Light penetration and the interrelationships between optical parameters in a turbid subtropical impoundment

Walmsley, R. D.; Butty, M.; Piepen, Heinz van der; Grobler, D. C.

doi:10.1007/bf00015500

Cited by 29 publications

(13 citation statements)

References 11 publications

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“…The variable contribution to absorption of the phytoplankton, which ranged between 4 and 4 8 mg chl a m-", was small in comparison to the scattering by inorganic pa.rticulates, and the relationship In Eq. (1) agrees well with that published by Walmsley et al (1980). Conversion of turbidity to an attenuation coefficient allowed estimation of the light attenuation through the water column where it was not well-mixed a n d for samples taken in March, when the llght meter was unavailable.…”

Section: Methodssupporting

confidence: 86%

Primary production by suspended and benthic microalgae in a turbid estuary:time-scales of variability in San Antonio Bay, Texas

MacIntyre¹,

Cullen²

1996

Mar. Ecol. Prog. Ser.

148

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The within-day, between-day and month-to-month variability of light attenuation and microalgal chlorophyll a (chl a ) and photosynthetic response was measured in San Antonio Bay, Texas, USA. Waters were shallow (<2 m) and turbid (attenuation coefficients of 0.7 to 15.3 m"), yet daily rates of primary production (0.1 to 2.5 g C d-') were comparable to those in much deeper and clearer estuaries. Chl a concentrations in the sediment (459 to 7837 mg m-3 in the surficial millimeter) were much higher than those In the water column ( 4 to 48 mg m-'). The benthic assemblages were photosynthetically competent, but dally benthic primary productivity was low (0.00 to 0.09 g C m-' d-'; an average of 2'Lb of productivity in the water colun~n) because of the very low irradiances at the sedimentwater interface. The high rates of production by the suspended mlci-oalgae were largely due to high chlorophyll-specific light-saturdted rates of photosynthesis. P:,:' 13.0 to 24.4 g C (g chl a)-' h -' ] , which were correlated positively wlth temperat~lre and inversely with the mean irradiance in the water column. The between-day and temperature-~ndependent variation in P$! was also correlated with F,,Chl-l, a n index of the proportion of functional photosystem 11 reaction centers. In turn, within-day variability in F,,Chl-l was inversely correlated with the mean irradiance in the water column in 8 of 10 observations, a pattern consistent with photoinhibition. A depression of P : ! ' caused by photoinhibition throughout the water column may therefore b e responsible for the inverse trend of P$' with mean irradiance in the water column. Short-term (h) variability in suspended chl a and turbidity was high (coefficient of variation = 13 to 7 5 % ) , but estimates of daily productivity could be predicted with reasonable fidelity (mean error 2 7 % ) from a single midday determination of chl a, the photosynthesis versus lrrad~a n c e response and the attenuation coefficient, along with daily incident radiation. The predictive power of a single observation was due to coherence in the variation of chl a, P: :' and the attenuation coefficient In the water column-the decrease in mean irradiance caused by resuspension was compensated for by concomitant Increases in Pc,hland suspended chl a Between-day variability in productivity of 15 to 5 2 % approached month-to-month differences, so the optimal use of resources in monitoring productivity would be to take slngle samples daily.

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Section: Methodssupporting

confidence: 86%

Primary production by suspended and benthic microalgae in a turbid estuary:time-scales of variability in San Antonio Bay, Texas

MacIntyre¹,

Cullen²

1996

Mar. Ecol. Prog. Ser.

148

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“…The attenuation of PAR was measured with a quantum meter and sensor (Lambda Instruments, . Transparency was determined with a standard Secchi disc (diameter 0 .2 m) and these data were used to calculate turbidity (NTU units) using the formula NTU = 1 .00 + 12 .94 x 1/Z sd , where Z sd is Secchi disc depth (Walmsley et al ., 1980). This formula was derived from data collected at Rust de Winter Dam .…”

mentioning

confidence: 99%

Phytoplankton and zooplankton population dynamics and production of a recently formed African reservoir

