Search

Since 2012, there has been a surge in the numbers of marine science publications that use the term ‘best practice’, yet the term is not often defined, nor is the process behind the best practice development described. Importantly a ‘best practice’ is more than a documented practice that an individual or institution uses and considers good. This article describes a rigorous process to develop an ocean best practice using examples from a case study from Australia in which a suite of nine standard operating procedures were released in 2018 and have since become national best practices. The process to develop a best practice includes three phases 1) scope and recruit, 2) develop and release, 3) revise and ratify. Each phase includes 2-3 steps and associated actions that are supported by the Ocean Best Practices System (www.oceanbestpractices.org). The Australian case study differs from many other practices, which only use the second phase (develop and release). In this article, we emphasize the value of the other phases to ensure a practice is truly a ‘best practice’. These phases also have other benefits, including higher uptake of a practice stemming from a sense of shared ownership (from scope and recruit phase) and currency and accuracy (from revise and ratify phase). Although the process described in this paper may be challenging and time-consuming, it optimizes the chance to develop a true best practice that is a) fit-for-purpose with clearly defined scope; b) representative and inclusive of potential users; c) accurate and effective, reflecting emerging technologies and programs; and d) supported and adopted by users.

The UN Decade of Ocean Science for Sustainable Development (Ocean Decade) challenges marine science to better inform and stimulate social and economic development while conserving marine ecosystems. To achieve these objectives, we must make our diverse methodologies more comparable and interoperable, expanding global participation and foster capacity development in ocean science through a new and coherent approach to best practice development. We present perspectives on this issue gleaned from the ongoing development of the UNESCO Intergovernmental Oceanographic Commission (IOC) Ocean Best Practices System (OBPS). The OBPS is collaborating with individuals and programs around the world to transform the way ocean methodologies are managed, in strong alignment with the outcomes envisioned for the Ocean Decade. However, significant challenges remain, including: (1) the haphazard management of methodologies across their lifecycle, (2) the ambiguous endorsement of what is “best” and when and where one method may be applicable vs. another, and (3) the inconsistent access to methodological knowledge across disciplines and cultures. To help address these challenges, we recommend that sponsors and leaders in ocean science and education promote consistent documentation and convergence of methodologies to: create and improve context-dependent best practices; incorporate contextualized best practices into Ocean Decade Actions; clarify who endorses which method and why; create a global network of complementary ocean practices systems; and ensure broader consistency and flexibility in international capacity development.

The Oceanic Shoals Marine Park is located within the Timor Sea offshore northern Australia and was established due to the conservation values associated with carbonate bank and terrace systems in the region. Between 2009 and 2012, ten grids covering ~3100 km2 were mapped and associated biological samples and benthic imagery collected. We describe three of these grids in detail, including banks but also other geomorphic features: the western grid includes banks that are characterized by flat tops and relatively steep sides supporting sponge gardens; the central grid is characterized by shallow channels and plains with low ridges, pockmarks, and depressions and associated rich polychaete communities; and the eastern grid encompasses a north–south oriented valley with flanking terraces and banks that supported sessile invertebrate assemblages, including dense reef-forming corals. Imagery data was applied to a predictive habitat map for the marine park. Sponge and polychaete biodiversity are characterized, but no strong environmental surrogates were identified. Overall, our geological and biological analyses confirm and further describe the carbonate banks and shoals as a key ecological feature in the Oceanic Shoals Marine Park.

Repeat multibeam mapping of two slope-confined canyons on the northwest Australian margin provides new understanding of the processes that are active in shaping these environments. The Cape Range and Cloates canyons initiate on the mid to lower continental slope but are now known to be connected to the shelf via small channels and gullies. Both canyons have areas of steep walls, with evidence of slides, and large depressions on the canyon floors. These canyons were first mapped systematically with multibeam sonar in 2008 and were remapped in 2020 during a biodiversity survey that also collected high-resolution imagery and biological samples. Comparison of seabed features between these two time periods indicates active sliding, minor headwall retreat and continued excavation of deep depressions on the canyon floor. Significantly, intact blades of displaced seagrass imaged at various depths up to 4200 m throughout both canyons indicates that material sourced from the adjacent continental shelf is being transported through these canyon systems. Turbidity currents are actively modifying canyon walls and floor depressions, while also providing a sediment source that has resulted in minor accretion on the canyon floor. Sedimentation likely regulates benthic communities in these canyons, with imagery showing highest densities of sessile invertebrates in habitats protected from sedimentation (e.g. rock overhangs, cliff edges). Since steep canyon habitats are rare within these canyons, and support high benthic abundance, they likely represent biologically significant areas of the Gascoyne Marine Park. Repeat mapping provides an understanding of the dynamics of these canyons and a context for assessing and monitoring the stability of the seabed habitats within this marine reserve.

