Explorers Inventory Hard-to-See Sea Life:
Tiny but Mighty Microbes, Plankton, Larvae, Burrowers --

Keys to Earth’s Food and Respiratory Systems

Sunday April 18, 2010
(Press Release excerpt)

Censusing the diverse, spectacular world of sea bugs called zooplankton Led by Ann Bucklin, head of the University of Connecticut Marine Sciences Department, the Census of Marine Zooplankton (CMarZ) has united the world’s specialists to paint an unprecedented global picture of the abundance, diversity and distribution of tiny, often transparent sea “bugs” that form a vital link in both the food chain and Earth’s carbon cycle.

Like microbes, plankton species are typically found in very low abundance in any given place, though there are exceptions. Census scientists sampling the Black Sea, for example, found blooms of tiny comb jellies (ctenophores) vacuuming up all available nourishment, while minute copepods (crustaceans) dominated parts of the North Atlantic.

When CMarZ began in 2004, scientists had described about 7,000 marine species that remain planktonic throughout their lives (called holozooplankton; another 26,000 known species are classified as plankton in their larval stage but change lifestyle as they grow larger). In decades to come, when all of the Census samples have been analyzed and described, Dr. Bucklin estimates the research will have roughly doubled to 14,000 the number of holozooplankton species known to science (of the estimated 15,000 to 20,000 thought to exist altogether).

“The Census has sampled more extensively, more intensively and more strategically than any previous project,” she says. “The Census created an unprecedented opportunity for the fragmented international taxonomic community to look collectively for global patterns of diversity. Funding of such work by national or regional bodies typically limits the involvement of non-national investigators, which divides and partitions the research.”

“The food web has a highly integrated structure; our research into it needs to be integrated too. The Census has helped develop a world view, and all of us who work in the field have treasured that.”

Dr. Bucklin adds that functional biodiversity -- understanding the inter-relationships of species, and the unique (or replaceable) role of each species in an ecosystem -- is a frontier field of study. It will help determine the extent to which the food web is stable and resilient as species migrate if ocean temperatures change and if oceans acidify, impairing the formation of calcium carbonate shells grown by some planktonic species.

Like those studying microbes, zooplankton researchers use modern genetic identification techniques (DNA barcoding) to reveal “cryptic” species (which can be differentiated only through genetics), and to match larvae with adults.

Last year, CMarZ Steering Group member Tracey Sutton of the Virginia Institute of Marine Science and colleagues, led by the Smithsonian Institution’s G. David Johnson, used genetics to correct a long-standing mistaken identity, an error in fish taxonomy.

Previously, the alien-like Mirapinnidae (tapetails), Megalomycteridae (bignose fishes) and Cetomimidae (whalefishes) constituted three different families in taxonomy based on their appearance, behaviour and other characteristics. Dr. Sutton and colleagues showed that they are, in fact, the larvae, males and females, respectively, of a single family, Cetomimidae.

Rare video of the red-headed baby of the family Cetomimidae, found down 1,450 m in the Gulf of Mexico, is available online at www.coml.org/embargo/hardtosee (along with many other images and videos of hard-to-see species).

Meanwhile, Colomban de Vargas, a CMarZ scientist from France, has called into question previous notions about climate conditions during the last ice age by revealing through DNA the hidden diversity of single-celled marine microorganisms called foraminifera (forams for short). The shells were associated with a particular temperature regime.

Thought at the time to be one species, fossil records of foram shells were advanced as evidence of ice age climate by the CLIMAP (Climate Investigation, Mapping, and Prediction) project of the 1970s and 1980s. Similar-looking shells may associated with different climates.

The new research shows there may be 20-50 times as many foram species as previously thought, potentially undermining CLIMAP conclusions.

“The discovery of this hidden diversity should encourage us to look back and re-examine previous studies,” says Dr. Vargas.

Census of Marine Life: Final summaries and report

Started in the year 2000, the Census of Marine Life has been a decade-long international research program uniting thousands of scientists worldwide with the goal of assessing and explaining the diversity, distribution and abundance of life in the seas. It has been supported by private sources and government agencies the world over, listed online at www.coml.org/support. The final reports of the Census of Marine Life will be presented and discussed in London in October. Three books will be launched. Many of the results described above will be documented in Life in the World’s Oceans: Diversity, Distribution and Abundance, A.D. McIntyre, ed., Wiley-Blackwell, in press).

Censusing the hard to see:

Some 300 scientists collaborate on the four Census projects focused on hard-to-see sea species: ICoMM, CMarZ, CeDAMar and ChEss. By the time the 10-year Census concludes in October 2010, the projects will have collectively fielded almost 300 expeditions (ICoMM: 66, CMarZ: 122, CeDAMar: 18, ChEss: 80).

Zooplankton (CMarZ)

The Census of Marine Zooplankton (CMarZ) is producing a global assessment of zooplankton species diversity, biomass, geographic distribution, and genetic diversity, focusing on the roughly 7,000 described species of animals that drift with ocean currents throughout their lives.

CMarZ focuses on the deep sea, under-sampled regions and biodiversity hotspots, using integrated morphological and molecular (DNA barcodes) approaches to analysis and assessment of species diversity. Education, professional training, and capacity-building efforts will increase the number of taxonomic experts.

The CMarZ database contains species-level, specimen-based, geo-referenced entries; data and information are accessed via the CMarZ and CMarZ-Asia websites, as well as the Ocean Biogeographical Information System (OBIS).

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