Summer zooplankton assemblages in the Barents Sea: Spatial variations and effects of environmental conditions as revealed from in situ and satellite data

Abstract

The Barents Sea is a productive region that is experiencing significant climatic fluctuations, making it essential to assess the impact of warming on the local ecosystems by summarizing information on different ecosystem components during various conditions and preceding trends. Our study aimed to reveal spatial patterns in the distribution and structure of zooplankton assemblages along a latitudinal gradient in summer 2013, a warm year, following the colder 2012. Cluster analysis grouped stations into three distinct categories based on the prevailing types of water masses, with higher abundance in colder waters due to the spring phase of plankton succession and higher biomasses in warmer waters. Boreal species were indicative of the southern and central sectors of the sea, while Arctic species and Copepoda nauplii were indicative of high-latitude stations. To elucidate the complex interplay between water mass characteristics, dynamics of nutrient conditions, and zooplankton community structure, both in situ and remote sensing data were used, with the latter covering a two-month period prior to sampling. Water temperature was identified as the primary factor influencing zooplankton assemblages, while nutrient concentrations, along with water currents, also played significant roles in controlling total abundance and biomass. Significant associations between environmental drivers and zooplankton variables were found when using lagged data, highlighting the importance of prior conditions for pelagic communities and shedding light on the underlying mechanisms driving zooplankton distribution and abundance patterns. This study provides valuable insights into the plankton ecology and community dynamics and creates a basis for further elucidating the effects of climate shifts on Arctic marine ecosystems.