Global Warming, The Carbon Cycle, and Fish Poop

http://scienceblogs.com/authority/2009/01/global_warming_the_carbon_cycl.php

Posted on: January 16, 2009 11:25 AM, by Mike Dunford

When we talk about the role of fossil fuels in climate chance, what we're really talking about is the carbon cycle. That's the term that scientists use to describe the different forms that carbon is stored in on the earth, and the different ways that it can move from form to form. Understanding the carbon cycle is one of the keys to understanding both the effect of burning carbon-based fuels and the issues involved in trying to take carbon dioxide out of the atmosphere. According to a paper in the latest edition of Science, there may still be some pretty significant gaps in our knowledge of the carbon cycle. In particular, it looks like our understanding of the way carbon moves through the oceans may have been suffering because we didn't know poop about fish poop.

Before we get down to the gritty details and talk about what poop has to do with anything, it might be good to start with a quick review of the carbon cycle. Actually, it might be even better to start with a quick review of one of those concepts that we all learn in third-grade physics, but don't think about much in our day to day world: the law of conservation of mass/matter.

Matter is not created or destroyed. Therefore the amount of mass in a closed system will remain constant no matter what happens.

Like most things in science, that might be a bit of a simplification, but when we're looking at something the size of the Earth, it's good enough. Relativity, quantum mechanics, and space dust might all complicate things a bit, but not enough to matter. For our purposes, we can reasonably assume that all the carbon that we're putting into the atmosphere in the form of carbon dioxide has been here since the earth was formed, and that if we want to take the carbon dioxide back out of the atmosphere, we're going to have to find somewhere on this planet to store the carbon.

With that in mind, let's look at the some of the more important ways that carbon can move through the crust, oceans, and biosphere, and atmosphere.

Source: NASA via Wikimedia.

Carbon can be found in the atmosphere in a few forms, the most important of which is carbon dioxide. It can be found on land and in the crust in any number of forms, both as organic compounds in living organisms and their remains (including the range of fossil fuels) and in rocks and soils as inorganic minerals like calcium carbonate. It can be found in the oceans as dissolved carbon dioxide, dissolved minerals, and in organisms that live in the oceans.

Carbon can be released into the atmosphere in a number of different ways. Carbonate rocks, for example, can produce carbon dioxide through natural weathering processes, and volcanoes can release carbon dioxide from magmas. At this point in the history of the earth, though, we know what the biggest cause of carbon dioxide entering the atmosphere is - and he is us.

It's possible that our entire success as a species has been the result of our learning how to use a particular chemical reaction:

Organic carbon + Oxygen = Carbon Dioxide + Water + Energy

For most of human history, we were mostly burning plant matter in relatively small quantities, so this wasn't a huge deal. The organic carbon in question had mostly come from photosynthesis, and most of it would have been released as carbon dioxide anyway - we use, along with lots of other living things, use that same chemical reaction when we produce our own energy.

The Industrial Revolution changed that. We started to burn fossil fuels - coal, petroleum products, and natural gas. The carbon that's in the fossil fuels comes from the remains of plants that pulled it out of the atmosphere and fixed it as organic compounds. Most plants, when they die, decompose and their carbon is released back into the atmosphere. The same thing happens to most animals. But not all. Some living things get fossilized after they die.

The thing is, we don't have lots of fossil fuel because lots of things get turned into fossils all the time. We have lots of fossil fuel because there's been a lot of time for things to get turned into fossil fuels. These are deposits of carbon that were formed very slowly, over tens and hundreds of millions of years. Left to themselves, these deposits would have been released back into the atmosphere through weathering and other natural processes over similarly long periods of time. We're taking these deposits that were formed over intervals of tens and hundreds of millions of years, and we're burning them over periods of tens to hundreds of years.

If you think that we're not pumping fossil-fuel derived carbon dioxide into the atmosphere millions of times faster than it would get there on its own, I'd suggest that you go back and look at the two bits of boldfaced text earlier in this article.

The increase in carbon dioxide in the atmosphere is leading to an increase in the amount of heat that we're retaining from the sun because carbon dioxide is a greenhouse gas - it traps energy that would otherwise have radiated out into space.

