Antarctic Krill: study finds krill releases iron, a part of the CO2 absorption process

Krill is one of the primary foundations in the ocean's food chain. And iron is an important component of sea water, involved in the complicated process of absorption of carbon dioxide (CO2) by microscopic plants. These two elements, krill and iron, were brought together in a press release released today from the British Antarctic Survey:

"A new discovery reveals that the shrimp-like creature at the heart of the Antarctic food chain could play a key role in fertilizing the Southern Ocean with iron – stimulating the growth of phytoplankton (microscopic plant-like organisms). This process enhances the ocean's capacity for natural storage of carbon dioxide.

Reporting this month in the journal Limnology and Oceanography, an international team of researchers describe how Antarctic krill (Euphausia superba), once thought to live mostly in surface waters, regularly feed on iron-rich fragments of decaying organisms on the sea floor. They swim back to the surface with stomachs full of iron, releasing it into the water.

Antarctic krill is the staple diet for fish, penguins, seals and whales; and is harvested by commercial fisheries for human consumption.

Lead author from British Antarctic Survey, Dr Katrin Schmidt says, 'We are really excited to make this discovery because the textbooks state krill live mainly in surface waters. We knew they make occasional visits to the sea floor but these were always thought as exceptional. What surprises us is how common these visits are – up to 20% of the population can be migrating up and down the water column at any one time.'

The scientists painstakingly examined the stomach contents of over 1000 krill collected from 10 Antarctic research expeditions. They found that the krill, caught near the surface, had stomachs full of iron-rich material from the seabed. The team also studied photographs of krill on the sea floor, acoustic data and net samples. All these provided strong evidence that these animals frequently feed on the sea floor.

This finding has implications for managing commercial krill fisheries and will lead to a better understanding of the natural carbon cycle in the Southern Ocean."

Iron is known to enter the seas through the upwellings of deep sediments, run-off and wind-blown dust from land, and melting icebergs. Iron stimulates plankton growth which, in turn, takes in CO2. Dying plankton settle on the bottom thereby capturing and holding the CO2 - and the iron. This new study indicates that krill may also be a vital component in the recycling of iron, thereby stimulating plankton growth, and the CO2 absorption cycle is further stimulated.

The need for managing commercial krill fisheries to ensure a healthy food cycle for a variety of sealife in the Southern Ocean is now given extra importance based on what disruptions could occur to the carbon cycle should krill be over-harvested.

Read the press release from the British Antarctic Survey.

Preserving Coastal Ecosystems: study shows loss of mangroves and salt marshes releases long-stored CO2

Surfbird News reports on all things related to coastal surfbirds and the environments that support them. The site recently reported on the findings of an international consortium of scientists on the impact on CO2 sequestration with the loss of coastal ecosystems like mangroves and marshlands.

Urgent Action Needed To Halt Increasing Carbon Emissions from Destroyed, Degraded Coastal Marine Ecosystems

The destruction of coastal carbon ecosystems, such as mangroves, seagrasses and tidal marshes, is leading to rapid and long-lasting emissions of CO2 into the ocean and atmosphere, according to 32 of the world’s leading marine scientists.

That key conclusion highlights a series of warnings and recommendations developed by the new International Working Group on Coastal “Blue” Carbon, which convened its first meeting in Paris last month. The Working Group was created as an initial step in advancing the scientific, management and policy goals of the Blue Carbon Initiative, whose founding members include Conservation International (CI), the International Union for Conservation of Nature (IUCN), and the Intergovernmental Oceanographic Commission (IOC) of UNESCO.

Much of the carbon emitted when mangroves, seagrasses or tidal marshes are destroyed is estimated to be thousands of years old because the CO2 stored in these ecosystems is found not only in the plants, but in layer upon layer of soil underneath. Total carbon deposits per square kilometer in these coastal systems may be up to five times the carbon stored in tropical forests, due to their ability to absorb, or sequester, carbon at rates up to 50 times those of the same area of tropical forest. The management of coastal ecosystems can supplement efforts to reduce emissions from tropical forest degradation.

