Location of the non-tidal current null zone in northern San Francisco Bay

Peterson, David H.; Conomos, T.J.; Broenkow, William W.; Doherty, Patrick C.

doi:10.1016/0302-3524(75)90002-x

Cited by 80 publications

(45 citation statements)

References 13 publications

(14 reference statements)

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“…2). The salt field moves considerably with changes in freshwater flow (Peterson et al 1975), so that the abundance peaks move as well. Temporal variation in abundance can therefore b e confounded with vallation due to movement of the salt field; similarly, seasonal effects can obscure longer-term trends.…”

Section: Methodsmentioning

confidence: 99%

Predation by an introduced clam as the likely cause of substantial declines in zooplankton of San Francisco Bay

Kimmerer¹,

Gartside²,

Orsi³

1994

Mar. Ecol. Prog. Ser.

209

161

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Wlthin a year, chlorophyll concentrat~on and the abundance of adults of 3 common estuarine copepod species had declined by 53 to 91 %, providing an opportunlty to examine mechanisms by which benthic grazing might control the abundance of pelaglc populations Decllnes in chlorophyll and abundance of the 3 species of copepod coincided a p p r o m a t e l y with the geographic range of the clam population The decllne in abundance of the copepod Eurytemora affinis was accompanied by a decrease in the ratlo of nauplil to adults, but not in the raho of eggs to females Therefore the decline in abundance may be due to elevated mortahty of nauplii rather than food hmitation of reproductive rate We argue that direct predation by P amurensls is the cause of the reduced survlval of nauplii, and therefore of the depressed abundance of adults Expenrnentally determined clearance rates of P arnurensls on E a f f i n~s nauphi averaged 0 11 1 clam-' d ' If that clearance rate applled in the fleld, the clams could remove 8 2 % of the n a u p h~ d-' This removal late is sufficient to explain the observed rate of population decline P amurensls appears to have become well established and copepod populations of the bay so far have failed to rebound Thus this invasion may have permanent effects In a broader sense, predation on zooplankton by soft-bottom benthos may be a n important and heretofore overlooked, source of mortality In shallow waters Selectivity occurnng through differences in escape response and vertical position could make bivalve predation an lrnportant influence on biomass and species composltlon of inshore zooplankton

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Section: Methodsmentioning

confidence: 99%

Predation by an introduced clam as the likely cause of substantial declines in zooplankton of San Francisco Bay

Kimmerer¹,

Gartside²,

Orsi³

1994

Mar. Ecol. Prog. Ser.

209

161

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“…In the San Francisco Estuary, the tidally-averaged mean penetration of salinity up the estuary depends primarily on freshwater flow, and to a lesser extent on spring-neap tidal oscillations and meteorological variation (Peterson et al 1975Knowles and Cayan 2002;Knowles 2000). The degree of penetration can be indexed by X2 (Jassby et al 1995;Monismith et al 2002), a convenient index of the physical response of the estuary to freshwater flow.…”

Section: Movement Of the Salt Fieldmentioning

confidence: 99%

“…Information flow has been equally rich in the opposite direction. For example, early ideas about estuarine circulation (Postma and Kalle 1955;Festa and Hansen 1978) have been extensively applied and modified in the San Francisco Estuary (e.g., Peterson et al 1975;Arthur and Ball 1979;Kimmerer et al 1998). Concepts about effects of salinity on estuarine zooplankton developed in the Saint Lawrence Estuary (Laprise and Dodson 1993) have proven very valuable in understanding patterns in the San Francisco Estuary (Kimmerer and Orsi 1996;Kimmerer et al 1998).…”

Section: This Paper Presents My View Of the Current State Of Understamentioning

confidence: 99%

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Open Water Processes of the San Francisco Estuary: From Physical Forcing to Biological Responses

