Cindy Bessey’s research while affiliated with The Commonwealth Scientific and Industrial Research Organisation and other places

Advances in methods for collecting environmental DNA (eDNA) are revolutionizing biomonitoring capabilities. The goal of this study was to leverage existing survey technology to design and test an eDNA sampler that captures an integrated eDNA sample over the length of a deep‐water transect. We manufactured a 300 × 100 × 100 mm mountable, open‐ended box made of high‐density polyethylene that could be attached to the frame of a preexisting deep tow camera system. The box (OCD; open–close device) was equipped with an actuator that attached to hinged doors at both ends, enabling it to be opened and closed remotely at depths up to 6000 m through preexisting communications, thereby exposing the internal chamber to the surrounding water upon activation. A sterile active carbon sponge was inserted into the internal chamber for eDNA capture during each deployment. The OCD sampler was field tested during a voyage to the Gascoyne Marine Park region off northwest Australia. We compared three different methods for processing the captured eDNA from the sampler: filtering OCD water, extracting eDNA from sponge pieces, and filtering sponge rinse water. Using fish as our example organism, we also compared the identities of fishes from eDNA detections with bottom trawl survey data collected during the same survey, and the known regional species pool, to confirm the eDNA identifications were plausible. A large number of fishes (193 taxa, from 87 families) were detected, and the majority were found within their expected depth ranges (> 75%), and in the trawl catches (60%). We discuss design and manufacturing lessons, ideas for increased eDNA capture efficiency for improved methodologies in sample processing, and how to establish appropriate field controls. We also discuss how this technology could advance our scientific understanding in ocean studies in terms of ecological metrics provided and the trade‐offs compared to other sampling tools.

Understanding connectivity in high impact corallivores is crucial for coral reef management. The obligate corallivorous Drupella cornus (Röding, 1798) has caused extensive damage to some Indian Ocean coral reef areas in the last four decades. This study used novel and previously published Cytochrome Oxidase I ( COI ) sequences to reveal patterns of genetic diversity, phylogeography and connectivity within D. cornus across the Indian Ocean. The genetic compositions of the Western Australian D. cornus groups from Ningaloo Reef, Houtman Abrolhos Islands, and a recently discovered group at Rottnest Island, were analysed and compared to D. cornus groups from the western Indian Ocean (Tanzania and the Gulf of Eilat). The findings indicated that these groups all belong to the same species, except for a few individuals from Rottnest Island, which were excluded from subsequent analyses. No genetically distinct D. cornus groups along the Western Australian coastline were found, whereas molecular population differences were seen between the western Indian Ocean D. cornus groups and the Western Australian D. cornus groups. The molecular differences between the Western Australian and Tanzanian groups were statistically significant; however, there was evidence of historic connections and possibly also occasional long-distance gene flow between these groups. We hypothesise that high-density D. cornus outbreaks have played an important role in the dispersal of this species across Western Australia and, more broadly, the Indian Ocean. This is important as Drupella spp. outbreaks are being reported more frequently in the Indo-Pacific, affecting coral reef health and ecosystem function.

By March 2020 coronavirus disease 2019 (COVID-19) was anticipated to present a major challenge to the work undertaken by scientists. This pandemic could be considered just one of the shocks that human society has had and will be likely to confront again in the future. As strategic thinking about the future can assist performance and planning of scientific research in the face of change, the pandemic presented an opportunity to evaluate the performance of marine researchers in prediction of future outcomes. In March 2020, two groups of researchers predicted outcomes for the Australian marine research sector, and then evaluated these predictions after 18 months. The self-assessed coping ability of a group experienced in ‘futures studies’ was not higher than the less-experienced group, suggesting that scientists in general may be well placed to cope with shocks. A range of changes to scientific endeavours (e.g., travel, fieldwork) and to marine sectors (e.g., fisheries, biodiversity) were predicted over the first 12–18 months of COVID-19 disruption. The predicted direction of change was generally correct (56%) or neutral (25%) for predictions related to the scientific endeavour, and correct (73%) or mixed (9%) for predictions related to sectors that are the focus of marine research. The success of this foresighting experiment suggests that the collective wisdom of scientists can be used by their organisations to consider the impact of shocks and disruptions and to better prepare for and cope with shocks. Graphical abstract Word cloud analysis of free text responses to questions about expected impact of COVID-19 on the activities associated with marine science

With increasing sea water temperatures, higher latitude temperate and sub-tropical coral reefs are becoming increasingly tropicalised. Although these cooler areas might offer refuge to tropical species escaping the heat, the reshaping of ecosystems can have devastating effects on the biodiversity in these areas, especially when habitat structure is affected. Recently, feeding aggregations of corallivorous gastropod Drupella cornus, a tropical species capable of large-scale reef degradation, were found at Rottnest Island in Western Australia (32°S). We provide evidence that D. cornus spawned at Rottnest Island for 2 consecutive years in 2021 and 2022, and Drupella veligers from an egg case collected at the island hatched and grew at temperatures in the laboratory that were predominantly lower than those at Rottnest Island at the same time. The spawning was possibly triggered by higher than usual La Niña-associated SSTs during the survey period, or the long period of high sea water temperature anomalies recorded around Rottnest Island. A spawning population of D. cornus can greatly affect these higher latitude reef areas, especially when accompanied by increased heat stress. Monitoring and management should be implemented to further understand what effects a breeding population of D. cornus has on Rottnest Island.