Now that we've figured out that this is a real problem - the odd conservative ideologue notwithstanding - we've started to try and find ways to fix the problem, while still producing enough energy to drive our modern world. A wide variety of solutions have been proposed, many of which involve continuing to burn fossil fuels, but trapping and storing the carbon dioxide that's produced. In fact, there's a coal plant in Germany that's started doing just that.

The German plant is storing (or at least planing to store) the carbon dioxide by injecting it into a depleted oil field, but another storage site that's frequently proposed is the deep ocean. At depth, the ocean is undersaturated with respect to carbon dioxide, which is a fancy way of saying that it can hold more than it currently does. That means, it's been suggested, that we can take the carbon dioxide from fossil fuel combustion and pump it down into the deep ocean through really long pipes.

And this, finally, brings us to the gut of the matter. And to fish poop.

The I haven't talked about it much yet, but the ocean is involved in the carbon cycle. Things like the depth at which the ocean is no longer carbon-dioxide saturated are determined by the chemistry of the ocean, and by the way carbon moves through the seas. An article that was just published in the journal Science by Wilson et al. suggests that we may not have known as much about the oceanic carbon cycle as we thought we did.

In particular, we might not have considered the impact that billions of fish can have, just by living, drinking, and pooping.

You see, the internal environment of a fish contains a higher concentration of water (and lower concentration of salt) than the ocean does. As we all learned at some point in school, this means that water is going to tend to move from the fish back into the ocean. This is the same process that's in play when salt is poured on a slug, and even in the ocean the effects would be similar if the fish weren't able to somehow counteract it.

Fish counteract the tendency of water to leave their body by actively pulling more water in. Fish drink like fish. But, because they're drinking saltwater, they need to do something to pull out the salts. In the case of the calcium and magnesium, they precipitate it out in their guts by forming inorganic calcium and magnesium carbonate crystals. What happens to these "piscine carbonates" is entirely predictable, as Wilson et al. point out:

Carbonate precipitates formed in the gut are excreted either within discrete mucus-coated tubes or pellets, or incorporated with feces when fish are feeding. The organic mucus-matrix is rapidly degraded in natural seawater, leaving only inorganic crystals of CaCO³ with high magnesium content (Mg:Ca ratio ranging from 10 to 33 mol %)
[endnotes omitted]

The importance of this effect is a bit less obvious. There's a lot less fish than plankton, after all, so how important is it really likely to be? The answer is a bit surprising. The authors did a range of calculations based on a number of different estimates of both fish biomass and the rate of production of "piscine carbonates":

To calculate the teleostean contribution to oceanic carbonate budgets requires knowledge of global marine fish biomass. We used two entirely independent models to describe the size composition and abundance of marine fish across the global oceans, one by using a size-based macro-ecological approach and the other by using Ecopath software. The fish biomass estimates generated for each size-class and the relevant average local sea temperatures were then combined with individual fish carbonate excretion rates to predict global fish CaCO3 production ranging from 3.2 x 10¹² to 8.9 x 10¹² mol year^-1 (0.04 to 0.11 Pg of CaCO₃^-C year^-1). This range accounts for 2.7 to 15.4% of estimates for total global new CaCO³ production in the surface oceans.

[endnotes omitted]

In simple terms, the authors of the paper have just informed us that we may not have noticed a process that's responsible for a substantial amount of the carbon movement in the oceans. That's kind of a big deal (which would explain the Science article).

The effect that climate change is going to have on this particular form of carbon movement is not entirely clear (at least to me), nor is the effect that this might have on climate change. "Not none" is probably a reasonable guess, and I'm sure that we'll learn more in the future.

What is clear is that this shows us something that we would be advised to remember when we start to talk about things like pumping a gajillion tons of CO₂ into the oceans:

Do we really want to take chances messing around with things that we might not know piscine carbonates about?

Reference:

R. W. Wilson, F. J. Millero, J. R. Taylor, P. J. Walsh, V. Christensen, S. Jennings, M. Grosell (2009). Contribution of Fish to the Marine Inorganic Carbon Cycle Science, 323 (5912), 359-362 DOI: 10.1126/science.1157972

Wetland Restoration: The Best Alternative to Carbon Capture and Sequestration Technologies?

