Ocean alkalinity enhancement (OAE) is an emerging carbon dioxide removal (CDR) strategy that leverages the natural processes of weathering and acid neutralisation to durably store atmospheric CO2 in seawater. OAE can be achieved with a variety of methods, all of which have different environmental implications. One widely considered method utilizes electrochemistry to remove strong acid from seawater, leaving sodium hydroxide (NaOH) behind. This study evaluates the impacts of OAE via NaOH (NaOH-OAE) on a coastal plankton bloom, with particular focus on how macronutrient regeneration in the aftermath of the bloom responds to the perturbation. To investigate this, we enclosed a natural coastal phytoplankton community, including coccolithophores, in nine microcosms. The microcosms were divided into three groups: control, unequilibrated (512.1 ± 2.5 µmol kg-1 alkalinity increase) and equilibrated (499.3 ±5.65 µmol kg-1 alkalinity increase). Light was provided for 11 days to stimulate a bloom (light phase) and lights were turned off thereafter to investigate alkalinity and nutrient changes for 21 days (dark phase). We found no detectable effect of equilibrated NaOH-OAE on phytoplankton community and bacteria abundances determined with flow cytometry but observed a small yet detectable restructuring of phytoplankton communities under unequilibrated conditions. NaOH-OAE had no significant effect on alkalinity, NOx- and phosphate regeneration, but increased silicate regeneration by 64% over 21 days under darkness in the unequilibrated treatments where seawater pH was highest (8.65 relative to 7.92 in the control). Additional dissolution experiments with two diatom species supported this outcome on silicate regeneration for one of the two species, thereby suggesting that the effect is species specific. Our results point towards the potential of NaOH-OAE to influence regeneration of silicate in the surface ocean and thus the growth of diatoms, at least under the very extreme NaOH-OAE conditions simulated here.

These files contain the data recorded from a mesocosm experiment conducted in Bergen, Norway 2022 which assessed the effect of simualted mineral-based (silicate or calcium) ocean alkalinity enhancement (OAE) on diatom silicification. Ten mesocosms were used in total, divided into two groups either the silicate- or calcium based group and alkalinity was increased by either 0, 150, 300, 450 or 600 µmol L-1 above natrually occuring levels. The PDMPO-fluorescence (an appropriate proxy for silicification) of diatoms was recorded on eight seperate days during the experiment. Accompanying data includes measured; macronutrients (nitrate, nitrite, phophate, silicate), total alkalinity, biogenic silica in the water column and sediment trap.

This record provides an overview of the scope and research output of NESP Marine Biodiversity Hub Project D7 - "NESP Hub support for Parks Australia’s Monitoring, Evaluation, Reporting and Improvement System (MERI) for Australian Marine Parks". No data outputs are expected for this project. -------------------- This application is to facilitate Hub engagement with Parks Australia during development and initiation of their Monitoring, Evaluation, Reporting and Improvement (MERI) System for Australian Marine Parks. A key priority for the Marine Parks Branch in the 2019-20 financial year is finalising the Australian Marine Park MERI system. The Marine Biodiversity Hub will play an important role in development and implementation of this system. Hub partners have had previous experience in developing the integrated monitoring framework for the Great Barrier Reef, developing a process for identifying indicators for monitoring Key Ecological Features, and also have collected much of the ecological data that exists within Australian Marine Parks. In discussions with Parks Australia, to ensure the MERI system is optimally integrated with current scientific knowledge and capability, there are a number of tasks and information needs that the Hub is well positioned to provide assistance with, these include: • Review the ‘common language’ proposed for Australian Marine Parks, including natural values and pressures classifications, hierarchies and definitions. • Contribute to the identification of natural values, pressures and human uses within Australian Marine Parks and, where required, provide spatial data layers for incorporation into Parks Australia’s spatial information systems (i.e. Wylie) and other mapping portals. • Review conceptual models developed for each of the key ecosystems across the Australian Marine Park networks. • Review ecological risk assessments for natural values and pressures. • Provide advice on the process and criteria for identifying monitoring and inventory priorities. • Develop detailed conceptual models for areas identified as monitoring priorities. • Contribute to the development of monitoring questions. • Provide advice on the process and selection criteria for identifying appropriate value and pressure indicators (noting that the NESP D6 project is helping to identify appropriate social and economic indicators and measures). • Provide advice on best practice approaches for assessing management effectiveness. • Identify the suitability of existing data sets to support the identified monitoring priorities. • Provide advice on evaluation and reporting including best approaches for using a combination of quantitative data and expert opinion, and to help ensure alignment and consistency across objectives, key evaluation questions and reporting.

