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IPY: Shedding dynamic light on iron limitation: The interplay of iron limitation and dynamic irradiance in governing the phytoplankton distribution in the Ross Sea

Entry ID: NSF-ANT07-32535

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Summary

Abstract: IPY: Shedding dynamic light on iron limitation: The interplay of iron limitation and dynamic irradiance in governing the phytoplankton distribution in the Ross Sea. The Southern Ocean plays an important role in the global carbon cycle, accounting for approximately 25% of total anthropogenic CO2 uptake by the oceans, mainly via primary production. In the Ross Sea, primary production is dominated ... by two taxa that are distinct in location and timing. Diatoms dominate in the shallow mixed layer of the continental shelf, whereas the colony forming Phaeocystis antarctica (Prymnesiophyceae) dominate in the more deeply mixed, open regions. Significantly, both groups have vastly different nutrient utilization characteristics, and support very different marine food webs. Their responses to climate change, and the implications for carbon export, are unclear. Previous studies show that light availability and the quality of the light climate (static versus dynamic) play a major role in defining where and when the different phytoplankton taxa bloom. However, iron (Fe) limitation of the algal communities in both the sub-Arctic and the Southern Ocean is now well documented. Moreover, phytoplankton Fe demand varies as a function of irradiance. The main hypothesis of the proposed research is: The interaction between Fe limitation and dynamic irradiance governs phytoplankton distributions in the Ross Sea. Our strategy to test this hypothesis is three-fold: 1) The photoacclimation of the different phytoplankton taxa to different light conditions under Fe limitation will be investigated in experiments in the laboratory under controlled Fe conditions. 2) The photophysiological mechanisms found in these laboratory experiments will then be tested in the field on two cruises with international IPY partners. 3) Finally, data generated during the lab and field parts of the project will be used to parameterize a dynamic light component of the Coupled Ice Atmosphere and Ocean (CIAO) model of the Ross Sea. Using the improved model, we will run future climate scenarios to test the impact of climate change on the phytoplankton community structure, distribution, primary production and carbon export in the Southern Ocean. The proposed research complies with IPY theme "Understanding Environmental change in Polar Regions" and includes participation in an international cruise. Detailed model descriptions and all of the results generated from these studies will be made public via a DynaLiFe website. Improving the CIAO model will give us and other IPY partners the opportunity to test the ecological consequences of physiological characteristics observed in Antarctic phytoplankton under current and future climate scenarios. Outreach will include participation in Stanford's Summer Program for Professional Development for Science Teachers, Stanford's School of Earth Sciences high school internship program, and development of curriculum for local science training centers, including the Chabot Space and Science Center.

Related URL

Link: GET DATA

Description: Original data submitted.
GEOTRACES International Data Assembly Centre
Accession# NIO100280

Link: VIEW RELATED INFORMATION

Description: NSF Award Abstract #0732535

Geographic Coverage

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Spatial coordinates

N: -67.0

S: -76.0

E: -101.0

W: -130.0

Temporal Coverage

Start Date: 2007-10-01

Stop Date: 2010-09-30

Location Keywords

OCEAN > SOUTHERN OCEAN

GEOGRAPHIC REGION > POLAR

Science Keywords

OCEANS > OCEAN CHEMISTRY > NUTRIENTS

OCEANS > OCEAN CHEMISTRY > TRACE ELEMENTS

OCEANS > OCEAN CHEMISTRY > CHLOROPHYLL

ISO Topic Category

BOUNDARIES

Access Constraints Source

Ancillary Keywords

ADMINISTRATIVE BOUNDARIES

Boundaries > Boundaries

Originating Center

GRID-Bangkok

Data Center

Regional Resource Centre, Asia and the Pacific, United Nations Environment Programme

Data Center URL: http://www.rrcap.unep.org/

Data Center Personnel
Name: SURENDRA SHRESTHA Phone: (66-2) 5162124, 5245365 Fax: (66-2) 5162125, 5246233 Email: Surendra.Shrestha at unep.org Contact Address: UNEP Regional Resource Centre for Asia and the Pacific (UNEP RRC.AP) 3rd Floor, Outreach Building c/o Asian Institute of Technology (AIT) P.O. Box 4, Klongluang City: Pathumthani Postal Code: 12120 Country: THAILAND