Williams et al. (2009) report on new multibeam sonar bathymetry and underwater video data collected from submarine canyons and seamounts on Australia's southeast continental margin to 'investigate the degree to which geomorphic features act as surrogates for benthic megafaunal biodiversity' (p. 214). The authors describe what they view as deficiencies in the design of the Marine Protected Areas (MPAs) in the southeast region of Australia, in which geomorphology information was employed as a surrogate to infer regional-scale patterns of benthic biodiversity. This comment is designed to support and underscore the importance of evaluating MPA designs and the validity of using abiotic surrogates such as geomorphology to infer biodiversity patterns, and seeks to clarify some of the discrepancies in geomorphic terminologies and approaches used between the original study and the Williams et al. (2009) evaluation. It is our opinion that the MPA design criteria used by the Australian Government are incorrectly reported by Williams et al. (2009). In particular, we emphasise the necessity for consistent terminology and approaches when undertaking comparative analyses of geomorphic features. We show that the MPA selection criteria used by the Australian Government addressed the issues of false homogeneity described by Williams et al. (2009), but that final placement of MPAs was based on additional stakeholder considerations. Finally, we argue that although the Williams et al. (2009) study provides valuable information on biological distributions within seamounts and canyons, the hypothesis that geomorphic features (particularly seamounts and submarine canyons) are surrogates for benthic biodiversity is not tested explicitly by their study.

The surface sedimentary record from six sediment cores collected from beneath the Amery Ice Shelf, East Antarctica, provides a unique view of the sedimentary and oceanographic processes in this sub-ice shelf setting. The composition and age of the surface sediments indicate spatial variations in ice shelf cavity-ocean interaction, which are consistent with patterns of ocean inflow and outflow modelled and observed beneath the ice shelf. Sediments within 100 km of the ice shelf front (site AM01b) show the greatest open ocean influence with a young surface age and the highest total diatom abundance, compared to older ages and lower diatom abundances at sites deeper in the cavity (AM03 to AM06). The variable marine influence between sites determines the nature of benthic communities, with seabed imagery indicating the existence of sessile suspension feeders in areas of strong marine inflow (site AM01b), while grazers, deposit feeders and a few suspension feeders occur at sites more distal from the shelf calving front where the food supply is lower (sites AM03 and AM04). Understanding the sedimentary and oceanographic processes within the sub-ice shelf environment allows better constraint of interpretations of down core sediment records, an improved understanding of the nature of biological communities in sub-ice shelf environments, and a baseline for determining the sensitivity of the system to any future changes in ocean dynamics.

A symposium was held at the University of Wales, Swansea in July 2007 to honour the career and achievements of Professor Michael Collins. The symposium was organised by Michael's former postgraduate students as a tribute to his contributions over the past 30 years as a scientist, teacher, mentor and friend. About 30 of the 50+ Ph.D. and M.Sc. students that Michael has supervised over the years were fortunate to attend the symposium, which offered the opportunity for all of us to learn about the many different subjects and projects that Michael supervised and to renew our friendships with the Collins family, as well as the extended, academic Collins 'family'.

Annular to crescent-shaped low back scatter SAR slicks over carbonate reefs and shoals in the Timor Sea with slick `feathering', and within the coral spawning period for the region, are interpreted to be caused by a coral spawn event. In contrast, ocean current data and detailed swath bathymetry of the sea floor to the southeast of the coral spawn slicks suggest that elongate repeating slicks in this area are related to current flow over submarine channels. Assessment of these slicks in association with ancillary data, such as bathymetry, current velocities, weather and timing of scene capture allow a more robust interpretation of their origins. Through differentiating coral spawn and bathymetric slicks from oil and other biological slicks in shallow carbonate systems, such as the Timor Sea, petroleum and environmental assessments for these areas can be improved.

Seagrass communities in the northwest of Torres Strait are known to disappear episodically over broad areas. Sediment mobility surveys were undertaken within two study areas during the monsoon and trade wind seasons, in the vicinity of Turnagain Island, to find out if the migration of bedforms could explain this disappearance. The two study areas covered sand bank and sand dune environments to compare and contrast their migration characteristics. Repeat multibeam sonar surveys were used to measure dune-crest migration during each season.

