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Sugar’s Role in Climate Change

Phytoplankton

Phytoplankton living in the surface waters of the oceans are responsible for absorbing up to 40% of all of the carbon that becomes incorporated into living things.

By Christel Hassler

Marine plankton account for up to 40% of carbon absorbed by all living things, but their growth is limited in half of the world’s oceans by iron bioavailability. New research has found that marine plankton can produce sugars that improve iron bioavailability – and hence plankton growth.

Christel Hassler is Chancellor's Post Doctoral Research Fellow with the University of Technology Sydney’s Plant Functional Biology and Climate Change Cluster. The research described here was a collaboration with the Royal Netherlands Institute for Sea Research, CSIRO, the Center for Australian Weather and Climate Research and New Zealand’s National Institute of Water and Atmospheric Research, and was published in the Proceedings of the National Academies of Science. Co-authors are V. Schoemann, E.C.V. Butler, C.A. Mancuso Nichols, M. Doblin, P.J. Ralph and P.W. Boyd.

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Phytoplankton living in the surface waters of the oceans are responsible for absorbing up to 40% of all of the carbon that becomes incorporated into living things, so their health, reproduction and productivity are of huge significance in regulating the amount of CO2 in the atmosphere.

Just like land plants and animals, the health of phytoplankton depends on access to trace elements and minerals such as zinc, cobalt and particularly iron. New research has found that the availability of iron to phytoplankton depends on complex sugars released by microorganisms, perhaps even by the phytoplankton themselves. The sugars interact with iron and provide it to the phytoplankton in a form they can use.

Iron is a critical micronutrient for phytoplankton. It plays a pivotal role in many of the enzymes and biochemical compounds that support critical biological functions such as photosynthesis and the uptake of other nutrients.

But large areas of our oceans, including the Southern Ocean, are defined as “high nutrient, low chlorophyll” (HNLC) regions where phytoplankton biomass is remarkably low despite containing high levels of nutrients. Most of these areas are extremely “anaemic” in iron, and this lack of iron restricts phytoplankton growth.

In other oceanic regions defined as “low nutrient, low chlorophyll” (LNLC) it is mostly the lack of nitrogen, in...

The full text of this article can be purchased from Informit.