Biodiversity conservation and management requires surveillance that captures the full spectrum of taxa. Here, we showcase the potential for a portfolio of visual, extractive, and molecular methods for detecting previously hidden components of tropical fish biodiversity in an economically and culturally valuable marine site that spans a tropical‐temperate ecotone—the Ningaloo Coast World Heritage Area. With scale and practicality in mind, we demonstrate how environmental DNA (eDNA) methods deployed in a stratified sampling design can yield a more comprehensive monitoring program for species presence than current alternatives (e.g., extractive sampling via anesthetic). eDNA from filtered water samples detected up to six times as many cryptobenthic fish species per site than samples collected with anesthetic, indicating it is a potentially powerful tool for assessing biodiversity of tropical fishes. However, there were also species that were only found when using anesthetic and the contribution of cryptobenthic species to overall diversity of the fish assemblage was unexpectedly low, suggesting not all cryptobenthic fish species have been detected with eDNA. There were also distinct differences in cryptobenthic assemblages both among sites and sample depths (2–3 m) when using eDNA from filtered water, suggesting this technique may be able to identify fine scale spatial differences in cryptobenthic fish assemblage. eDNA collected from water detects the most cryptobenthic species and is therefore an efficient tool for rapidly assessing biodiversity, but extractive techniques may still be required for biological and monitoring studies, and when combined with eDNA sampling provides the most comprehensive assessment of cryptobenthic fishes.

With increasing seawater temperatures, higher latitude temperate and sub-tropical reefs are becoming increasingly tropicalised. Although these cooler areas might offer refuge to tropical species escaping the heat, the reshaping of ecosystems can have devastating effects on the biodiversity in these areas, especially when habitat structure is affected. Recently, feeding aggregations of corallivorous gastropod Drupella cornus , a tropical species capable of large-scale reef degradation, were found at Rottnest Island in Western Australia (32 °S). We provide evidence that D. cornus spawned at Rottnest Island for two consecutive years in 2020–2022. Drupella veligers are also shown to hatch and develop successfully at lower temperatures (17.5–23.2°C) in the laboratory, showing high plasticity in the early life stages of D. cornus . The spawning was possibly triggered by higher than usual La Niña-associated SSTs during the survey period, or the long period of high sea water temperature anomalies recorded around Rottnest Island. A spawning population of D. cornus can greatly affect these higher-latitude reef areas, especially when accompanied by increased heat stress. Monitoring and management should be implemented to further understand what effects a breeding, and potentially self-sustaining population of D. cornus has on Rottnest Island.

Coral reefs face increasing pressures in response to unprecedented rates of environmental change at present. The coral reef physical framework is formed through the production of calcium carbonate (CaCO3) and maintained by marine organisms, primarily hermatypic corals, and calcifying algae. The northern part of Western Australia, known as the Kimberley, has largely escaped land-based anthropogenic impacts and this study provides important metabolic data on reef-building organisms from an undisturbed set of marine habitats. From the reef platform of Browse Island, located on the mid-shelf just inside the 200 m isobath off the Kimberley coast, specimens of the dominant coral (six species) and algal (five species) taxa were collected and incubated ex situ in light and dark shipboard experimental mesocosms for 4 h to measure rates of calcification and production patterns of oxygen. During experimental light and dark incubations, all algae were net autotrophic producing 6 to 111 mmolO2m-2d-1. In contrast, most corals were net consumers of O2 with average net fluxes ranging from -42 to 47 mmolO2m-2d-1. The net change in pH was generally negative for corals and calcifying algae (-0.01 to -0.08 h-1). Resulting net calcification rates (1.9 to 9.9 gCaCO3m-2d-1) for corals and calcifying algae (Halimeda and Galaxura) were all positive and were strongly correlated with net O2 production. In intertidal habitats around Browse Island, estimated relative contributions of coral and Halimeda to the reef production of CaCO3 were similar at around 600 to 840 gm-2yr-1. The low reef platform had very low coral cover of < 3 % which made a smaller contribution to calcification of ∼ 240 gCaCO3m-2yr-1. Calcification on the subtidal reef slope was predominantly from corals, producing ∼ 1540 gCaCO3m-2yr-1, twice that of Halimeda. These data provide the first measures of community metabolism from the offshore reef systems of the Kimberley. The relative contributions of the main reef builders, in these undisturbed areas, to net community metabolism and CaCO3 production is important to understand exclusively climate-driven negative effects on tropical reefs.