HR: 09:15h
AN: OS51D-06    [Abstracts]
TI: Fine Resolution Termohaline Structure Of The Yuctatan Coastal Sea
AU: Marino-Tapia, I
EM: imarino@mda.cinvestav.mx
AF: Ismael Marino-Tapia, Carretera Antigua a Progreso KM6 Apdo. Postal 73 CORDEMEX, Merida, YUC 97310, Mexico
AU: * Enriquez-Ortiz, C
EM: cenriquez@mda.cinvestav.mx
AF: Ismael Marino-Tapia, Carretera Antigua a Progreso KM6 Apdo. Postal 73 CORDEMEX, Merida, YUC 97310, Mexico
AU: Capurro, L
EM: lcapurro@mda.cinvestav.mx
AF: Ismael Marino-Tapia, Carretera Antigua a Progreso KM6 Apdo. Postal 73 CORDEMEX, Merida, YUC 97310, Mexico
AU: Euan-Avila, J
EM: euan@mda.cinvestav.mx
AF: Ismael Marino-Tapia, Carretera Antigua a Progreso KM6 Apdo. Postal 73 CORDEMEX, Merida, YUC 97310, Mexico
AB: In the Yucatan peninsula there are a variety processes that drastically affect the thermohaline structure of the coastal seas. Some of these include hyperhaline lagoons that export salt to the ocean, upwelling events that propagate to the coast, persistent submarine groundwater discharges, and very high evaporation rates caused by the intense solar radiation. On July 2006 a fine resolution oceanographic campaign was performed on the Yucatan coast to study the detailed structure of thermohaline processes and currents from the shore to the 10 m isobath. A total of sixty nine transects that cover the entire northern stretch of the Yucatan coast were made. The transects extend seven kilometers in the offshore direction and have an alongshore spacing of 5 km. The temperature and salinity characteristics of the water column were monitored with a SEABIRD SBE 19 CTD performing profiles every 500 m along each transect. Ocean currents were measures along the same transect using a 1.5 MHz Acoustic Doppler Profiler (Sontek). The results clearly show the effects of coastal lagoons on the adjoining sea, with net salt export associated with hyperhaline lagoons (e.g. Ria Lagartos) or more estuarine influence of lagoons such as Celestun, where groundwater discharges play the role of rivers on the estuary. An assessment of this influence on the coastal ocean will be presented. It is well known the meteor impact at the end of the Cretacic era at Chicxulub, Yucatan, generated a crater with multiple rings which is evident from horizontal gravity gradients of the Yucatan mainland, and that associated with the outer ring there is a high concentration of cenotes (sinkholes) (Pope et al. 1991; Hildebrand, et al. 1995). It has also been shown that groundwater flows along this cenote ring towards the ocean, and the zones where the ring intersects the coast (Celestun and Dzilam Bravo) have impressive geologic features known as ‘submarine water springs' where freshwater springs as a fountain in the ocean. Additional (higher resolution) field campaigns have been performed in the vicinity of such features. Results will be presented where the effect of such intense submarine groundwater discharges (SGD) on the coastal ocean of the Yucatan is evident. The salinity in the surrounding areas of the SGD sites can vary from 10 to 26 psu, this is a substantial effect when considering that the background coastal salinity ranges between 35 to 36 psu. The salinity signal also shows that SGD events in some regions of the Yucatan coast can alter the ambient salinity dramatically and be momentarily more important than those SGD associated with the cenote ring. Pope K.O. et al. 1991. Nature. Mexican site for K/T impact crater? V-351, 105. Hildebrand, A.R. et al. 1995. Nature. Size and structure of the Chicxulub crater revealed by horizontal gravity gradients and cenotes. V-376. p. 415-417.
DE: 4500 OCEANOGRAPHY: PHYSICAL
DE: 4536 Hydrography and tracers
DE: 4546 Nearshore processes
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly