Constraining the Movement of the Eastern Pacific Oxygen Minimum Zone Through Rapid Climate Transitions

EPA Grant Number: FP917196
Title: Constraining the Movement of the Eastern Pacific Oxygen Minimum Zone Through Rapid Climate Transitions
Investigators: Myhre, Sarah Butler
Institution: Sarah Lawrence College
EPA Project Officer: Michaud, Jayne
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Global Change

Objective:

In the context of modern climate change, the expansion of low oxygen waters along the continental margin of North America is an immediate conservation and management concern. This research will examine the history of the Eastern Pacific Oxygen Minimum Zone. The goal of the research is to fluidly couple climate science with deep-sea ecology and natural history in order to reconstruct how global-scale climate change determines ecosystem-scale structure and function.

Synopsis:

The distribution of dissolved oxygen in the ocean fundamentally defines the composition and ecology of benthic and pelagic ecosystems. In the context of modern climate change, the expansion of low oxygen waters along the continental margin of North American is an immediate conservation and management concern. In order to understand modern ecological change we must delve into historical analogues where ocean systems underwent changes in parallel to what is currently happening. This project will focus on the Eastern Pacific Oxygen Minimum Zone (OMZ) through the most recent and significant climate transition in the modern climate system: the shift from the cold glacial period into today’s modern, warm climate, which occurred from ~12-15,000 years ago (ka). The proposed research will utilize geochemical, ecological and sedimentary records to reconstruct the movement of low oxygen waters through rapid warming events. These data will broaden the existing scientific basis for interpreting both past and present ecological and oceanographic change along the Eastern Pacific OMZ, and provide a baseline from which to predict future OMZ conditions.

Approach:

This project will focus on the Eastern Pacific Oxygen Minimum Zone (OMZ) through the most recent and significant climate transition in the modern climate system: the shift from the cold glacial period into today’s modern, warm climate, which occurred from ~12 to 15,000 years ago (ka). Three recently acquired sediment cores from Santa Barbara Basin will be used to describe oceanographic and ecological changes in the Oxygen Minimum Zone in the past 20,000 years. This investigation will be established upon a suite of data, including radiocarbon dating, geochemical temperature proxies, and faunal record constructions (including protistan and invertebrate communities). This work will allow for core-to-core comparisons with a unified chronology and provide a foundation upon which to map ecological changes through rapid warming events. It will also provide the first reconstruction of benthic community responses to shifting oxygen concentrations that are driven by global-scale warming.

Expected Results:

The goal of this research is to understand the movement and ecology of the eastern Pacific Oxygen Minimum Zone (OMZ) during time periods of rapid global warming. Fundamental gaps exist in our current knowledge of how OMZs persist through time, what drives their contraction and expansion in the water column, how they are related to surface productivity regimes, and what role they play in shaping coastal biological communities. Because of this research vacuum, there are broad scientific implications for the research that I propose to conduct. Constraining the rate and magnitude of vertical expansion of the Eastern Pacific OMZ during the last 20,000 years will both describe the processes by which the modern eastern Pacific OMZ developed and provide an analytical basis on which to predict how the Eastern Pacific OMZ expansion will occur in the immediate future. Through this, I hope to broaden the existing scientific basis of the linkages between rapid global warming, changing oxygen concentrations, and benthic ecology.

Potential to Further Environmental/Human Health Protection:

This research is highly applicable to informing how conservation and management policy are established, because the future of both maritime economies and marine ecosystems in a changing ocean is dependent on the integration of climate and environmental science. Understanding the movement of Oxygen Minimum Zones is relevant to both marine management and coastal fishing economies. Because oxygen concentrations strongly organize marine communities, spatially explicit commercial fisheries policy and industrial development must incorporate low-oxygen zones as natural barriers to marine life. This investigation will provide policy makers and conservationists with the tools to make policy and management decisions, specifically in regards to activities within the Exclusive Economic Zone adjacent to the Pacific coast.

Supplemental Keywords:

climate change, oxygen, rapid warming events, benthic ecology, California Margin Oxygen Minimum Zone,, RFA, Scientific Discipline, Air, climate change, Oceanography, Air Pollution Effects, Environmental Monitoring, Atmospheric Sciences, Ecology and Ecosystems, Atmosphere, ecosystem models, extreme weather events, climate models, atmospheric oxidant concentrations, ecosystem sustainability

Progress and Final Reports:

  • 2011
  • 2012
  • Final