The assemblage composition, biomass and dynamics of zooplankton and epibenthos were examined in a commercial prawn pond in southeast Queensland over two seasons. Physico-chemical characteristics of the pond water were measured concurrently. Numbers and biomass of zooplankton in the surface tows (140 micrometre mesh) varied from 8 ind. L-1 (44 micrograms L-1) to 112 ind. L-1 (324 micrograms L-1) in the first season, with peaks in biomass corresponding to peaks in numbers. In the second season the zooplankton numbers varied from 12 to 590 ind. L-1, but peaks in numbers did not correspond with peaks in biomass, which varied from 28 to 465 micrograms L-1. This was due to differences in the size of the dominant taxa across the season. Although this occurred in both seasons, the effect on biomass was more pronounced in the second season. In both seasons, immediately after the ponds were stocked with prawn postlarvae there was a rapid decline in zooplankton numbers, particularly of the dominant larger copepods. This was probably due to predation by the postlarvae. Subsequent peaks in zooplankton numbers were principally due to barnacle nauplii. The largest peaks in zooplankton numbers occurred before stocking in the first season, but the largest peaks were in the middle of the second season. While changes in abundance and biomass of the zooplankton assemblage were not correlated with physico-chemical characteristics in the first season, there were correlations between zooplankton numbers and temperature, dissolved oxygen, pH and secchi disk readings in the second season. No correlations were found with zooplankton biomass and physico-chemical characteristics in the second season. The correlations in the second season were mainly due to the high prevalence of barnacle nauplii through the middle part of the season, and may reflect suitable conditions for barnacle reproduction. Epibenthic faunal abundance in the beam trawls (1 mm mesh) peaked at 14 ind. m-2 and 7 ind. m-2 in the first and second seasons respectively and the biomasses at 0.8 g m-2 and 0.7 g m-2. Peaks in abundance of epibenthos did not correspond to peaks in biomass. This was due to large differences in the size of the taxa across the seasons. Sergestids (Acetes sibogae) and amphipods were the most abundant taxa in beam trawl samples. Amphipods were only abundant in the first season, with their numbers increasing towards the end of the grow out period. Acetes were abundant in both seasons, but were dominant in the second season. Correlations between physico-chemical parameters and epibenthos numbers were found to be strongly influenced by the dominant taxa in each season. In the first season, negative correlations were found between epibenthos abundance and pH and temperature. These relationships may reflect an effect on the growth of macroalgae in the pond, with which the amphipods were strongly associated, rather than a direct effect on the epibenthos. In the second season, a positive correlation existed between temperature and epibenthos abundance, however this was strongly influenced by the very high abundance of Acetes in the last sampling period. No correlations were found between epibenthic fauna biomass and physico-chemical parameters. Abundances of epibenthic fauna were not related to zooplankton densities indicating this source of food was not likely to be a limiting factor. Neither the pond water exchange regime nor moon phase could explain changes observed in abundances of zooplankton or epibenthos assemblages in the first season, however the sampling regime was not designed to specifically investigate these effects. In the second season water exchanges were sampled more rigorously. The density of zooplankton in the outlet water was from 2 to 59% of the density of zooplankton in the pond, and the zooplankton density of the inlet water was from 9 to 50% of the outlet water. The number of zooplankton recruited into the pond from the inlet water, after the prawns were stocked, was negligible and contributed little to changes observed in zooplankton assemblages. Reproduction of barnacles within the pond appeared to play the most important role in changes in the assemblage. Water exchange did, however, appear to play a greater role in the changes observed in epibenthic fauna assemblages. In the last season of sampling the feeding of the dominant epibenthic species, Acetes sibogae, was examined using a combination of gut content and stable isotope analysis. Acetes gained little nutrition directly from the pelleted feed, probably relying primarily on zooplankton as their direct food source. Other dietary items such as macroalgae also played a role in the nutrition of the Acetes. If Acetes numbers were high at the beginning of a season they may compete with the newly stocked prawns for the zooplankton resource. However, they will not compete with the prawns later in the season when the prawns are gaining most of their nutrition from the pelleted feed. Overall it appears that zooplankton are important to the nutrition of the prawns at the beginning of the season when the assemblage is usually dominated by copepods. Later in the season the assemblage is dominated by barnacle nauplii which are recruited from within the pond. The establishment of an abundant assemblage of suitable zooplankton species before stocking prawn postlarvae would appear to be beneficial, if not essential. The assemblage of epibenthic fauna changes throughout the season as new recruits are brought in from outside the pond. Epibenthic faunal assemblages in ponds from southeast Queensland are dominated by Acetes which are not likely to adversely affect the production of prawns unless they are particularly abundant early in the grow out season when the prawns would be utilising the same food resources as Acetes.