The Marine Futures Project was designed to benchmark the current status of key Western Australian marine ecosystems, based on an improved understanding of the relationship between marine habitats, biodiversity and our use of these values. Approximately 1,500 km2 of seafloor were mapped using hydroacoustics (Reson 8101 Multibeam), and expected benthic habitats "ground-truthed" using towed video transects and baited remote underwater video systems. Both sources of information were then combined in a spatial predictive modelling framework to produce fine-scale habitat maps showing the extent of substrate types, biotic formations, etc. Surveys took place across 9 study areas, including Geographe Bay in the southwest Capes region. The marine environment at this location varies from extensive seagrass meadows in protected waters, to kelp-dominated granite and limestone reefs in areas of high wave energy. A small number of corals are also found throughout the region, reflecting the influence of the southward flow of the Leeuwin Current. The fish fauna is also diverse, with a high proportion of endemic species.

The survey comprises two streams of data, including (1) the availability of different attachment sites and (2) the algal composition of abalone attachment sites ('homesites'). The survey was conducted at three sites at each of three regions on the east coast of Tasmania.

This data represents research conducted as part of a PhD project on Striped Trumpeter (Latris lineata). Performed morphological histology of swim bladder development in Striped Trumpeter at various ages. Also recorded water temperature, photo period, intensity of light and buoyancy control (in relation to water salinity).

Total organic carbon (TOC) sediment stocks as a CO2 mitigation service require exclusion of allochthonous black (BC) and particulate inorganic carbon corrected for water–atmospheric equilibrium (PICeq). For the first time, we address this bias for a temperate salt marsh and a coastal tropical seagrass in BC hotspots that represent two different blue carbon ecosystems of Malaysia and Australia. Seagrass TOC stocks were similar to the salt marshes with soil depths < 1 m (59.3 ± 11.3 and 74.9 ± 18.9 MgC ha-1, CI 95% respectively). Both ecosystems showed larger BC constraints than their pristine counterparts did. However, the seagrass meadows’ mitigation services were largely constrained by both higher BC/TOC and PICeq/TOC fractions (38.0% ± 6.6% and 43.4% ± 5.9%, CI 95%) and salt marshes around a third (22% ± 10.2% and 6.0% ± 3.1% CI 95%). The results provide useful data from underrepresented regions, and, reiterates the need to consider both BC and PIC for more reliable blue carbon mitigation assessments.

The Marine Futures Project was designed to benchmark the current status of key Western Australian marine ecosystems, based on an improved understanding of the relationship between marine habitats, biodiversity and our use of these values. Approximately 1,500 km2 of seafloor were mapped using hydroacoustics (Reson 8101 Multibeam), and expected benthic habitats "ground-truthed" using towed video transects and baited remote underwater video systems. Both sources of information were then combined in a spatial predictive modelling framework to produce fine-scale habitat maps showing the extent of substrate types, biotic formations, etc. Surveys took place across 9 study areas, including Rottnest Island, a popular family holiday destination just 20 km off the Perth coast. One of the main drawcards of the island is the diverse marine life inhabiting the surounding waters, which Western Australian locals and tourists can experience by snorkelling, diving, boating and fishing. The marine environment around Rottnest includes seagrass meadows, kelp-covered reef tops, coral patches, and sponge gardens in deeper water. As a result of the warm, southward flowing Leeuwin Current, the island represents the southern limit of the distributions of many tropical corals and fish. The marine life around Rottnest therefore represents a unique mix of tropical and temperate species and habitats.