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EARTH SCIENCE | BIOSPHERE | ECOSYSTEMS | MARINE ECOSYSTEMS | PELAGIC | OCEANIC ZONE

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    δ18Oara profile for shelled pteropod calcification depth estimate based on seawater salinity and temperature measured by Argo floats. The oxygen isotopic composition of pteropod shells (δ18Optero) was compared to the δ18Oara at different depths. The calcification depth is defined as the depth where the values of δ18Optero and δ18Oara were equal within their respective uncertainties. Shelled pteropods are at risk from ocean acidification, with known effects on their shell durability and calcification. Pteropods typically form their aragonitic shells over specific depth ranges known as the ‘calcification depth’, which varies depending on species and habitats. Some Southern Ocean waters are already undersaturated with respect to aragonite and this could negatively affect shelled pteropods. However, the calcification depths of the pteropods have not been determined nor used to infer consequences of changing seawater carbonate chemistry in the Southern Ocean. In this study, we analysed the stable oxygen isotopic composition of Limacina rangii shells, collected by sediment traps in the subantarctic zone, to estimate their calcification depth. Shallow calcification depths (13-126 m) were detected in summer-autumn, while L. rangii calcified their shells deeper in the water column during winter-spring, with an average maximum calcification depth of 525 m. Recent shoaling of the aragonite saturation horizon is likely to negatively affect pteropods that calcify their shells in deep water. Such shoaling is likely to reduce shell formation and threaten population viability.

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    These data were collected on Southern Surveyor transit voyage SS2013_T01 from Sydney to Hobart in February 2013. The voyage was a teaching voyage as part of KSA724. Masters students participated in the collection of standard oceanographic data, focusing on eddies of the East Australian Current. This dataset includes for reference the nutrient and hydrography bottle data as produced by the Marine National Facility, as well as the fluorometrically determined extracted chlorophyll concentration

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    Thorium-234 samples were collected to determine the particulate organic carbon (POC) export fluxes in two East Antarctica polynyas, Dalton and Mertz. The samples were collected along the water column using the CTD deployed at several stations. The seawater Th-234 data was used in combination with POC:234Th ratios obtained from particulate samples collected using in situ pumps in order to derive the POC fluxes. This record describes Th-234 and U-238_data: sample ID, depth, CTD file, station ID, latitude and longitude, Th-234 concentration and its uncertainty, U-238 concentration and its uncertainty. See linked record for associated POC data from Aurora Australis Voyage 2 2016/17.

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    This repository contains data files (netCDF format) related to the model configuration developed and used by Joan Llort between 2011 and 2019. The model is a 1D configuration based on PISCES v1 and the specific routines and namelist are here: https://github.com/jllort/PISCESv1_1D The data in this repository is organised in two groups: - The first group contains the forcing files used to create and idealised representation of Southern Ocean water columns. Forcing files were automatically modified to force PISCES models with different mixed layer depth and iron environments. The files presented here are for a single water column but they can be modified using the python routines in the GitHub link above. - The second group contains the outputs for one of the experiments. We studied the impact of changes in ferricilne, winter mixed layer and summer mixed layer depths over Southern Ocean primary production.

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    Baited remote underwater stereo-video (stereo-BRUV) were used to sample the fish assemblages of the Hunter Marine Park and adjacent Port Stephens - Great Lakes Marine Park at equivalent depths. Stereo-BRUV were deployed in both autumn and spring from spring 2016 to autumn 2018 and at depth of 32-105m. The videos were analyse to all fish species to the lowest taxonmic level and estimate relative abundance (MaxN) and lengths of all species. This information was used to form a baseline of the benthic fish assemblages of the Hunter Marine Park. This study was done as part of the NESP Marine Biodiversity Hub D3 project (https://www.nespmarine.edu.au/project/project-d3-implementing-monitoring-amps-and-status-marine-biodiversity-assets-continental).

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    This dataset describes visual sightings of marine megafauna (whales, dolphins and sharks) obtained during a series of dedicated aerial surveys conducted as part of a NESP Marine Biodiversity Hub project within and around the Bremer Marine Park, southern Western Australia. The data reflect 25 hours of observer effort (on transect), and 62 sightings of four identifiable species, including killer whales (Orcinus orca), sperm whales (Physeter macrocephalus), long-finned pilot whales (Globicephala melas), and bottlenose dolphins (Tursiops sp.). Numerous unidentified cetaceans and sharks were also seen. For more information, see: https://www.nespmarine.edu.au/project/ep2-surveying-marine-life-canyons-bremer-bay

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    This dataset relates to deployments of pelagic stereo-BRUVS conducted by the University of Western Australia within and to the west of the Bremer Marine Park in February/March 2017. The survey was undertaken to provide a baseline assessment of the pelagic assemblages occurring in the region as part of the NESP Marine Biodiversity Hub Emerging Priorities Project #EP2 (https://www.nespmarine.edu.au/project/ep2-surveying-marine-life-canyons-bremer-bay). A total of 791 individuals from 13 taxa were identified.