Image from doortoriver

While widespread wetland destruction could unleash the mother of all "carbon bombs," scientists are discovering that the restoration of these vulnerable ecosystems could provide a valuable bulwark to climate change by creating a worldwide network of potent carbon sinks. A $12.3 million research project to capture and store carbon by growing tules and cattails in wetlands launched by the U.S. Geological Survey this summer has already shown some promising results, according to Environmental Science & Technology's Janet Pelley:

The USGS project has captured eye-popping amounts of carbon—an average of 3000 grams of carbon per square meter per year (g-C/m2/yr) over the past 5 years. For comparison, reforested agricultural land, eligible for carbon credits under the Kyoto Protocol on climate change, socks away carbon at a rate much less than 100 g-C/m2/yr, says Gail Chmura, a biogeochemist at McGill University (Canada).

Image from Dvortygirl

Saltwater marshes provide biggest cooling potential
The USGS researchers determined that saltwater marshes provided the most bang for the buck. Wetlands are great at storing carbon dioxide because of their near-constant water cover, which prevents oxygen from entering the muddy soil; this effectively keeps bacterial decomposition, a process which releases a lot of CO2 (this is one of the reasons why permafrost thawing is so worrisome), to a minimum.

In fact, unperturbed wetlands are so effective that their peat soils can sometimes be 60 ft deep and over 7,000 years old. The project, which started out in California's Sacramento-San Joaquin River Delta, will be expanded to determine whether the restored wetlands can help regain the land elevation lost when the delta island was drained a century ago and to see whether "wetland carbon credits" could be sold on the state's upcoming carbon market.

Concerns remain over methane release
This all sounds well and good, but some scientists are urging caution, pointing out that the project has yet to provide reliable figures for the amount of methane emissions being released. Though they may not cancel out the beneficial cooling effects of the wetlands' carbon storage, the emission levels could still be relatively significant -- especially on a large scale.

One reason for concern, according to University of Florida biogeochemist Ramesh Reddy, is that the same low oxygen to anoxic conditions that favor carbon storage also favor the release of methane. Even if the bacteria can't access oxygen, they can use iron oxides, CO2 or sulfate as sources of electron acceptors. Using CO2 produces methane emissions.

This makes saltwater marshes all the more appealing, says Chmura:

Because saltwater is high in sulfate, microbes in saltwater marshes don’t have to use CO2 as an electron acceptor, and therefore they produce negligible amounts of methane, Chmura says. She estimates that North American salt marshes sequester an average of 210 g-C/m2/yr. These hefty rates, along with an ability to accrete carbon faster as the sea level rises, make saltwater marshes ideal sites for restoration and carbon storage, she says.

Restoring ecosystems and naturally sequestering carbon dioxide? Sounds like a plan. Kudos to Florida for getting the ball rolling on what will (hopefully) be an international trend in the coming years.

Via: ES&T: Can wetland restoration cool the planet?

More about wetlands
Destruction of Wetlands Could Unleash a "Carbon Bomb"
Florida to Buy Back Wetlands from U.S. Sugar
Wetland ‘Carbon Bomb’ Has One of Its Wires Cut: Democratic Republic of Congo Creates World’s Largest Protected Wetland

Restoration of saltwater marshes is a sure bet for sequestering carbon

http://carbon-based-ghg.blogspot.com/2008/10/restoration-of-saltwater-marshes-is.html

Wednesday, October 22, 2008

ACS Publications: Wetlands are champions at carbon storage, but they also release methane, a greenhouse gas 20 times more potent than CO2. Scientists are boosting research efforts to determine whether the cooling power of carbon storage outstrips the global warming potential of methane in wetlands. They are finding that the greatest cooling occurs from saltwater marshes.

