Characterisation of selected micro-estuaries and micro-outlets in South Africa using microalgal, zooplanktonic and macrozoobenthic assemblages

Magoro, Mandla L.; Dalu, Tatenda; Human, L.R.D.; Perissinotto, Renzo; Deyzel, S.H.P.; Wooldridge, T.; Adams, Janine B.; Whitfield, Alan K.

doi:10.2989/16085914.2019.1677211

Cited by 7 publications

(3 citation statements)

References 54 publications

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“…Nine small systems previously classified as estuaries were reclassified as micro-systems under the new classification (Table 2), because of clear indications that they do not support typical estuarine functionality, e.g. some systems have limited estuarine biota (Magoro et al 2019), with no fish fauna recorded in micro-outlets over a number of visits (Magoro 2018). Micro-systems were classified into three categories based on spatial features (e.g.…”

Section: Micro-system Typesmentioning

confidence: 99%

“…Micro-estuaries These are defined as small, permanent coastal waterbodies where mixing of salt-and freshwater can periodically occur owing to overwash from the sea or tidal exchange following breaching of the mouth. These small systems are likely to support low densities of a limited number of estuarine and marine species (Bate et al 2017;Dalu et al 2018;Human et al 2018;Magoro et al 2019).…”

Section: Micro-system Typesmentioning

confidence: 99%

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An Estuary Ecosystem Classification that encompasses biogeography and a high diversity of types in support of protection and management

Niekerk

Adams

James

et al. 2020

African Journal of Aquatic Science

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For nearly three decades, the Whitfield (1992) characterisation scheme served as a reference framework to type South African estuaries. We outline a revised ecosystem classification scheme that incorporates biogeographical zonation and introduces new types. Coastal outlets were re-categorised as estuaries or micro-systems. For functional estuaries, the Estuarine Lakes, Estuarine Bays and Predominantly Open Estuary types were largely retained. New types are Estuarine Lagoons and Arid Predominantly Closed Estuaries. The numerically dominant, temporarily open/closed category was subdivided into Small and Large Temporarily Closed Estuaries, with a total habitat area of 15 ha, serving as threshold separating these two subdivisions. River mouths were renamed Fluvially Dominated Estuaries and divided into large and small size categories to reflect dissimilar catchment influences. Micro-systems were separated into micro-estuaries, micro-outlets, and waterfalls. South Africa's 290 estuaries were classified into 22 estuarine ecosystem categories arising from nine estuary types occurring across four biogeographical zones. In addition, 202 micro-systems were classified into nine ecosystem types, of which only the micro-estuaries (42) share possible functionality with estuaries. Estuaries subjected to functional shifts were also identified. The classification system provides a framework that integrates biogeography and the range of biophysical parameters evident in South Africa, and can be used for red listing of ecosystem types and determining estuarine sensitivity to pressures.

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Section: Micro-system Typesmentioning

confidence: 99%

Section: Micro-system Typesmentioning

confidence: 99%

An Estuary Ecosystem Classification that encompasses biogeography and a high diversity of types in support of protection and management

Niekerk

Adams

James

et al. 2020

African Journal of Aquatic Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…While most of these systems fall within the subtropical bioregion, previous ecological assessments have largely been focused within the southern warm-temperate bioregion. In that region the diversity and abundance of biotic assemblages (i.e., phytoplankton, microphytobenthos, zooplankton, macrozoobenthos, and fish) were found to differ between micro-estuaries and micro-outlets (Dalu et al, 2018(Dalu et al, , 2020Magoro et al, 2019Magoro et al, , 2020aMagoro et al, , 2020b.…”

Section: Introductionmentioning

confidence: 98%

The water quality status of estuarine micro-system types along the coast of KwaZulu-Natal Province, South Africa

GC Bate,

DA Lemley,

M Nunes

et al. 2023

WSA

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A survey of the quality of water flowing from micro-system types to the ocean, along the subtropical east coast of South Africa, showed a wide variation in the concentrations of total nitrogen, phosphorus and phytoplankton biomass in the different systems located, in many cases, only a short distance from each other along the coastline. The origins of the high phytoplankton growth indicate pollutants caused by the land-use in this highly populated coastal region. The main agricultural activities in the area are sugarcane, permanent orchards, and forestry. The levels of N and P in the water varied from ‘good’ to ‘poor’, i.e., TN 0.15–3.99 mg‧L−1, TP 0.02–0.33 mg‧L−1 and chlorophyll-a from 0 to almost 45 µg‧L−1. Rapid coastal population densification appears to have been the cause of the pollution levels measured for total nitrogen, phosphorus, and phytoplankton biomass. Most of the micro-systems with a total modified peri-catchment above 80% were enriched by both TN and TP. While the hypothesis tested was that the main cause was residential development (e.g., septic tank effluent), it was not possible to show any statistical significance to support such a specific conclusion. Although these systems are small individually, the great number along the coastline warrants recognition as important sources of freshwater inflow and nutrients to the marine environment.

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Ecosystem and Biotic Classifications of Estuaries and Coasts

Whitfield,

Elliott

2024

Treatise on Estuarine and Coastal Science (Second Edition)

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Characterisation of selected micro-estuaries and micro-outlets in South Africa using microalgal, zooplanktonic and macrozoobenthic assemblages

Cited by 7 publications

References 54 publications

An Estuary Ecosystem Classification that encompasses biogeography and a high diversity of types in support of protection and management

An Estuary Ecosystem Classification that encompasses biogeography and a high diversity of types in support of protection and management

The water quality status of estuarine micro-system types along the coast of KwaZulu-Natal Province, South Africa

Ecosystem and Biotic Classifications of Estuaries and Coasts

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