Observations and modelling of plankton dynamics in a tropical upwelling region, Cabo Catoche, Mexico

REYES-MENDOZA, OSCAR; MARIÑO-TAPIA, ISMAEL; HERRERA-SILVEIRA, JORGE ALFREDO; MARINA, TOMÁS IGNACIO; RUIZ, GABRIEL

Congreso; 17th Ocean Sciences Meeting; 2014

In the northeast of the Yucatan Peninsula a dynamic upwelling event occurs between spring and summer, which enriches the otherwise oligothrophic waters, generating phytoplankton growth and enhancing the food web process. During spring and summer 2012, two intensive field experiments were carried out at the site which included CTD profiling, Photosynthetic Active Radiation (PAR), water samples for nutrients and plankton, and two moorings (installed at 8 and 15 m depth) for physical (waves and currents) and environmental parameters (CTD, turbidity, chlorophyll, oxygen). Results clearly show the start and end of upwelling pulses and the associated trigger in biological productivity. The pulses are observed to occur every 13 days, and intense northerly winds can suppress the whole process. The in-situ information was then used to construct a Nitrogen-Phytoplankton-Zooplankton model (NPZ). The model fairly accurately reproduced the observed response of the plankton to the upwelling nutrient input. After this validation, the model was used for experimenting with the nutrient input and oceanographic conditions to better understand the ecosystem dynamics that lead to such high biological productivity and phytoplankton bloom formation.