Monterey Bay Aquarium Research Institute
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Marine Chemistry


GonyaulaxNutrients are organic and inorganic forms of Carbon, Nitrogen, Phosphorus, and many other elements. Nutrient cycles are influenced by biological, geographical, geological, and chemical processes. For example, in coastal systems nitrogen is present as molecules that range from dissolved gases to complex biological proteins. Inputs of nitrogen include N2 fixation in the water column, and run-off from land. Export includes biochemical reactions in the sediment that release nitrogen gas and fishing or aquaculture that remove organic nitrogen.

Even relatively simple ecosystems are difficult to study because of the money and time required for scientific research. Coastal environments are both spatially and temporally dynamic, and therefore long term and carefully planned observations and experiments are the only was to make sense of the changing conditions. Not surprisingly, few studies are able to accomplish all of these tasks, and therefore researchers must make the best of their partial knowledge to characterize the biogeochemical cycles of a given study area.

During this unit, students will use real- and near-real-time data to explore the significance of oceanic iron fertilization, including the potential positive and negative effects of activating the biological pump.

Nutrient Cycle Activities | Back to top

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The Biological Pump

This slide show will take students step-by-step through the processes that are involved the biological pump.  Students will be encouraged to think about how the availability of nutrients such as nitrate and iron affect the amount of carbon dioxide that is eventually sequestered in the deep oceans.
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The SOFeX Expedition

This activity will help students understand the rationale, questions, research, technology and people involved in the Southern Ocean Iron Experiment (SOFeX) Cruise in 2002.
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Graphing Iron Data

This activity will help students understand how scientists assess the impacts of iron on ecosystem processes. Students will look at a spreadsheet of data collected from buoys in Monterey Bay. 


Nutrient Cycles in the news | Back to top

ScienceNews: (03/15/10)
Iron fertilization in ocean nourishes toxic algae

ScienceDaily: (01/29/09)
Iron Fertilization To Capture Carbon Dioxide Dealt A Blow: Plankton Stores Much Less Carbon Dioxide Than Estimated

Oceanus: (11/13/07)
Fertilizing the Ocean with Iron
(First article in a six-part series)

Science Daily: (06/10/07)
Iron Fertilization Of Oceans: A Real Option For Carbon Dioxide Reduction?

USA Today: (04/02/07)
Project aims to ‘seed’ oceans to heal them

Science Daily: (03/01/07)
Iron in Northwest Rivers Fuels Phytoplankton, Fish Populations

Web Resources | Back to top

MBARI—Southern Ocean Iron Experiment (SOFeX) Cruise
This cruise report page hosts information about the purpose, equipment and people involved in the SOFeX project, designed to investigate the effects of iron fertilization on the productivity of the Southern Ocean.

US Joint Global Ocean Flux Study (USJGOFS)
This site provides information on research and publications of this component of an international effort to further global climate research.  Includes a data section with Live Access Server to allow viewers to select data for investigation and analysis.  Their brochure also includes an excellent diagram and explanation of the biological pump.

Southern Ocean Iron RElease Experiment (SOIREE)
Another cruise report from an earlier attempt at oceanic iron fertilization, this site includes information on rationale, procedures and results of the experiments, as well as participating scientists and institutions.

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Last updated: Jul. 09, 2012