Phytoplankton Production in Langebaan Lagoon and Saldanha Bay

Henry, J. L.; Mostert, S. A.; Christie, N. D.

doi:10.1080/00359197709519923

Cited by 22 publications

(6 citation statements)

References 6 publications

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“…Assimilation efficiency in relation to the variables mentioned above was studied during November and December. The following authors have described the physical, chemical and biological characteristics of False Bay: Griffiths (1980b), McQuaid (1980, Cliff (1982a, b); Southwest Cape: Field et al (1980a, b) and Langebaan Lagoon: Moldan (1977), Du Plessis (1977), Henry et al (1977) and Mazure and Branch (1979).…”

Section: Methodsmentioning

confidence: 99%

Nutritional ecology of the ascidian Pyura stolonifera: influence of body size, food quantity and quality on filter-feeding, respiration, assimilation efficiency and energy balance

Klumpp¹

1984

Mar. Ecol. Prog. Ser.

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Effects of body size, cell density and food type on filtration rate, respiration rate and assimilation efficiency in the ascidian Ppra stolonifera were determined using a continuous-flow circulating seawater system. Filtration and respiration rates were related to body size according to the regressions: FR (m1 min-') = 8.15 and RR (m1 h-') = 0.14 W9? Assimilation efficiency was independent of body size for the consumption of the alga Dunaliella prirnolecta but was correlated (AE = 21.1 + 3.3 W, r = 0.66) with size for natural food. Different types of food, such as phytoplankton species and kelp detritus which occur in the natural environment, were filtered by the ascidian at equal efficiency and rate. Under controlled conditions, the organic fraction of kelp particles is assimilated at 42 % efficiency while D. primolecta cells are assimilated at 75 % efficiency. Food in nature, comprising a high proportion of detritus with varying amounts of silt, was assimilated at 34 % efficiency. Filtration. respiration and assimilation rate were all independent of cell density which varied between 1.0 and 70 X 106 cells 1-I of D. primolecta. At the lower cell densities there was a 'switching-off' of filtering. High silt loads (25 mg 1-l , 3 % OM) or high density of large-sized particles (> 65 ~m) resulted in 'backsquirting' to reject this material through the inhalent siphon. Additions of silt which produce particle concentrations found in the natural environment of P. stolonifera did not affect filtration rate. Net energy balance and the conversion efficiency for artificial and natural diets were estimated. The potential for utilization of natural food resources by P. stolonifera is compared with other members of the filter-feeding community.

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Section: Methodsmentioning

confidence: 99%

Nutritional ecology of the ascidian Pyura stolonifera: influence of body size, food quantity and quality on filter-feeding, respiration, assimilation efficiency and energy balance

Klumpp¹

1984

Mar. Ecol. Prog. Ser.

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“…The final compilation (summarized in the Supplement Table S1) includes 1148 values of APPP from 483 sampling sites within 131 ecosystems (places). Primary production has been measured in many other studies (e.g., Gilmartin, 1964;Henry et al, 1977), but the results were not reported with the information required to calculate APPP. In order to streamline our presentation we define our uses of "primary production" as the phytoplankton contribution to system production; "production" as either the process or the mass of carbon fixed over a period of time; and "productivity" as a rate of production -usually an hourly or daily rate.…”