This summer, the U.S. Geological Survey (USGS) announced that it was launching a $12.3 million project to capture carbon by growing tules (a species of sedge also known as bulrushes) and cattails in wetlands created on abandoned farmland on islands in California’s Sacramento−San Joaquin River Delta. Two months later, the carbon-storing capacity of wetlands headlined 2 days of workshops at the September 16 meeting of the Association of State Wetland Managers in Portland, Ore. The USGS project has captured eye-popping amounts of carbon—an average of 3000 grams of carbon per square meter per year (g-C/m2/yr) over the past 5 years. For comparison, reforested agricultural land, eligible for carbon credits under the Kyoto Protocol on climate change, socks away carbon at a rate much less than 100 g-C/m2/yr, says Gail Chmura, a biogeochemist at McGill University (Canada).

Wetlands capture carbon by incorporating CO2 from the air into new plant growth, explains Roger Fujii, a soil chemist with USGS. When the plant material dies, near-constant water cover keeps oxygen out of the rich mud, slowing decomposition that would otherwise emit CO2. Undisturbed wetlands are so effective at accreting carbon that their organic peat soils can be 60 feet deep and 7000−10,000 years old, he says. USGS is now expanding the delta project to see whether it can regain the land elevation lost since farmers drained the delta island marshes 100 years ago, causing the soil to decompose, emit CO2, and subside, Fujii says. A secondary goal is to find out whether the extraordinary carbon storage capacity of the tule and cattail “farms” could be sold as carbon credits on California’s upcoming CO2 cap-and-trade market, he says....

The Sacramento-San Joaquin River Delta covers the right half of this image. Matthew Trump created this image, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2

Wetland ‘Carbon Bomb’ Has One of Its Wires Cut: Democratic Republic of Congo Creates World’s Largest Protected Wetland

http://www.treehugger.com/files/2008/07/congo-creates-worlds-largest-protected-wetland.php

Congo River photo by LM TP via flickr.

Scientists warned the world last week that due to human interference in wetlands, a potential 'carbon bomb' is waiting to go off. As wetlands are increasingly drained due to urban sprawl or expansion of agricultural lands the 771 billion tons of carbon dioxide sequestered begins to be released. Now, thanks to action by the Democratic Republic of Congo, at least some of that sequestered carbon will remain out of the atmosphere.

Wetland Twice the Size of Belgium Protected
Announced yesterday, the Ngiri-Tumba-Maindombe region of the DR Congo has become the world’s largest area of protected wetland. The 65,696 square kilometer region is located around Lake Tumba, the largest body of freshwater in Africa.

Speaking about the importance of the region, a local WWF representative said, “The Ngiri-Tumba-Maindombe area contributes to the regulation of flooding are regional climate and ensures the quality of the water remains good enough for the millions of people who depend on it.”

The protected region has one of the highest concentrations of biodiversity in the world, acts as buffer zone for flooding of the Congo River, as well being utilized for agricultural purposes.

The previous world record holder in the World’s Largest Protected Wetland category was Canada’s Queen Maud Gulf at 62,782 square kilometers.

via :: ENS

Wetlands
Destruction of Wetlands Could Unleash a “Carbon Bomb”
Kenyan Biofuel Expansion in Wetland Halted by Court, Temporarily
Florida to Buy Back Wetlands from U.S. Sugar

Marine conservation introduced as a climate solution

Q: How was marine conservation was introduced as a climate solution?

A: Through a series of meetings I organized in Washington, DC, between April 9 and 16, 2008, with Greenpeace USA, Conservation International, The Ocean Foundation, White House CEQ, Heinz Center, and the World Bank.

References:

Lutz, M. 2008a. Overfishing has reduced ocean CO2 sequestration. Powerpoint presentation to Greenpeace USA. April 2008. Greenpeace USA, Washington D.C.
Lutz, M. 2008b. Overfishing has reduced ocean CO2 sequestration. Powerpoint presentation to Conservation International. April 2008. Conservation International, Arlington, Virginia.
Lutz, M. 2008c. Overfishing has reduced ocean CO2 sequestration. Powerpoint presentation to The Ocean Foundation. April 2008. The Ocean Foundation, Washington D.C.
Lutz, M. 2008d. Overfishing has reduced ocean CO2 sequestration. Powerpoint presentation to White House Council on Environmental Quality CEQ. April 2008. The White House, Washington D.C.
Lutz, M. 2008e. Overfishing has reduced ocean CO2 sequestration. Powerpoint presentation to Heinz Center for Science, Economics and the Environment. April 2008. Heinz Center for Science, Economics and the Environment. Washington D.C.
Lutz, M. 2008f. Overfishing has reduced ocean CO2 sequestration. Powerpoint presentation to World Bank Global Program on Fisheries (PROFISH) Steering Committee. April 2008. The World Bank, Washington D.C.
Lutz, M. 2008g. Overfishing has reduced ocean CO2 sequestration. [Pamphlet]. Author’s personal collection (Lutz S), Arendal, Norway. 1 pp.

