Draft 3 Global Climate Change and Primary Productivity

This topic submitted by Jenny Gatt and Kari Panza ( Gattje@Muohio.edu and Panzake@muohio.edu ) on 4/1/04 .

Global Climate Change -Western Program-Miami University

Abstract:
We propose to look at a possible solution to higher Carbon Dioxide levels in the atmosphere. Carbon emissions are at an all time high and much of it is due to humans and the burning of fossil fuels. Higher carbon emissions add significantly to the greenhouse effect and global warming. We are going to look at a specific case of primary production in the ocean, and how it can help lower levels of carbon in the atmosphere through photosynthesis. This process is known as iron fertilization, which involves the manipulation of marine phytoplankton by adding their limiting nutrient, iron, to the ocean waters, heavily increasing their productivity and, in turn, taking more carbon in through the process of photosynthesis. We intend to gather as much data and statistical evidence to weigh the effects of this process on the atmosphere as well as the marine ecosystems. We will look at the levels of primary productivity of the phytoplankton to determine weather this process will have a significant enough effect on greenhouse gas reductions in the atmosphere and the slowing of global climate change.

Introduction:
Will oceanic iron fertilization be effective in significantly reducing global temperatures through the sequestering of carbon from the atmosphere without seriously harming or altering marine ecosystems? We predict that oceanic iron fertilization has the potential to significantly decrease global temperatures. Through our research we plan to investigate not only the benefits but also the possible consequences of putting large amounts of iron in to the ocean. We will look at data from places where this has method has been used and weigh the pros and cons to see if this is truly an effective way to slow global climate change.

We will investigate benefits such as the slowing of global warming, extracting carbon from the atmosphere, and creating a large carbon source at the ocean floor, and find out exactly how much a positive impact it could have. Also, there are negative effects that need to be considered such as throwing off natural marine ecosystems, changing levels of the nutrient availability, and how effective it would be considering the limited amounts of sunlight available. By looking at the pros and cons we hope to form an strong opinion either for or against iron fertilization and have a reasonable amount of information to back it up.

The relevance of our investigation of iron fertilization is to possibly find a way to slow climate change. Carbon Dioxide in the atmosphere is one of the many factors affecting the increasing global climate. The process of photosynthesis helps balance carbon dioxide levels in the atmosphere by taking in the carbon dioxide and releasing oxygen. So, globally, primary productivity greatly influences climate changes. If primary production increases, then we may be able to stop the increasing temperature depending how much we can raise it. Iron fertilization is one of our first attempts to control the climate.

Relevance:

Global warming is occurring whether due to natural earth cycles or human pollution, and the major reason is what is known as Òthe greenhouse effect.Ó Scientists have found that the biggest culprit among these greenhouse gases is carbon dioxide thatÕs produced by the burning of fossil fuels, such as coal. The greenhouse effect is the rise in temperature that the Earth experiences because certain gases found in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun. The entire process is similar to that of a green house, thus the name Ògreenhouse effectÓ, which is a major cause of global warming in recent years.
Carbon Dioxide is the most frequent greenhouse gas and is having the biggest effect. CO2 concentrations in our atmosphere have steadily risen from 280 ppm (before the industrial revolution) to a concentration of about 370 ppm according to the EPA. If we continue this rate of
emissions, this number is expected to double in the next fifty to one hundred years. This rise in Carbon in our atmosphere will have a direct effect on the primary productivity, or the amount of energy produced by plants and other photosynthetic organisms.

In the process of photosynthesis, carbon is needed in the production of the 2 bi-products:
glucose and oxygen. The overall reaction is: 6H2O + 6CO2 ----> C6H12O6+ 6O2. Photosynthesis is the set of processes by which plants acquire energy from sunlight and fix carbon from the atmosphere. The plant then uses the organic molecules (glucose) that it forms for its own metabolic needs. This process takes place in chloroplast cells of the leaves in a two step process: the light reactions and carbon fixation. The light reactions occur in the thylakloid membranes in the interior of the chloroplasts. The thylakoid membranes exist in structures called grana stacks that are connected by stroma thylakoids. The molecules that are involved in capturing light are in two molecular complexes, made up of accessory pigments, known as photosystem I and photosystem II. Photons of light enter these molecule complexes and move through them via resonance transfer, until they are captured by the chlorophyll molecules. The now "excited" chlorophyll molecule passes an "excited" electron, which is gained from water, to an electron receptor. From here the excited electron is passed from photosystem II to photosystem I, while at the same time producing ATP. Then in Photosystem I the electron produces NADPH. In the dark reactions is where CO2 comes in to play. It is taken in from the atmosphere and via the energy in ATP and NADPH that were produced in the light reactions it is used to make glucose (Gurevitch).

There are three different types of photosynthesis. C3 photosynthesis occurs in the majority of plants. In the initial steps of the calvin cycle CO2 is joined with a five-carbon molecule, to form a six-carbon compound that instantly separates into two three carbon molecules. Therefore, it is named C3. The next type of of photosynthesis is referred to as C4 photosynthesis. Prairie grasses make up the majority of C4 species. In this type of photosynthesis the first stable product of carbon fixation is a four carbon molecule. The last type of photosynthesis is Crassulacean Acid Metabolism (CAM). This type of photosynthesis evolved especially for desert and dry regioned plants. At night the plant opens its stomata to capture CO2. This way during the day when the light reactions are occuring it can keep its stomata closed, allowing for a decrease in water loss (Gurevitch).

There are two possible solutions to this rise in CO2: decrease emissions or increase sinks. In most of the journals and websites we have looked at scientists have agreed that photosynthesis could be a major solution to high levels of carbon dioxide in the atmosphere. High CO2 increases
primary productivity of terrestrial plants, according to several journal sources.

