Assoc Prof Tom Trull
Program Leader, Ocean Control of Carbon Dioxide

03 6226 2988 or 03 6232 5268
tom.trull@acecrc.org.au
A/Prof Tom Trull, IASOS/CSIRO Marine Research
Project Leader, Ocean Control of Carbon Dioxide

03 6226 2988 or 03 6232 5069
tom.trull@acecrc.org.au
CO2-02: Carbon Export Processes

Project Overview

Deposition and storage of carbon dioxide (CO2) in the deep ocean, where it can remain for centuries, is one of the main ways to effectively remove excess anthropogenic CO2 from the atmosphere. Once absorbed into the ocean surface, CO2 is transferred to the deep ocean by two main mechanisms: ocean currents (the 'Physical Pump') and through sinking of particles containing carbon (particulate carbon) incorporated from CO2 by planktonic plants and animals (the 'Biological Pump'). Understanding the balance between CO2 in the atmosphere and the ocean, therefore, requires that we know the rates at which CO2 that is taken into the surface ocean is transferred to the deep ocean.

In this project, we are deriving estimates of rates of transfer of particulate carbon between the ocean surface and the deep sea. We are identifying the major processes that control these rates, and developing conceptual models of the sensitivity of these processes to climate variability and change. 

The overall outcome will be a clearer view of the role of the biological pump (the transfer of carbon to the deep sea in particulate form) in the Southern Ocean in regulating atmospheric CO2. This is a necessary step towards the development and verification of reliable carbon cycle models for the simulation of future atmospheric CO2 levels and thus future climate change. Understanding of the modern biological pump is also useful to aid in the interpration of past changes in the Southern Ocean environment, and thus their their application to estimating future changes.

Project Objectives

  • Determine particle fluxes to the deep sea, and their relationship to surface environmental and ecosystem conditions. 
  • Characterise mesopelagic (midwater) biogeochemical processes and their role in reducing the flux of particles to the deep sea and changing the character of the particles.
  • Develop 'proxy methods' from studies of modern sedimentation processes for use in the interpretation of sedimentary records of past climate and ecosystem conditions. 

Understanding the past is key to planning for the future and we need proxy methods to gain information about the past because we usually do not have direct measures of past conditions or events.  

National Collaborators

International Collaborators