Abstract/Description/Artist Statement

Phytoplankton blooms form the foundation of the Antarctic marine food web and play a critical role in regional carbon cycling. Recent observations along the West Antarctic Peninsula indicate shifts in bloom phenology, the seasonal timing of biological events in nature, with accumulation seasons occurring later in recent decades. This study investigates how different variability in spring wind speed influences phytoplankton bloom start dates and peak dates across five ecological regions of the West Antarctic Peninsula.

Bloom timing is derived from 25 years of satellite-based chlorophyll-a observations, including annual start date and peak date. Wind speed data derived from atmospheric reanalysis products is produced as an annual average of July through June conditions, which is referred to Antarctic Summer Bloom to represent the southern hemisphere austral seasonal cycle. By comparing years characterized by higher versus lower wind speeds, this study evaluates whether wind driven mixing alters bloom development.

We hypothesize that elevated wind speeds delay bloom initiation and peak timing by deepening the mixed layer and reducing light availability for phytoplankton growth. On the other hand, years with weaker winds are expected to promote earlier stratification and earlier bloom onset. Regional differences are examined to determine whether offshore, shelf, and marginal ice zone environments respond differently to wind forcing.

Understanding how wind speed regulates phytoplankton bloom phenology is essential for predicting future ecosystem responses in a region experiencing rapid climate driven changes in sea ice and atmospheric circulation.

Presenting Author Name/s

Alizana M Cummings

Faculty Advisor/Mentor

Jessie S. Turner

Faculty Advisor/Mentor Email

jturners@odu.edu

Faculty Advisor/Mentor Department

Ocean and Earth Sciences

College/School Affiliation

College of Sciences

Student Level Group

Undergraduate

Presentation Type

Poster

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The Influence of Wind Speed on Phytoplankton Bloom Timing in Antarctica's 5 regions

Phytoplankton blooms form the foundation of the Antarctic marine food web and play a critical role in regional carbon cycling. Recent observations along the West Antarctic Peninsula indicate shifts in bloom phenology, the seasonal timing of biological events in nature, with accumulation seasons occurring later in recent decades. This study investigates how different variability in spring wind speed influences phytoplankton bloom start dates and peak dates across five ecological regions of the West Antarctic Peninsula.

Bloom timing is derived from 25 years of satellite-based chlorophyll-a observations, including annual start date and peak date. Wind speed data derived from atmospheric reanalysis products is produced as an annual average of July through June conditions, which is referred to Antarctic Summer Bloom to represent the southern hemisphere austral seasonal cycle. By comparing years characterized by higher versus lower wind speeds, this study evaluates whether wind driven mixing alters bloom development.

We hypothesize that elevated wind speeds delay bloom initiation and peak timing by deepening the mixed layer and reducing light availability for phytoplankton growth. On the other hand, years with weaker winds are expected to promote earlier stratification and earlier bloom onset. Regional differences are examined to determine whether offshore, shelf, and marginal ice zone environments respond differently to wind forcing.

Understanding how wind speed regulates phytoplankton bloom phenology is essential for predicting future ecosystem responses in a region experiencing rapid climate driven changes in sea ice and atmospheric circulation.