HOT news: Pacific carbon pump speeds up in summer

http://www.hawaii.edu/news/2012/02/07/summer-export-pulse/

HOT news: Pacific carbon pump speeds up in summer
February 7, 2012 | Cheryl Ernst

An international team of scientists led by University of Hawaiʻi at Mānoa oceanographer David Karl has documented a regular, significant and unexpected increase in the amount of particulate matter exported to the deep sea in the North Pacific Subtropical Gyre.

They suspect the previously undocumented phenomenon may be a response to day length, a general phenomenon known as photoperiodism.

Measuring the biological carbon pump

Deployment of sediment traps from the R/V Kilo Moana on a 2007 Hawaiʻi Ocean Time-series cruise (photo by Adriana Harlan and Susan Curless)

Using 13 years of Hawaiʻi Ocean Time-series (HOT) data from Station ALOHA (A Long-term Oligotrophic Habitat Assessment) about 100 miles north of Oʻahu, the scientists identified a rapid, predictable summer jump in the amount of total carbon, organic carbon, nitrogen, phosphorus and biogenic silica transferred from sunlit surface waters to the ocean depths through what is called the biological carbon pump.

This summer export pulse is approximately threefold greater than mean wintertime particle fluxes and fuels more efficient carbon sequestration, according to an article published in the February 7 PNAS, the Proceedings of the National Academy of Sciences. Co-authors are Matthew Church from the University of Hawaiʻi at Mānoa, John Dore from Montana State University, Ricardo M. Letelier from Oregon State University and Claire Mahaffey from the University of Liverpool.

Half of the photosynthesis on Earth is attributable to microscopic, single-celled phytoplankton that inhabit the sea. The vast majority of photosynthetic carbon fixation takes place in low-biomass, low-nutrient open ocean gyres, with about 15 percent of particulate organic matter settling into deep-sea reservoirs to await eventual resurfacing.

The researchers suspect that the unanticipated summer jump in deep-sea sequestration of carbon is due to seasonal increases in the biomass and productivity of symbiotic nitrogen-fixing cyanobacteria in association with diatoms.

This increase in microbial presence and activity is distinct from surface blooms, which don’t necessarily result in transfer of particulate matter, but does have ecological implications, said Karl. Besides identifying the probable mechanism and documenting seasonal variability and efficiency in carbon sequestration, the findings confirm the importance of nitrogen fixation and diatom-cyanobacteria symbiosis in the efficient transfer of carbon and energy to the deep sea.

In the absence of any obvious predictable stimulus or habitat condition, the scientists hypothesize that changes in day length may be an important environmental cue to initiate aggregation and subsequent export of organic matter to the deep sea. Nearly all cyanobacteria and eukaryotic algae studied to date, including marine diatoms, have light-activated molecular switches, they note.

Their conceptual model provides a testable hypothesis for future laboratory and field experimentation.

Becoming a microbial oceanography pioneer

Congratulated by researchers and crew on his last cruise as HOT principal investigator in 2009, David Karl has logged more than 1,000 days at sea (photo by Dan Sadler)

It’s not the first time that Karl has been out front with unexpected findings that spur new science. A three-page profile that accompanies the PNAS article describes the origin and high points of a remarkable oceanographic career.

A baseball-playing, motorcycle-riding youth who served as high school class president and aspired to become a commercial fisherman, Karl was captivated by the sea from his first glimpse of the ocean, viewed from atop a Maine mountain when he was 17.

As a master’s student at Florida State University, he helped improve the assay used to quantify ocean microbes and applied it to marine sediments—the first of many tools and processes he had a hand in developing.

A newly minted PhD just hired by the University of Hawaiʻi, he set off on his first National Science Foundation–funded grant to study newly discovered life forms at hydrothermal vents on the Galapagos Rift. In 1999, he published the first account of microorganisms in another extreme environment, the accreted ice of Antarctica’s Lake Vostok.

Karl conceived of the Hawaiʻi Ocean Time-series program, launched by the National Science Foundation with a $1 million grant in 1988 and is still collecting crucial microbial and biogeochemical data such as that providing the basis for the current paper. (UH Mānoa colleague Roger Lukas leads the companion physical oceanography portion of HOT.)

Along the way, Karl has garnered numerous professional awards and been elected to the National Academy of Sciences. He has published hundreds of papers and helped secure more than $62 million in extramural funds. His proposal of “Southern Ocean” as the name for waters south of the 60° south latitude was formally designated by the U.S. Geographical Board of Names, and he is credited with helping create the discipline of microbial oceanography.


