habitat
Type of resources
Keywords
Publication year
Topics
-
The Tasmanian Shelf survey was conducted on the Challenger in collaboration with the Tasmanian Aquaculture and Fisheries Institute between the 13-16th June, 2008 and 23rd February to the 14th March, 2009 (GA survey #0315). The survey was operated as part of the Surrogates Program of the CERF Marine Biodiversity Hub. The objective was to collect co-located physical and biological data to enable the robust testing of a range of physical parameters as surrogates of benthic biodiversity patterns. A total of 55 video transects were surveyed from five study areas (Tasman Peninsula, Freycinet Peninsula, The Friars, Huon river, and Port Arthur channel) in water depths ranging from 15-110 m. Video was recorded to mini DV tapes, and copied to digital format. For further information on this survey please refer to the post-survey report (GA Record 2009/043 - Geocat #69755).
-
Geoscience Australia carried out a marine survey on Carnarvon shelf (WA) in 2008 (SOL4769) to map seabed bathymetry and characterise benthic environments through co-located sampling of surface sediments and infauna, observation of benthic habitats using underwater towed video and stills photography, and measurement of ocean tides and wave-generated currents. Data and samples were acquired using the Australian Institute of Marine Science (AIMS) Research Vessel Solander. Bathymetric mapping, sampling and video transects were completed in three survey areas that extended seaward from Ningaloo Reef to the shelf edge, including: Mandu Creek (80 sq km); Point Cloates (281 sq km), and; Gnaraloo (321 sq km). Additional bathymetric mapping (but no sampling or video) was completed between Mandu creek and Point Cloates, covering 277 sq km and north of Mandu Creek, covering 79 sq km. Two oceanographic moorings were deployed in the Point Cloates survey area. The survey also mapped and sampled an area to the northeast of the Muiron Islands covering 52 sq km. TheGA0308_Carnarvon_SOL4976 folder contains video footage and still images. The MS databse, the Excel files are video characterisation datasets: Carnarvon_video data (export).mdb; all_substrata_tx.xls (transect level); all_substrata_patch.xls (patch level); all_benthos_tx.xls (transect level); all_benthos_patch.xls (patch level); Carnarvon_QAQC_VIDEOlog.doc (QAQC document); Attribute_metadata.xls (attribute definition). Underwater towed-video footage abd still images represent the raw data. Video characterisation datasets include percent cover of substrata and benthic taxa characterised at two spatial scales: transect scale (mean values per transect) and patch scale (mean values for each patch type within a transect).
-
Submarine canyons have been recognised as areas of significant ecological and conservation value for their enhanced primary productivity, benthic biomass and biodiversity. In Australia, 753 submarine canyons were mapped on all margins of the continent by the Marine Biodiversity Hub through the Australian Government's National Environmental Research Program. An analysis of canyon geomorphic metrics provided the basis to objectively classify these canyons across a hierarchy of physical characteristics (e.g. volume, depth range, rugosity) separately for shelf-incising and slope-confined canyons (Huang et al., 2014). Here we extend this analysis to include oceanographic variables in presenting a first pass assessment of habitat quality for all canyons on the Australian margin, with a focus on their upper reaches. This study is based on the premise that habitat heterogeneity, productivity and disturbance are the three factors that potentially determine the quality of a canyon habitat. For each factor we derived a range of variables to inform the assessment of habitat quality (see Table). Habitat heterogeneity was measured using a selection of eight geomorphic metrics including canyon volume and rugosity that are considered likely to have a positive relationship with habitat heterogeneity. Canyon productivity was assessed from five variables including: distance to the shelf break as a proxy of nutrient inputs from land and the continental shelf; bottom current speed as an indicator of nutrient supply to benthic epifauna (derived from time-series re-analysis of the BLUElink oceanographic model and in-situ data), and; measures of the probability, frequency and intensity of upwelling (also from BLUElink data). The BLUElink variables have positive relationships with productivity whereas the relationship between distance to shelf and productivity is negative. Benthic disturbance was assessed from the maximum and range of bottom current speeds, and the frequency and intensity of tropical cyclones. According to these relationships, individual canyons were assigned habitat quality scores, first separately for each variable and then aggregated for the three habitat factors. The final scores were obtained by averaging the scores of the three habitat factors. The results show that many submarine canyons on the eastern Australian margin have high habitat quality scores (see Figure). This is interpreted to be mainly due to the influence of the upwelling-favourable East Australian Current which generates high productivity throughout the year. The Albany canyons on the south-western margin also offer high habitat quality for marine species due to complex geometrical and geophysical structures. They also benefit from the upwelling-favourable Flinders Current. In contrast, canyons on the northern and western margins have lower habitat quality. Many of these canyons receive little input from land and continental shelf. In addition, the downwelling- favourable Leeuwin Current, which flows along the western margin of the continent, hampers the supply of deep water nutrients from reaching the upper reaches of canyons, particularly canyon heads that intersect the euphotic zone. Overall, these results provide a framework for targeted studies of canyons aimed at testing and verifying the habitat potential identified here and for establishing monitoring priorities for the ongoing management of canyon ecosystems.
-
Anthropogenic threats to benthic habitats do not pose an equal risk, nor are they uniformly distributed over the broad depth range of marine habitats. Deep sea benthic environments have, by and large, not been heavily exploited and most are in relatively good condition. In contrast, shelf and coastal habitats, and deep ocean pelagic fisheries, have been exploited extensively and human impacts here are locally severe. A critical point is that anthropogenic threats do not act in isolation; rather, they are cumulative and the impacts are compounded for every affected habitat. In general, the impacts of humans on benthic habitats is poorly understood. Habitat mapping provides condition assessments and establishes baselines against which changes can be measured. GeoHab scientists ranked the impacts on benthic habitats from fishing as the greatest threat, followed by pollution and litter, aggregate mining, oil and gas, coastal development, tourism, cables, shipping, invasive species, climate change and construction of wind farms. The majority of authors (84%) reported that monitoring changes in habitat condition over time was a planned or likely outcome of the work carried out. In this chapter the main anthropogenic threats to benthic habitats are reviewed in relation to their potential impacts on benthic environments.
-
The identification of marine habitats based on physical parameters is increasingly important for marine reserve design, allowing characterisation of habitat types over much wider areas than is possible from often patchy biological data. Marine management zones often contain a wide array of physical environments, which may not be captured in the biological sampling effort. The mismatch between biological and physical information leads to uncertainty in the application of bio-physical relationships at the broader management scale. In this study, a case study from northern Australia is used to demonstrate a methodology for defining uncertainties which result from the extrapolation of bio-physical associations across areas where detailed biological data is absent. In addition, uncertainties relating to the interpolation of physical data sets and that resulting from the cluster analysis applied to the physical data are calculated and mapped, providing marine managers with greater robustness in their analysis of habitat distributions.
-
The Vlaming Basin survey (GA survey # 334) was conducted under the Nation CO2 Infrastructure Plan (NCIP) on the MV Southern Supporter between the 12th to the 21st April 2012, with technical support provided from Fugro. The survey obtained geological (sedimentological, geochemical, geophysical) and biological data to support assessments of offshore acerage release areas for potential CO2 storage, and investigate the relationships between the physical environment and associated biota for biodiversity prediction. The purpose of the survey was to contribute to the assessment of the Vlaming Sub-basin for containment risk, as well as complement and validate interpretation of seismic data in the same area. Underwater footage was collected from 12 stations, although quality varies between sites and among transect lines. Video folders are named according to station number, followed by gear code (CAM=Ray Tech Underwater system), then the deployment number, and followed by region. For example, 12CAM02_D1 represents a video transect from station 12 that was the 2nd video transect of the survey and located in area region D1. Multiple files within transect folders indicate location metadata (Start of line location). In addition, USBL (Ultra-short baseline) text files located in the same folder provide continuous navigational information on location, time (UTC) and depth of each video transect line.