Marine seismic surveys are a fundamental tool for geological research, including the exploration of offshore oil and gas resources, but the sound generated during these surveys represents a source of noise pollution in the marine environment. Recent evidence has shown that seismic surveys may negatively affect some cetaceans, fish and invertebrates, although the magnitude of these impacts remains uncertain. This paper applies a case study on marine seismic impacts (the Gippsland Marine Environmental Monitoring (GMEM) project) to the critical assessment of the advantages and challenges of field-based methods in the context of future research and management priorities. We found that an interdisciplinary approach, using both conventional (e.g. dredging) and innovative (e.g. autonomous imagery) experimental components, make for more robust interpretations and also provide a failsafe in case of limited suitable data (e.g. equipment issues related to image acquisition). Field observational studies provide an unparalleled capability to undertake ecologically realistic research, although their practical challenges must be considered during research planning. We also note the need for appropriate environmental baselines and accessible time-series data to account for spatiotemporal variability of environmental and biological parameters that may mask effects, as well as the need for a standardised technique in sound monitoring and equipment calibration to ensure accuracy and comparability among studies.

Marine seismic surveys are an important tool to map geology beneath the seafloor and manage petroleum resources, but they are also a source of underwater noise pollution. A mass mortality of scallops in the Bass Strait, Australia occurred a few months after a marine seismic survey in 2010, and fishing groups were concerned about the potential relationship between the two events. The current study used three field-based methods to investigate the potential impact of marine seismic surveys on scallops in the region: 1) dredging and 2) deployment of Autonomous Underwater Vehicles (AUVs) were undertaken to examine the potential response of two species of scallops (Pecten fumatus, Mimachlamys asperrima) before, two months after, and ten months after a 2015 marine seismic survey; and 3) MODIS satellite data revealed patterns of sea surface temperatures from 2006-2016. Results from the dredging and AUV components show no evidence of scallop mortality attributable to the seismic survey, although sub-lethal effects cannot be excluded. The remote sensing revealed a pronounced thermal spike in the eastern Bass Strait between February and May 2010, overlapping the scallop beds that suffered extensive mortality and coinciding almost exactly with dates of operation for the 2010 seismic survey. The acquisition of in situ data coupled with consideration of commercial seismic arrays meant that results were ecologically realistic, while the paired field-based components (dredging, AUV imagery) provided a failsafe against challenges associated with working wholly in the field. This study expands our knowledge of the potential environmental impacts of marine seismic survey and will inform future applications for marine seismic surveys, as well as the assessment of such applications by regulatory authorities.

Marine seismic surveys produce high intensity, low-frequency impulsive sounds at regular intervals, with most sound produced between 10 and 300 Hz. Offshore seismic surveys have long been considered to be disruptive to fisheries, but there are few ecological studies that target commercially important species, particularly invertebrates. This review aims to summarise scientific studies investigating the impacts of low-frequency sound on marine fish and invertebrates, as well as to critically evaluate how such studies may apply to field populations exposed to seismic operations. We focus on marine seismic surveys due to their associated unique sound properties (i.e. acute, low-frequency, mobile source locations), as well as fish and invertebrates due to the commercial value of many species in these groups. The main challenges of seismic impact research are the translation of laboratory results to field populations over a range of sound exposure scenarios and the lack of sound exposure standardisation which hinders the identification of response thresholds. An integrated multidisciplinary approach to manipulative and in situ studies is the most effective way to establish impact thresholds in the context of realistic exposure levels, but if that is not practical the limitations of each approach must be carefully considered.

The Evidence Based Decision Making (EBDM) paradigm encourages managers to base their decisions on the strongest available evidence, but it has been criticized for placing too much emphasis on the choice of study design method without considering the types of questions that are being addressed as well as other relevant factors such as how well a study is implemented. Here we review the objectives of Australia’s Marine Park network, and identify the types of questions and data analysis that would address these objectives. Critically, we consider how the design of a monitoring program influences our ability to adequately answer these questions, using the strength of evidence hierarchy from the EBDM paradigm to assess the adequacy of different design strategies and other sources of information. It is important for conservation managers to recognize that the types of questions monitoring programs are able to answer depends on how they are designed and how the collected data are analyzed. The socio-political process that dictates where protected areas are placed typically excludes the strongest types of evidence, Random Controlled Trials (RCTs), for certain questions. Evidence bases that are stronger than ones commonly employed to date, however, could be used to provide a causal inference, including for those questions where RCTs are excluded, but only if appropriate designs such as cohort or case-control studies are used, and supported where relevant by appropriate sample frames. Randomized, spatially balanced sampling, together with careful selection of control sites, and more extensive use of propensity scores and structured elicitation of expert judgment, are also practical ways to improve the evidence base for answering the questions that underlie marine park objectives and motivate long-term monitoring programs.