Karl at the blessing of C-MORE Hale on the UH Mānoa campus in November 2010 with, from left, U.S. Senator Daniel Inouye, University of Hawaiʻi President M.R.C. Greenwood and National Science Foundation Director Subra Suresh (UH photo)

As director of the new Center for Microbial Oceanography: Research and Education, a National Science Foundation–sponsored Science and Technology Center with five partner institutions, he continues to advance the understanding of the life of the sea “from genome to biome.”

Reflecting on his first Galapagos Rift dives, Karl says the mesmerizing deep-sea hydrothermal vents “revealed how little we actually knew about our planet.”

With unflagging enthusiasm, he continues to do his best to change that.

About the research

The research was supported by grants from the National Science Foundation and the Gordon and Betty Moore Foundation.

Carbon Sequestration by Diatoms

A report on carbon sequestration by Diatoms -

http://www.examiner.com/paeleontology-in-national/diatoms-provide-natural-
carbon-sequestration

"After thirteen years of work scientists have determined that diatoms perform a
natural carbon sequestration annually according to a report released at the
Proceedings of the National Academy of the Sciences web site on January 30,
2011 [ should be 2012 ]."

A paper about role of Diatoms in oceans -
http://hahana.soest.hawaii.edu/lab/dkarl/1999MEPS-182-55-67.pdf

Real Challenges in Algae-based CO2 Capture

Oilgae

Real Challenges in Algae-based CO₂ Capture

I thought it would be good to revisit the topic of CO₂ capture (and partial sequestration) by algae, where the idea is to use the CO₂ from concentrated CO₂ emitting sources, especially power plants, to grow algae and use the biomass to produce biofuels. The concept is enticing in that it solves two problems in one go – reduces the net amount of CO₂ released into the atmosphere while providing us with a renewable source of biofuel.

But, as will not be surprising, there are significant challenges this concept faces, and it can be safely said that it will take at least five years before anyone can convincingly come up with a biological/engineering model that can accomplish this sustainably. All the same, it is a domain that has exceptional potential. With this in mind, the Oilgae team does a continuous review of this field; I thought I’d share some of our latest thoughts about algae-based CO₂ capture with you.

You will appreciate this is a relatively vast topic to be covered in a single newsletter; so I will limit myself to revisiting the real challenges that we see in algae-based CO₂ capture.

I would request who would like more details on any of the challenges listed below to send me a note so I could answer specific questions (to the extent possible, that is).

1	It is difficult, if not impossible, to capture 100% of CO2 that is pumped into the ponds This could be an important challenge, given that the total cost of CO2 capture, cooling, transportation and ultimate transfer to the ponds is one of the largest cost contributors for algae biofuel production. A literature review suggests that it might be difficult to achieve capture %s that are higher than 75%.
2	Energy costs for constructing sumps The % of absorption of CO2 increases significantly if sumps are constructed in a customized manner within the ponds. However, construction of these pumps could add a few % points to the total cost.
3	Storage of CO2 during night Algae consume CO2 during the daytime and they do not consume any CO2 during night when they in fact respire and let out CO2. Thus, any system needs to ensure that there is a storage of CO2 piped from the power plant. This could add to costs.
4	Overall economic viability Ultimately, the challenge for algae-based CO2 might not be technical or biological in nature, it is more likely to be economic. The costs of algae-based CO2 capture are still quite unclear.
5	Industrial incentives and perception Where the power plants have no penalties for not sequestering the CO2 that they generate, there is little incentive for these plants to invest in uncertain technologies such as algae-based CCS. And at a time when implementing even a pilot-scale algae-based CCS effort could cost in millions, a lack of clear incentive or penalties will be a severe inhibitor to research efforts. While Copenhagen was a disaster, I am not sure how much better Cancun has performed in the context of getting national mandates on CO2 capture / sequestration.
6	Water source near the power plants It requires about a million liters of water to make 1 T of dry algae biomass. In order for a large power plant to have algae cultivation that sequesters millions of T of CO2 per year, it is imperative to have access to large quantities of water., which the power plants might not have access to. Narasimhan Santhanam www.oilgae.com

US Forests

http://www.scientificamerican.com/article.cfm?id=us-forests-soak-up-carbon-dioxide

U.S. Forests Soak Up Carbon Dioxide, but for How Long?

Forests play a key role in offsetting U.S. emissions of greenhouse gases, but that ability may shrink as the climate changes

By Douglas Fischer and The Daily Climate October 18, 2010

The findings, released last week, estimate the nation's expanding forests sequester an additional 192 million metric tons of carbon annually due to increases in both the total area of forest land and the amount of carbon stored per acre.

