Lobster (Jasus edwardsii) tissue isotope data

Carbon and nitrogen isotope data for J. edwardsii lobsters from eight sites in SE Australia.

Seasonality of phytoplankton growth limitation by iron and manganese in subantarctic waters

Phytoplankton indirectly influence climate through their role in the ocean biological carbon pump. In the Southern Ocean, the subantarctic zone represents an important carbon sink, yet variables limiting phytoplankton growth are not fully constrained. Using three shipboard bioassay experiments on three separate voyages, we evaluated the seasonality of iron (Fe) and manganese (Mn) co-limitation of subantarctic phytoplankton growth south of Tasmania, Australia. We observed a strong seasonal variation in a phytoplankton Fe limitation signal, with a summer experiment showing the greatest response to Fe additions. An autumn experiment suggested that other factors co-limited phytoplankton growth, likely low silicic acid concentrations. The phytoplankton responses to Mn additions were subtle and readily masked by the responses to Fe. Using flow cytometry, we observed that Mn may influence the growth of some small phytoplankton taxa in late summer/autumn, when they represent an important part of the phytoplankton community. In addition, Mn induced changes in the bulk photophysiology signal of the spring community. These results suggest that the importance of Mn may vary seasonally, and that its control on phytoplankton growth may be associated with specific taxa.

Characterization of a Southern Ocean deep chlorophyll maximum: response of phytoplankton to light, iron, and manganese enrichment

Southern Ocean phytoplankton growth is limited by low iron (Fe) supply and irradiance, impacting the strength of the biological carbon pump. Unfavourable upper ocean conditions such as low nutrient concentrations can lead to the formation of deep chlorophyll or biomass maxima (DCM/DBM). While common in the Southern Ocean, these features remain under-studied due to their subsurface location. To increase our understanding of their occurrence, we studied the responses of phytoplankton communities from a Southern Ocean DCM to increasing light, Fe, and manganese (Mn) levels. The DCM communities were light- and Fe-limited, but light limitation did not increase phytoplankton Fe requirements. The greatest physiological responses were observed under combined Fe/light additions, which stimulated macronutrient drawdown, biomass production and the growth of large diatoms. Combined Mn/light additions induced subtle changes in Fe uptake rates and community composition, suggesting species-specific Mn requirements. These results provide valuable information on Southern Ocean DCM phytoplankton physiology.

Effect of dissolved iron (II) and temperature on growth of the Southern Ocean phytoplankton species Fragilariopsis cylindrus and Phaeocystis antarctica

In this dataset, we compared growth of Fraglariopsis cylindrus and Phyaeocystis antarctica collected from coastal and open ocean water at 3 °C, 5 °C and 7 °C, with and without additions of 5 nM dFe(II).

Microplastics in sea ice methodology cores

Five subsections of Antarctic ice cores were used to create a new methodology for analyzing microplastics in sea ice.

BRUV and AUV annotation data for Elizabeth and Middleton reefs

This submission creates a static snapshot of data from the Autonomous Underwater Vehicle (AUV) and stereo-BRUV annotation data from the National Environmental Science Program (NESP) Elizabeth and Middleton Reef survey. More details on the survey can be found at https://www.nespmarine.edu.au/document/elizabeth-and-middleton-reefs-lord-howe-marine-park-post-survey-report.

Satellite Mapping of Bathymetry and Habitats of Ashmore Reef and Cartier Island Marine Parks

Parks Australia - Our Marine Parks Grants Round 3 Project: Satellite Mapping of Bathymetry and Habitats of Ashmore and Cartier Island Marine Parks This project aimed to map the satellite-derived bathymetry (SDB) and benthic habitats at 2m horizontal spatial resolution, for the shallow waters (~0-25 m) of the Ashmore Reef and Cartier Island Marine Parks. These critical geospatial data layers provide the essential environmental baseline information for the long-term monitoring and management of these Marine Parks. Mapping the shallow water zone is of importance both from an environmental and socioeconomic perspective. Having access to digital, georeferenced, high-resolution, satellite-derived maps of bathymetry and benthic habitats of shallow water areas, is of fundamental use in the areas of navigation, ecological research, environmental modelling, management and conservation, and monitoring the impacts from climate change.

Longspined sea urchin size and movement metrics (data accompanying: "The risky nightlife of undersized urchins")

This data package consists of two files to accompany the manuscript Smith J., Flukes E., Keane J.P. (2024) The risky nightlife of undersized sea urchins. Marine and Freshwater Research IN PRESS. Dataset A: 211 Centrostephanus rodgersii (longspined sea urchin) were measured for test diameter and spine canopy at Fortescue Bay, Tasmania, Australia in May-June 2023 (FB_TD_SC.csv) Dataset B: Urchin movement data from Flukes et al. 2023 and associated urchin sizes measured in this study (whole_measured_df.csv)

Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification - data

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.

Fish and invertebrate communities show greater day/night partitioning on tropical than temperate reefs

Diel partitioning of animals within ecological communities is widely acknowledged, yet rarely quantified. Investigation of most ecological patterns and processes involves convenient daylight sampling, with little consideration of the contributions of nocturnal taxa, particularly in marine environments. Here we assess diel partitioning of reef faunal assemblages at a continental scale utilizing paired day and night visual census across 54 shallow tropical and temperate reefs around Australia. Day/night differences were most pronounced in the tropics, with fishes and invertebrates displaying distinct and opposing diel occupancy on coral reefs. Tropical reefs in daytime were occupied primarily by fishes not observed at night (64% of all species sighted across day and night, and 71% of all individuals). By night, substantial emergence of invertebrates not otherwise detected during sunlit hours occurred (56% of all species, and 45% of individuals). Nocturnal emergence of tropical invertebrates corresponded with significant declines in the richness and biomass of predatory and herbivorous diurnal fishes. In contrast, relatively small diel changes in fishes active on temperate reefs corresponded to limited nocturnal emergence of temperate invertebrates. This reduced partitioning may, at least in part, be a result of strong top-down pressures from fishes on invertebrate communities, either by predation or competitive interference. For shallow reefs, the diel cycle triggers distinct emergence and retreat of faunal assemblages and associated trophic patterns and processes, which otherwise go unnoticed during hours of regular scientific monitoring. Improved understanding of reef ecology, and management of reef ecosystems, requires greater consideration of nocturnal interactions. Without explicit sampling of nocturnal patterns and processes, we may be missing up to half of the story when assessing ecological interactions.

IMAS Data Manager