Relation Between Circulation and Planktonic Populations in Estuaries

Ketchum, Bostwick H.

doi:10.2307/1931117

Cited by 155 publications

(50 citation statements)

References 8 publications

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“…Hence zooplankton will tend to aggre-gate in the bottom more saline water (cf. comments on field distribution made by Sewell, 1913;Rees, 1938;Rogers, 1940;Carriker, 1951;Mankowski, 1951;Pritchard, 1953;Ketchum, 1954;Barlow, 1955;Bousfield, 1955;Hulburt, 1957) while species such as Temora longicornis and Porcellana longic~rnis which show strong swarming reactions (Farran, 1910;Lebour, 1943;Spooner, 1933) may collect at intermediate depths.…”

Section: Discussionmentioning

confidence: 99%

Effects of water of reduced salinity on the vertical migration of zooplankton

Lance

1962

J. Mar. Biol. Ass.

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Under estuarine conditions, the restriction of different species of zooplankton to certain ranges of salinity may be partly determined by behavioural patterns which tend to maintain each species in a suitable environment. The presence of a salinity discontinuity layer (i.e. a boundary between two types of water of varying salinity) is thought to restrict upward or downward movements of certain animals (Henschel, 1939;Hansen, 1951; Carrriker, 1951;Mankowski, 1951) and in stratified estuaries it is probable that discontinuity layers will influence the dispersal of zooplankton by modifying the position of individuals relative to prevailing water currents. There is an obvious need to supplement existing field records by laboratory experiments, but although the reactions of small copepods have been investigated in the laboratory by several workers, it would appear that only Loeb (1893), Rose (1925), Lukjanova (1938 and Harder (1952aHarder ( , b, 1954Harder ( , 1957a have conducted work on the behaviour of copepods in diluted sea water. The experiments described in this paper were designed to simulate the type of stratification likely to occur in estuaries such as Southampton Water where fresh water flows out over denser sea water, vertical mixing being incomplete. By recording the vertical distribution of planktonic crustaceans in stratified water and by observing the effects of specific dilutions on swimming activity, it was hoped that some indication of the way in which animals react to hydrographic events occurring in the field might be obtained. MATERIALS AND METHODSPlankton was collected from Southampton Water in the main channel parallel to the New Docks at Marchwood and in the vicinity of Hook Buoy at Calshot. While the salinity of sea water at the more seaward station Calshot varies between approximately 34 and 31%0' considerable reduction in salinity occurs at Marchwood where fresh water flows out from the River Test. Net hauls of 10 min duration were always taken during the 2 h period which separates

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Section: Discussionmentioning

confidence: 99%

Effects of water of reduced salinity on the vertical migration of zooplankton

Lance

1962

J. Mar. Biol. Ass.

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“…As a result, peak of abundance should shift from nutrient-rich habitats to regions away from the borders. In estuaries, the importance of water circulation on the spatial distribution of planktonic populations has been long recognized (Ketchum, 1954;Pace et al, 1992). This effect, however, is dependent on the relative scales of population growth and water turnover (Ketchum, 1954).…”

Section: Fig 2 -Spatial Distribution Of Cells (Mean ± Se) In the Gramentioning

confidence: 99%

“…In estuaries, the importance of water circulation on the spatial distribution of planktonic populations has been long recognized (Ketchum, 1954;Pace et al, 1992). This effect, however, is dependent on the relative scales of population growth and water turnover (Ketchum, 1954). Bacteria have generation times of the order of hours, phytoplankton of a few days, and zooplankton of a few days to months.…”

Section: Fig 2 -Spatial Distribution Of Cells (Mean ± Se) In the Gramentioning

confidence: 99%

Population dynamics of Pseudomonas sp. along a spatial gradient of phosphate: an experimental approach for spatial ecology

Codeço

Grover

2000

Rev. Bras. Biol.

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Many theoretical models have been proposed to study the effect of space on population dynamics and interactions, but most of them are difficult to translate into experimental setups due to their abstract nature. Here we defend the gradostat as a valuable experimental tool for testing such theories. The gradostat is a culture system with bi-directional flow that forms nutrient gradients at steady state. In this study, we use a 3-vessel gradostat with a phosphate gradient to study the effect of spatial heterogeneity on the spatial distribution of Pseudomonas sp., an heterotrophic aquatic bacterium. The observed distributions partially agree with theoretical predictions, obtained from a mathematical model.

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“…growth rate effects controlled by salinity and temperature), the distributional effects due to variations in physical processes must be clarified (Ketchum, 1954;Barlow, 1955). TO our knowledge, only the studies of the Tees estuary by Alexander et al (1931,1935) describe both the non-tidal circulation and plankton distribution in a river-null zone-estuary system.…”

Section: Imgiplmentioning

confidence: 99%