(This post has been backdated)

Reforesting mangroves + mitigating global warming

http://newsinfo.inquirer.net/inquirerheadlines/regions/view/20080305-122814/Reforesting-mangroves--mitigating-global-warming

By Yolanda Sotelo-Fuertes
Philippine Daily Inquirer
First Posted 00:22:00 03/05/2008

BOLINAO, Pangasinan – They only wanted to stop the destruction and degradation of marine resources – their main source of livelihood – in Bolinao, Pangasinan, but in their own little way, they are helping mitigate the serious problem of global warming.

Members of Kaisaka (Kaisahan ng mga Samahan Alay sa Kalikasan or Union of Organizations for the Environment), a federation of 10 village-based fishermen’s groups, have replanted 74 hectares of mangroves, established eight marine sanctuaries with a total area of 90 hectares, and helped implement livelihood projects and formulate the town’s coastal development plan.

“There was a rapid reduction in our income because the fish were fast disappearing. Illegal fishing was rampant and the corals were mostly dead,” Jesem Gabatin, Kaisaka board chair, said. “Old residents had told us that our town used to have thick mangrove forests, but these were depleted because the areas were turned into fishponds. The mangroves were cut and used as housing materials or firewood.”

Gabatin, one of the organizing pioneers, said all he knew then was that he wanted to help stop the environmental degradation. “It was only later that we found that we were helping abate global warming.”

Vested interest

Nileema Noble, resident representative of the United Nations Development Program in the Philippines, assured the fishermen that nothing was wrong with starting projects laden with “vested interests.”

“As human beings, we do things with our vested interest first,” Noble said when she visited Bolinao to monitor projects of the Sagip Lingayen Gulf Project (SLGP) of the Marine Environment Resources Foundation Inc.

In the island town of Anda, Mayor Nestor Pulido said people who had reforested the mangrove areas several years ago were already reaping the fruits of their labor.

When a storm surge hit the town in November last year, houses in the coastal villages were spared because of the presence of mangroves. People have also learned that mangrove areas are nurseries for fish.

Noble said she was “impressed” by the projects of the fishermen, whom she described as “not scientists but people with a lot of common sense.” She called on local officials to consider global warming in all their development projects.

Mangroves absorb carbon dioxide sent into the atmosphere by industries and other human activities. “Through photosynthesis, mangroves absorb carbon from the atmosphere and store it in all their parts, just like any terrestrial (land) plants. But unlike terrestrial plants, mangroves store carbon in the sediments as well. Less Carbon means low global warming,” said Severino Salmo, a mangrove researcher pursuing a doctoral degree in marine science at the University of Queensland in Australia.

A hectare of mangrove forest can absorb around 20 tons of carbon each year, Salmo said.

But Noble said the fishermen’s efforts were not enough to counter global warming. “It is a problem that should be addressed on international, provincial, community, individual levels. All of us [should] contribute in reducing global warming,” she said.

Early days

Cesar Junsan, president of Kaisaka, said it was in 1995 when the Marine Environment Resources Foundation (MERF) and the local government started the community-based coastal resources management (CBCRM).

Seeds for marine development projects were sown, including the formation of five grassroots organizations and the establishment of a mangrove reforestation site in Barangay Pilar and a protected area in Balingasay.

In 1997, the CBCRM project was stopped. “We coordinated with the local government to survive. When we had meetings, we all contributed to buy our snacks,” Gabatin said.

The fishermen started planting mangroves in Pilar and Arnedo, two of the four original member-villages of Kaisaka. The others are Binabalian and Balingasay.