With that much said, we now turn to the productivity of the ocean primary producers such as phytoplankton and algae. In a website created by the University of Michigan Global Change Project they discuss many aspects of iron fertilization. Scientists recently thought of the concept of iron fertilization to suck in a large amount of the Carbon in our atmosphere. Could the answer lie in the deliberate nutrient fertilization of large areas of relatively unproductive open ocean? This type of fertilization could create large phytoplankton blooms that could consume large amounts
of atmospheric CO2, and possibly slow the effects of global warming according to this site. When the carbon is sequestered from the atmosphere scientists hope that the remains of the phytoplankton will sink to the bottom, to create a large carbon reserve, which will keep the carbon from being recycled in to the atmosphere. In the Southern Ocean, there have been three open-ocean iron-enrichment experiments. All three produced increases in biomass and associated decreases in dissolvedinorganic carbon and macronutrients. These experiments allow an initial assessment of the export efficiency and the size of ocean area affected, both of which are needed to determine whether iron fertilization can be an effective mitigation strategy (Buesseler).

Materials and Methods:

The topic of global climate change provides many sources for our specific research idea. We will use these sources and refine our search to information pertinent to the effects of global climate change on primary productivity, specifically detailed data on photosynthesis, carbon intake, and how these relate to other organisms in the environment. In addition, we will further our search to include the few, but very relevant experiments in oceanic iron fertilization. After covering this broad basis we intend to answer, if possible, our question: How does oceanic iron fertilization affect marine species and/or ocean metabolism?
We intend to obtain large amounts of data through articles, the internet, and PDF files. Hopefully, through a wide basis of resources we can come to some conclusion that is supported evidentially.

These are our predictions for what we will discover as we further research this topic.
We predict the relationship between increasing CO2 and primary producer growth to be positive. Of the articles we have researched so far, there seems to be significant evidence that plant growth, both terrestrial and aquatic, increases as atmospheric CO2 increases.

We predict the relationship between oceanic iron fertilization and marine life health will be negative. We feel our research will uncover the negative effects of oceanic iron fertilization, such as the shifting of the limiting nutrient or algae blooms, will cause a decrease in marine species health.

Our timeline of research will consist of establishing our general research concept, forming a hypothesis, gathering information from a well rounded base of sources, analyze the data, graphs, and information from those sources, formulating results, and then form an opinion on the benefits/disadvantages of oceanic iron fertilization.

Bibliography:

Journals:

Benemann, J.R. The use of iron and other trace element fertilizers in mitigating global warming. Journal of plant nutrition. 15, no. 10 (1992): pp.2277-2313.
This article has specific information on the nature of iron as a limiting nutrient

Behrenfeld, Michael J.; Bale, Anthony J.; Kolber; Zbigniew S.; Aiken, James; Falkowski, Paul G. Conformation of iron limitation of phytoplankton photosynthesis in the equatorial Pacific Ocean. Nature (London) 383(6600), (1996): pp.508-511.
This article gives us a specific example to work with

Buesseler, Ken O. and Boyd, Phillip W. Will Ocean Fertilization Work? Science. April 4, 2003. vol. 300 Issue 5616, P67.
This source provides specific data on three experiments
Steinberg, Paul A.; Millero, Frank J.; Zhu, Xiaorong. Carbonate system response to iron enrichment. Marine Chemistry. 62(1-2) (1998): pp.31-48.
This article is pretty technical, but we feel if we can sift through it we will find helpful information on the chemical level

Raven JA; Falkowski PG. Oceanic sinks for atmospheric carbon dioxide. Plant, Cell and Environment. 22, no. 6 (June 1999): pp.741-755.
This article is pretty general but helps to give us a more well-rounded idea

Websites:
http://jrscience.wcp.muohio.edu/climatechange03/ProposalArticles/draft2.primaryproductivit.html
This is the website for the people who did our topic last year. we like the diagrams

http://earthobservatory.nasa.gov/Library/Phytoplankton/
This has good information on phytoplankton

http://maritime.haifa.ac.il/departm/lessons/ocean/lect26.htm

http://www.whrc.org/science/carbon/carbon.htm

http://www.ucsusa.org/global_environment/global_warming/page.cfm?pageID=529
Good information on general global warming

http://www-personal.umich.edu/~rstey/Site%20files/Introduction.html

http://www.whoi.edu/media/iron.html

Book:

Gurevitch, Scheiner, Fox. The Ecology of Plants. Sinauer Associates. MA. 2002.
This text book provides very critical background information on photosynthesis

PDF:
Pena, Angelica M. " Modelling the response of the planktonic food web to iron fertilization and warming in the NE Subartic Pacific." Progress in Oceanography, Vol 57, Issue 3-4, (2003):pp.453-479
Good source because it is a specific example

Cooper, D.J.; Watson, A.J.; Nightingale, P.D. "Large decrease in ocean-surface CO2 fagacity in response to insitu iron fertilization." Oceanographic Literature Review, Vol 44, Issue 3,(1997):pp.198.
A little technical, but good information once it is sorted out

Coale, K.H.;Johnson, K.S.;Fitzwater,S.E. "A massive phytoplankton Bloom induced by an eco-system-scale iron fertilization experiment in equatorial Pacific Ocean." Oceanographic Literature Review, Vol 44, Issue 3, (1997):pp.234.
Good negative information

Dufour,P; Berland,B. "Nutrient control of phytoplankton biomass in atoll lagoons and pacific ocean waters; studies with factoral enrichment bioassays." Journal of experimental Marine Biology and Ecology, Vol 234, Issue 2, (1999):pp.147-166.
Good because it also includes iron fertilization of lagoons

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