Kimmerer¹,

Francisco²

2004

SFEWS

163

225

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“…In many northern temperate estuaries a group of planktonic species occupies the low salinity zone (LSZ), a region just seaward of the limit of salinity intrusion, commonly the site of an estuarine turbidity maximum (ETM) or entrapment zone (Peterson et al 1975;Arthur and Ball 1979;Simenstad et al 1990). This group of species includes the Calanoid copepod Eurytemora affinis (e.g., Katona 1970;Heinle and Flemer 1975;Bousfield et al 1975;Miller 1983;Soltanpour and Wellershaus 1984;Orsi and Mecum 1986;Runge and Simard 1990;Simenstad et al 1990), mysids (Siegfried et al 1979;Runge and Simard 1990), and fish larvae (Fortier and Leggett 1983;Dauvin and Dodson 1990;Dodson et al 1989;Jones et al 1990;Bennett 1997).…”

mentioning

confidence: 99%

Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary

Kimmerer

Burau

Bennett

1998

Limnology & Oceanography

143

101

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In many estuaries, maxima in turbidity and abundance of several common species of zooplankton occur in the low salinity zone (LSZ) in the range of 0.5-6 practical salinity units (psu). Analysis of zooplankton abundance from monitoring in [1972][1973][1974][1975][1976][1977][1978][1979][1980][1981][1982][1983][1984][1985][1986][1987] revealed that historical maxima in abundance of the copepod Eurytemora affinis and the mysid Neomysis mercedis, and in turbidity as determined from Secchi disk data, were close to the estimated position of 2 psu bottom salinity. The copepod Sinocalanus doerrii had a maximum slightly landward of that of E. affinis. After 1987 these maxima decreased and shifted to a lower salinity, presumably because of the effects of grazing by the introduced clam Potamocorbula amurensis. At the same time, the copepod Pseudodiaptomus forbesi, the mysid Acanthomysis sp., and amphipods became abundant with peaks at salinity around 0.2-0.5 psu.Plausible mechanisms for maintenance of these persistent abundance peaks include interactions between variation in flow and abundance, either in the vertical or horizontal plane, or higher net population growth rate in the peaks than seaward of the peaks. In spring of 1994, a dry year, we sampled in and near the LSZ using a Lagrangian sampling scheme to follow selected isohalines while sampling over several complete tidal cycles. Acoustic Doppler current profilers were used to provide detailed velocity distributions to enable us to estimate longitudinal fluxes of organisms. Stratification was weak and gravitational circulation nearly absent in the LSZ. All of the common species of zooplankton migrated vertically in response to the tides, with abundance higher in the water column on the flood than on the ebb. Migration of mysids and amphipods was sufficient to override net seaward flow to produce a net landward flux of organisms. Migration of copepods, however, was insufficient to reverse or even greatly diminish the net seaward flux of organisms, implying alternative mechanisms of position maintenance.Zooplankton in estuaries are often distributed by species along a salinity gradient (Miller 1983;Laprise and Dodson 1994). In many northern temperate estuaries a group of planktonic species occupies the low salinity zone (LSZ), a region just seaward of the limit of salinity intrusion, commonly the site of an estuarine turbidity maximum (ETM) or entrapment zone (Peterson et al. 1975;Arthur and Ball 1979;Simenstad et al. 1990). This group of species includes the Calanoid copepod Eurytemora affinis (e.g., Katona 1970;Heinle and Flemer 1975;Bousfield et al. 1975;Miller 1983;Soltanpour and Wellershaus 1984; Orsi and Mecum 1986;Runge and Simard 1990;Simenstad et al. 1990), mysids (Siegfried et al. 1979Runge and Simard 1990), and fish larvae (Fortier and Leggett 1983;Dauvin and Dodson 1990;Dodson et al. 1989;Jones et al. 1990;Bennett 1997). In AcknowledgmentsThis study was supported by the Interagency Ecological Program for the San Francisco Estuary. We thank Randy ...

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Location of the non-tidal current null zone in northern San Francisco Bay

Cited by 80 publications

References 13 publications

Predation by an introduced clam as the likely cause of substantial declines in zooplankton of San Francisco Bay

Predation by an introduced clam as the likely cause of substantial declines in zooplankton of San Francisco Bay

Open Water Processes of the San Francisco Estuary: From Physical Forcing to Biological Responses

Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary

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