Dr. Emily Pidgeon, Marine Climate Change Director at Conservation International, and a leading blue carbon conservation scientist emphasized, “We have known for some time the importance of coastal ecosystems for fisheries and for coastal protection from storms and tsunamis. We are now learning that, if destroyed or degraded, these coastal ecosystems become major emitters of CO2 for years after the plants are removed. In the simplest terms, it’s like a long slow bleed that is difficult to clot. So we need to urgently halt the loss of these high carbon ecosystems, to slow the progression of climate change.”

“The capacity of coastal wetlands to reduce climate change by capturing and storing carbon dioxide is considerable, but has been overlooked” says Jerker Tamelander, Oceans and Climate Change Manager for IUCN. “If valued and managed properly, coastal ecosystems can help many countries meet their mitigation targets, while supporting adaptation in vulnerable coastal areas.”

Read the entire article in Surfbird News.

Geoengineering: changing the earth's climate for better or worse?

Geoengineering - this is a concept that we will be hearing more and more about with regards to managing climate change. It doesn't necessarily involve us on a personal level, like buying fluorescent light bulbs or driving more fuel-efficient cars; this is large-scale proactive approaches where science and commerce are utilized to directly counter the effects of climate change and CO2 emissions rather than deal with root causes.

Basically, we are talking about taking the CO2 we have in the atmosphere and finding some other place to park it, often referred to as CO2 sequestration. There have been proposals to store it underground while others have focused on methods of increasing absorption by the oceans where it is stored at deep depths.

I was reading several reports on ocean sequestration and there are many techniques that have been studied and even experimented with on a small scale. The results and/or recommendations have been conflicting - in part due to the fact that none of this has been undertaken on a large, truly global scale so we are walking into unknown territory with only projections and theories to guide us. Here are some of the current concepts regarding ocean CO2 sequestration:

Ocean Fertilization: Using the addition of iron particles to induce greater phytoplankton blooms which will, as part of their normal biological process, consume more CO2 and then sink to the ocean bottom. Some scientists say this is a viable approach, others say that the results are not substantial enough compared to the costs and related effects that would impact the ocean ecosystem.

Ocean Nourishment: A variation on ocean fertilization wherein additional nutrients are added to the process that could enhance the growth of feeder fish populations, thereby providing additional benefits with an increased food source and potential commercial value to developing countries.

Alkalinity Change: A land-based process where a CO2 source is combined with limestone and sea water. Basically the reaction alters the pH level and binds the CO2 to the sea water, which is then discharged back into the ocean. The use of limestone, which introduces calcium carbonate, is expected to neutralize acidification and therefore have minimal impact on the marine ecology.

Direct Injection: When ocean sequestration is discussed, the storage of CO2 is to take place at great depths where CO2 actually forms a liquid more dense than seawater (below 3000 meters). There are proposals for direct injection that involve piping CO2 directly from sources like industrial plants or energy refineries into the ocean depths where it is trapped at depth, forming a kind of deep sea lake of near-solid CO2.

These are techniques that are currently being experimented with, but whether they ultimately prove to be physically or financially practical on a large scale remains to be seen. And what of the unforeseen ecological implications? Attitudes range and proposals are hotly debated within the scientific community. There are those that say that geoengineering represents "doing something rather than nothing" with the current and future volume of CO2 in the atmosphere, regardless of what preventive steps are taken. (Remember the Carbon Bathtub analogy I cited earlier this week? Even if we radically cut back on CO2 emissions, we will have excess amounts in the atmosphere to deal with for centuries.)

Geoengineering is not a silver bullet solution nor does it free us from addressing the ongoing sources of CO2 emissions. At best it could work in concert with CO2 reduction strategies, but it is technology that is new with unforeseen consequences and perhaps must operate on unimaginable scales worldwide. However, it may find its place because we don't have a choice.