The next year, the MERF and the Haribon Foundation resumed implementation of the CBCRM project until 2002. The Asian Social Institute, provincial government, the Bolinao Marine Ecological Fund Foundation and Glaxo-Smith Klein, a pharmaceutical firm, contributed to the mangrove rehabilitation efforts.

Kaisaka became a partner of the SLGP for the implementation of the CBCRM programs and other activities in 2002. The original four groups increased to 10 when more villages joined the federation.

Challenges

Challenges were plenty along the way, said Annabelle Echavez, Kaisaka secretary. She cited an incident when a resident asked then Bolinao Mayor Jesus Celeste to stop fishermen from planting mangroves in a proposed fishpond site.

“The mayor sent somebody to stop us. With muddied feet, we trooped to his office and explained what we were doing. In the end, he told us to go on planting,” Echavez said.

In 2004, Kaisaka obtained P2.5 million from the UNDP for the mangroves projects and sanctuaries.

The fishermen learned some lessons in planting mangroves, Gabatin said. For one, mortality rate was high because “we did not put nets around the plantation.” During high tide, plastic and dead sea grasses would wound around the plants, depriving these of sunlight. Barnacles suffocated the plants.

“We will replant the areas again,” Junsan said.

Kaisaka had already included nets in a proposal for a P1.5-million funding which the Philippine Tropical Conservation Foundation approved.

While most residents are already aware of environmental protection, others are stubborn, Gabatin said. Some people would gather shells in the mangrove sites, killing the plants, although these already abound with crustaceans and fish. Others, however, would drive them away, telling them to fish elsewhere.

Rivers are Carbon Processors, not Inert Pipelines

http://www.waterlink-international.com/news/id342-Rivers_are_Carbon_Processors,_not_Inert_Pipelines.html

Rivers are Carbon Processors, not Inert Pipelines

02/12/2008 Waterlink International -

Microorganisms in rivers and streams play a crucial role in the global carbon cycle that has not previously been considered. Freshwater ecologist Dr. Tom Battin, of the University of Vienna, told a COST ESF Frontiers of Science conference in October that our understanding of how rivers and streams deal with organic carbon has changed radically. Microorganisms such as bacteria and single-celled algae in rivers and streams decompose organic matter as it flows downstream. They convert the carbon it contains into carbon dioxide, which is then released to the atmosphere.

Recent estimates by Battin's team and others conclude there is a net flux, or outgassing, of carbon dioxide from the world's rivers and streams to the atmosphere of at least two-thirds to three-quarters of a gigatonne (Gt) of carbon per year. This flux has not been taken into account in the models of the global carbon cycle used to predict climate change.

"Surface water drainage networks perfuse and integrate the landscape, across the whole planet," says Battin, "but they are missing from all global carbon cycling, even from the IPCC (Intergovernmental Panel on Climate Change) reports. Rivers are just considered as inert pipelines, receiving organic carbon from Earth and transporting it to the ocean." This thinking, according to Battin, has changed radically in last few years.

He argues that the latest estimates of how much carbon is transferred to the atmosphere from rivers and streams are very conservative. "The actual outgassing of carbon dioxide is probably closer to 2 Gt of carbon per year," says Battin. "Our surface area estimates only consider larger streams and rivers, because it is very hard to estimate accurately the surface area of small streams. So small streams are excluded, although in terms of microbial activity, they are the most reactive in the network."

Two gigatonnes of carbon per year is close to half the estimated net primary production of the world's vegetation each year. Realising that this quantity of carbon may be delivered straight back to the atmosphere, rather than being taken to the ocean where some of it is removed by marine organisms and ends up in sediment, could have profound consequences for our understanding of the system.

In a disturbing development, Battin's team lab has recently found that engineered nanoparticles can significantly compromise the freshwater microbes involved in carbon cycling. "This finding is a real challenge to science," says Battin. "Engineered nanoparticles such as titanium dioxide are expected to increase in the environment, but it remains completely unknown how they might affect the functioning of ecosystems."

This research was presented at the "Complex Systems: Water and Life" Frontiers of Science conference, organized by European Science Foundation (ESF) and COST, 29-31 October, Taormina, Sicily.