Productivity in the barents sea--response to recent climate variability

Area of Science:

• Marine ecology
• Oceanography
• Climate change impacts

Background:

• The Barents Sea ecosystem exhibits significant interannual variations in temperature, open water area, chlorophyll a, and zooplankton biomass.
• Climatic variability is particularly pronounced in the northern and eastern regions of the Barents Sea.

Purpose of the Study:

• To examine the temporal and spatial dynamics of primary and secondary production in the Barents Sea since the late 1990s.
• To validate remote sensing products and model results using field observations of mesozooplankton biomass and chlorophyll a data.
• To identify key drivers influencing changes in net primary production and zooplankton biomass.

Main Methods:

• Utilized remote sensing data, in-situ observations, and a coupled physical-biological model.
• Validated satellite-derived chlorophyll a and model-based secondary production estimates with field data.
• Analyzed interannual variations in temperature, open water area, chlorophyll a, and zooplankton biomass.

Main Results:

• Satellite data effectively capture temporal and spatial dynamics of chlorophyll a; the model is crucial for estimating secondary production.
• Net primary production shows a moderate increase, likely an ecosystem response to climate change.
• Increased open water area and duration, linked to elevated temperatures, are key drivers of primary production changes in northern and eastern areas.
• Zooplankton biomass variability is primarily influenced by predation pressure.
• Statistically significant linkages between chlorophyll a and zooplankton biomass, and between net primary production and fish biomass, indicate bottom-up trophic interactions in the southeastern Barents Sea.

Conclusions:

• Climate warming and associated increases in open water are driving changes in Barents Sea primary production.
• Predation pressure significantly influences zooplankton biomass dynamics.
• Evidence supports bottom-up trophic control within the Barents Sea ecosystem, particularly in the southeastern region.