Distribution of dinoflagellate cysts in surface sediments from the northeastern Pacific Ocean (43–25°N) in relation to sea-surface temperature, salinity, productivity and coastal upwelling

Abstract

Fifty-six surface sediment samples from the northeastern Pacific (43–25°N) were investigated in order to examine the spatial distribution of modern organic-walled dinoflagellate cysts in relation to hydrological conditions and marine productivity. The analyzed dinoflagellate cyst assemblages are diverse, and include over 60 taxa. Multivariate statistical analysis (CCA) of dinoflagellate cysts and environmental variables identifies annual productivity and sea-surface temperature as main factors affecting dinoflagellate cyst distribution in the region. In the studied area, marine productivity is greatly influenced by the strength of the coastal upwelling. Cyst assemblages from the coastal sites associated with active upwelling are characterized by the dominance of heterotrophic taxa, particularly Brigantedinium spp., Echinidinium spp. and cysts of Protoperidinium americanum. Taxa associated with low productivity offshore sites are Impagidinium spp., Nematosphaeropsis labyrinthus, Pyxidinopsis reticulata and Operculodinium centrocarpum. Dinoflagellate cyst species associated with warmer waters are Lingulodinium machaerophorum, Spiniferites mirabilis, S. ramosus, S. delicatus/bulloideus, Bitectatodinium spongium and Polykrikos cf. kofoidii, while those from cooler environments include Selenopemphix nephroides, Trinovantedinium variable and cysts of Pentapharsodinium dalei. Combining the present cyst dataset with other published cyst data from the Northeastern Pacific, we have compiled a “NE Pacific 188” database. This database can be used as a basis for the quantitative reconstructions of (paleo)temperature and productivity in the Northeastern Pacific.