et al. 1992

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The study provides a 2 .5 year record of Rhenosterkop Dam (KwaNdebele, South Africa) plankton population dynamics and production in relation to physical and chemical changes which occurred during the trophic depression and stabilization phases of the reservoir . The mean volume of the reservoir was 4 % of full storage capacity . Water temperatures ranged from 14 ° C to 27 'C . Due to inorganic suspensoids, the euphotic zone averaged 2 .6 m . An anaerobic zone developed each summer . The nitrogen, soluble reactive phosphorus (SRP) and silica concentrations did not display a seasonal pattern, but the latter two nutrients declined over the study . The dominant phytoplankton group was the cryptophytes while the zooplankton population was dominated by crustaceans . Chlorophyll a concentrations ranged from 1 .1 to 27 mg m-3 and were positively correlated to silica and SRP concentrations and inversely with NH 4-N concentrations . Primary production ranged from 22 .6 to 375 mgC m -2 h-' ; changes in A,,, a, were positively correlated to silica and SRP concentrations . Total zooplankton dry weight biomass varied from < 0 .5 to > 4 mg I -' . Annual zooplankton (secondary) production was 8 to -15 gC m -3 a -'; both primary and secondary production were greatest in the first 12 months of study and remained at low levels for the remainder, similar to the trends for silica and SRP . The data indicate that the reservoir shifted from eutrophic to mesotrophic during the study, typical of events in new reservoirs, and that changes in the plankton populations were largely the result of changing nutrient concentrations .Introduction 1990). Groundwater resources are limited and the surface waters are relied upon for urban, indusThe majority of water resources in southern Aftrial and agricultural purposes . Irrigation is the rica are riverine and south of the Zambezi River major use of surface waters in this region, adding there are very few natural lakes (Allanson et al., to the load placed on limited surface resources

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“…The presence of high concentrations of suspended sediments in the water column reduces light penetration and tends to limit the growth of phytoplankton as well as benthic algae and aquatic macrophytes, even when high concentrations of nutrients are available (Allanson et al 1990). Under these conditions, buoyant gas-vacuolate cyanobacteria are able to circumvent the light limiting effects of suspended sediments by occupying the upper part of the water column, adding to the light-shading effects of the suspended sediments and thereby gaining a competitive advantage over other phytoplankton species (Walmsley et al 1980;Allanson et al 1990). In Lake Krugersdrift high concentrations suspended solids were recorded throughout the study (average at all four sampling sites were 131 ± 4 mg/l) possibly due to the wind-induced particle resuspension which cause low Secchi disc readings (≤1.5 m).…”

Section: Discussionmentioning

confidence: 99%

The influence of a toxic cyanobacterial bloom and water hydrology on algal populations and macroinvertebrate abundance in the upper littoral zone of Lake Krugersdrift, South Africa

2008

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The biological interactions and the physical and chemical properties of the littoral zone of Lake Krugersdrift were studied for a 4-month period when a dense, toxic cyanobacterial bloom dominated by Microcystis aeruginosa was present in the main lake basin. The presence of a toxic strain of M. aeruginosa was confirmed through the use of ELISA and molecular markers that detect the presence of the mcyB and mcyD genes of the mcy gene cluster that synthesizes microcystin. An increase in Microcystis toxicity at sites dominated by the cyanobacterial scum was accompanied by an increase in total abundance of the macroinvertebrate families Hirudinae, Chironomidae, and Tubificidae. Sites located away from the cyanobacterial scum had a lower abundance but a higher diversity of macroinvertebrates. The water quality under the Microcystis scum was characterized by low pH values, low concentrations of dissolved oxygen, and lower total alkalinity values. The periphytic alga Ulothrix zonata was absent in areas dominated by the cyanobacterial scum, possibly as a result of overshadowing by the scum or direct toxic allelopathic effects on growth and photosynthesis. The diatom Diatoma vulgare dominated the benthic algal flora beneath the cyanobacterial scum.

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Light penetration and the interrelationships between optical parameters in a turbid subtropical impoundment

Cited by 29 publications

References 11 publications

Primary production by suspended and benthic microalgae in a turbid estuary:time-scales of variability in San Antonio Bay, Texas

Primary production by suspended and benthic microalgae in a turbid estuary:time-scales of variability in San Antonio Bay, Texas

Phytoplankton and zooplankton population dynamics and production of a recently formed African reservoir

The influence of a toxic cyanobacterial bloom and water hydrology on algal populations and macroinvertebrate abundance in the upper littoral zone of Lake Krugersdrift, South Africa

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