Arctic plankton blooms

http://www.washingtonpost.com/wp-dyn/content/article/2011/03/06/AR2011030603417.html

Shifting spring: Arctic plankton blooming up to 50 days earlier now

A light micrograph shows plankton including water fleas (family Daphniidae). (Laguna Design)

By Brian Vastag

Washington Post Staff Writer
Monday, March 7, 2011

Climate researchers have long warned that the Arctic is particularly vulnerable to global warming. The dramatic shrinking of sea ice in areas circling the North Pole highlights those concerns.

A new report finds that the disappearing ice has apparently triggered another dramatic event - one that could disrupt the entire ecosystem of fish, shellfish, birds and marine mammals that thrive in the harsh northern climate.

Each summer, an explosion of tiny ocean-dwelling plants and algae, called phytoplankton, anchors the Arctic food web.

But these vital annual blooms of phytoplankton are now peaking up to 50 days earlier than they did 14 years ago, satellite data show.

"The ice is retreating earlier in the Arctic, and the phytoplankton blooms are also starting earlier," said study leader Mati Kahru, an oceanographer at the Scripps Institution of Oceanography in San Diego.

Drawing on observations from three American and European climate satellites, Kahru and his international team studied worldwide phytoplankton blooms from 1997 through 2009. The satellites can spot the blooms by their color, as billions of the tiny organisms turn huge swaths of the ocean green for a week or two.

The blooms peaked earlier and earlier in 11 percent of the areas where Kahru's team was able to collect good data. Kahru said the impacted zones cover roughly 1 million square kilometers, including portions of the Foxe Basin and the Baffin Sea, which belong to Canada, and the Kara Sea north of Russia.

"The trend is obvious and significant, and in my mind there is no doubt it is related to the retreat of the ice," said Kahru, who published the work in the journal Global Change Biology.In the late 1990s, phytoplankton blooms in these areas hit their peak in September, only after a summer's worth of relative warmth had melted the edges of the polar ice cap. But by 2009 the blooms' peaks had shifted to early July.

"A 50-day shift is a big shift," said plankton researcher Michael Behrenfeld of Oregon State University, who was not involved in the study. "As the planet warms, the threat is that these changes seen closer to land may spread across the entire Arctic."

Ecologists worry that the early blooms could unravel the region's ecosystem and "lead to crashes of the food web," said William Sydeman, who studies ocean ecology as president of the nonprofit Farallon Institute in Petaluma, Calif.

When phytoplankton explode in population during the blooms, tiny animals called zooplankton - which include krill and other small crustaceans - likewise expand in number as they harvest the phytoplankton. Fish, shellfish and whales feed on the zooplankton, seabirds snatch the fish and shellfish, and polar bears and seals subsist on those species.

The timing of this sequential harvest is programmed into the reproductive cycles of many animals, Sydeman said. "It's all about when food is available." So the disrupted phytoplankton blooms could "have cascading effects up the food web all the way to marine mammals."

But the Arctic food web is poorly studied, and so any resulting decline in fish, seabirds and mammals will be difficult to spot.

As the Arctic Ocean north becomes less and less icy, commercial fisherman have begun eyeing these vast, untapped waters as an adjunct to the famously rich fishing grounds of the subarctic Bering Sea, west of Alaska.

But in 2009, the U.S. body overseeing fishing in the region, the North Pacific Fishery Management Council, banned commercial fishing in the Arctic Ocean, citing a lack of knowledge about how many - or even what kind - of fish live there.

"There are no catches authorized because we don't know enough about the fish populations there to set a quota," said Julie Speegle, a spokeswoman for the Alaska office of the National Marine Fisheries Service.

Last week, that service reported results from the first fish survey in 30 years of the Beaufort Sea, an arm of the Arctic Ocean north of Alaska. The survey found sizeable populations of several commercially valuable species, including pollock, Pacific cod and snow crab.

Last week, the National Snow and Ice Data Center, in Boulder, Colo., reported that in February, Arctic sea ice covered a smaller area than ever seen in that month, tying with February 2005 as the most ice-free February since satellites began tracking Arctic ice in 1979.How these populations will respond to the ever-earlier plankton blooms is a big unknown, Sydeman said. But other research has shown that northern Atlantic cod populations crash when plankton blooms in that region shift in time.

The annual average Arctic sea ice coverage has decreased about 12 percent since then, a trend that appears to be accelerating, said Walt Meier, a research scientist at the center. Summer ice coverage has declined even more dramatically, he said, with the Arctic losing almost a third of its late-summer ice over the past 30 years.

