The effect of ocean alkalinity enhancement on a coastal phytoplankton community was assessed via a microcosm experiment. The effect of alkalinity enhancement in two scenarios (i) when enclosed seawater was in equilibrium with atmospheric CO2 and (ii) when enclosed seawater was not in equilibrium with atmospheric CO2 were explored. Alkalinity was increased by ~497 umol/kg in these two treatments and plankton communities, carbonate chemistry, dissolved inorganic nutrients, particulate matter and chlorophyll a dynamics monitored over a 22 day period where a spring bloom occurred.

Efforts to restore Posidonia seagrass meadows in NSW are reliant on collecting beachcast fragments as collection of donor material from extant beds is prohibited. However, to maximise the collection efforts it necessary to understand where to collect fragments from and what environmental conditions (e.g. wind direction, wind strength, tidal height) increase the availability of fragments and where to collect the most healthy fragments. This data set captures the abundance of fragments at 7 sites in Gamay (Botany Bay), an area of interest for restoration of Posidonia australis. It investigates how characteristics of wind (speed and direction), tidal height and swell (height, direction) influence the availability (abundance) and health (as determined by observations of necrosis) of shoots at sites throughout Botany Bay. The Excel data workbook is comprised of two sheets: Fragments_data sheet shows the number of P. australis fragments collected at different sites, when they were collected, and the environmental conditions at collection (see data attributes section). Shoot_data sheet shows the proportion of necrosis of shoots attached to collected fragments.

The abundance of macroinvertebrates associated with 28 experimental artificial reefs supporting different patch sizes and density of kelp (Ecklonia radiata) off Maria Island, Tasmania. Macroinvertebrates were assessed by diver-based visual census conducted between November 2015 and December 2016. This data was collected to examine how the patch size and density of kelp influences the establishment of macroinvertebrate assemblages.

Collection of processed BGC-Argo float profiles, used to calculate phytoplankton phenology from chlorophyll, phytoplankton carbon and nitrate.

This record provides an overview of the NESP Marine and Coastal Hub project "Aerial survey of the Southern Right Whale 'western' sub-population off southern Australia". For specific data outputs from this project, please see child records associated with this metadata. -------------------- Southern right whales are listed as Endangered under the EPBC Act and are a species of national conservation significance. Monitoring of their recovery is guided by the Southern Right Whale Conservation Management Plan, which aims to improve the population’s conservation status through regular assessment of population size, calving intervals, and spatial trends. This project continued the long-term aerial survey program of southern right whales along the southern Australian coast, spanning from Perth (WA) to Ceduna (SA). Annual surveys have been conducted since 1993, providing a continuous long-term dataset for the 'western' population and supporting national assessments of connectivity with the smaller ‘eastern’ population. The surveys contribute essential data on population trends, calving rates, and movements of individuals. The August 2022 aerial survey ensured an uninterrupted time series in the long-term population trend data. This is particularly important given the species' non-annual breeding cycle (typically every three years). Annual surveys are essential to maintain an acceptable level of precision in estimating population trends and key life history parameters. A total of 526 whales were recorded, including 247 cow–calf pairs, 31 unaccompanied adults and one yearling. Based on long-term models, this equated to a population estimate of approximately 2,675 individuals, with an average annual growth rate of ~5.3%. While this represents a continued population growth, results suggest a possible slowing in the rate of growth over the past 13 years (from 7.5% in 2009). The 2022 survey also recorded the lowest number of unaccompanied animals in the entire time series, extending a five-year trend of low sightings in this group. Continued monitoring of the population is needed to assess whether these changes represent longer-term shifts in population dynamics and calving intervals, and to inform adaptive management for this long-lived, slow-recovering species. Outputs • Estimate of relative abundance and population trend compared to long-term aerial survey sightings [dataset] • Individual whale photo-identification data - 2021-22 season [imagery - published to ARWPIC] • Final technical report detailing overall numbers of southern right whales observed within the survey region, their gender (and life stage where possible) and spatial distribution of individuals [written]

This record described kelp growth and ecophysiological data relevant to the thermal tolerance of specific warm-tolerant and 'normal' family-lines of giant kelp (Macrocystis pyrifera) from Tasmania, Australia. Australia’s giant kelp forests are listed as a Threatened Ecological Community under the Environment Protection and Biodiversity Conservation Act 1999. Habitat restoration is a potential tool for the conservation and management of giant kelp ecosystems. For habitat restoration to be effective, the cause of habitat decline must be understood and overcome. This is problematic when climate change is driving habitat loss since it cannot be reversed or ameliorated prior to restoration. A previous NESP project led by this team (Project E7, Marine Biodiversity Hub) identified warm-tolerant strains of giant kelp from remnant patches in eastern Tasmania, where the species has experienced precipitous declines due to ocean-warming. These strains have high potential to assist with ‘future-proofing’ kelp forest restoration, however it is still unclear what the physiological mechanisms are that provide their improved thermal tolerance. This work cultivated the warm-tolerant strains of giant kelp previously identified, along with giant kelp strains of normal tolerance, at both cool (16 °C) and warm temperatures (20 °C). The juvenile kelp was then harvested, and a suite of physiological traits that may be responsible for their differences in thermal tolerance were examined. These included nutrient usage (carbon and nitrogen content), cellular membrane processes (fatty acid contents), and photosynthesis (PAM fluorometry and photosynthetic pigments). The cultivation trials again illustrated the improved ability of the warm-tolerant strains to develop at stressful warm temperatures relative to normal giant kelp. This work demonstrated for their first time that the improved thermal performance of these strains may extend to the development and fertilisation of the earlier kelp ‘gametophyte’ life-stage. Despite the clear differences in growth between the two test groups, the physiological assessments illustrated a complex pattern of responses, some of which are contrary to expected based on prior knowledge of thermal performance in kelps. Nonetheless, these results indicate that the warm-tolerant strains of giant kelp have a greater capacity to alter the composition of their fatty acids and may be more efficient users of nitrogen (a key nutrient for growth and development). This new information will help inform ongoing kelp breeding and selection programs for future-proofing kelp restoration in Australia and globally. The improved understanding of the physiology of kelp thermal tolerance might also help with identifying individuals and populations of Macrocystis, and other kelps, that may be resilient to (or especially threatened by) ocean warming and climate change.