-
In order to protect the diversity of marine life in Australia's Exclusive Economic Zone (EEZ), the federal parliament has passed the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. The Act is being implemented through the design of a national representative system of marine protected areas (MPAs) that will place under protection a representative portion of Australia's EEZ by 2012. A total of 13 MPAs have already been nominated for the southeast region in 2006. Limited biological data in Australia's EEZ has resulted in biophysical information compiled by Geoscience Australia being used as a proxy for seabed biodiversity in support of marine conservation planning. Information we use to characterise the seabed includes bathymetry, geomorphology, acoustic properties, sediment properties, slope and sediment mobilisation due to waves and tides. To better characterise habitats on the Australian continental shelf, Geoscience Australia is creating 'seascape' maps (similar to geological facies maps) that integrate these multiple layers of spatial data, and are useful for the prediction of the distribution of biodiversity in Australia's EEZ. This information provides 100% spatial coverage based on objective, multivariate statistical methods and offers certainty for managers and stakeholders including the oil and gas industry, who are involved with designing Australia's national MPA system. Certainty for industries operating in the EEZ is enhanced by a reproducible, science-based approach for identifying conservation priorities and the classification of seafloor types within multiple use areas.
-
Physical and biological characteristics of benthic communities on the George V Shelf have been analysed from underwater camera footage collecting during Aurora Australis voyages in 2007/08 and 2010/11. The 2007/08 data revealed a high degree of variability in the benthic communities across the shelf, with the benthic habitats strongly structured by physical processes. Iceberg scouring recurs over timescales of years to centuries along shallower parts of this shelf, creating communities in various stages of maturity and recolonisation. Upwelling of modified circumpolar deep water (MCDW) onto the outer shelf and cross-shelf flow of high salinity shelf water (HSSW) create spatial contrasts in nutrient and sediment supply, which are largely reflected in the distribution of deposit and filter feeding communities. Long term cycles in the advance and retreat of icesheets (over millennial scales) and subsequent focussing of sediments in troughs such as the Mertz Drift create patches of consolidated and soft sediments, which also provide distinct habitats for colonisation by different biota. These interacting physical processes of iceberg scouring, current regimes and depositional environments, in addition to water depth, are important factors in the structure of benthic communities across the George V Shelf. In February 2010, iceberg B09B collided with the Mertz Glacier Tongue, removing about 80% or 78km from the protruding tongue. This event provided a rare opportunity to access a region previously covered by the glacier tongue, as well as regions to the east where dense fast ice has built up over decades, restricting access. The 2010/11 voyage imaged 3 stations which were previously beneath the floating tongue, as well as 9 stations covered by multi-year and annual fast ice since the mid 1970s.
-
Demands are being made of the marine environment that threaten to erode the natural, social and economic benefits that human society derives from the oceans. Expanding populations ensure a continuing increase in the variety and complexity of marine based activities - fishing, power generation, tourism, mineral extraction, shipping etc. The two most commonly acknowledged purposes for habitat mapping in the case studies contained in this book are to support government spatial marine planning, management and decision-making and to support and underpin the design of marine protected areas (MPAs; see Ch. 64).
-
Dense coral-sponge communities on the upper continental slope at 570 - 950 m off George V Land have been identified as a Vulnerable Marine Ecosystem in the Antarctic. The challenge is now to understand their likely distribution. Based on results from the Collaborative East Antarctic Marine Census survey of 2007/2008, we propose some hypotheses to explain their distribution. Icebergs scour to 500 m in this region and the lack of such disturbance is probably a factor allowing growth of rich benthic ecosystems. In addition, the richest communities are found in the heads of canyons. Two possible oceanographic mechanisms may link abundant filter feeder communities and canyon heads. The canyons in which they occur receive descending plumes of Antarctic Bottom Water formed on the George V shelf and these water masses could entrain abundant food for the benthos. Another possibility is that the canyons harbouring rich benthos are those that cut the shelf break. Such canyons are known sites of high productivity in other areas because of a number of oceanographic factors, including strong current flow and increased mixing with shelf waters, and the abrupt, complex topography. These hypotheses provide a framework for the identification of areas where there is a higher likelihood of encountering these Vulnerable Marine Ecosystems.