Phytoplankton population decline

http://dalnews.dal.ca/2010/07/28/photoplank.html

July 28, 2010

Phytoplankton in retreat

By Melissa Hennigar

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Use of the Secchi disk, ca. 1910. Historical Secchi disc data are one of the two main data sources in our analysis (Yonge, C.M., Scientists measuring the water transparency with a Secchi disk, Queensland, ca. 1928, Part of Album of the Great Barrier Reef Expedition in the Low Islands region, Queensland, 1928-1929. (Photo courtesy of the National Library of Australia).

Research collected for more than a century is helping Dalhousie University researcher Daniel Boyce in his quest to examine the health of the world’s oceans.

A simple tool known as a Secchi disk as been used by scientists since 1899 to determine the transparency of the world’s oceans. The Secchi disk is a round disk, about the size of a dinner plate, marked with a black and white alternating pattern. It’s attached to a long string of rope which researchers slowly lower into the water. The depth at which the pattern is no longer visible is recorded and scientists use the data to determine the amount of algae present in the water.

More specifically, the research is focused on a particular type of algae known as phytoplankton. This is the first time that significant research has been complied and examined to study the algae levels in the world’s oceans.

It is hard to imagine this tiny photosynthetic plant may be one of the most urgent indicators of the declining health of the world’s oceans. “Phytoplankton provides food for basically everything in the ecosystem, from fish right up to human beings,” says Mr. Boyce, a PhD candidate with the Department of Biology at Dalhousie. “Phytoplankton is also important in maintaining sustainable fisheries operations and the overall health of the ocean. We need to make sure that the numbers do not continue to decline.”

The researchers found that the number of phytoplankton has been decreasing by a rate of about one per cent per year, for the past 110 years. While this might not seem like a large number, this translates into a decline of about 40 per cent since 1950. In total, just under half a million observations were compiled to be able to estimate phytoplankton levels through the years.

Daniel Boyce is a PhD candidate at Dalhousie.

The two main objectives of the research were to examine global trends in phytoplankton over time and to determine what might be driving these trends. Preliminary conclusions suggest that rising ocean temperatures are the leading cause of the decline. “As the water temperature rises, the ocean becomes more stable which limits the nutrients present in the water. This in turn limits the amount of phytoplankton,” explains Mr. Boyce.

Based on the research collected, phytoplankton levels have decreased in eight out of 10 ocean regions.

“Unfortunately, we as scientists don’t fully understand what exactly the effects of a decline in phytoplankton will be. We need to do more research into the effects of less phytoplankton. Obviously, doing whatever we can to lower the temperature of the world’s oceans is an excellent start,” says Mr. Boyce.

The full report, Global phytoplankton decline over the past century, appears in the journalNature on Thursday, July 29. The report is co-authored by oceanographer Marlon Lewis and marine biologist Boris Worm.

SEE THE ARTICLE: Global phytoplankton decline over the past century in Nature

Phytoplankton population declining

www.gsfc.nasa.gov/topstory/20020801plankton2.html

SATELLITES SEE BIG CHANGES SINCE 1980s IN KEY ELEMENT OF OCEAN'S FOOD CHAIN

Since the early 1980s, ocean phytoplankton concentrations that drive the marine food chain have declined substantially in many areas of open water in Northern oceans, according to a comparison of two datasets taken from satellites. At the same time, phytoplankton levels in open water areas near the equator have increased significantly. Since phytoplankton are especially concentrated in the North, the study found an overall annual decrease in phytoplankton globally.

The authors of the study, Watson Gregg, of NASA's Goddard Space Flight Center, Greenbelt, Md., and Margarita Conkright, a scientist at the National Oceanic and Atmospheric Administration's (NOAA) National Oceanographic Data Center, Silver Spring, Md., also discovered what appears to be an association between more recent regional climate changes, such as higher sea surface temperatures and reductions in surface winds, and areas where phytoplankton levels have dropped.

Phytoplankton consist of many diverse species of microscopic free-floating marine plants that serve as food to other ocean-living forms of life. "The whole marine food chain depends on the health and productivity of the phytoplankton," Gregg said.

The researchers compared two sets of satellite data -- one from 1979 to 1986 and the other from 1997 to 2000 -- that measured global ocean chlorophyll, the green pigment in plants that absorbs the Sun's rays for energy during photosynthesis. The earlier dataset came from the Coastal Zone Color Scanner (CZCS) aboard NASA's Nimbus-7 satellite, while the latter dataset was from the Sea-Viewing Wide Field of View Sensor (SeaWiFS) on the OrbView-2 satellite.

The researchers re-analyzed the CZCS data with the same processing methods used for the SeaWiFS data, and then blended both satellite measurements with surface observations of chlorophyll from ocean buoys and research vessels over corresponding time periods. By doing so, the researchers reduced errors and made the two records compatible.

