Abstract: : The purpose of studying the biological organisms in the Mpenjati estuary-beach system is to distinguish between organisms and estimate diversity within the estuary found at different locations along the estuary-beach profile in accordance with factors affecting the daily routines of these marine life and other aspects in which these organisms concur with. The organisms found in these waters play an important role in the ecosystems they function in therefore it is imperative to seek a way to keep a close relationship between the estuary-beach systems to prevent breaks in the ecosystems. The goal of an estuary-beach system is to be able to sustain and diversify the life that exists in these biomes. ‘Organisms that live in beach-estuary systems are phytoplankton, zooplankton and fish (in the water-column) and microphytobenthos, macrofauna and meiofauna which inhabit the sediment. The above mentioned organisms are the main organisms that drive ecosystem functioning in a beach-estuary system’. If the present environments had to disappear, there would be devastating effects not only in the biological sector but also the environmental and economical aspects. To avoid catastrophes among ecosystems, tests need to be performed in essence to keep the ecosystems from being harmed. If, for example, diatoms and dinoflagellates were to be removed from the food web due to certain chemical factors many organisms (mollusc larvae, copepods, etc) will not have a food supply therefore resulting in the extinction of many organisms. This leads to disruptions in the ecosystem. The preservation in estuaries is vital for the study of past life and climates, as well as present living organisms and the abiotic factors influencing them. Introduction: In the Mpenjati beach-estuary system organisms that contribute to a variety of factors and ecosystem functioning include a diverse range of meiofauna, macrofauna, zooplankton, fish and other species that live in either a benthic or pelagic life-cycle.
Meiofauna are a complex group of microscopic animals found in waters domineering along beach-estuarine systems. These organisms are benthic- they need a surface substrate to attach themselves onto e.g. sediments. Meiofauna mainly include nematodes, ploychaetes and harpacticoid copepods. Perissinotto & Smit (2010). These organisms are important as they clean the waters they live in.
Zooplankton organisms can be divided into the pelagic (living in the water-column) or the benthic phases depending on the stages of their life cycle. The animals' life cycle that lie within the plankton are holoplankton and the ones that spend part of their life cycle in the plankton are meroplankton. Thurman (1997). Zooplankton includes copepods, mysids, amphipods as well as fish larvae, crabs and other benthic organisms.
Macrofauna are organisms that can be seen with the naked eye. These organisms are not large enough to be termed megafauna but they are relatively larger than microfauna. Macrofauna marine animals include crabs, prawns, annelids, insects, amphipods and many other coastal-estuarine water dominated marine species. Many of these organisms are human food sources.
Fish are abundant in most bodies of water. Humans use fish as a food source. Fish exhibit the greatest diversity than any other class of vertebrates. Fish use estuarine waters for spawning. In estuarine systems one can expect to find mullets, gobiidae and clupeid species. Materials and Methods: The procedures at the location on the ocean-estuary-south was to seek information on the different locations that were sampled to account for the variations in not only the biotic factors but also the abiotic factors affecting the present closed beach-estuary system.
Zooplankton. One sample was obtained using a hyperbenthic sled(40cm mouth diameter, 200µm mesh) pulled at a distance of 27m.The material collected in the cod-end is placed into a bottle, and fixed with 10% formalin. At the...