The oceans play a key role in global issues such as climate change, food security, and human health. Given their vast dimensions and internal complexity, efficient monitoring and predicting of the planet’s ocean must be a collaborative effort of both regional and global scale. A first and foremost requirement for such collaborative ocean observing is the need to follow well-defined and reproducible methods across activities: from strategies for structuring observing systems, sensor deployment and usage, and the generation of data and information products, to ethical and governance aspects when executing ocean observing. To meet the urgent, planet-wide challenges we face, methods across all aspects of ocean observing should be broadly adopted by the ocean community and, where appropriate, should evolve into “Ocean Best Practices.” While many groups have created best practices, they are scattered across the Web or buried in local repositories and many have yet to be digitized. To reduce this fragmentation, we introduce a new open access, permanent, digital repository of best practices documentation (oceanbestpractices.org) that is part of the Ocean Best Practices System (OBPS). The new OBPS provides an opportunity space for the centralized and coordinated improvement of ocean observing methods. The OBPS repository employs user-friendly software to significantly improve discovery and access to methods. The software includes advanced semantic technologies for search capabilities to enhance repository operations. In addition to the repository, the OBPS also includes a peer reviewed journal research topic, a forum for community discussion and a training activity for use of best practices. Together, these components serve to realize a core objective of the OBPS, which is to enable the ocean community to create superior methods for every activity in ocean observing from research to operations to applications that are agreed upon and broadly adopted across communities. Using selected ocean observing examples, we show how the OBPS supports this objective. This paper lays out a future vision of ocean best practices and how OBPS will contribute to improving ocean observing in the decade to come.

One of the main challenges in assessing marine biodiversity is the lack of consistent approaches to monitor it. This threatens to undermine ocean best practice in marine monitoring, as it impedes a reduction in the bias and variance of sampled data and restricts the confidence in the advice that can be given. In particular, there is potential for confounding between the monitoring methods, their measured ecological properties, and the questions they seek to answer. Australia has developed significant long-term marine monitoring and observing programs and has one of the largest marine estates, including the world’s largest representative network of marine parks. This new network will require ongoing monitoring and evaluation, beyond what direct funding can support, which needs to be integrated in a standardized way with other national programs to develop sufficient monitoring capacity. The aim of this paper is to describe the process undertaken in developing a suite of field manuals that provide Standard Operating Procedures (SOPs) for marine sampling in Australian waters so that data are comparable over time and space, thereby supporting a robust, cost-effective, and objective national monitoring program. We encourage readers to refer to the complete manuals of interest at www.nespmarine.edu.au/field-manuals. We generally limit SOP development to benthic or demersal sampling, (multibeam, autonomous underwater vehicles, baited remoted underwater video (BRUV), towed imagery, grabs and box corers, sleds and trawls), with a few exceptions (e.g., pelagic BRUVs). Collaboration was a key characteristic of our approach so rather than single groups trying to impose their standards, more than 70 individuals from over 30 organizations contributed to the first version of this field manual package. We also discuss the challenges that arose while developing these national SOPs, the associated solutions that were implemented, and the plans for ensuring their long-term maintenance and national and international uptake. We anticipate that this paper will contribute to international collaborations by evoking valuable suggestions and sharing of lessons learnt from other national initiatives so that we might work toward a global ocean best practice for biological and geoscientific monitoring of the marine environment. Publisher PDF

The impact of seismic surveys on the catchability of marine fish is a contentious issue, with some claims that seismic surveys may negatively affect catch rates. However little empirical evidence exists to quantify the impacts or identify the mechanisms of such impact. In this study, we used a 2-D seismic survey in the Gippsland Basin, Bass Strait, Australia in April 2015 as an opportunity to quantify fish behaviour (field-based) and commercial fisheries catch (desktop study) across the region before and after airgun operations. Three species found in abundance (gummy shark, swell shark, tiger flathead) were acoustically tagged and released within one of two acoustic arrays (experimental and control zone) and monitored before, during and after the seismic survey. In the field study, only 35% of the gummy sharks and 30% of the swell sharks were subsequently detected two days after release, suggesting movement outside the study area. Various tagged individuals returned sporadically over the monitoring period, including during the seismic survey operations. Behaviour consistent with a possible response to the seismic survey operations was observed for flathead which increased their swimming speed during the seismic survey period and changed their diel movement patterns after the survey. We also investigated the potential impacts of the seismic survey on catch rates using Commonwealth fisheries logbook data from Jan 2012-Oct 2015. Fifteen species and two gear types (Danish seine, gillnet) were modelled to examine differences in catch rates before and after the seismic survey. The catch rates in the six months following the seismic survey were significantly different than predicted in nine out of the 15 species examined, with six species (tiger flathead, goatfish, elephantfish, boarfish, broadnose shark and school shark) showing increases in catch following the seismic survey, and three species (gummy shark, red gurnard, and sawshark) showing reductions. With the exception of flathead movement, we found little evidence for consistent behavioural or catch rate changes induced by the seismic survey in the targeted species, although behavioural data were limited because many sharks left the acoustic receiver array prior to the commencement of the seismic survey.