Results indicated that phytoplankton in the North Pacific Ocean dropped by over 30 percent during summer from the mid-80s to the present. Phytoplankton fell by 14 percent in the North Atlantic Ocean over the same time period.

Also, summer plankton concentrations rose by over 50 percent in both the Northern Indian and the Equatorial Atlantic Oceans since the mid-80s. Large areas of the Indian Ocean showed substantial increases during all four seasons.

"This is the first time that we are really talking about the ocean chlorophyll and showing that the ocean's biology is changing, possibly as a result of climate change," said Conkright. The researchers add that it remains unclear whether the changes are due to a longer-term climate change or a shorter-term ocean cycle.

Phytoplankton thrive when sunlight is optimal and nutrients from lower layers of the ocean get mixed up to the surface. Higher sea surface temperatures can reduce the availability of nutrients by creating a warmer surface layer of water. A warmer ocean surface layer reduces mixing with cooler, deeper nutrient-rich waters. Throughout the year, winds can stir up surface waters, and create upwelling of nutrients from below, which also add to blooms. A reduction in winds can also limit the availability of nutrients.

For example, in the North Pacific, summer sea surface temperatures were .4 degrees Celsius (.7 Fahrenheit) warmer from the early 1980s to 2000, and average spring wind stresses on the ocean decreased by about 8 percent, which may have caused the declines in summer plankton levels in that region.

Phytoplankton currently account for half the transfer of carbon dioxide from the atmosphere back into the biosphere by photosynthesis, a process in which plants absorb carbon dioxide (CO2) from the air for growth. Since carbon dioxide acts as a heat-trapping gas in the atmosphere, the role phytoplankton play in removing carbon dioxide from the atmosphere helps reduce the rate at which CO2 accumulates in the atmosphere, and may help mitigate global warming.

The paper appears in the current issue of Geophysical Research Letters.

Have you thanked a phytoplankton today?

Have you thanked a phytoplankton today?
August 20, 9:16 PM
Charleston Green Living Examiner
Patti Romano

http://www.examiner.com/x-4390-Charleston-Green-Living-Examiner~y2009m8d20-Have-you-thanked-a-phytoplankton-today?#comments

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Mesocosm Experiments

Mesocosm Experiments are the right way to test Nualgi.

http://www.noc.soton.ac.uk/soes/staff/tt/eh/mesocosms.html

Mesocosm Experiments to Investigate Phytoplankton Competition

Several years of mesocosm experiments in the Norwegian fjords near Bergen (where Ehux is a common part of the phytoplankton succession) looked at the effects of nutrient and other factors on phytoplankton species composition. In particular, nutrients were added in different amounts and different ratios to different bags, and the resulting phytoplankton species numbers were counted. The mesocosm bags experienced natural temperatures and irradiances (they were suspended in the fjord water). The polyethylene mesocosm bags (90% light transmittance) were 4 metres deep, 2 metres in diameter, and constantly stirred. Each bag was initially filled by pumping in unfiltered fjord water, and so natural communities of zooplankton, bacteria and viruses were introduced at the beginning of each experiment. See (Egge & Hemidal, 1994) for a full description of the experimental set-up.



Many phytoplankton species were present in the bags, but the abundances of just two have been plotted against various parameters, in the diagram shown above. Concentrating solely on Ehux cell numbers, the diagram shows no correlation with nitrate, greater Ehux numbers at low phosphate, and a tendency for blooms to occur at higher temperatures and irradiances. Irradiances are averaged over the previous 5 days. Temperature and light will be highly correlated in the shallow mesocosm bags, and it is thought likely that the correlation with high temperature is probably because Ehux does better at high light, rather than because it competes better at high temperatures.


Ehux home page
http://www.genomics.ceh.ac.uk/mm/Bergen.php

Ocean acidification – why were we experimenting in Norway?


During the Bergen experiment, a blog of our daily activities was kept. This is now closed to further commenting, but a PDF archive of the entries can be downloaded here. The experiment was also mentioned on the CEH news site, and can be seen on both this page and, in more detail, on this one.

The effect of burning fossil fuels
It is well known that we are changing the climate by burning coal and oil. Everyone is aware of the greenhouse effect – increasing carbon dioxide (CO2) in the air is trapping heat in the atmosphere. With a warmer planet, we know that the polar ice caps will shrink, releasing huge amounts of freshwater into the ocean. We expect sea level to rise, causing flooding of coastal areas; we expect the warmer ocean to increase the intensity of storms and hurricanes; we think it is possible (but we are not certain about this) that Northern Europe could get colder in an overall warmer world, because the major oceanic current – the Gulf stream – that brings heat to us, may became weaker or even switch off. There is much to be concerned about as we enter a high CO2 world.

