Annual trend patterns of phytoplankton species abundance belie homogeneous taxonomical group responses to climate in the NE Atlantic upwelling. (September 2015)

• Record Type: Journal Article
• Authors: Bode, Antonio; Estévez, M. Graciela; Varela, Manuel; Vilar, José A.
• Is Part Of: Marine environmental research. Volume 110(2015:Sep.)
• Page Start: 81
• Page End: 91
• Publication Date: 2015-09
• Subjects: Biodiversity -- Series -- Plankton -- Climate -- Upwelling; Marine pollution -- Environmental aspects -- Periodicals; Marine ecology -- Periodicals; Mer -- Pollution -- Aspect de l'environnement -- Périodiques; Écologie marine -- Périodiques; Electronic journals; 577.705
• DOI: 10.1016/j.marenvres.2015.07.017
• Languages: English
• ISSNs: 0141-1136

Abstract

Abstract: Phytoplankton is a sentinel of marine ecosystem change. Composed by many species with different life-history strategies, it rapidly responds to environment changes. An analysis of the abundance of 54 phytoplankton species in Galicia (NW Spain) between 1989 and 2008 to determine the main components of temporal variability in relation to climate and upwelling showed that most of this variability was stochastic, as seasonality and long term trends contributed to relatively small fractions of the series. In general, trends appeared as non linear, and species clustered in 4 groups according to the trend pattern but there was no defined pattern for diatoms, dinoflagellates or other groups. While, in general, total abundance increased, no clear trend was found for 23 species, 14 species decreased, 4 species increased during the early 1990s, and only 13 species showed a general increase through the series. In contrast, series of local environmental conditions (temperature, stratification, nutrients) and climate-related variables (atmospheric pressure indices, upwelling winds) showed a high fraction of their variability in deterministic seasonality and trends. As a result, each species responded independently to environmental and climate variability, measured by generalized additive models. Most species showed a positive relationship with nutrient concentrations but only a few showed a direct relationship with stratification and upwelling. Climate variables had only measurable effects on some species but no common response emerged. Because its adaptation to frequent disturbances, phytoplankton communities in upwelling ecosystems appear less sensitive to changes in regional climate than other communities characterized by short and well defined productive periods. Highlights: Stochastic variability dominated phytoplankton species abundance in the Galician upwelling. Species responses largely unrelated to taxonomical or functional groups. Only a few species showed direct relationships with climate, stratification or upwelling intensity. Independent response of species to nutrient inputs favored by relative climate and oceanographic stability. Phytoplankton in upwelling ecosystems well adapted to changes in climate.