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Abstract: The timing of sea ice retreat, light availability, and sea surface stratification largely control the phytoplankton community composition in the Chukchi Sea. This region is experiencing a significant warming trend, an overall decrease in sea ice cover, and a documented decline in annual sea ice persistence and thickness over the past several decades. The consequences of earlier seasonal sea ice retreat and a longer sea-ice-free season on phytoplankton community composition warrant investigation. We applied multivariate statistical techniques to elucidate the mechanisms that relate environmental variables to phytoplankton community composition in the Chukchi Sea using data collected during a single field campaign in the summer of 2011. Three phytoplankton groups emerged that were correlated with sea ice, sea surface temperature, nutrients, salinity, and light. Longer ice-free duration in a future Chukchi Sea will result in warmer sea surface temperatures and nutrient depletion, which we conclude will favor other phytoplankton types over larger diatoms. Plain Language Summary: In the Chukchi Sea, the seasonality of sea ice shapes ecosystem structure of the water column under both sea-ice-covered and sea-ice-free conditions. As such, phytoplankton community composition under both conditions responds to water column structure and nutrient availability. Owing to recent warming in the Arctic, sea ice is thinner and retreats earlier. To date, we do not fully understand the long-term consequences of earlier sea ice retreat on phytoplankton community composition and carbon biomass. To this end, we used environmental and phytoplankton data to relate how differences in ecosystem function under sea-ice-covered and sea-ice-free conditions govern phytoplankton communities. The results from this data set suggest that a future, sea-ice-free Chukchi Sea will exhibit lower phytoplankton biomass, impacting the food web and carbon export.
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This content will become publicly available on December 1, 2026
Impact of glacial meltwater on phytoplankton biomass along the Western Antarctic Peninsula
Abstract The Western Antarctic Peninsula is undergoing rapid environmental change. Regional warming is causing increased glacial meltwater discharge, but the ecological impact of this meltwater over large spatiotemporal scales is not well understood. Here, we leverage 20 years of remote sensing data, reanalysis products, and field observations to assess the effects of sea surface glacial meltwater on phytoplankton biomass and highlight its importance as a key environmental driver for this region’s productive ecosystem. We find a strong correlation between meltwater and phytoplankton chlorophyll-a across multiple time scales and datasets. We attribute this relationship to nutrient fertilization by glacial meltwater, with potential additional contribution from surface ocean stabilization associated with sea-ice presence. While high phytoplankton biomass typically follows prolonged winter sea-ice seasons and depends on the interplay between light and nutrient limitation, our results indicate that the positive effects of increased glacial meltwater on phytoplankton communities likely mitigate the negative impact of sea-ice loss in this region in recent years. Our findings underscore the critical need to consider glacial meltwater as a key ecological driver in polar coastal ecosystems.
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- Award ID(s):
- 2224611
- PAR ID:
- 10611329
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Communications Earth & Environment
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2662-4435
- Subject(s) / Keyword(s):
- Glacial melt, Phytoplankton, Palmer LTER
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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