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EARTH SCIENCE | BIOSPHERE | ECOSYSTEMS | MARINE ECOSYSTEMS | BENTHIC

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  • The CSIRO’s Oceans & Atmosphere Shallow Survey Internal Facility (SSIF) was contracted by the Institute for Marine and Antarctic Studies (IMAS) of the University of Tasmania (UTAS) in collaboration with Parks Australia, to undertake a hydrographic survey of the Boags Commonwealth Marine Reserve in the southwestern Bass Strait. This site was surveyed in conjunction with other smaller sites for Petuna Aquaculture, as part of a broader survey campaign. All of the sites covered in this campaign are located in the vicinity of the Hunter Group of Islands, off the north-western coast of Tasmania.

  • Genomic sampling locations and meadow indices for ribbon weed (Posidonia australis) and wire weed (Amphibolis antarctica) in Shark Bay (Gathaagudu)

  • Biodiversity assessments of invertebrates within seagrass (Amphibolis antarctica and Posidonia australis) transplant plots, compared to adjacent bare sand and healthy meadows at Middle Bluff, Dubaut Point and Useless Loop, Shark Bay.

  • Growth (shoot count) of Amphibolis antarctica and Posidonia australis following transplant to Middle Bluff and Dubaut Point, Shark Bay. Plants were transplanted by the Malgana people with assistance from UWA staff then assessed for shoot counts after 8 months.

  • Assessment of Posidonia australis transplant survival at 3, 8, 12, 18, and 26 months (August transplant); and 3, 8, 12, 18, 26 and 30 months (April transplant), after planting at Middle Bluff, and Dubaut Point, Shark Bay.

  • We performed a 5-week experiment in controlled laboratory settings to investigate the effects of different types of microparticles (i.e., PVC/red clay) on the performance of the Mediterranean mussel. Several response variables including respiration rate, byssus production, body condition index and survival were collected. Our study's main purpose is to examine effects of synthetic microparticles on bivalves using a more relevant methodological approach, i.e., in comparison to naturally-occurring particles, since these filter-feeders are exposed to not just microplastics in the real-world environment, but also to various naturally suspended seston particles, such as detritus and sediments.

  • Sediment organic carbon assessments within plots of transplanted Posidonia australis seagrass, and compared to adjacent bare sand and healthy meadows, in Shark Bay, WA.

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    The data is the quantitative abundance of fish derived from underwater visual census methods involving transect counts at rocky reef sites around Tasmania. This data forms part of a larger dataset that also surveyed megafaunal invertebrate abundance and algal cover for the area. The aggregated dataset allows examination of changes in Tasmanian shallow reef floral and faunal communities over a decadal scale - initial surveys were conducted in 1992-1995, and again at the same sites in 2006-2007. There are plans for ongoing surveys. An additional component was added in the latter study - a boat ramp study looking at the proximity of boat ramps and their effects of fishing. We analysed underwater visual census data on fishes and macroinvertebrates (abalone and rock lobsters) at 133 shallow rocky reef sites around Tasmania that ranged from 0.6 - 131 km from the nearest boat ramp. These sites were not all the same as those used for the comparison of 1994 and 2006 reef communities. The subset of 133 sites examined in this component consisted of only those sites that were characterized by the two major algal (kelp) types (laminarian or fucoid dominated). Sites with atypical algal assemblages were omitted from the 196 sites surveyed in 2006. This study aimed to examine reef community data for changes at the community level, changes in species richness and introduced species populations, and changes that may have resulted from ocean warming and fishing. The methods are described in detail in Edgar and Barrett (1997). Primarily the data are derived from transects at 5 m depth and/or 10 m depth at each site surveyed. The underwater visual census (UVC) methodology used to survey rocky reef communities was designed to maximise detection of (i) changes in population numbers and size-structure (ii) cascading ecosystem effects associated with disturbances such as fishing, (iii) long term change and variability in reef assemblages.

  • Sea urchins have the capacity to destructively overgraze kelp beds and cause a wholesale shift to an alternative and stable ‘urchin barren’ state. However, their destructive grazing behaviour can be highly labile and contingent on behavioural shifts at the individual and local population level. Changes in supply of allochthonous food sources, i.e. availability of drift-kelp, is often suggested as a proximate trigger of change in sea urchin grazing behaviour, yet field tests of this hypothesis are rare. Here we conduct a suite of in situ behavioural surveys and manipulative experiments within kelp beds and on urchin barrens to examine foraging movements and evidence for a behavioural switch to an overgrazing mode by the Australian sea urchin Heliocidaris erythrogramma (Echinometridae). Tracking of urchins using time-lapse photography revealed urchin foraging to broadly conform to a random-walk-model within both kelp beds and on barren grounds, while at the individual level there was a tendency towards local ‘homing’ to proximate crevices. However, consistent with locally observed ‘mobile feeding fronts’ that can develop at the barrens-kelp interface, urchins were experimentally inducible to show directional movement toward newly available kelp. Furthermore, field assays revealed urchin grazing rates to be high on both simulated drift-kelp and attached kelp thalli on barren grounds, however drift-kelp but not attached kelp was consumed at high rates within kelp beds. Time-lapse tracking of urchin foraging before/ after the controlled addition of drift-kelp on barrens revealed a reduction in foraging movement across the reef surface when drift-kelp was captured. Collectively results indicate that the availability of drift-kelp is a pivotal trigger in determining urchin feeding modes, which is demonstrably passive and cryptic in the presence of a ready supply of drift-kelp. Recovery of kelp beds therefore appears possible if a sustained influx of drift-kelp was to inundate urchin barrens, particularly on reefs where local urchin densities and where grazing pressure is close to the threshold enabling kelp bed recovery.

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    The data set provides outlines for the maximum extent of geomorphic units for the North West Marine Region. The dataset is clipped from Geoscience Australia’s original Geomorphic Features of Australia’s Exclusive Economic Zone (EEZ) to the East Marine Region extent. These data were compiled as part of Geoscience Australia’s integrated digital information system to provide improved accessibility and knowledge relating to the environmental management of Australian’s oceans resources. The geomorphic units are to be used as surrogates for benthic habitats and can be best applied to the construction of bioregionalisations of the seabed. The data set also includes the name of units in the attribute table, where known, the source(s) of the names, feature codes, province codes, as well as the area and perimeter of each unit. The data are accompanied by Geoscience Australia Record 2003/30. Dataset has been updated (2006) to correct errors in original file.