That's the equivalent of removing about half the cars on the roads nationwide, or almost 135 million vehicles.

Ocean Biological Carbon Pump

The Biological Carbon Pump

http://earthguide.ucsd.edu/virtualmuseum/climatechange1/06_2.shtml

How important is the biological pump overall? It turns out, it is very important. For instance, if the biological pump were turned off, atmospheric CO₂ would rise to about 550 ppm (compared to the current 360 ppm). If the pump were operating at maximum capacity (that is, if all the ocean’s nutrients were used up) atmospheric CO₂ would drop to a low of 140 ppm.

-------------

Interesting estimate by the University of California, San Diego.

http://earthguide.ucsd.edu/virtualmuseum/climatechange1/06_3.shtml

The Marine Carbon Cycle

Altering this ratio of carbon atoms can be done, for example, by changing the amount of silicate (SiO₄) in seawater. If there is plenty of silicate, marine organisms called “diatoms” will grow more happily. They fix carbon into organic matter, and they take much of it down to deep waters because many diatoms, at the end of their life cycle, tend to settle out of the water where they grew. If there is very little silicate available, organisms called “coccolithophores” grow more readily than diatoms.

...

Let us remember at least one element concerning the carbonate cycle: Unusually intense blooms of carbonate-fixing plankton, like coccolithophores, would have the effect of bringing carbon dioxide from surface waters to the air above it – that is, increasing the atmospheric CO₂ concentration. The same is true for coral and shell growth in shallow waters. We would like to know, then, what precisely causes the blooms of coccolithophores that can be seen on satellite surveys, and whether their intensity is increasing or decreasing as the planet warms. Unfortunately, this is not known at present.

...

During the overall cooling of the planet, in the last 40 million years, more and more silicate has been removed from ocean in the upwelling regions around the continents (due to stronger mixing from stronger winds). We know this because radiolarians (plankton organisms using silicate to make their skeletons) have been getting thinner and more delicate through time. In the last 3 million years this process of silicate extraction has enormously accelerated, as the Antarctic Ocean started to deposit vast amounts of diatom shells.

-------------------------------

Diatoms sequester carbon but Coccoliths do not.

Diatoms, the secret sequesterer

Diatoms, the secret sequesterer

Posted In: R&D Daily | Climate | Global Climate Change | Oceanography | Biology | Chemistry | Argonne National Laboratory (DOE)

Friday, April 23, 2010

Even though you can’t see them with the naked eye, certain tiny sea algae make a big difference to the world’s climate. By taking in carbon dioxide from the atmosphere, they convert it into solid plant matter and sequester it in the world's oceans.

But what makes these particular algae, called diatoms, of interest to scientists at Argonne and around the country is their ability to sequester a different organic compound: phosphorous. That's because phosphorous in the seas helps the algae grow faster, which allows them to remove more carbon from the atmosphere during their lifetimes.

A photomicrograph of an oceanic diatom, which can turn dissolved phosphorous into an inorganic mineral shell.

Though recent attention has focused more strongly on the relationship between atmospheric carbon and climate, researchers like Argonne X-ray physicist Ian McNulty also believe that the balance of dissolved phosphorous in the world’s oceans also plays a vital role in maintaining the planet’s fragile ecological equilibrium.

"If we can understand how phosphorus uptake and sequestrations takes place, we could uncover information that might give us clues as to how carbon uptake and sequestration take place in the ocean and affect the global carbon balance," said McNulty, who leads a collaborative effort to study how diatoms sequester various dissolved compounds. "This research is of huge interest to climatologists and bears directly on and the potential to combat global climate change."

McNulty and his colleagues have spent years studying diatoms, which absorb phosphorous from the surrounding water during photosynthesis. Unlike the carbon dioxide or several other elements that diatoms take in during their lifetimes, absorbed phosphorous does not re-enter the environment in its original state. Instead, the diatoms convert it into an inorganic mineral known as apatite. During the course of a diatom’s life, naturally occurring dissolved phosphorous is transformed into a mineral shell. When a diatom dies, this shell sinks to the ocean floor, sequestering the phosphorous from the ecosystem for millennia.

“Even though each individual diatom is exceptionally small, the scale at which they sequester phosphorous and carbon from the environment is vast,” McNulty said. “When you add it all up, the diatoms in the world’s ocean are taking up gigatons of phosphorous.”