One other feature of high CO2 in the atmosphere is that it makes the oceans more acidic. When CO2 dissolves in seawater, it forms carbonic acid. This is a basic consequence of chemistry – there may be sceptics who doubt that the greenhouse effect will change our climate – but they cannot argue with chemistry. The amounts of CO2 that we are putting into the atmosphere WILL change the oceans and WILL make them more acidic.

Acidity
What do we mean by ‘more acidic’? Well, it will not mean that ships will dissolve in sea water, nor will it fizz like a cola drink. In fact, there will be a relatively small change. We measure acidity or alkalinity with something called pH, which is a measure of hydrogen ion concentration. The pH scale goes from 0 (very, very acid) to 14 (very, very alkaline). The oceans are currently slightly alkaline, with an average pH of about 8.2. How much will the pH change in the future? Within a century, we expect the pH of seawater to be about 7.8 – doesn’t sound much but is actually a huge change. pH is a logarithmic scale; since the beginning of the industrial revolution 200 years ago, CO2 entering the atmosphere and dissolving in the ocean has changed the pH by 0.1 units – but this small number hides a massive increase of about 30% in the hydrogen ion concentration. The important point is that apparently small changes in pH are caused by very large changes in hydrogen ion concentration.

Why does this matter?
The oceans have been slightly alkaline for a very long time. In the geological past, there have been times when oceans have been much more acidic than we predict for the next century but ocean pH has actually been very constant for a very long time – probably for as much as 20 or 25 million years. More important, never in the history of the planet has there been as rapid a change in pH as we are now seeing. We do not know how life in the oceans will adjust to this rapid change.

We already know that some marine creatures may disappear. Corals will not form so readily in a high CO2 world – their hard structures are made from calcium carbonate that is only laid down at current pH; it will dissolve at more acidic pH. Other organisms that are under threat are minute plants called coccolithophores which also have a calcium carbonate shell. These are the organisms that formed chalk (e.g. the white cliffs of Dover) in previous phases of the history of the planet – and are still important today forming vast blooms in the ocean that can be seen from satellites in space. In a high CO2 world, they too will have difficulty in making the calcium carbonate structures that they need.

These are obvious potential problems in a more acidic ocean but we know almost nothing about how the rest of the ocean will respond. We – humans – have only known a stable world. In the million or so years of our existence, mankind has always relied on a productive ocean. We get food from the sea but there are also other essential services that we take for granted. For example, about half of the oxygen that is produced by plants each year comes from the sea. In fact, it was the activity of minute plants in the ocean that first produced oxygen – about 3 billion years ago – that led to favourable conditions for animals to evolve. Today, the oceans are very important in regulating the whole planet – the oceans interact with the atmosphere, the atmosphere with the land to form an interdependency that maintains the whole planet – the Earth system. One of the most significant, yet invisible players in this control mechanism are microbes such as bacteria and phytoplankton.

Life in the ocean
Seawater does not look as though it contains much life. Mostly the water looks clear and blue and empty. There are some obvious plants, such as seaweeds, but they are restricted to a very narrow band around the coasts. However, in the vast majority of the oceans, the plants that produce so much of the oxygen that we need are tiny, microscopic algae called phytoplankton.

Other microbes, such as bacteria are also very abundant. In any litre of seawater, there will an average of one thousand million bacteria. They have a crucial role in maintaining the health of the Earth system. They recycle nutrients that are needed by plants; they breakdown waste organic matter; they degrade harmful compounds. In short, they maintain the planet. How will marine microbes respond to a more acidic ocean? We do not know – which why we are doing this experiment.

What is a mesocosm experiment?
A mesocosm has been defined as “an experimental system that simulates real-life conditions as closely as possible, whilst allowing the manipulation of environmental factors”.Basically, this means “a large enclosure that we can manipulate”.

The mesocosms that we are using in this experiment each contain about 12000 litres of seawater. This is a large enough volume to contain most of the bacteria, plants and animals (except fish) that interact together to form a community. They are also a manageable size that can be manipulated. By bubbling with air enriched with high CO2 (at 750 parts per million – the concentration that will be in the atmosphere in the year 2100 at the current rate of coal and oil burning), we have reduced the pH to 7.8 in just 3 days.

We can now begin to investigate how ocean acidification will affect microbial life in the seas. Will everything be the same as at current pH levels? In which case, we have little to worry about. Will undesirable phytoplankton and bacteria find the new conditions to their liking? In which case, how will that affect the future of the oceans? We do not have answers to these questions. But this experiment will begin to give us some clues about the future of the oceans in a high CO2 world.


