Role of episodic events in the settling particulate matter composition and element fluxes in Alfonso Basin

The oceanic biogeochemical cycle creation requires settling particulate matter composition and vertical element flux quantification. This approach was conducted in Alfonso Basin, 410 m deep part of La Paz Bay, Gulf of California, with a desertic-arid limate. Settling particulate matter was collected each 7-15 days by an automated sediment trap during 2002-2008. Major and trace elements were determined using instrumental neutron activation analysis. The particles collected so far show that the total mass flux, composition and different particulate element fluxes show a high variability, not exactly coinciding with each other. Some element changeability seems to be influenced by different origin extraordinary events. Tropical cyclone effect was noted for "Ignacio" (24-26 August, 2003), "Marty" (21-23 September, 2003) and "Henriette" (4-5 September, 2007) hurricanes, on scandium composition, and represents the fluvial terrigenous input. Dust storm effect was found for scandium content and fluxes, related to increased aeolian input during strong northwestern winds on fall-winter. Plankton blooms in June and August of 2002 enhanced the calcium and bio-calcium content in settling particles. A reported silicoflagellate bloom during December, 2007 correlated with the highest particulate calcium and bio-calcium flux. Earthquake influence wasn't registered during the time period, even for a maximum 6.3 magnitude event.