Section: An Inventory Of Annual Phytoplankton Primary Production Measmentioning

confidence: 99%

Phytoplankton primary production in the world's estuarine-coastal ecosystems

2014

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Abstract. Estuaries are biogeochemical hot spots because they receive large inputs of nutrients and organic carbon from land and oceans to support high rates of metabolism and primary production. We synthesize published rates of annual phytoplankton primary production (APPP) in marine ecosystems influenced by connectivity to land – estuaries, bays, lagoons, fjords and inland seas. Review of the scientific literature produced a compilation of 1148 values of APPP derived from monthly incubation assays to measure carbon assimilation or oxygen production. The median value of median APPP measurements in 131 ecosystems is 185 and the mean is 252 g C m−2 yr−1, but the range is large: from −105 (net pelagic production in the Scheldt Estuary) to 1890 g C m−2 yr−1 (net phytoplankton production in Tamagawa Estuary). APPP varies up to 10-fold within ecosystems and 5-fold from year to year (but we only found eight APPP series longer than a decade so our knowledge of decadal-scale variability is limited). We use studies of individual places to build a conceptual model that integrates the mechanisms generating this large variability: nutrient supply, light limitation by turbidity, grazing by consumers, and physical processes (river inflow, ocean exchange, and inputs of heat, light and wind energy). We consider method as another source of variability because the compilation includes values derived from widely differing protocols. A simulation model shows that different methods reported in the literature can yield up to 3-fold variability depending on incubation protocols and methods for integrating measured rates over time and depth. Although attempts have been made to upscale measures of estuarine-coastal APPP, the empirical record is inadequate for yielding reliable global estimates. The record is deficient in three ways. First, it is highly biased by the large number of measurements made in northern Europe (particularly the Baltic region) and North America. Of the 1148 reported values of APPP, 958 come from sites between 30 and 60° N; we found only 36 for sites south of 20° N. Second, of the 131 ecosystems where APPP has been reported, 37% are based on measurements at only one location during 1 year. The accuracy of these values is unknown but probably low, given the large interannual and spatial variability within ecosystems. Finally, global assessments are confounded by measurements that are not intercomparable because they were made with different methods. Phytoplankton primary production along the continental margins is tightly linked to variability of water quality, biogeochemical processes including ocean–atmosphere CO2 exchange, and production at higher trophic levels including species we harvest as food. The empirical record has deficiencies that preclude reliable global assessment of this key Earth system process. We face two grand challenges to resolve these deficiencies: (1) organize and fund an international effort to use a common method and measure APPP regularly across a network of coastal sites that are globally representative and sustained over time, and (2) integrate data into a unifying model to explain the wide range of variability across ecosystems and to project responses of APPP to regional manifestations of global change as it continues to unfold.

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“…It was higher than that measured on the continental shelf off Durban by Burchall (1968) who measured a mean surface production of 1.52 m g C m-3h-' (range 0.01 to 9.52 mg C m-3h-') over a period of 5 years, but considerably lower than that which occurs in areas of upwelling such as the south west Cape coast. For example, daily rates recorded by Henry and Mostert (1977) at a station exposed to the sea in the mouth of Langebaan lagoon indicate approximate primary production of 24 m g C mT3h-' in winter (April to August), 54 m g C m-3h-' in spring (September to November) a n d 66 mg C m-3h-1 in summer (December to February). In adjacent Saldanha Bay an annual mean primary production of 55.7 mg C m-3h-1 (range 28.0 to 125.7 m g C m-3h-') was estimated from chlorophyll analyses.…”

Section: Discussionmentioning

confidence: 99%

Microorganisms and Detritus in the Water Column of a Subtidal Reef of Natal

Schleyer¹

1981

Mar. Ecol. Prog. Ser.

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The parameters measured in this study were light and dark-bottle uptake of NaHI4CO3, the chlorophyll content of seawater, direct counts of bacteria, microbial uptake of 14C glucose and a labelled algal extract, organic carbon in the seawater and the composition of debris washed onto the reef. The phytoplankton consisted largely of nannoplankton and primary production was low with an annual mean of P = 12.82 mg C n1r3h-', while the mean chlorophyll a content of 2.13 mg m-3 was equivalent to a dry biomass of 170.1 mg m-3 Microbial heterotrophic activity was relatively high with an annual mean glucose assimilation of V,,, = 0.612 @g l-'h-' and a total bacterial count of 2.02 X 106 ml-', equivalent to a dry biomass of 20.3 rng m-3. The largest proportion of this activity, measured by differential filtration and using antibiotic inhibitors, is performed by free bacteria as opposed to the smaller proportion conducted by bacteria attached to particles, or by microflagellates. Uptake of the labelled algal extract (V,,, -13.2-72.6 mg C m-3h-') indicates that microbial heterotrophic activity exceeds phytoplankton production. Carbon analyses gave an annual mean of 18.3 g m-3 total organic carbon, of which 20 % was particulate, the rest being dissolved organic carbon. Analysis of debris revealed that it consisted almost exclusively of seaweed, except when rivers were in flood, providing a large influx of terrestrial plant debris. These findings are compared with other published results, and their ecological significance is discussed in relation to the remainder of the environment. It is concluded that primary production by phytoplankton is not as important in supporting the biomass of filter feeders on the reef as is heterotrophic activity associated with organic detritus.

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Phytoplankton Production in Langebaan Lagoon and Saldanha Bay

Cited by 22 publications

References 6 publications

Nutritional ecology of the ascidian Pyura stolonifera: influence of body size, food quantity and quality on filter-feeding, respiration, assimilation efficiency and energy balance

Nutritional ecology of the ascidian Pyura stolonifera: influence of body size, food quantity and quality on filter-feeding, respiration, assimilation efficiency and energy balance

Phytoplankton primary production in the world's estuarine-coastal ecosystems

Microorganisms and Detritus in the Water Column of a Subtidal Reef of Natal

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