in the C:N ratios of the sediments.The high C:N ratios in the upper bay and the tidal freshwater portion of the Susquehanna River indicate a high detrital content. An estimate of net primary production would extrapolate to the fixation of PN of approximately 1600 metric tons per year in the upper bay or about 34% of that supplied by upland drainage. The major source of PN in the lower study area is probably provided by photosynthetic fixation, since the physical circulation of the estuary retards a large movement of particulate material seaward.

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