Nualgi can reduce ocean acidification.

LOHAFEX - Iron Fertilization Expreiment

http://www.nio.org/projects/narvekar/Lohafex_news.pdf

LOHAFEX: An Indo-German experiment to test the effects of iron fertilization on the
ecology and carbon uptake potential of the Southern Ocean.
The German research vessel “Polarstern” left Cape Town on 7th January with a team of 48 scientists (30 from India) and one cameraman on board to carry out the Indo-German iron fertilization experiment LOHAFEX (LOHA is Hindi for iron, FEX stands for Fertilization EXperiment) in the Southwest Atlantic Sector of the Southern Ocean. About 20 days will be required to reach the area and carefully select a suitable location, after which a patch of 300 km2 will be fertilized with 6 tonnes dissolved iron. This will lead to rapid growth of the minute, unicellular algae known as phytoplankton that not only provide the food sustaining all oceanic life, but also play a key role in regulating concentrations of the greenhouse gas CO2 in the atmosphere. The development and impact of the phytoplankton bloom on its environment and the fate of the carbon sinking out of it to the deep ocean will be studied in
great detail with state-of-the-art methods by integrated teams of biologists, chemists and physicists over a period of about 45 days. The cruise will end in Punta Arenas, Chile on 17th March 2009.

LOHAFEX is being jointly conducted by the Alfred Wegener Institute for Polar and Marine Research (AWI), Germany, and the National Institute of Oceanography (NIO), India, together with scientists from 9 other institutions in India, Europe and Chile. Prof. Victor Smetacek (AWI) and Dr. Wajih Naqvi (NIO) are co-Chief scientists. The experiment is part of the Memorandum of Understanding between the two Institutes signed by the heads of their respective parent organisations, the Helmholtz Association, Germany and the Council of Scientific and Industrial Research, India, in the presence of the Chancellor of the Federal Republic of Germany and the Prime Minister of India in New Delhi on the 30th October 2007.
Planning for the experiment has been underway since 2005.

Five previous experiments carried out in the Southern Ocean, including 2 conducted from RV Polarstern, have induced phytoplankton blooms of similar size and composition to natural blooms fertilized by iron in settling dust and from melting ice bergs. However, in contrast to the land-remote regions previously fertilized, LOHAFEX will be located in a more productive region of the Southern Ocean inhabited by coastal species of phytoplankton that grow faster and are more palatable to the zooplankton, including the shrimp-like krill, than their spiny open-ocean counterparts. Krill is the main food of Antarctic penguins, seals and whales but
their stocks have declined by over 80% during the past decades, so their response to the ironfertilized bloom (if they are present in the experimental area) will indicate whether the alarming decline is due to declining productivity of the region, for which there is evidence.

Because it will last much longer, the LOHAFEX patch will also be twice the size of previous experiments to counteract the effects of dilution due to spreading over the 45 days of the experiment. Previous experiments have shown that effects on the environment are benign and short-lived.

Contrary to what is being claimed in some reports appearing in print and electronic media, LOHAFEX does not violate any existing international law. It is being erroneously reported that there exists a moratorium on Ocean Iron Fertilization (OIF) experiments placed by the UN Convention on Biological Diversity (CBD). The CBD recommendation was aimed at preventing large-scale commercial OIF activities, making an exception for scientific experiments. That such experiments were to be restricted to coastal waters was perhaps an aberration. The resolution adopted by the Parties to the London Convention and Protocol of the International Maritime Organization (IMO) during a meeting held at London in October 2008 does, in fact, call for further research on OIF. It clearly states that legitimate scientific experiments should go on, without restricting such experiments to coastal waters. The IMO resolution, although not legally binding, prescribes that proposals for such experiments be evaluated on a case-to-case basis taking into account possible environmental impacts. In the case of LOHAFEX, this has already been done by NIO and AWI. There is no doubt that this small-scale experiment will not cause any damage to the environment. As an example, the level to which the surface-water iron concentrations will be enhanced during this experiment is an order of magnitude lower than natural iron levels in coastal marine environments. In fact, this concentration is so low that most analytical laboratories in the world cannot measure
it. In addition, the scale of the experiment will be of the same order as that of previous OIF experiments. It is clear that the groups opposing LOHAFEX are not only unaware of the legal status, they are also not knowledgeable enough about marine environments. Thus, they are indulging in disruptive activities merely to draw media attention to themselves.

Weekly reports on the progress of the experiment will be posted at the web sites of NIO and AWI.