Many countries are now using or investigating offshore geological storage of CO2 as a means to reduce atmospheric CO2 emissions. Although associated research often focuses on deep-basin geology (e.g. seismic, geomagnetics), environmental data on the seabed and shallow subseabed is also crucial to (1) detect and characterise potential indicators of fluid seeps and their potential connectivity to targeted storage reserves, (2) obtain baseline environmental data for use in future monitoring, and (3) acquire information to facilitate an improved understanding of ecosystem processes for use in impact prediction. This study reviews the environmental considerations, including potential ecological impacts, associated with subseabed geological storage of CO2. Due to natural variations in CO2 levels in seafloor sediments, baseline CO2 measurements and knowledge of physical–chemical processes affecting the regional distribution of CO2 and pH are critical for the design of appropriate monitoring strategies to assess potential impacts of CO2 seepage from subseabed storage reservoirs. Surficial geological and geophysical information, such as that acquired from multibeam sonar and sub-bottom profiling, can be used to investigate the connectivity between the deep reservoirs and the surface, which is essential in establishing the reservoir containment properties. CO2 leakage can have a pronounced effect on sediments and rocks which in turn can have carryover effects to biogeochemical cycles. The effects of elevated CO2 on marine organisms are variable and species-specific but can also have cascading effects on communities and ecosystems, with marine benthic communities at some natural analogue sites (e.g. volcanic vents) showing decreased diversity, biomass, and trophic complexity. Despite their potential applications, environmental surveys and data are still not a standard and integral part of subseabed CO2 storage projects. However, the habitat mapping and seabed characterisation methodology that underpins such surveys is well developed and has a strong record of providing information to industry and decision makers. This review provides recommendations for an integrated and interdisciplinary approach to offshore geological storage of CO2, which will benefit national programs and industry and will be valuable to researchers in a broad range of disciplines.

Northern Australia has been the focus of recent marine biodiversity research to support natural resource management for both industry and conservation, including management of the Oceanic Shoals Australian Marine Park (AMP). Much of this research has targeted habitat-forming sessile invertebrates and charismatic megafauna, but smaller macrofauna and infauna may also be important because of their roles in ecosystem functions. In this study we characterised the biodiversity of polychaetes collected from four marine surveys to the Oceanic Shoals AMP between 2009 and 2012 from which sediment samples were elutriated (500μm) to separate macrofauna. We used this species-level inventory to examine several questions related to marine management, namely: (1) do polychaete assemblages vary among surveys; (2) can environmental variables or geomorphology explain differences in community structure; and (3) how do ecological patterns change according to taxonomic resolution (species, family) and functional group (feeding, habitat, mobility)? A total of 2561 individual polychaetes were collected from 266 samples, representing 368 species and 43 families, including new species and genera, as well as new family records for Australia (Iospilidae, Lacydoniidae). Polychaete species assemblages and functional groups showed variation among the surveys, but this was not observed at the family level. Species and family assemblages were weakly related to environmental factors, but functional groups showed stronger relationships. Plains and banks each supported distinct polychaete assemblages, although the latter showed temporal variation. The results provide baseline biodiversity and ecological data about polychaetes on the northern Australian shelf, and these are discussed in relation to marine management strategies. Notably, intersurvey and environmental patterns differ from those of larger sessile fauna (sponges) collected on the same surveys, highlighting the need to consider small macrofauna in monitoring programs of marine protected areas.

We reassess whether range shifts in marine organisms are occurring in a direction predicted by causation due to climate using two different methods: a global meta-analysis and a regional analysis of museum records focussing on marine molluscs. Globally we used rigorous selection criteria to investigate studies describing range shifts in marine organisms, including exclusion of single-species studies and those that inferred range shifts through shifting abundance. For each species meeting these criteria (311 species from 13 studies), the distance in kilometres moved per year was calculated, and life history characteristics such as mobility, habitat, dispersal potential and trophic level were recorded to assess if these were linked to the shifts. We also examined the potential correlation between changing sea surface temperatures and range shifts. Regionally we analysed the intertidal mollusc collection of the Australian Museum and Museum of Victoria and consulted with mollusc experts to determine if museum records could be used to detect range shifts in marine invertebrates. The global meta-analysis showed that individual species shifted on average 8.9 km polewards per year. Range shifts were not significantly related to temperature change or life history characteristics with the exception of intertidal and nearshore subtidal fauna showing poleward shifts (6.8 and 14.3 km per decade, respectively) and shelf fauna showing a slight equatorial shift (2.7 km per decade). Our regional analysis showed that 54 of the 634 mollusc species examined shifted their range into or out of the well-surveyed Sydney region. However, closer examination by mollusc experts revealed that the evidence for these shifts was unreliable, and we conclude that caution is required when using museum records in range shift studies. Overall, our study supports previous research showing a poleward shift in response to climate change, although this is an order of magnitude less than values reported in the only other meta-analysis on marine range shifts, possibly owing to the strict selection criteria applied here.

