Mesoscale Eddies and Upwelling Filaments Around the O'Higgins Seamount (32.8°S and 73.8°W), Chile
Understanding the oceanographic processes around seamounts (SMs) is a crucial aspect for the conservation and management of the vulnerable ecosystems associated with them in the eastern South Pacific, though at present little knowledge is available. The O'Higgins SM (OH-SM) is one of the closes...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2020 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/246040 |
| Acceso en línea: | https://hdl.handle.net/10533/246040 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Naturales Ciencias de la Tierra y del Medio Ambiente Otras Especialidades de la Biología |
| Sumario: | Understanding the oceanographic processes around seamounts (SMs) is a crucial aspect for the conservation and management of the vulnerable ecosystems associated with them in the eastern South Pacific, though at present little knowledge is available. The O'Higgins SM (OH-SM) is one of the closest to the coastal upwelling zone off central Chile and, therefore, it is expected to be under a strong influence of mesoscale processes generated in the coast. In this study, the frequencies of spatial and temporal variability in the area of the OH-SM (30-35ºS, 72-76ºW), the frequency of interaction of mesoscale eddies (MEs) and upwelling filaments (UFs) from the coast with the OH-SM, and the effects of such interaction on the physical and biogeochemical properties of the water column around the OH-SM, were examined. Satellite time series (2003 to 2015) of wind stress and wind stress curl, satellite altimetry, sea surface temperature, and ocean color were analyzed, together with in situ data from an oceanographic cruise (spring 2015) around OH-SM. Results show that the study region is dominated by inter-annual (~2.56 years) fluctuations associated with El Niño-Southern Oscillation, annual and semi-annual fluctuations associated with the propagation of Rossby waves, and by fluctuations with periods of ~160 and ~120 days associated with MEs. Waters of the OH-SM were influenced by coastally-originated MEs and UFs on 57% of the total days in the time series. The mesoscale structures that usually interact with the OH-SM originate between 32° and 34°S, where the interaction of MEs with opposite rotation stimulates the generation of the UFs that arrive to the OH-SM. MEs arriving to the OH-SM interacted with it for periods close to one month, whereas the UFs did so during half that time. In situ data indicated that an intrathermocline eddy (ITE) contributes to modify the physical and biogeochemical properties of the water column around the OH-SM. These findings highlight that the ecosystem that harbors the OH-SM could be benefitted by the arrival of coastal nutrient-rich waters through MEs (surface and subsurface) and UFs, as well as by the disturbance of the pycnocline associated to the pass of Rossby waves, which could enhance the primary productivity. All these mechanisms being able to play a key role in sustaining this highly vulnerable marine ecosystem. |
|---|