Temporal trends in total phosphorus, temperature, oxygen, chlorophyll<i>a</i>and phytoplankton populations in Hartbeespoort Dam and Roodeplaat Dam, South Africa, between 1980 and 2000

Ginkel, C. E. van; Silberbauer, Michael

doi:10.2989/ajas.2007.32.1.9.146

Cited by 21 publications

(13 citation statements)

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“…Detailed information on the limnology and phytoplankton dynamics of Hartbeespoort is available (e.g., [15][16][17]). It is one of the most productive reservoirs in the world, with so-called hyperscums of Microcystis Aeruginosa [18].…”

Section: Study Areas and Sampling Strategymentioning

confidence: 99%

Characterizing the Absorption Properties for Remote Sensing of Three Small Optically-Diverse South African Reservoirs

Matthews

Bernard

2013

Remote Sensing

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Characterizing the specific inherent optical properties (SIOPs) of water constituents is fundamental to remote sensing applications.Therefore, this paper presents the absorption properties of phytoplankton, gelbstoff and tripton for three small, optically-diverse South African inland waters. The three reservoirs, Hartbeespoort, Loskop and Theewaterskloof, are challenging for remote sensing, due to differences in phytoplankton assemblage and the considerable range of constituent concentrations. Relationships between the absorption properties and biogeophysical parameters, chlorophyll-a (chl-a), TChl (chl-a plus phaeopigments), seston, minerals and tripton, are established. The value determined for the mass-specific tripton absorption coefficient at 442 nm, a * tr (442), ranges from 0.024 to 0.263 m 2 ·g −1 . The value of the TChl-specific phytoplankton absorption coefficient (a * φ ) was strongly influenced by phytoplankton species, size, accessory pigmentation and biomass. a * φ (440) ranged from 0.056 to 0.018 m 2 ·mg −1 in oligotrophic to hypertrophic waters. The positive relationship between cell size and trophic state observed in open ocean waters was violated by significant small cyanobacterial populations. The phycocyanin-specific phytoplankton absorption at 620 nm, a * pc (620), was determined as 0.007 m 2 ·g −1 in a M. aeruginosa bloom. Chl-a was a better indicator of phytoplankton biomass than phycocyanin (PC) in surface scums, due to reduced accessory pigment production. Absorption budgets demonstrate that monospecific blooms of M. aeruginosa and C. hirundinella may be treated as "cultures", removing some complexities for remote sensing applications. These results contribute toward a better Remote Sens. 2013, 5 4371 understanding of IOPs and remote sensing applications in hypertrophic inland waters. However, the majority of the water is optically complex, requiring the usage of all the SIOPs derived here for remote sensing applications. The SIOPs may be used for developing remote sensing algorithms for the detection of biogeophysical parameters, including chl-a, suspended matter, tripton and gelbstoff, and in advanced remote sensing studies for phytoplankton type detection.

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Section: Study Areas and Sampling Strategymentioning

confidence: 99%

Characterizing the Absorption Properties for Remote Sensing of Three Small Optically-Diverse South African Reservoirs

Matthews

Bernard

2013

Remote Sensing

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“…Contemporary analyses merely seem to mimic earlier assessments and provide no impetus for an advanced understanding (e.g. Van Ginkel & Silberbauer 2007). Singular exceptions are the three-year study conducted at Rietvlei (Harding et al, 2012;Harding & Hart, 2013), a body of work that illustrated the fallacy of attempting top-down lake management to shape the bio-coenotic structure (see also Hart, 2006Hart, , 2011, and work undertaken in the Olifants River catchment (e.g.…”

Section: A History Of Lake Management Science In South Africamentioning

confidence: 99%

Living with eutrophication in South Africa: a review of realities and challenges

Harding¹

2015

Transactions of the Royal Society of South Africa

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The socio-economic well-being of South Africa is largely dependent on reservoir lakes. Contrastingly, the country lacks reservoir management skills and training, with a generation having passed since there was limited activity in this field. This review introduces two new, independent analyses which, using in-lake total phosphorus or satellite-measured chlorophyll-a, respectively, reveal that between 41% and 76% of total storage is eutrophic or hypertrophic. This is in stark contrast to a claimed 5% made by the responsible government agency (Department of Water and Sanitation). Data and information on the incidence and toxicity of cyanobacterial blooms are sparse, yet severe problems exist. There is a concentration of focus on water quantity, with absent parallel consideration of the additional limitations posed by poor water quality. The most seriously impacted reservoirs are located in the economic heartland of South Africa, which has an extant regional water quality crisis. The reasons behind the startling lack of attention to reservoir limnology, despite clear and long-standing warnings, are examined and placed in the perspective of an acknowledged and impending water crisis. It will take considerable time to up-skill South African limnologists to meet the needs highlighted by worsening reservoir water quality, and to offset the social and economic impacts that will transpire, if not timeously ameliorated. The responsible agency urgently needs to establish a reservoir-management programme that embraces remaining individual and institutional memory, integrates all available relevant knowledge and scientific findings, prioritises needs and acquires those skills and resources necessary to meet what is likely to become a crippling legacy of inaction.

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“…Examples are the total nitrogen >1500 mg l À1 and total phosphorus >75 mg l À1 from sampling points downstream of a sewage treatment plant for the Rietvlei Lake near Pretoria (Oberholster et al, 2008), and the hypertrophic Roodeplaat Dam reservoir north of Pretoria at which total phosphorous values up to 4014 lg l À1 (4.014 mg l À1 ) have been determined (van Ginkel and Silberbauer, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…On Rietvlei Lake Oberholster et al (2008) determined moderate concentrations of total nitrogen (>1500 mg l À1 ) and total phosphorus (>75 mg l À1 ) at sampling points downstream of a sewage treatment plant. In the lake at Roodeplaat Dam, maximum total phosphorous concentrations in excess of 1000 lg l À1 were observed between 1996 and 2000 (van Ginkel and Silberbauer, 2007).…”

Section: Introductionmentioning

confidence: 98%

A spatial analysis of eutrophication in dam reservoir water on the Molopo River at Mafikeng, South Africa

Munyati

2015

Sustainability of Water Quality and Ecology

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Temporal trends in total phosphorus, temperature, oxygen, chlorophyllaand phytoplankton populations in Hartbeespoort Dam and Roodeplaat Dam, South Africa, between 1980 and 2000

Cited by 21 publications

References 1 publication

Characterizing the Absorption Properties for Remote Sensing of Three Small Optically-Diverse South African Reservoirs

Characterizing the Absorption Properties for Remote Sensing of Three Small Optically-Diverse South African Reservoirs

Living with eutrophication in South Africa: a review of realities and challenges

A spatial analysis of eutrophication in dam reservoir water on the Molopo River at Mafikeng, South Africa

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