Phytoplankton Biomass and Production in a Southern Benguela Kelp Bed System

Carter, RA

doi:10.3354/meps008009

Cited by 18 publications

(12 citation statements)

References 8 publications

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“…The standing stocks of phytoplankton and the primary production in the coastal waters of the Cape Peninsula have been studied by Brown (1981), and more recently near to kelp beds by Carter (1982). The chlorophyll a concentrations recorded by Brown (1981) at Robben Island in Table Bay and at Oudekraal are shown together with values recorded by Seiderer (1983) in Table 1.…”

Section: Standing Stocks Of Phytoplanktonmentioning

confidence: 94%

Relative significance of phytoplankton, bacteria and plant detritus as carbon and nitrogen resources for the kelp bed filter-feeder Choromytilus mendionalis

Seiderer¹,

Newell²

1985

Mar. Ecol. Prog. Ser.

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(1) Standing stocks of phytoplankton on the West Coast of the Cape Peninsula. South Africa, show marked short-term variations, reaching maximal values of 8.9 pg chlorophyll a l-' at the end of a downwelling phase when warm surface water of approximately 16°C impinges on the coast. Following a period of south-east winds, cold water of ca. 11 "C or less upwells in the nearshore waters and chlorophyll a concentrations may fall within 24 h to 0.6 pg 1-l or less. At the same time, the standing stocks of bacteria ranged from a 0.4 X 106 cells ml-' during strong upwelling pulses to 5.9 X 106 cells ml-' during downwelling phases. (2) Total resource availability in the water column is generally in the range 307 to 450 pg C 1-I with an associated nitrogen pool of 46 to 71.1 pg N 1-' during upwelling and downwelling phases. At the end of a downwelling phase the carbon represented by the phytoplankton component amounts to > 50 % of the total particulate carbon in the water column and may dominate the resource as a whole. Bacteria, however, represent a carbon resource which is of comparable importance to the detrital component especially during periods of weak upwelling. Because of their relatively low C:N ratio of 3.5 compared with values as high as 18.9 for the detrital component, bacteria represent a nitrogen resource which may even exceed that of the phytoplankton under some conditions. (3) Estimates of the carbon consumption requirements of the black mussel Choromytilus rneridionalis Krauss in relation to the potential yield from phytoplankton, bacterial and detrital pools suggest that a major utilisation of the detrital component would be required to meet the carbon demands even if phytoplankton were retained with a high efficiency. In contrast, the estimated nitrogen demands of 2.8 to 45.5 pg N h-' at 1ZoC, depending on shell length, could be met from the phytoplankton alone which could supply 12.5 to 127.4 pg N h-' at 100 % efficiency. C. meridionalis does not therefore appear to require utilisation of bacteria to support its nutritional needs, a conclusion which is substantiated by the experimental work of others which suggests that particles in the bacterial size range are inefficiently retained by this mussel. (4) Phytoplankton and detrital pools are thus of importance as a carbon resource for bivalve consumers such as C. rneridionalis. Bacteria, however, represent a nitrogen pool of comparable importance to the phytoplankton and which is likely to be of major significance to those filter-feeders which are capable of exploiting particles in the bacterial size range.

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Section: Standing Stocks Of Phytoplanktonmentioning

confidence: 94%

Relative significance of phytoplankton, bacteria and plant detritus as carbon and nitrogen resources for the kelp bed filter-feeder Choromytilus mendionalis

Seiderer¹,

Newell²

1985

Mar. Ecol. Prog. Ser.

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“…Previous studies have shown that particulate and chlorophyll concentrations decline to very low levels during upwelling when offshore winds move surface waters away from the coast (Field et al 1980, Carter 1982, Brown 1984, Brown & Field 1986. These data were calculated from water samples taken at the outer edge of the Oudekraal kelp beds.…”

Section: Particulate Loadmentioning

confidence: 99%

“…Carter 1982. Furthermore, Carter (1982) expressed reservations about annual phytoplankton production estimates because of the accumulated errors in extrapolating daily and seasonal rates to annual rates in such a variable system. Brown & Field (1985) described largescale die1 fluctuations in phytoplankton productivity over 4 d periods at different times of the year.…”

Section: Introductionmentioning

confidence: 99%

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Carbon and nitrogen resources available to kelp bed filter feeders in an upwelling environment

Fielding¹,

Davis²

1989

Mar. Ecol. Prog. Ser.

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ABSTRACT. Environmental variables, and summer and winter particulate concentrations in the water column of a kelp bed in an upwelling region on the western Cape coast of South Africa, were measured daily to assess short-term fluctuations. There were significant differences between the summer and winter upwelling index, water temperature and wave height. Summer part~culate carbon and nitrogen concentrations of 533 11g 1-' and 66 pg 1-' respectively were lower than winter levels of 764 pg C 1-' and 79 pg N 1-'. However, summer upwelling events did not reduce particulate carbon and nitrogen to the very low levels that might be expected from previous studies of chlorophyll concentrations in the kelp bed. Large waves resulted in C:N ratios that were significantly hlgher in winter than in summer @ < 0.01), and during continuous winter downwelling, a large proportion of the particulate material in the water column was of macrophyte rather than phytoplankton origin. In summer the carbon and nitrogen load was most highly correlated with temperature, while wind and wave size were the most important factors affecting particulate concentrations in winter. Mean particulate organic concentrations were 380 big C I-' and 43 pg N I-' and these compare weU with concentrations of 301 k~g C 1-' and 4 1 pg N 1-' estimated from previous primary production studies. The estimated carbon demands of Choromytilus meridjonalis and Aulacomya ater, 2 mussels that commonly occur in kelp beds on the west coast, could be met in winter and summer by the particulate organic component in the kelp bed water column. Particulate nitrogen resources probably meet most of the nitrogen requirements of the 2 mussels.

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“…Primary production off the west coast of southern Africa varies significantly both spatially and over seasonal and shorter time scales (Andrews and Hutchings 1980;Brown 1984;Carter 1982;Brown and Field 1985). Investigations by Brown and Hutchings (1985) have led to a better understanding of the factors regulating primary production in the Cape Peninsula upwelling system, variations of nutrients and light in the upper mixed layer being considered the major environmental regulators of primary production.…”

mentioning

confidence: 99%

Volumetric estimates of phytoplankton production in newly upwelled waters of the southern Benguela Current1

Olivieri¹,

Hutchings²

1987

Limnology & Oceanography

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Production, in terms of volume of particulate matter, was studied in four developing phytoplankton communities in newly upwelled waters of the southern Benguela Current. Growth (max doublings d-' -2.9, max C production -21 g m-2 d-l) of phytoplankton upwellcd from source water was rapid, with little evidence of a lag phase. The growth pattern differed for each community encountered and was related to the rate of mixing of the water column and the nutrient and light regimes. Production rates were highest in newly upwelled waters and lowest under limiting light and during periods of nitrate depletion in the upper mixed layer. Changes in growth rates were also attributed to short-term wind variations that caused water bodies to mix and change the nutrient regimes.Growth occurred over a wide size range of particles, mostly in the range 20-80-pm equivalent spherical diameters (ESD), corresponding to chains of diatoms, but occasionally also in the range of 6-l 4-pm ESD, suggesting some growth of small-celled algae and microflagellates. A diel variation was observed, with volume increases during the day greatly exceeding those at night except under extreme limiting conditions when thcrc was some growth in the dark.

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Phytoplankton Biomass and Production in a Southern Benguela Kelp Bed System

Cited by 18 publications

References 8 publications

Relative significance of phytoplankton, bacteria and plant detritus as carbon and nitrogen resources for the kelp bed filter-feeder Choromytilus mendionalis

Relative significance of phytoplankton, bacteria and plant detritus as carbon and nitrogen resources for the kelp bed filter-feeder Choromytilus mendionalis

Carbon and nitrogen resources available to kelp bed filter feeders in an upwelling environment

Volumetric estimates of phytoplankton production in newly upwelled waters of the southern Benguela Current1

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