High Levels of Sediment Contamination Have Little Influence on Estuarine Beach Fish Communities

While contaminants are predicted to have measurable impacts on fish assemblages, studies have rarely assessed this potential in the context of natural variability in physico-chemical conditions within and between estuaries. We investigated links between the distribution of sediment contamination (metals and PAHs), physico-chemical variables (pH, salinity, temperature, turbidity) and beach fish assemblages in estuarine environments. Fish communities were sampled using a beach seine within the inner and outer zones of six estuaries that were either heavily modified or relatively unmodified by urbanization and industrial activity. All sampling was replicated over two years with two periods sampled each year. Shannon diversity, biomass and abundance were all significantly higher in the inner zone of estuaries while fish were larger on average in the outer zone. Strong differences in community composition were also detected between the inner and outer zones. Few differences were detected between fish assemblages in heavily modified versus relatively unmodified estuaries despite high concentrations of sediment contaminants in the inner zones of modified estuaries that exceeded recognized sediment quality guidelines. Trends in species distributions, community composition, abundance, Shannon diversity, and average fish weight were strongly correlated to physico-chemical variables and showed a weaker relationship to sediment metal contamination. Sediment PAH concentrations were not significantly related to the fish assemblage. These findings suggest that variation in some physico-chemical factors (salinity, temperature, pH) or variables that co-vary with these factors (e.g., wave activity or grain size) have a much greater influence on this fish assemblage than anthropogenic stressors such as contamination

Photogeneration and transport in thin films of p- and n-type discotic liquid crystals

Thin layers of discotic liquid crystals, p-type: HBC-C8,2, HBC-C12 and n-type: HATNA 4D, RDlSCl and perylene derivative were prepared by drop- and zone-casting. It is shown, that zone-casting yields aligned, anisotropic films with "edge-on" orientation suitable for FET construction. In the isotropic, obtained by drop-casting films the charge-carrier photogeneration, recombination and transport were investigated by means of xerographic discharge. For the first time it is demonstrated experimentally that in the nominally n-type discotics the majority charge carriers are electrons.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Cyclonic entrainment? The ichthyoplankton attributes of three major water mass types generated by the separation of the East Australian current

The relationship between larval fish assemblages and coastal oceanography is the basis for much of our understanding of connectivity and productivity of fish populations. Larval fish assemblages were sampled from the upper mixed layer (depth) at three prominent circulation features [separation of the East Australian Current (EAC), anticyclonic eddy, and cyclonic eddy] off the southeast Australian coast across three bathymetric zones (shelf, slope and ocean) for each feature. The separation of the EAC from the coast at ∼32°S was characterized by warmer, less saline water compared with the cyclonic and anticyclonic eddies further to the south (∼34 and ∼35°S, respectively), which were both characterized by cooler Tasman Sea water and greater fluorescence. The anticyclonic eddy had separated from the EAC three months prior to sampling, which facilitated the movement of a cyclonic eddy from the Tasman Sea westwards to the shelf at ∼34°S. The larval assemblage in the EAC had high numbers of fish of the families Labridae and Stomiidae. The cyclonic eddy was characterized by larval clupeids, carangids, scombrids and bothids, indicating recent entrainment of shelf waters and proximity to major spawning regions. In contrast, the anticyclonic eddy had fewer larval fish, with little evidence for entrainment of shelf assemblages into the near-surface waters. Myctophids were found in high abundance across all oceanographic features and bathymetric zones. The evidence of selective entrainment of coastal larval fish into the near-surface waters of a cyclonic eddy compared with a similar anticyclonic eddy indicates a potential offshore nursery ground