“The phosphorous balance in the oceans is intimately connected with the carbon balance in the atmosphere – you can’t alter one without altering the other,” he added. “High phosphorous levels in the environment allow the algae to grow and reproduce, and as they expand they take in more carbon dioxide from the atmosphere.”

Ellery Ingall and Julia Diaz, both of Georgia Tech, rinse particle samples aboard a research vessel. The diatoms collected in these samples were then taken to Argonne’s Advanced Photon Source for analysis.

Phosphorus is one of the principal ingredients of fertilizer, and makes up a large portion of agricultural runoff that winds up in large bodies of water, said oceanographer Jay Brandes of the Skidaway Institute of Oceanography in Georgia, who collaborated with McNulty on the research. Researchers from Skidaway and the Georgia Institute of Technology helped to collect and analyze the diatom samples.

"Oceans are the repositories of everything that washes off the lands, and phosphorus is an important nutrient for all kinds of life, especially plant life," Brandes said. "Because these diatoms need it to survive, the levels of phosphorus will control the size of the algae population. As the diatoms use up the available phosphorus and turn it into polyphosphates, they will die off in large numbers, altering the phosphorus balance."

In order to study the molecular dynamics that underlie how diatoms capture and convert phosphorous, scientists need a high-energy synchrotron light source that can generate just the right type of light to illuminate phosphorous’s chemical structure. Fortunately, Argonne is home to the Advanced Photon Source (APS), which provides exactly the kind and intensity of X-rays that McNulty and his colleagues need. “In order to study the chemistry of phosphorous, you need a very specialized facility,” he said. “The APS is and will remain at least for a few years the brightest star on the horizon for this kind of research.”

Experiments performed on the APS use a physical phenomenon known as X-ray diffraction, in which the object under study – in this case, the phosphorous compounds contained with the diatom – scatter the oncoming X-ray beam. The pattern produced by the scattering allows scientists to determine the precise atomic configuration of the phosphorous in the sample. Argonne also is home to a world-class scanning X-ray microscope that provides another key that can unlock the chemical secrets of phosphorous compounds.

The APS allows researchers from around the world to observe and analyze structures that cannot be seen anywhere else, and an anticipated upgrade to the facility will give scientists an even more comprehensive view of diatoms at the molecular level. For instance, at the upgraded APS, Argonne researchers and users could study cryogenically preserved living algae to see the exact mechanism that allows them to form their apatite coatings.

After the more concentrated X-ray beams are built, physicists from Argonne and partner institutions could also examine the diatoms' ability to sequester other trace elements, such as iron and arsenic. Some of these elements are toxic, not only to the environment but also to people, and McNulty and his colleagues are eager to find new ways to prevent these chemicals from ending up in our bodies. “If you can image the concentrations of trace elements in cells, you can understand the root cause of many diseases or monitor the uptake of anti-cancer drugs. All of these advances depend on improving the sensitivity and resolution of the facility we have here,” McNulty said.

Role of Increased Marine Silica Input on Paleo-pCO2 Levels

http://www.agu.org/journals/pa/v015/i003/1999PA000427/

PALEOCEANOGRAPHY, VOL. 15, NO. 3, PAGES 292–298, 2000

Role of Increased Marine Silica Input on Paleo-pCO2 Levels

Kevin G. Harrison
Geology and Geophysics Department, Boston College, Chestnut Hill, Massachusetts

Abstract

Changing the supply of silica to the ocean may alter pCO2 levels. The increase in dust delivered to the ocean during glacial times increased the availability of silica for biological uptake. The increased silica levels shifted species composition: Diatom populations increased and coccolith populations decreased. Decreasing the population of coccoliths decreased the flux of calcite to the sediments, which, in turn, lowered pCO2 levels enough to explain the glacial-interglacial pCO2 transition. Furthermore, the contemporary increase in dust delivered to the ocean’s mixed layer may be removing significant amounts of carbon dioxide from the atmosphere at present. To set the stage, this silica hypothesis is compared with the iron fertilization and nitrogen fixation hypotheses.

---------------

Silica flow into oceans has decreased in 20th Century and has not increased, this is one of the causes of Dead Zones in estuaries and coastal waters and for fish kills and harmful algal blooms in lakes and rivers.

The reduction is silica is both actual and in proportion to N and P flow.
Dams reduce the amount of silt flowing down rivers and higher agricultural activity results in higher N and P flow down rivers.

Its well documented that in River Mississippi Si : N ratio was 3 : 1 fifty years ago and not its < 1 : 1. This has resulted in the Gulf of Mexico Dead Zone.