This study is aiming to investigate the distribution of epibenthic shrimp communities in relation to the environmental factors of their habitats in the coastal sandy bottom of southwestern Taiwan. Shrimp samples were collected from April 2002 to July 2003, with a beam trawl operated at seven stations along the coasts. Simultaneously, water temperature, salinity, dissolved oxygen were measured and sediments were collected. Particle size and organic matter of the sediments were then analyzed in the laboratory. The results of PCA analyses on these environmental factors revealed that the observations could be segregated into two groups along the PC1, representing rainy season with high temperature, low salinity and dry season with low temperature, high salinity, respectively. The observations with coarse particle (>0.125 mm), representing samples from north sites, were found to distribute in the upper part of the PC2; while those with fine particle (<0.125 mm), representing samples from south sites, distributed in the lower part. In total, 15,591 individuals of shrimp were collected, including 20 genus, 39 species. Metapenaeopsis palmensis (88.2%), Trachysalambria curvirostris (3.6%), M. barbata (3.5%) and Parapenaeopsis cornuta (1.4%) were the four dominant species. Significant differences in the spatial distribution were due to the different composition of the dominant species. Although M. palmensis was the most abundant species in most stations, its percentage abundance was the lowest at Fangliao and Jiading, where the dominant species were T. curvirostris for the former and M. barbata and P. cornuta for the latter. Species preferences for various combinations of environmental variables are responsible for shifts in the structure and overall abundance of assemblages and dictated some patterns. Higher abundances of T. curvirostris, Trachypenaeus granulosus, and Solenocera koelbeli were associated with the appearance of high temperature, low salinity and very fine sand, representing the environmental features of Fangliao and Linbian during the rainy season. Stenopus hispidus, Metapenaeus moyebi, Metapenaeus ensis and M. palmensis were abundant coinciding with low temperature, high salinity and high silt and clay that reflecting the dry season of Linyuan and Linbian waters. Metapenaeopsis dalei and M. barbata appeared in large numbers at habitats with high temperature, low salinity and coarse sand, which mainly occurred in Zouying to Jhongjhou during the rainy season. Moreover, Scyllarus rugosus and Parapenaeopsis cornuta seemed to prefer coarse sandy bottom mainly distributed from Jiading to Linyuan. Temporal fluctuations were associated with the population dynamic of the dominant species. The abundance was reduced while the M. palmensis migrated to open sea in late summer and early autumn. As the juveniles of M. palmensis and M. barbata back to the inshore waters, the abundance were increased and reached the peak in spring. Because of the limited distribution, T. curvirostris and P. cornuta were not influence the overall temporal fluctuations but the local fluctuations. Overall, temporal fluctuations act more at a specific level even structural one, and may be linked to some particular stages of the benthic shrimp life cycle, but do not significantly influence the spatial organization.

The deep ocean (> 200-m depth) covers more than 65 percent of earth's surface and is known as the largest active carbon sink of the planet. Photosynthesis fixes inorganic carbon into organic rich-compounds to fuel the biological production in the upper ocean. A small portion of the photosynthetic carbon eventually sinks to the seafloor to support diverse deep-sea life. In this dissertation, the phytoplankton production and export flux of particulate organic carbon (POC) to the seafloor were linked to standing stocks and compositional changes of the deep-sea soft bottom assemblages. The pattern and processes of energy transfer from the surface ocean to the deep sea was examined by modeling the global benthic bacteria, meiofauna, macrofauna, and megafauna biomass from remotely sensed ocean color images and the seafloor relief. The analysis was then scaled down to the macrofauna of the Gulf of Mexico (GoM) to examine the global pattern on regional oceanic features with contrasting productivity regimes. These results suggested a universal decline of benthic standing stocks down the continental margins that is caused by an exponential decrease of export POC flux with depth. A revisit of historical epibenthic invertebrate sampling in the North Atlantic showed that both individual species and multi-species assemblages occurred in narrow depth bands that hugged the topography from the upper continental slope out to the Hatteras Abyssal Plain. The continuum compositional change suggested that the continuous decline of benthic food supply with depth was the potential driving force for the pattern of bathymetric faunal zonation. A broad, systematic survey across multiple depth transects in the northern GoM suggested that macrofauna zonation is not only taking place across isobaths, but also form the northeast to the northwest GoM due to a horizontal productivity gradient created by the nutrient-laden Mississippi River. Analyses of long-term demersal fish data from 1964 to 2002 in the northern GoM showed no evidence of large-scale faunal change across different sampling times. Base on the pooled data, a shift in rate of fish species replacement may be caused by complex biological interactions or changes in environmental heterogeneity along depth or productivity gradients.