Much of the deep sea comprises soft-sediment habitats dominated by comparatively low abundances of species-rich macrofauna and meiofauna. Although often not observed, these animals bioturbate the sediment during feeding and burrowing, leaving signs of their activities called Lebensspuren (‘life traces’). In this study, we use still images to quantify Lebensspuren from the eastern (1921 images, 13 stations, 1300–2200 m depth) and western (1008 images, 11 stations, 1500–4400 m depth) Australian margins using a univariate measure of trace richness and a multivariate measure of Lebensspuren assemblages. A total of 46 Lebensspuren types were identified, including those matching named trace fossils and modern Lebensspuren found elsewhere in the world. Most traces could be associated with waste, crawling, dwellings, organism tests, feeding, or resting, but the origin of 15% of trace types remains unknown. Assemblages were significantly different between the two regions and depth profiles, with five Lebensspuren types accounting for over 95% of the differentiation (ovoid pinnate trace, crater row, spider trace, matchstick trace, mesh trace). Lebensspuren richness showed no strong relationships with depth, total organic carbon, or mud, although there was a positive correlation to chlorin index (i.e., organic freshness) in the eastern margin, with richness increasing with organic freshness. Lebensspuren richness was not related to epifauna either, indicating that epifauna may not be the primary source of Lebensspuren. Despite the abundance and distinctiveness of several traces both in the current and previous studies (e.g., ovoid pinnate, mesh, spider), their origin and distribution remains a mystery. We discuss this and several other considerations in the identification and quantification of Lebensspuren. This study represents the first comprehensive catalogue of deep-sea Lebensspuren in Australian waters and highlights the potential of Lebensspuren as valuable and often untapped deep-sea datasets that can be used for biogeographical, evolutionary, behavioural, and ecological studies.

Przeslawski, R., Currie, D. R., Sorokin, S. J., Ward. T. M., Althaus, F., and Williams, A. 2011. Utility of a spatial habitat classification system as a surrogate of marine benthic community structure for the Australian margin. – ICES Journal of Marine Science, 68: 1954–1962. This study tests whether a continental-scale classification of Australian benthic habitats (termed “seascapes”) and the interpolated environmental data from which they are derived are useful as abiotic surrogates of biodiversity at a local [tens of kilometres, Great Australian Bight (GAB)] and regional scale [hundreds of kilometres, Western Australian (WA) margin]. Benthic invertebrate community structure is moderately associated with specific seascapes in both the GAB (R = 0.418) and WA margin (excluding hard substrata, R = 0.375; all substrata, R = 0.313). Mud content, seafloor slope, and seafloor temperature are significantly correlated with invertebrate communities at both scales, with disturbance and primary production correlated with GAB communities. Seascapes are not consistently useful surrogates because the strength and significance of relationships between seascapes and community structure differs among seascapes, regions, and spatial scales. Nevertheless, a national system of seascapes is an appropriate surrogate for broad-scale benthic invertebrate community patterns when biological data are limited, provided the uncertainty is acknowledged and, where possible, an assessment made of each seascape's ability to differentiate biological communities. Further refinement of seascape derivations may include updated and additional environmental data (particularly for hard vs. soft substrata) and validation among biological datasets from a range of habitats and scales.

Little is known about diversity patterns of biological assemblages in deep-sea environments, primarily because sampling deep-sea biota over vast areas is time consuming, difficult, and costly. In contrast, physical mapping capabilities are increasing rapidly, and are becoming more cost-effective. Consequently, the growing need to manage and conserve marine resources, particularly deep-sea areas that are sensitive to anthropogenic disturbance and change, is leading the promotion of physical data as surrogates to predict biological assemblages. However, few studies have directly examined the predictive ability of these surrogates. The physical environment and biological assemblages were surveyed for two adjacent areas – the western flank of Lord Howe Rise (LHR) and the Gifford Guyot - spanning combined water depths of 250-2200 m depth on the northern part of the LHR, in the Coral Sea. Multibeam acoustic surveys were used to generate large-scale geomorphic classification maps that were superimposed over the study area. Forty towed-video stations were deployed across the area capturing 32 h of seabed video, 6229 still photographs, that generated 3413 seabed characterisations of physical and biological variables. In addition, sediment and biological samples were collected from 36 stations across the area. The northern Lord Howe Rise was characterised by diverse but sparsely distributed faunas for both the vast soft-sediment environments as well as the discrete rock outcrops. Substratum type and depth were the main variables correlated with benthic assemblage composition. Soft-sediments were characterised by low to moderate levels of bioturbation, while rocky outcrops supported diverse but sparse assemblages of suspension feeding invertebrates, such as cold-water corals and sponges which in turn supported epifauna, dominated by ophiuroids and crinoids. While deep environments of the LHR flank and lower slopes of the Gifford Guyot were characterised by bioturbation with high occurrences of trails, burrows, and mounds, evidence for bioturbation was significantly less on the upper sections of Gifford Guyot, with mostly trails on the more sediment starved environments. The seamount summit also supported a variety of taxa, such as benthic ctenophores and rock-associated fishes that were not recorded in the deeper basin habitats. Physical characteristics of the seabed, particularly geomorphology, were good predictors of biological assemblage composition and percent cover of key taxa. Of the nine geomorphic classes assessed in this study, six predicted different physical habitats that supported distinct biological assemblages. However, other classes that were defined by spatial features (e.g., valleys, seamount dunes) where surficial physical variables were not unique, provided little predictive power of biological assemblages, but rather had characteristics that were shared with adjacent/surrounding geomorphic classes. Given the growing need to use surrogates in the management and conservation of marine environments, these results are promising. However, our findings suggest that there is a pressing need for careful testing and validation of surrogates, such as geomorphic classes, before classification schemes can be deemed effective and employed as a management tool to predict seabed habitats and their biological assemblages.

