Mollusk Thanatocoenoses Unravel the Diversity of Heterogeneous Rhodolith Beds (Italy, Tyrrhenian Sea)

Emerging evidence of rhodolith bed complexity and heterogeneity poses a challenge to monitoring strategies and questions about the role of abiotic factors in controlling the observed morphostructural diversity. Mollusk thanatocoenoses quickly respond to environmental conditions, expressing fidelity to biocoenosis and representing, thus, a useful ecological/paleoecological tool to unravel this heterogeneity. In this research, we studied three distinct rhodolith beds from the Tyrrhenian Sea (Italy), in a range between 40 and 100 m of water depth, together with their mollusk thanatocoenoses, sediment size, and oceanographic conditions. The beds are all heterogeneous and rarely correspond to a specific rhodolith morphotype and shape. On the contrary, the study of the associated thanatocoenoses led to distinguish at least five different assemblages within the known variability of the Coastal detritic (DC) association. DC and deep mud (VP) mollusk species dominate hanatocoenosis A, which is associated with mixed sediment and a low hydrodynamic regime. Thanatocoenosis B corresponds to an assemblage in which DC species mixed with species of adjacent vegetated bottoms in sandy sediment with a medium hydrodynamic. Thanatocoenosis C includes species related to muddy coastal detritic (DE) and offshore detritic (DL) associated with sand and a variable proportion of praline and branch morphotypes. Thanatocoenoses D and E include a wide range of detritic species (DE DC, DL) together with VP and coralligenous (C), associated with exclusive praline and gravelly sand (Thanat. D), or a mixed proportion of branch and praline and mixed sediment (Thanat. E). Our results demonstrate that the study of mollusk thanatocoenoses provides insights into the diversity within and among heterogeneous rhodolith beds. Moreover, rhodoliths, as part of the sediment, create microhabitats suitable for a wide range of mollusk species that contribute to the formation of complex thanatocoenoses

Fast atmospheric response to a cold oceanic mesoscale patch in the north‐western tropical Atlantic

International audienc

The EUREC4A-Ocean/Atmosphere campaign: status

International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation

The EUREC4A-Ocean/Atmosphere campaign: status

International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation

The EUREC4A-Ocean/Atmosphere campaign: status

International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation

The EUREC4A-Ocean/Atmosphere campaign: status

International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation