CADIC   02618
CENTRO AUSTRAL DE INVESTIGACIONES CIENTIFICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Hydrography, circulation and suspended particle distribution in Ushuaia Bay and the Beagle Channel
Autor/es:
MARTIN DO NASCIMENTO, JACOBO; BOURRIN, F; MALITS, ANDREA; FLORES MELO, X; DURRIEU DE MADRON, X; LOVRICH, G.
Lugar:
Viena
Reunión:
Congreso; EGU General Assembly; 2019
Institución organizadora:
EGU
Resumen:
The Beagle Channel and in particular Ushuaia Bay, are subantarctic environments where mixing processes between oceanic and continental waters, and strong land-to-sea exchanges of water and particulate matter are takingplace. Multiple sources of particulate matter to the channel can be identified: glaciers, rivers, direct runoff fromforests along steep slopes next to the seashore, marine primary production as well as an anthropogenic contributionrelated to navigation and human settlements, especially the city of Ushuaia. This study is a preliminary assessmentof suspended matter concentrations, composition, distribution and particle size spectra in Ushuaia Bay and theneighbouring Beagle Channel for two contrasting hydrographic settings: late summer stratified and late winterunstratified conditions. The relationships of the nephelometric and particle spectra results are compared with themain hydrographic features. Intermediate nepheloid layers evolving into bottom nepheloid layers are recurrentlyobserved on the slopes of the 150-m deep drowned glacier valley that occupies the eastern half of Ushuaia Bay.These relatively turbid layers are associated with relative oxygen minima that in certain years result in a hypoxicarea developing in the deep valley. The volumic size spectra of suspended particles is dominated by aggregatesof few tens to few hundreds microns. Particle size spectra show a bimodal distribution in the austral winter thattends to unimodal in the austral summer, in concordance with the vertical structure of the water column: seasonalhalocline separates both particle pools in summer while winter mixing homogenizes them.