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Kelps are in global decline due to climate change, including ocean warming. To identify vulnerable species, we need to identify their tolerances to increasing temperatures and whether tolerances are altered by co-occurring drivers such as inorganic nutrient levels. This is particularly important for those with restricted distributions, which may already be experiencing thermal stress. To identify thermal tolerance of the range restricted kelp Lessonia corrugata, we conducted a laboratory experiment on juvenile sporophytes to measure performance (growth, photosynthesis) across its thermal range (4 – 22 °C). We found the upper thermal limit for growth and photosynthesis to be ~ 22 – 23 °C, with an optimum of ~ 16 °C. To determine if elevated inorganic nitrogen availability could enhance thermal tolerance, we compared performance of juveniles under low (4.5 µmol/day) and high (90 µmol/day) nitrate conditions at and above the thermal optimum (16 – 23.5 °C). Nitrate enrichment did not enhance thermal performance at temperatures above the optimum but did lead to elevated growth rates at the thermal optimum 16 °C. Our findings indicate L. corrugata is likely to be extremely susceptible to moderate ocean warming and marine heatwaves. Peak sea surface temperatures during summer in eastern and northeastern Tasmania can reach up to 20 – 21 °C and climate projections suggest that L. corrugata’s thermal limit will be regularly exceeded by 2050 as south-eastern Australia is a global ocean-warming hotspot. By identifying the upper thermal limit of L. corrugata we have taken a critical step in predicting the future of the species in a warming climate.
Data from multibeam echosounder surveys taken as part of the Ningaloo Outlook project were classified into various seafloor cover types according to their hardness, rugosity and depth. The classifications were validated with towed video ground truth where it was available. This dataset describes two AOIs which are explicitly part of the Ningaloo Outlook Deep Reefs project. Substratum classifications were applied using multibeam backscatter angular response curves along with rugosity as input to a maximum likelihood classifier. See original metadata record(s) and associated attached documents for accuracy estimates, alternate classification techniques, and additional surveyed areas. https://doi.org/10.25919/kssa-5b46 https://doi.org/10.25919/kttc-x397 https://doi.org/10.25919/8m65-7k26
The National Outfall Database (NOD) project addresses the need of government and community to understand the impacts on health and the ocean environment that occur from sewerage outfalls around Australia. This dataset is part of the assessment and mapping of the marine impacts of wastewater disposal to ocean and estuarine waters in Australia. The data collected in this study is intended to be used to assist decision makers to understand risk and prioritise investment, to help the public understand water and wastewater management and make decisions when choosing recreation locations, and private operators seeking to re-use wastewater or products found within wastewater. Each outfall is divided into three levels of data; one (1) being basic information such as location, treatment, governance and size; two (2) being more detailed information taken from publicly available annual environmental monitoring reports, licence and other information; and three (3) containing highly detailed information such as daily performance data and receiving waters ecosystem assessments and studies to enable researchers and others to undertake comparative studies. The data custodian will make a data report and methodology available to provide a full explanation of this database. The National Outfall Database is an online resource available here: https://www.outfalls.info/ The database currently tracks 38 indicators across 181 monitoring sites. The data is also available for download in CSV format in the "online resources" section of this record, and will continue to be updated as new data becomes available (data currently available to 30/06/2021 - last checked 20/02/2023.