The two principal aims of this study were to synthesise physical and biological information to characterise the Lord Howe Rise (LHR) region and to use recent survey collections of benthic invertebrates (mostly large benthic epifauna) to describe its biogeography at regional and sub-regional scales. The LHR region is large (1.95 million km2), spans tropical and cool temperate latitudes (18.4 to 40.3°S), and is influenced by several ocean currents, notably the East Australian Current and the Tasman Front. Our analyses revealed that biological patterns were related to two groups of geomorphic morphotypes found in this topographically complex region: subdued bathymetric features (expansive soft sediment basins and plateaus) and raised bathymetric features (scattered seamounts, guyots, knolls, and pinnacles). Raised bathymetric features in the LHR region were more likely to support richer and more abundant epifaunal assemblages dominated by suspension feeding invertebrates on hard substrata compared to subdued features which were dominated by infauna and detritivores in soft sediments. However, this trend does not apply to all raised bathymetric features (e.g., Gifford Guyot), with variations in depth, elevation, latitude, and particularly substrata affected the composition of biological assemblages. In addition, some demersal fishes, ophiuroids, and other benthic invertebrates showed distinct north-south delineations that coincide with the influence of the Tasman Front and thermal gradients. While the lack of spatially- and temporally- replicated data in the region limits our interpretation of survey data, paleo-environmental processes and examples from other regions provide some indication of how dispersal influences migration, speciation, and endemism in the LHR region. Although our current knowledge is limited, it is hoped that this review will help inform future studies in the area, as equitable examination of biological, geological, and oceanographic characteristics will facilitate future assessments of LHR biogeography and permit the inclusion of this region in biogeographic studies with a national or global context.

Acorn worms (Enteropneusta), which were previously thought to be a missing link in understanding the evolution of chordates, are an unusual and potentially important component of many deep-sea benthic environments, particularly for nutrient cycling. Very little is known about their distribution, abundance, or behaviour in deep-sea environments around the world, and almost nothing is known about their distribution within Australian waters. In this study, we take advantage of two large-scale deep-sea mapping surveys along the eastern (northern Lord Howe Rise) and western continental margins of Australia to quantify the distribution, abundance and trail-forming behaviour of this highly unusual taxon. This is the first study to quantify the abundance and trail behaviour of acorn worms within Australian waters and provides the first evidence of strong depth-related distributions. Acorn worm densities and trail activity were concentrated between transect-averaged depths of 1600 and 3000 m in both eastern and western continental margins. The shallow limit of their depth distribution was 1600 m. The deeper limit was less well-defined, as individuals were found in small numbers below 3000 down to 4225 m. This distributional pattern may reflect a preference for these depths, possibly due to higher availability of nutrients, rather than a physiological constraint to greater depths. Sediment characteristics alone were poor predictors of acorn worm densities and trail activity. High densities of acorn worms and trails were associated with sandy-mud sediments, but similar sediment characteristics in either shallower or deeper areas did not support similar densities of acorn worms or trails. Trail shapes varied between eastern and western margins, with proportionally more meandering trails recorded in the east, while spiral and meandering trails were both common in the west. Trail shape varied by depth, with spiral-shaped trails dominant in areas of high acorn worm densities (2000–3000 m water depth) while meandering trails were common over a much broader depth range and were the only trails recorded in deep environments >3000 m. While species-specific patterns may in part explain these differences, evidence suggests that nutrient availability is also likely to be an important driving factor, supporting the hypothesis put forward by Smith et al. (2005) that acorn worms meander when searching for food and form a spiral when feeding in a nutrient-rich area.

