title: Dynamics in benthic community composition and influencing factors in an upwelling-exposed coral reef on the Pacific coast of Costa Rica.
abstract: Seasonal upwelling at the northern Pacific coast of Costa Rica offers the opportunity to investigate the effects of pronounced changes in key water parameters on fine-scale dynamics of local coral reef communities. This study monitored benthic community composition at Matapalo reef (10.539°N, 85.766°W) by weekly observations of permanent benthic quadrats from April 2013 to April 2014. Monitoring was accompanied by surveys of herbivore abundance and biomass and measurements of water temperature and inorganic nutrient concentrations. Findings revealed that the reef-building corals Pocillopora spp. exhibited an exceptional rapid increase from 22 to 51% relative benthic cover. By contrast, turf algae cover decreased from 63 to 24%, resulting in a corresponding increase in crustose coralline algae cover. The macroalga Caulerpa sertularioides covered up to 15% of the reef in April 2013, disappeared after synchronized gamete release in May, and subsequently exhibited slow regrowth. Parallel monitoring of influencing factors suggest that C. sertularioides cover was mainly regulated by their reproductive cycle, while that of turf algae was likely controlled by high abundances of herbivores. Upwelling events in February and March 2014 decreased mean daily seawater temperatures by up to 7 °C and increased nutrient concentrations up to 5- (phosphate) and 16-fold (nitrate) compared to mean values during the rest of the year. Changes in benthic community composition did not appear to correspond to the strong environmental changes, but rather shifted from turf algae to hard coral dominance over the entire year of observation. The exceptional high dynamic over the annual observation period encourages further research on the adaptation potential of coral reefs to environmental variability.
authors.affiliation: Leibniz Center for Tropical Marine Ecology , Bremen , Germany ; Faculty of Biology and Chemistry, University of Bremen , Bremen , Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Stuhldreier
authors.affiliation: Leibniz Center for Tropical Marine Ecology , Bremen , Germany ; Centro de Investigación en Ciencias del Mar y Limnología, Universidad de Costa Rica , San Pedro, San José , Costa Rica.
authors.forename: Celeste
authors.initials: C
authors.lastname: Sánchez-Noguera
authors.affiliation: Leibniz Center for Tropical Marine Ecology , Bremen , Germany ; Faculty of Biology and Chemistry, University of Bremen , Bremen , Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Roth
authors.affiliation: Centro de Investigación en Ciencias del Mar y Limnología, Universidad de Costa Rica , San Pedro, San José , Costa Rica ; Energy, Environment and Water Research Center, Cyprus Institute , Nicosia , Cyprus.
authors.forename: Carlos
authors.initials: C
authors.lastname: Jiménez
authors.affiliation: Leibniz Center for Tropical Marine Ecology , Bremen , Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Rixen
authors.affiliation: Centro de Investigación en Ciencias del Mar y Limnología, Universidad de Costa Rica , San Pedro, San José , Costa Rica.
authors.forename: Jorge
authors.initials: J
authors.lastname: Cortés
authors.affiliation: Leibniz Center for Tropical Marine Ecology , Bremen , Germany ; Faculty of Biology and Chemistry, University of Bremen , Bremen , Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wild
keywords: Community dynamics; Coral reef; Costa Rica; Eastern Tropical Pacific; Gulf of Papagayo; Phase shift; Upwelling