Resumen

MARINA, Tomás I; HERRERA-SILVEIRA, Jorge A  y  MEDINA-GOMEZ, Israel. Respuesta de la comunidad de fitoplancton y zooplancton al afloramiento de agua subterránea y surgencia costera en la península de Yucatán, México. Ecol. austral [online]. 2017, vol.27, n.2, pp.219-231. ISSN 1667-782X.

Groundwater discharges (GWD) and coastal upwelling are oceanographic phenomena that generate new hydrochemical conditions in coastal areas. The change in the composition and structure of the phytoplankton and zooplankton community under these conditions determines the dynamics of low trophic levels in marine-coastal ecosystems. The present study describes the phytoplankton and zooplankton community response to the hydrochemical framework in two coastal ecosystems influenced by these phenomena in the Yucatan peninsula, a tropical region. For this purpose, three field campaigns were conducted during 2012 (June, August and November), sampling 10 km extension transects. Temperature, salinity and dissolved oxygen were measured in situ. In addition, water samples were collected for the determination of dissolved inorganic nutrients (O₂, NO₃, NH₄, PO₄ y SiO₄) and chlorophyll a, and analysis of components of the plankton community. At the study site influenced by GWD (Dzilam de Bravo, 21°23'33'' N - 88°53'29'' O), increases in Copepod density (2484±890 org/L) synchronized with considerable decreases in the density of centric and pennate diatoms and dinofagellates (1600±1704, 8730±8951 y 22010±3557 cel/L, respectively) in November suggest that the phytoplankton community might be controlled by such zooplanktonic group during intensification of the discharges. On the other hand, the coastal upwelling of Cabo Catoche (21°36'21'' N - 87°06'12'' W) produced an increase in centric diatoms´ density (248000±126417 cel/L), which resulted in a clear dominance of this group in the period of intensification of the phenomenon, whereby dinofagellates dominate during relaxation of the upwelling. GWD in Dzilam de Bravo and coastal upwelling of Cabo Catoche generate diferential responses in the community of coastal plankton, infuencing the structure of such community and the relationships between its components.

Palabras clave : Community structure; Copepods; Diatoms; Dinoflagellates; Gulf of México; Hydrochemistry; Marine plankton.