This study presents new information on the regional geochemical characteristics of deep-sea floor sediments (1300–2423 m water depth) on the Lord Howe Rise (deep–sea plateau) and Gifford Guyot (seamount/tablemount), remote areas off eastern Australia. The aim was to provide a coherent synthesis for a suite of geochemical data that can be used to make habitat inferences and to develop surrogates of biodiversity. Sediment characteristics analysed were mineralogy, organic carbon and nitrogen concentrations and isotopic compositions, and concentrations of major and trace elements. We also measured parameters that convey information about the reactivity of organic matter and on the bio-availability of bioactive trace elements (e.g., chlorin indices and acid-extractable elements). Surface sediments from the region were calcareous oozes that were carbon-lean (0.26±0.1%) and had moderate to high chlorin indices (0.62 – 0.97). With the exception of arsenic, inorganic element concentrations were generally low by global standards. Statistical and geochemical analyses identified two major dimensions of variation in the elemental composition: (i) the degree of mixing between the detrital sediment and carbonate end-members; and (ii) the concentrations of bio-available bioactive elements. The causes of compositional variation are discussed, and include: (i) a strong latitudinal gradient in detrital atmospheric dust deposition; (ii) size fractionation and cation exchange of dust components during transit (for non-carbonates); (iii) water depth controls on carbonate dissolution; and (iv) topographic/hydrodynamic focussing of reactive organic matter. Reactive organic matter indicators were not well correlated with water depth, and did not reflect the regional ocean productivity pattern. Basalt source signatures were not evident in the mineralogy or geochemistry of sediments overlying the seamount or in the vicinity of volcanoes.

A growing need to manage marine biodiversity sustainably at local, regional and global scales cannot be met by applying existing biological data. Abiotic surrogates of biodiversity are thus increasingly valuable in filling the gaps in our knowledge of biodiversity patterns, especially identification of hotspots, habitats needed by endangered or commercially valuable species and systems or processes important to the sustained provision of ecosystem services. This review examines the use of abiotic variables as surrogates for patterns in benthic biodiversity with particular regard to how variables are tied to processes affecting species richness and how easily those variables can be measured at scales relevant to resource management decisions. Direct gradient variables such as salinity, oxygen concentration and temperature can be strong predictive variables for larger systems, although local stability of water quality may prevent usefulness of these factors at fine spatial scales. Biological productivity has complex relationships with benthic biodiversity and although the development of local and regional models cannot accurately predict outside the range of their biological sampling, remote sensing may provide useful information. Indeed, interpolated values are available for much of the world’s seas, and these are continually being refined by the collection of remote sensing and field data. Sediment variables often exhibit complex relationships with benthic biodiversity. The strength of the relationship between any one sediment variable and biodiversity may depend on the state of another sediment variable in that system. Percentage mud, percentage gravel, rugosity and compaction hold the strongest independent predictive power. Rugosity and the difference between gravel and finer sediments can be established using acoustic methods, but to quantify grain size and measure compaction, a sample is necessary. Pure spatial variables such as latitude, longitude and depth are not direct drivers of biodiversity patterns but often correspond with driving gradients and can be of some use in prediction. In such cases it would be better to identify what the spatial variable is acting as a proxy for so boundaries for that variable are not overlooked. The utility of these potential surrogates vary across spatial scales, quality of data, and management needs. A continued focus on surrogate research will address the need of marine scientists and resource managers worldwide for accurate and robust predictions, extending from simple measures of diversity to species distributions and patterns of assemblage.

Infauna play key roles in nutrient cycling and bioturbation by facilitating exchange across the sediment-water interface, but the effects of environmental stressors on the behavior of infauna are poorly studied compared to epifauna. Here we used laboratory experiments to examine the effects of temperature (15, 21, and 32°C), salinity (16, 22, 28, and 34), and food availability (low, moderate, high) on the burrowing activity of the opportunistic deposit-feeding polychaete Capitella sp. 1. We also used pH and O2 fluorosensors to investigate the effects of burrowing on marine sedi- ment chemistry. Worms buried significantly deeper at 21 than at 15°C, and they died at 32°C. Salin- ity only marginally affected the area of burrowing activity, with greater area at 35 than at 22. Burrows in highly enriched treatments were significantly more shallow than those in moderate and low food treatments. The fluorosensors showed that the exchange of solutes between the sediment and over- lying water was associated with burrowing activity. These results show that changes in environmen- tal conditions affect infaunal burrowing activity, which in turn affects sediment characteristics. We discuss the need to consider infaunal responses to abiotic stress in order to understand community and ecosystem responses to environmental changes associated with climate change, pollution, and eutrophication.

Climate change and ocean acidification will expose marine organisms to synchronous multiple stressors, with early life stages being potentially most vulnerable to changing environmental conditions. We simultaneously exposed encapsulated molluscan embryos to three abiotic stressors—acidified conditions, elevated temperate, and solar UV radiation in large outdoor water tables in a multifactorial design. Solar UV radiation was modified with plastic filters, while levels of the other factors reflected IPCC predictions for near-future change. We quantified mortality and the rate of embryonic development for a mid-shore littorinid, Bembicium nanum, and low-shore opisthobranch, Dolabrifera brazieri. Outcomes were consistent for these model species with embryos faring significantly better at 26°C than 22°C. Mortality sharply increased at the lowest temperature (22°C) and lowest pH (7.6) examined, producing a significant interaction. Under these conditions mortality approached 100% for each species, representing a 2- to 4-fold increase in mortality relative to warm (26°C) non-acidified conditions. Predictably, development was more rapid at the highest temperature but this again interacted with acidified conditions. Development was slowed under acidified conditions at the lowest temperature. The presence of UV radiation had minimal impact on the outcomes, only slowing development for the littorinid and not interacting with the other factors. Our findings suggest that a warming ocean, at least to a threshold, may compensate for the effects of decreasing pH for some species. It also appears that stressors will interact in complex and unpredictable ways in a changing climate.

Infauna are important in many ecological processes but have been rarely considered in biodiversity assessments of coral reefs and surrounding areas. We surveyed infaunal assemblages and associated environmental factors (depth, seabed reflectance, sediment characteristics) in three areas (Mandu, Point Cloates, Gnaraloo) along the Carnarvon Shelf, Western Australia. This region supports Ningaloo Reef, a relatively pristine coral reef protected by the Ningaloo Marine Park and a Commonwealth marine reserve. Macrofauna were sampled with a Smith-McIntyre grab and sieved through 500 µm. A total of 423 species and 4036 individuals was recorded from 145 grabs, with infauna accounting for 67% of species and 78% of individuals. Rare species (≤2 individuals per species) represented 42% of the total assemblage. Assemblages were significantly different among all three areas, with the most distinct recorded from the southern-most area (Gnaraloo). Although assemblages varied significantly with depth and sediment composition (mud and gravel), these relationships were weak. Results from the current study broadly quantify macrofaunal diversity in the region and identify potential spatial and environmental patterns which will help inform future marine management plans, including the provision of baseline information to assess the efficacy of protected areas in soft-sediment habitats adjacent to coral reefs.

Mapping of benthic habitats seldom considers biogeochemical variables or changes across time. We aimed to: (i) develop winter and summer benthic habitat maps for a sandy embayment; and (ii) compare the effectiveness of various maps for differentiating infauna. Patch types (internally homogeneous areas of seafloor) were constructed using combinations of abiotic parameters and are presented in sediment-based, biogeochemistry-based and combined sediment–biogeochemistry-based habitat maps. August and February surveys were undertaken in Jervis Bay, NSW, Australia, to collect samples for physical (% mud, sorting, % carbonate), biogeochemical (chlorophyll a, sulfur, sediment metabolism, bioavailable elements) and infaunal analyses. Boosted decision tree and cokriging models generated spatially continuous data layers. Habitat maps were made from classified layers using geographic information system (GIS) overlays and were interpreted from a biophysical-process perspective. Biogeochemistry and % mud varied spatially and temporally, even in visually homogeneous sediments. Species turnover across patch types was important for diversity; the utility of habitat maps for differentiating biological communities varied across months. Diversity patterns were broadly related to reactive carbon and redox, which varied temporally. Inclusion of biogeochemical factors and time in habitat maps provides a better framework for differentiating species and interpreting biodiversity patterns than once-off studies based solely on sedimentology or video-analysis.

Between October 2008 and January 2009, Geoscience Australia conducted a marine mapping survey to document the seabed environments and subsurface geology of the Zeewyck, Houtman, Exmouth sub-basins and the deep-water Wallaby (Cuvier) Plateau, Western Australia. The seabed mapping survey, the second and largest mapping survey of the Federal Government’s Offshore Energy Security Program, documented seabed environments and biota from multibeam sonar and sub-bottom profiler data, towed video footage and physical samples. Preliminary analysis of the data indicates that for all of the sub-basins the seabed is comprised of carbonate mud that supports relatively sparse infaunal populations. Rocky substrates, principally in the numerous submarine canyons, supported sparse communities of sessile organisms. Interestingly, some of these hard-grounds were associated with volcanic (basaltic) peaks on the upper slope that attain 200 metres above the surrounding seabed. Data collected from the survey are being analysed in conjunction with existing environmental data to establish a series of environmental summaries that describe the key seabed habitats and biota for the offshore basins. The environmental summaries are being made available to support future acreage release in the sub-basins. The marine mapping survey was run in combination with a regional 2D seismic survey of the same offshore basins, also completed as part of the Offshore Energy Security Program.

Spawning of marine invertebrates may be affected by environmental factors (e.g. food availability, environmental stress) or intrinsic factors (e.g. phylogenetic constraints, developmental mode); intrinsic factors may obscure environmental effects. Two-year surveys of gastropod egg mass deposition were conducted at two rocky intertidal sites in south-eastern Australia to test the following hypotheses: (1) temporal patterns of spawning are more similar within taxonomic order than across orders; and (2) species with planktotrophic larvae are more likely to spawn in seasons coinciding with maximum food availability. There were no discernible effects of either order or developmental mode on spawning patterns, suggesting that spawning behaviour is unrelated to taxonomic order or larval food availability. Alternatively, low numbers of species in certain groups may have increased the risk of not detecting significant effects (type II error). Comparisons with anecdotal data from other regions suggest that developmental mode may indeed play a role in marine gastropod spawning. Criteria are provided for future comparative studies, including a direct focus on specific families and the inclusion of similar latitudes and habitats to those used here. Such studies will help to determine the roles of developmental mode, food availability and environmental stress in the evolution of egg mass deposition.