• Energy Research

This upload contains three datasets in CSV files and a PDF file with the specific description of the CSV files. These data was used for the analysis of the mass mortality events reported during the period 2015-2019 across the Mediterranean. The datasets are 1) a CSV file with the data used for the description of the spatial-temporal, depth and biological patterns of mortality observed in the Mediterranean Sea in the 2015-2019 period; 2) a CSV file with the data used to conduct the analyses on the relationship between marine heatwaves (MHW) days found on the surface (averaged per monitored area and year) and the corresponding mass mortality incidence of benthic organisms; 3) a CSV file with the data used to conduct the analyses on the relationship between in-situ MHW days (averaged per monitored area, depth and year) and the corresponding mass mortality incidence. Data were obtained through benthic community field surveys conducted by 33 research teams from 11 Mediterranean countries. Surveys covered thousands of kms of coastline, spanning 13º of latitude (32 °S to 45 °N) and 40º of longitude (-5°W to 35°E) in the Mediterranean Sea. The dataset provides the most updated inventory of mass mortality events records for benthic species between 2015-2019 in the region. The surveys were conducted in 142 monitoring areas. Monitoring areas were considered as geographic areas (10-25 km coastline, e.g., a marine protected area and the nearby coast) sharing common environmental features. In situ temperature conditions datasets base consists of high frequency (hourly) time series obtained using HOBO data loggers (accuracy ± 0.21°C) set-up at standard depths along rocky walls by divers, generally every 5 m from the surface to 40 m depth.This dataset as in the case of the mortality was assembled under the T-MEDNet initiative (www.t-mednet.org). Satellite derived sea surface temperature (SST) across the Mediterranean Sea was obtained from CMEMS (https://resources.marine.copernicus.eu/?option=com_csw&view=details&product_id=SST_MED_SST_L4_REP_OBSERVATIONS_010_021). The data consists of daily (night-time), gap free, optimally interpolated foundation SST at ~4 km resolution from AVHRR with improved accuracy and stability over the 1982-2019 period

Arctic marine ecosystems are experiencing rapid environmental change with respect to warming. This is leading to an increased frequency, duration, and intensity of marine heatwaves. The impact of these stochastic heatwave events have the potential to negatively effect temperature-sensitive, habitat forming, kelp, that exist in the lower Arctic region. We tested the potential impacts of two heatwave events on mixed kelp communities occurring in the lower Arctic by conducting a 1-month ex situ mesocosm experiment in Tromsø, Norway. Each mesocosm was stocked with ~ 2.5 kg fw (fresh weight) of kelp, 200 g fw of snails and mussels, and ~ 750 g of sea urchins. Three experimental conditions were tested: a constant high temperature which was + 1.76°C above a dynamic control, and two heatwave scenarios. Scenario 1 was a long duration at + 2.8°C above the control for 2 weeks, and scenario 2 was a high frequency and magnitude treatment with conditions + 3.8°C above the control. This occurred at two peaks that were one weak apart and returned to + 1.76°C in-between. Three-hour incubations were performed to examine net community productivity (NCP) for the mixed kelp communities. We identified that both heatwave scenarios diminished the total gross production over the experimental period compared to the control and between scenario 1 and scenario 2. Scenario 1 appeared to exhibit the lowest total gross community production over the experimental period.

Arctic marine ecosystems are experiencing rapid environmental changes with respect to warming, ice melt, and terrestrial run-off. The effects of these perturbations can act as multi-stressors where warming sea seawater, in combination with freshening from ice melt, and increased turbidity from terrestrial run-off affect benthic community structure and function. To examine the effects of warming, freshening, and turbidity on habitat forming macroalgae, we conducted a 2-month long ex situ experiment on mixed Arctic kelp communities in Ny-Ålesund, Svalbard from 03/07/2021 - 26/08/2021. Three experimental conditions (with 3x replicates) were tested against a dynamic real-time control where temperature was increased by + 3.3 and + 5.3 °C, salinity was reduced by ~ 4 and ~ 5, and irradiance was statically attenuated by ~ 25 and 40 % in 2 treatments. The third treatment was only warmed by + 5.3 °C from the control. In each 1 m³ mesocosm, oxygen (% O2), temperature, salinity, and photosynthetically active radiation (PAR) were continuously monitored. Mixed kelp communities comprised a biomass of ~ 4 kg fw (fresh weight) and ~ 500 g fw of small fauna. Weekly incubations were performed to calculate net community productivity (NCP) and used to estimate kelp benthic metabolism. We determined non-significant differences across treatments and provide NCP rates for mixed kelp communities in the Arctic.

AbstractThe risk of aquatic invasions in the Arctic is expected to increase with climate warming, greater shipping activity and resource exploitation in the region. Planktonic and benthic marine aquatic invasive species (AIS) with the greatest potential for invasion and impact in the Canadian Arctic were identified and the 23 riskiest species were modelled to predict their potential spatial distributions at pan‐Arctic and global scales. Modelling was conducted under present environmental conditions and two intermediate future (2050 and 2100) global warming scenarios. Invasion hotspots—regions of the Arctic where habitat is predicted to be suitable for a high number of potential AIS—were located in Hudson Bay, Northern Grand Banks/Labrador, Chukchi/Eastern Bering seas and Barents/White seas, suggesting that these regions could be more vulnerable to invasions. Globally, both benthic and planktonic organisms showed a future poleward shift in suitable habitat. At a pan‐Arctic scale, all organisms showed suitable habitat gains under future conditions. However, at the global scale, habitat loss was predicted in more tropical regions for some taxa, particularly most planktonic species. Results from the present study can help prioritize management efforts in the face of climate change in the Arctic marine ecosystem. Moreover, this particular approach provides information to identify present and future high‐risk areas for AIS in response to global warming.

AbstractClimate change is causing an increase in the frequency and intensity of marine heatwaves (MHWs) and mass mortality events (MMEs) of marine organisms are one of their main ecological impacts. Here, we show that during the 2015–2019 period, the Mediterranean Sea has experienced exceptional thermal conditions resulting in the onset of five consecutive years of widespread MMEs across the basin. These MMEs affected thousands of kilometers of coastline from the surface to 45 m, across a range of marine habitats and taxa (50 taxa across 8 phyla). Significant relationships were found between the incidence of MMEs and the heat exposure associated with MHWs observed both at the surface and across depths. Our findings reveal that the Mediterranean Sea is experiencing an acceleration of the ecological impacts of MHWs which poses an unprecedented threat to its ecosystems' health and functioning. Overall, we show that increasing the resolution of empirical observation is critical to enhancing our ability to more effectively understand and manage the consequences of climate change.