Mineral deposits can be described in terms of their mineral systems, i.e., fluid source, migration pathway, and trap. Source regions are difficult to recognize in seismic images. Many orebodies lie on or adjacent to major fault systems, suggesting that the faults acted as fluid migration pathways through the crust. Large faults often have broad internal zones of deformation fabric, which is anisotropic. This, coupled with the metasomatic effects of fluids moving along faults while they are active, can make the faults seismically reflective. For example, major gold deposits in the Archaean Eastern Goldfields province of Western Australia lie in the hanging-wall block of regional-scale faults that differ from other nearby faults by being highly reflective and penetrating to greater depths in the lower crust. Coupled thermal, mechanical, and fluid-flow modeling supports the theory that these faults were fluid migration pathways from the lower to the upper crust. Strong reflections are also recorded from two deeply penetrating faults in the Proterozoic Mt. Isa province in northeastern Australia. Both are closely related spatially to copper and copper-gold deposits. One, the Adelheid fault, is also adjacent to the large Mt. Isa silver-lead-zinc deposit. In contrast, other deeply penetrating faults that are not intrinsically reflective but are mapped in the seismic section on the basis of truncating reflections have no known mineralization. Regional seismic profiles can therefore be applied in the precompetitive area selection stage of exploration. Applying seismic techniques at the orebody scale can be difficult. Orebodies often have complex shapes and reflecting surfaces that are small compared to the diameter of the Fresnel zone for practical seismic frequencies. However, if the structures and alteration haloes around the orebodies themselves, seismic techniques may be more successful. Strong bedding-parallel reflections were observed from the region of alteration around the Mt. Isa silver-lead-zinc orebodies using high-resolution profiling. In addition, a profile in Tasmania imaged an internally nonreflective bulge within the Que Hellyer volcanics, suggesting a good location to explore for a volcanic hosted massive sulfide deposit. These case studies provide a pointer to how seismic techniques could be applied during mineral exploration, especially at depths greater than those being explored with other techniques.

A seismic structure imaged in a single 2D seismic profile from the offshore Canning Basin, Western Australia, is interpreted to be a possible complex impact crater on the basis of its seismic character. The feature, herein referred to as the Haines Structure, is symmetrical in two dimensions over ~2.5 km and comprises a centrally uplifted basal surface, a depressed upper surface, a highly deformed intervening package and an overlying horizon that is `sagging' over the depression. The possible impact structure lies within carbonate units of Eocene or Early Oligocene age as determined from seismic correlation to petroleum exploration wells. The structure has not been drilled; therefore distinguishing characteristics used to define an impact origin, such as shock metamorphism, are not available. Comparison with other features in the Neogene succession of Australia's North West Shelf that have previously been interpreted as impact structures highlights the presence of key elements in the Haines Structure that characterise known complex impact craters, and the absence of seismic features related to alternative processes, such as a link to deeper structures that would be expected beneath a volcanic pipe.

Hemipelagic, sediment drift deposits have been discovered and mapped on the Antarctic Peninsula shelf in 300-500 m water depth. The drift located adjacent to Andvord Bay covers 44.5 km2 and exhibits continuous and discontinuous parallel reflections that conform to peaks and valleys in the acoustic basement as observed in deep-tow boomer and sparker seismic records. This style of drift deposit is a common feature of deep oceanic sediments, but is not normally found in continental shelf environments.

In ecology, a common form of statistical analysis relates a biological variable to variables that delineate the physical environment, typically by fitting a regression model or one of its extensions. Unfortunately, the biological data and the physical data are frequently obtained from eparate sources of data. In such cases there is no guarantee that the biological and physical data are co-located and the regression model cannot be used. A common and pragmatic solution is to predict the physical variables at the locations of the biological variables and then to use the predictions as if they were observations.We show that this procedure can cause potentially misleading inferences and we use generalized linear models as an example. We propose a Berkson error model which overcomes the limitations. The differences between using predicted covariates and the Berkson error model are illustrated by using data from the marine environment, and a simulation study based on these data.

During the Quaternary, the Mac. Robertson shelf of East Antarctica was deeply eroded by glaciers and currents exposing the underlying basement, resulting in a scalped shelf.