Dynamics of the Spatial Chlorophyll-A Distribution at the Polar Front in the Marginal Ice Zone of the Barents Sea during Spring

Pavel R Makarevich,Veronika V Vodopianova,Aleksandra S Bulavina

doi:10.3390/w14010101

Abstract

Effects of the sea-ice edge and the Polar Frontal Zone on the distribution of chlorophyll-a levels in the pelagic were investigated during multi-year observations in insufficiently studied and rarely navigable regions of the Barents Sea. Samples were collected at 52 sampling stations combined into 11 oceanographic transects over a Barents Sea water area north of the latitude 75° N during spring 2016, 2018, and 2019. The species composition, abundance and biomass of the phytoplankton community, chlorophyll-a concentrations, hydrological and hydrochemical parameters were analyzed. The annual phytoplankton evolution phase, defined as an early-spring one, was determined throughout the transects. The species composition of the phytoplankton community and low chlorophyll-a levels suggested no phytoplankton blooming in April 2016 and 2019. Not yet started sea-ice melting prevented sympagic (sea-ice-associated) algae from being released into the seawater. In May 2018, ice melting began in the eastern Barents Sea and elevated chlorophyll-a levels were recorded near the ice edge. Chlorophyll-a concentrations substantially differed in waters of different genesis, especially in areas influenced by the Polar Front. The Polar Front separated the more productive Arctic waters with a chlorophyll-a concentration of 1–5 mg/m3 on average from the Atlantic waters where the chlorophyll-a content was an order of magnitude lower.

Highlights

IntroductionAbout half of all Atlantic waters penetrating the Arctic Basin flow through the Barents Sea. The other part enters the Arctic Ocean directly through the Fram Strait [1]
The Barents Sea lies in the area whereby the Atlantic water flux intrudes into the ArcticOcean
Researchers distinguish several frontal zones across the Barents Sea water area located along the pathway of Atlantic water advection into the Arctic Basin [4,5,6,7]

Summary

Introduction

About half of all Atlantic waters penetrating the Arctic Basin flow through the Barents Sea. The other part enters the Arctic Ocean directly through the Fram Strait [1]. The Atlantic water flowing through the Barents Sea transforms more slowly. It can be traced even at the eastern border of the Barents Sea [3]. Researchers distinguish several frontal zones across the Barents Sea water area located along the pathway of Atlantic water advection into the Arctic Basin [4,5,6,7]. The Polar Frontal Zone is well traced throughout the year. It mainly separates Atlantic waters from Arctic waters

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Discussion

Conclusion