Arctic Ocean Diversity

An international collaborative effort to inventory biodiversity in the Arctic sea ice, water column and sea floor from the shallow shelves to the deep basins using a three-step approach: compilation of existing data, taxonomic identification of existing samples, and new collections focusing on taxonomic and regional gaps.

Project Leaders:

Dr. Rolf Gradinger, Dr. Russ Hopcroft, Dr. Bodil Bluhm, Institute of Marine Science, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Alaska, USA

The Arctic
The Arctic Ocean is also the area where the effect of climate change appears to be expressed the strongest. The already ongoing changes make the effort to identify the diversity of life in the major three realms (sea ice, water column and sea floor) an urgent issue. Changes in the environmental conditions will have direct effects on the marine biota on multiple levels, from populations to individuals. Species level information is, therefore, essential to discussions about climate change or anthropogenic impact, their expressions and effects. These effects can only be detected through long-term monitoring of key species, communities and processes. For monitoring and assessment of changes, the availability of baseline data is crucial.

 

Goals

The Census of Marine Life is implementing the Arctic Ocean Census of Marine Life, which is aimed at documenting the present Arctic Ocean Biodiversity on a Pan-Arctic scale. The operational approach is to coordinate research efforts, designed to examine the diversity in the three major realms: sea ice, water column and seafloor. This will be accomplished by increasing the number of samples, extending the sampling area, providing the material to taxonomic experts worldwide, and compiling the results in a data base accessible to scientists and the public. This program aims for active participation in the International Polar Year 2007/2008. Most recent research efforts in the Arctic Ocean focus on processes. The emphasis of this program is on biodiversity because processes are critically impacted by the composition of biota involved in them.

The major scientific objectives are to:

  • Compile a species inventory of the Arctic sea ice, water column and sea floor and to identify species community and richness trends relative to latitude, depth, spatial scale, etc.;
  • Identify bio-geographic affinities and barriers and their relevance in the past and present of the Arctic; and
  • Identify the relation between species distribution patterns, species richness with environmental data and attempt to draw conclusions and predictions about Arctic climate change.

Arctic Sea Ice

 

The Arctic sea ice covers approximately 7x106 km2 in summer and twice that in winter. The multi-year sea ice of the deep basins reaches a thickness of 2-3m and allowed the development of ice endemic species, meaning species that are not found anywhere else. Ice organisms live either in the tiny (mostly <1mm in diameter), liquid-filled pores and brine channels within the ice or at the ice-water interface. The biota within the sea ice is consequently small (<1mm) and dominated by bacteria, unicellular plants and animals and small multi-cellular animals (metazoa). Protozoans and metazoans (in particular turbellarians, nematodes, crustaceans and rotifers) can be abundant in all ice types year-round. A partially endemic fauna, comprised mainly of gammaridean amphipods, thrive at the underside of ice floes with up to several 100 individuals m-2. The amphipods are important as the major prey for the Arctic cod (Boreogadus saida

), which in turn acts as the major link to seals, birds and whales.

While previous studies provided a glimpse of the seasonal and regional abundances of ice-associated biota, biodiversity in these communities is virtually unknown for most groups, from bacteria to metazoans. Many taxa are likely still undiscovered due to the methodological problems in analyzing ice samples. The study of diversity of ice-related environments is urgently required before they ultimately change with altering ice regimes and the predicted loss of the multi-year ice cover.


Arctic pelagic realm

Planktonic research in Arctic waters can be traced back more than a century, with the earliest records restricted primarily to the coastal waters. Waters of the continental shelves have been studied in variable taxonomic detail in the Barents, Kara, Laptev and Chukchi/Beaufort Seas, while the East Siberian Sea, and Canadian Archipelago through northern Greenland have been particularly understudied. The deep basins remain even more mysterious due to the logistic challenges of penetrating their year-round ice cover, and the much greater effort required to properly sample to several kilometres of depth.

Due to their high abundance and ease of capture, the taxonomic composition and life history of the larger more common copepods in the Arctic Ocean is relatively well understood. The same cannot be said for the smallest copepod species that are invariably missed by collection techniques, all deep-water species, and the more fragile gelatinous forms. Although copepods typically predominate, there is a broad assemblage of other planktonic groups in the Arctic that are only occasionally reported in detail. These non-copepod groups, in particular, hold the greatest promise for discovery of new species and trophic importance because they have been largely ignored or biased against by collection techniques. The basic biodiversity of all these gelatinous animals is grossly underestimated in polar waters. Based on submersible experience in other oceans, we expect to discover at least twice as many species in most groups as are currently described.


Arctic benthos

 

It is the food supply and not the low water temperatures per se

that restrains growth and survival of the seafloor animals in the Arctic. On some Arctic continental shelves, the benthos receives large food input from the water column and, therefore, plays a greater role in system production than at lower latitudes. This explains the locally high abundance of bottom-feeding mammals like gray whales and walrus. In contrast, food availability and benthic biomass in the deep Arctic basins are substantially lower than on the shelves.

The large Arctic seafloor fauna has received most attention while the meiofauna, <1 mm, and microbial communities are less well studied. On the continental shelves, crustaceans (in particular sand fleas), polychaetes (bristle worms) and bivalve mollusks dominate the fauna living inside the sediments. The larger animals living on top of the Arctic seafloor are often dominated by brittle stars with up to several hundred individuals per square meter. The Arctic deep-sea has received much less attention because of the permanent ice cover and, hence, difficult access. The main groups (but not the species) of animals in the Arctic deep-sea sediments appear to be similar to those of shallow regions, but they occur in much lower densities.

Over 90% of the known approximately 5000 species of Arctic marine invertebrates live at the seafloor. About 350-400 of those occur in the Arctic deep-sea. Their distribution patterns and Atlantic, Pacific or Arctic origins give evidence about the geological history of the Arctic. However, much more research is needed for an adequate overview of the biodiversity of the Arctic seafloor and to evaluate its implications in the light of climate change, vulnerability and the Arctic history.


Fish

 

Fish can be found in associated with all three Arctic realms. Unlike most other oceans, commercial fisheries do not exist in the high Arctic with the exception of open waters in the more southern Eurasian regions, and lack of fisheries catch and by-catch data yield of void of basic knowledge. The traditional methods of collecting fish (nets and trawls) do not work well in ice-covered waters, consequently of knowledge of abundance, species composition and distribution is rudimentary in many part of the Arctic Ocean. We expect considerable advancement in our understanding of fish biodiversity over the course of this project.


The Arctic Ocean is the most extreme ocean on the planet in regards to the seasonality of light and its year-round existing ice cover. The Arctic seas hold a multitude of unique life forms, highly adapted in their life history, ecology and physiology to the extreme and seasonal conditions of their environment. Our knowledge of what currently lives in the Arctic Ocean is still rudimentary compared to other oceans, due to the logistical challenges imposed by its multi-year ice and inhospitable climate.

 

The Arctic Ocean is also the area where the effect of climate change appears to be expressed the strongest. The already ongoing changes make the effort to identify the diversity of life in the major three realms (sea ice, water column and sea floor) an urgent issue. Changes in the environmental conditions will have direct effects on the marine biota on multiple levels, from populations to individuals. Species level information is, therefore, essential to discussions about climate change or anthropogenic impact, their expressions and effects. These effects can only be detected through long-term monitoring of key species, communities and processes. For monitoring and assessment of changes, the availability of baseline data is crucial.

 


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