A Tracer Study of the Phosphorus Cycle in Lake Water

Rigler, F. H.

doi:10.2307/1930179

Cited by 207 publications

(104 citation statements)

References 10 publications

(19 reference statements)

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“…55 On the face of it, it would seem that reduced phosphate loads together with sedimentation would remove phosphate from water bodies and reduced phosphate loads would lead to a rapid reduction in eutrophication. However, internal phosphorus cycling results in the release of phosphate from the sediment, with rates modified by various physicochemical and biotic parameters.…”

Section: Discussionmentioning

confidence: 99%

rise and fall of dissolved phosphate in South African rivers

Griffin

2017

S. Afr. J. Sci.

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Eutrophication of water resources following nutrient loading is a global threat to water quality, and has been found to be one of the major threats to water quality in South Africa. Eutrophication is large-scale autotroph growth following nutrient enrichment and has several consequences, including loss of biodiversity, oxygen depletion, taste/odour generation and algal toxin production. Phosphate enrichment is often (but not always) the cause of freshwater eutrophication, and limitation of phosphate is commonly used as a means of controlling eutrophication. This study reports on a survey of trends in nutrient levels in South African freshwater resources. The research reported on here shows a significant decrease in dissolved phosphate levels in recent years, following a long period during which phosphate levels had been increasing with time. While changes in inorganic nitrogen were found, these changes did not match those in phosphate levels. Several potential causes of these changes were assessed, and it is concluded that no one cause can explain the changes observed. While the decrease in freshwater phosphate levels bodes well for water quality management, internal phosphorus cycling and other mechanisms are likely to mask the short-term impact of phosphate decreases.

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Section: Discussionmentioning

confidence: 99%

rise and fall of dissolved phosphate in South African rivers

Griffin

2017

S. Afr. J. Sci.

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“…Therefore, most of the phosphate uptake must be attributed to bacteria. Many laboratory studies have established the rapid uptake of inorganic phospherus by bacteria (Rigler, 1956;Harris, 1957;Johannes, 1964;Rhee, 1972;Beuchler and Dillon, 1974). We have less knowledge of this density.…”

Section: Discussionand ~Nclusionsmentioning

confidence: 99%

Relationship between phytoplankton cell size and the rate of orthophosphate uptake: in situ observations of an estuarine population

1978

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Orthophosphate uptake by a natural estuarine phytoplankton population was estimated using two methods: (I) 32p uptake experiments in which filters of different pore sizes were used to separate plankton size-fractions; (2) 33p autoradiography of phytoplankton cells. Results of the first method showed that plankton cells larger than 5 ~um were responsible for 2% of the total orthophosphate uptake rate. 98% of the total uptake rate occurred in plankton composed mostly of bacteria, which passed the 5 ~m screen and were retained by the 0.45 Lum pore-size filter. There was no orthophosphate absorption by particulates in a biologically inhibited control containing iodoacetic acid. Orthophosphate uptake rates of individual phytoplankton species were obtained using 33p autoradiography. The sum of these individual rates was very close to the estimated rate of uptake by particulates larger than 5 H/n in the 32p labelling experiment. Generally, smaller cells were found to have a faster uptake rate per bm3 biomass than larger cells. Although the nannoplankton constituted only about 21% of the total algal biomass, the rate of phosphate uptake by the nannoplankton was 75% of the total phytoplankton uptake rate. Results of the plankton autoradiography showed that the phosphate uptake rate per unit biomass is a power function of the surface:volume ratio of a cell; the relationship is expressed by the equation Y = 2x70-11 xi.7, where Y is ~gP ~m-3 h-1 and x is the surface:volume ratio. These results lend support to the hypothesis that smaller cells have a competitive advantage by having faster nutrient uptake rates. Introdu~io.plankton has varied between cells with a diameter of 65 bm to those less than 3bm. The phytoplankton is normally an assemHowever, it is clear from these studies blage of one-celled or multi-celled auto-and from the work of Watt (1971), who trophs with diverse shapes and sizes, used autoradiography to measure primary Hutchinson (1961) was puzzled that such production rates of individual phytodiversity could exist in an isotropic en-plankton species, that the smaller cells vironment where competition for reprovide a large fraction of the total sources is supposedly occurring.Phytoplankton species not only display diversity in shapes and sizes, but they differ in their contribution to the total algal biomass and metabolic activity. Nannoplankton (very small algal cells) which, in the past, were overprimary production in the euphotic zone. Although nannoplankton were the most important producers in all environments studied by Malone (1971a), the netplankton:nannoplankton productivity and chlorophyll ratios were higher in coastal waters than in oceanic waters. Nannoplanklooked with net phytoplankton sampling, ton populations varied within a narrow have recently been recognized as very im-margin, but generally netplankton standportant autotrophs in the plankton coming crop increased in areas of upwelling munity, along the California Current (Malone, Many studies have documented the domi-1971b). Yentsch an...

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“…Samples were analyzed for chlorophyll-a using a model 10AU fluorometer (Turner Designs, CA, USA), with acidification analyzed by the EPA Method 445.0 (Rigler 1956). Samples were analyzed for dissolved organic carbon (DOC), total dissolved nitrogen (TDN), total dissolved phosphate (TDP), total phosphorus (TP), particulate phosphorus (PP), particulate nitrogen (PN), and total nitrogen (TN).…”

Section: Field and Laboratory Methodsmentioning

confidence: 99%

Screening Assessment of Cyanobacteria and Cyanotoxins in Southern California Lentic Habitats

Magrann

Meredith

Sutula

et al. 2015

EMSD

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Harmful bloom-forming cyanobacteria (CyanoHABs) and associated toxins are increasingly prevalent world-wide. We conducted a screening-level study to determine if cyanobacteria and associated cyanotoxins were present in Southern California coastal lakes, ponds, and seasonally tidal lagoons. We evaluated waterbody nutrient status and physiochemical parameters, land use, waterbody type, and habitat type, to determine their utility as screening factors for risk of CyanoHAB blooms. One-time grab samples were collected from 30 sites during July-September 2009. Samples were analyzed for phytoplankton taxonomic composition, nutrients, other physiochemical parameters, and three cyanotoxins: microcystins (MCY), anatoxin-a, and cylindrospermopsin. Cyanobacteria was the predominant taxonomic group in most water bodies in this study, and Microcystis spp. was the predominant genus in 96% of the study sites. Cyanobacteria were equally prevalent among coastal lagoons, depressional wetlands, and lakes in this study. We detected MCY in high concentrations in 10% of our sites, but neither anatoxin-a nor cylindrospermopsin were detected. All of the MCY-positive sites exceeded California action levels for recreational use and World Health Organization (WHO) guidance for human health effects. The prevalence of Microcystis spp. from all study sites indicates a high potential for MCY in these water bodies, although the one-time toxin grab samples likely underestimated the overall toxicity of these sites. Landscape variables, such as developed land use and dominant habitat type, were not found to be predictive indicators of cyanobacterial dominance. However, because cyanobacteria become consistently dominant when chlorophyll-a levels exceed 15 µg L -1 , chlorophyll-a can serve as a significant predictor of MCY.

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A Tracer Study of the Phosphorus Cycle in Lake Water

Cited by 207 publications

References 10 publications

rise and fall of dissolved phosphate in South African rivers

rise and fall of dissolved phosphate in South African rivers

Relationship between phytoplankton cell size and the rate of orthophosphate uptake: in situ observations of an estuarine population

Screening Assessment of Cyanobacteria and Cyanotoxins in Southern California Lentic Habitats

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