The Role of Changing Polar Phytoplankton Communities in Global Carbon Cycling

EPA Grant Number: F13E20897
Title: The Role of Changing Polar Phytoplankton Communities in Global Carbon Cycling
Investigators: Joy-Warren, Hannah
Institution: Stanford University
EPA Project Officer: Lee, Sonja
Project Period: September 22, 2014 through September 22, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text |  Recipients Lists
Research Category: Fellowship - Oceanography , Academic Fellowships


Harmful algal bloom (HAB) species pose both an environmental and human health threat. Some species of Phaeocystis are considered HAB species due to their large, productive blooms and subsequent oxygen depletion during cellular degradation. Phaeocystis is found throughout the world’s oceans and its large blooms contribute substantially to global carbon cycling, however the biogeochemical dynamics that mediate Phaeocystis populations are not yet fully understood. This research will help to understand the mechanisms, including light and nutrient availability, that govern whether Phaeocystis populations dominate the natural phytoplankton assemblage in polar regions.


This research will be conducted through fieldwork in the Arctic and Antarctic during the phytoplankton growing season. Fieldwork will include analysis of the natural phytoplankton communities and measurements of physiological parameters through both field population measurements and shipboard incubation experiments. Field data will be coupled with satellite remote sensing. This will provide a greater spatial and temporal perspective on the contribution of Phaeocystis to global biogeochemical cycling.

Expected Results:

Phaeocystis is an environmentally and biogeochemically important genus that differs from other phytoplankton groups (such as diatoms) in its nutrient requirements, thereby playing a different role in the ecosystem. Phaeocystis can uptake more carbon per unit of phosphorus than the globally averaged phytoplankton carbon-to-phosphorus uptake ratio. As a result, Phaeocystis is uniquely efficient at removing carbon from surface waters, thus enhancing air-sea carbon dioxide exchange. Nutrient avail- ability affects the distribution of different phytoplankton species and alters the community composition. Given the different nutrient require- ments for Phaeocystis and diatoms, a different community composition could have a large effect on local and global biogeochemical cycling and, more specifically, the carbon cycle.

Potential to Further Environmental/Human Health Protection

Understanding Phaeocystis population dynamics and its role in global biogeochemical cycling is essential to understanding the changing carbon cycle. With increasingly rapid changes occurring in the polar regions, it is essential to understand how natural phytoplankton communities will respond and how this response will further alter global carbon cycling and, more generally, global biogeochemical cycles.

Supplemental Keywords:

carbon cycling, harmful algal blooms, polar regions

Progress and Final Reports:

  • 2015
  • Final