Abstract

HERNANDEZ-TRUJILLO, Sergio et al. Mesozooplankton grazing on phytoplankton in La Paz Bay B. C. S., Mexico. Hidrobiológica [online]. 2007, vol.17, n.3, pp.225-231. ISSN 0188-8897.

During October 2002 a time series was generated to measure the daily grazing rates of mesozooplankton, it was recorded the changes of the chlorophyll a concentration at a station in La Paz Bay, Mexico. The grazing coefficient (g), phytoplankton growth coefficient (k), clearance rate (F), and ingestion rate (I) were estimated as initial reference for the study area. Grazing rates presented values ranging from 0.72^-1 to 2.74 ind·d^-1; phytoplankton growth coefficient ranked from 0.03 to 0.76 d^-1 Clearance rate was from 11.9 to 45.6 ml·ind^-1·d^-1, and the ingestion rate fluctuated from 5.2 to 18.4 Cla·ind^-1·d^-1. The mesozooplankton was capable of remove 1.0 to 43 % of potential daily production. The ingestion and clearance rates had similar daily variation pattern along the study; phytoplankton growth coefficient values were lower than grazing rate. The results showed that mesozooplankton might consume about 17% of phytoplankton production in this coastal area. This assessment on mesozooplankton feeding at La Paz Bay is a step to a better understanding of the plankton dynamic in this subtropical area.

Keywords : Grazing rate; clearance rate; ingestion rate; zooplankton.