Spatial Patterns of Macromolecular Composition of Phytoplankton in the Arctic Ocean

Keyseok Choe,Jinyoung Jung,Jaejoong Kang,Jaehong Kim,Sanghoon Park,Misun Yun,Naeun Jo,Jaesoon Kim,Sang Heon Lee,Eunjin Yang

doi:10.3390/w13182495

Keyseok Choe, Jinyoung Jung + Show 8 more

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https://doi.org/10.3390/w13182495

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Abstract

The macromolecular concentrations and compositions of phytoplankton are crucial for the growth or nutritional structure of higher trophic levels through the food web in the ecosystem. To understand variations in macromolecular contents of phytoplankton, we investigated the macromolecular components of phytoplankton and analyzed their spatial pattern on the Chukchi Shelf and the Canada Basin. The carbohydrate (CHO) concentrations on the Chukchi Shelf and the Canada Basin were 50.4–480.8 μg L−1 and 35.2–90.1 μg L−1, whereas the lipids (LIP) concentrations were 23.7–330.5 μg L−1 and 11.7–65.6 μg L−1, respectively. The protein (PRT) concentrations were 25.3–258.5 μg L−1 on the Chukchi Shelf and 2.4–35.1 μg L−1 in the Canada Basin. CHO were the predominant macromolecules, accounting for 42.6% on the Chukchi Shelf and 60.5% in the Canada Basin. LIP and PRT contributed to 29.7% and 27.7% of total macromolecular composition on the Chukchi Shelf and 30.8% and 8.7% in the Canada Basin, respectively. Low PRT concentration and composition in the Canada Basin might be a result from the severe nutrient-deficient conditions during phytoplankton growth. The calculated food material concentrations were 307.8 and 98.9 μg L−1, and the average calorie contents of phytoplankton were 1.9 and 0.6 kcal m−3 for the Chukchi Shelf and the Canada Basin, respectively, which indicates the phytoplankton on the Chukchi Shelf could provide the large quantity of food material and high calories to the higher trophic levels. Overall, our results highlight that the biochemical compositions of phytoplankton are considerably different in the regions of the Arctic Ocean. More studies on the changes in the biochemical compositions of phytoplankton are still required under future environmental changes.

Highlights

The Arctic Ocean is one of the most affected geographical locations in the world due to global climate change
In the areas of the Arctic Ocean where sea ice was absent, satellite observations have shown a significant increase in annual net primary production (NPP) [15,16,17]
This study reported the spatial distributions of macromolecular concentrations, compositions, and energy contents of phytoplankton on the Chukchi Shelf and in the Canada

Summary

Introduction

The Arctic Ocean is one of the most affected geographical locations in the world due to global climate change. In the Arctic, there has been a rapid decline of sea ice for several decades [1,2], which can be visualized by the downward trend of sea ice range through continuous satellite observations over the past decade [3,4,5]. Recent and rapid changes in the marine environment in the Arctic Ocean have been revealed to have significant impacts on the phytoplankton community [10,11,12]. Kahru et al [13] revealed that early phytoplankton blooms were caused by a decrease in sea ice in the Arctic Ocean. In the areas of the Arctic Ocean where sea ice was absent, satellite observations have shown a significant increase in annual net primary production (NPP) [15,16,17]. Other than the quantitative changes of phytoplankton, the physiological conditions of phytoplankton appear to be affected by the recent environmental conditions [18,19,20]

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