Young Blonde Girl Shows Off On The Sandy Beach At The Sea

Latitudinal biodiversity patterns of meiofauna from sandy littoral beaches
Recently, large-scale patterns of marine biodiversity were the subject of many discussions. These attempts to develop a general picture of diversity in the sea are hampered by the small number of key studies, the varied sampling protocols applied, the different diversity indices and the varying levels of taxonomic resolution. A general trend of species impoverishment towards the poles was reported for some taxa (e.g., corals, gastropods), but this does not hold for others (e.g., amphipods and decapods crustaceans). In addition, it seems probable that there is a cline in increasing diversity from the arctic to the tropics, but the cline from the Antarctic to the tropics is far less well-established since the Antarctic has high diversity for many taxa. Broad latitudinal gradients in species richness are illustrated for open-ocean pelagic and deep-sea taxa, but some debate continues to surround evidence for shallow-water systems, particularly for non-calcareous taxa. Gray (1997) stated that marine biodiversity is higher in benthic (bottom-related) rather than in pelagic (in the water column) systems, and on coasts rather than in the open ocean, since there is a greater range of habitats near the coasts. A good comparison of multispecies macrofaunal assemblages inhabiting the same type of habitat (sublittoral, fine sediment bottom) showed little if any difference among tropical, temperate and arctic sites in terms of diversity. There was some dispute on how far the observed latitudinal patterns are size-dependant and small bodied taxa (Protoza and meiofauna) tend to be more ubiquitous and their richness is less latitude dependant compared to large organisms.
In coastal environments the interactions between coastal morphology, land-ocean exchanges, meteorological and tidal conditions, create a highly complex and finely scaled network of environmental boundaries. These boundary conditions explain why coastal waters have both higher species richness and a richer ecosystem than their oceanic counterparts . Sandy beaches are among the most ‘simple’ systems in terms of habitat complexity in comparison to other coastal ecosystems as, for example, rocky shores, algae and seagrass beds. Biodiversity and biomass of interstitial organisms are rather low. However, recent findings have shown that marine sands transfer energy very effectively, and that chemical and biological reactions take place faster there than in fine-grained sediments.
The maximum meiofauna densities reported in the study of Kotwicki et. al (2005) ranged between 15 and 4312 individuals 10 cm sq. The reported densities rank among the meiofauna densities in sandy beaches reported in available literature. In general, high meiofauna density can be found in intertidal muddy estuarine habitats, while much lower values are recorded in the deep sea. In fine sediments such as organic rich muds, meiofauna densities of 104 individuals 10 cm sq and more are common. The available meiofauna data showed a large within-site (within-region) variation in the temperate zone while there was very little variation within the meiofauna densities of the antarctic and arctic zones. These patterns demonstrate that attempts to project global biodiversity from the results of regionally based studies must include the significant variation in diversity among sampling sites. The low salinity effect on meiofauna occurrence was not clear – two brackish water locations have the same range of meiofauna density as full marine sites (Kotwicki et. al 2005). As was reported in cited literature, the lower salinity was not associated with decrease of meiofauna.