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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.
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We hypothesised that New Zealand sea lions from Campbell Island/Motu Ihupuku of various sex and age classes would utilise the water column differently due to differing physiological constraints and therefore have different accessibility to prey resources. We tested whether sea lion diving behaviour varied in relation to (i) age and sex class, (ii) time of day and (iii) water depth. We also hypothesized that the proportion of benthic/pelagic diving, and consequently risk of fisheries interaction, would vary in relation to age and sex. Satellite telemetry tags were deployed on 25 NZSL from a range of age/sex classes recording dive depth, duration and location. Adult females and juveniles used inshore, benthic habitats, while sub-adult males also utilised benthic habitats, they predominantly used pelagic habitat at greater distances from the island. Adult females and juveniles exhibited shorter dives than the same age/sex classes at the Auckland Islands, suggesting a lower dive effort for these age/sex classes at Campbell Island.
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Data to accompany publication on wild diet of southern rock lobster on the east coast of Tasmania. In this study we collected 64 lobsters and analysed the diet of each individual using stomach contents, stable isotope analysis and DNA identification of prey species in faecal samples.
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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.
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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.
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1. Workforce Tasmania’s commercial fishing industry workforce is defined as those people engaged in economic activity (work) within the sector across or at a given time, either in paid employment or self-employment. For fisheries this includes skippers and crew employed as sub-contractors and paid on a share of catch arrangement. It can include people engaged in unpaid work undertaken as part of these activities, although this has not been included in this assessment. Monitoring workforce changes is important because these changes indicate changes in social and economic benefits at a statewide and regional community level. Factors which affect workforce size include the extent to which a policy of maximizing technical efficiency is pursued through management, which typically reduces the fleet size and therefore the number of people employed. Other factors include the level of stock availability and access, the cost of entry into the fishery, and the financial profitability of fishing. Because of these factors, many fishers are engaged in employment in multiple fisheries or other marine sectors in order to supplement fishing incomes and pursue full-time employment. 1.1. Abalone The commercial harvesters catching abalone species operate within the Tasmanian Abalone Fishery. Assessment of workforce indicators is undertaken at fishery level. The data provided for this fishery is for the Tasmanian Abalone Fishery as a whole, which includes harvesting activity for this species as well as all other species caught in this fishery. 1.2. Commercial Dive species The commercial harvesters catching these species operate within the Tasmanian Commercial Dive Fishery. Assessment of workforce indicators is undertaken at fishery level. The data provided here is for the Tasmanian Commercial Dive species as well as all other species caught in this fishery. 1.3. Giant crab species The commercial harvesters catching giant crab operate within the Tasmanian Giant Crab Fishery. Assessment of workforce indicators is undertaken at fishery level. 1.4. Scalefish species The commercial harvesters catching this scalefish species operate within the Tasmanian Scalefish Fishery. Assessment of workforce indicators is undertaken at fishery level. The data provided here is for the Tasmanian Scalefish Fishery as a whole, which includes harvesting activity for this species as well as all other species caught in this fishery. 1.5. Scallop species The commercial harvesters catching species of scallop operate within the Tasmanian Scallop Fishery. Assessment of workforce indicators is undertaken at fishery level. 1.6. Southern rock lobster The commercial harvesters catching southern rock lobster operate within the Tasmanian Rock Lobster Fishery. Assessment of workforce indicators is undertaken at fishery level. 2. Workforce Indicators 2.1. Persons Workforce size (the total number of people directly employed) includes both skippers and crew, and those employed full time and part time. 2.2. Employment FTE The number of Full Time Equivalent (FTE) positions in each fishery is also estimated. This indicator shows that while a higher number of people may be employed in a fishery, some of these jobs may be part-time. Therefore, the number of FTEs is typically lower than the number of people in the workforce. In this iteration of the dataset, this value is unavailable for the abalone fishery in 2016, 2017, and 2019, and does not apply to the scallop fishery in any of the years available (2016-2020). 2.3. Active Supers The number of supervisors (skippers) employed in the fishery. 2.4. Harvest Units (TAS HP) The number of harvest units (combination of licensed vessel and fishing entitlement) active in a fleet and the number of people who actively harvest fish as supervisors (skippers) in a commercial fishery are directly linked to the size of the workforce in each fishery. In many cases, multiple supervisors may be linked to the same harvest unit, so the number of supervisors is often higher.
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This is a collection of data in East Antarctica from Southern Elephant seal's between 2004 and 2009. The monthly data set has been further classified by polynya and year. Additionally, we provide a dataset of the polynyas contours defined following a criteria of 75% of sea-ice concentration for each individual month between 2004 and 2019. Data are provided in .mat format
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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.
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Five subsections of Antarctic ice cores were used to create a new methodology for analyzing microplastics in sea ice.
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This record presents data used in the paper 'Controls on polar Southern Ocean deep chlorophyll maxima: viewpoints from multiple observational platforms,' Philip W Boyd 𝘦𝘵. 𝘢𝘭., submitted to Global Biogeochemical Cycles, November 2023. All methods for the following datasets are detailed and cross-referenced in the paper. Data were collected from a range of methods, including: • vertical profiles (from 1 m resolved profiling using sensors on a CTD rosette: temperature, salinity, chlorophyll fluorescence, transmissivity - all calibrated) • vertical profiles (from discrete samples collected from CTD rosette or trace metal clean rosette, for nutrients, chlorophyll, POC, dissolved and particulate iron, active fluorescence, net primary productivity, biological iron uptake) • tow-body sections (undulating tow body (Triaxus) for temperature, salinity, chlorophyll fluorescence, transmissivity (and the ratio of chlorophyll fluorescence, transmissivity) • time-series observations from a robotic profiling float (BGC-ARGO) for temperature, salinity, chlorophyll fluorescence, and transmissivity).
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