BUFFALO, N.Y. -- Freshwater ecosystems in northern regions are
home to significantly more species of water fleas than
traditionally thought, adding to evidence that regions with
vanishing waters contain unique animal life.
The new information on water fleas -- which are actually tiny
crustaceans -- comes from a multi-year, international study that
was published Feb. 24 in the journal Zootaxa.
The researchers scoured the globe seeking the creatures and
found them inhabiting northern lakes and ponds in locations from
Alaska to Russia to Scandinavia.
After analyzing the anatomy and genetic makeup of many different
specimens, the team conclusively determined that at least 10
species of the crustaceans existed -- five times as many as thought
for much of the last century.
More than half the diversity was found in northern latitudes,
where rapid freshwater habitat loss is occurring due to melting
permafrost, increased evaporation and other changes tied to climate
change.
"It is well known that parts of Alaska and Siberia have suffered
a huge reduction in freshwater surface area, with many lakes and
ponds disappearing permanently in the past few decades," said Derek
J. Taylor, a University at Buffalo biologist and member of the
research team. "What we're now finding is that these regions with
vanishing waters, while not the most diverse in the world, do
contain some unique aquatic animals."
"Some of these subarctic ponds that water fleas inhabit are held
up by permafrost, so when this lining of ice melts or cracks, it's
like pulling the plug out of a sink," Taylor said. "When you see
the crop circle-like skeletons of drained ponds on the tundra you
can't help but wonder what animal life has been lost here."
Taylor's colleagues on the study included Eugeniya I. Bekker and
Alexey A. Kotov of the A. N. Severtsov Institute of Ecology and
Evolution in Moscow.
The research focused on water fleas of the genus Eurycercus,
which can reach lengths of about 6 millimeters. The findings add to
a body of evidence suggesting that the species diversity of water
fleas is greater in northern regions than in the tropics.
This is a counterintuitive concept, as scientists have long
supposed that the advance and readvance of ice sheets reduced much
of the species diversity in colder climates, Taylor said. However,
there is growing evidence that some northern areas remained
ice-free and acted as hideouts during the harsh glacial
advances.
The researchers not only convincingly documented new species
diversity, but identified one likely new species and provided a
detailed, formal description of another: Eurycercus beringi.
Like other water fleas, E. beringi is an important source of
nutrients for fish and aquatic birds.
The new species -- from Alaska's remote Seward Peninsula -- has
unusual anatomical features that force a rewrite of the taxonomy of
Eurycercus above the species level. Moreover, the new anatomical
details should aid future studies that use preserved body parts of
Eurycercus found in lake sediments to reconstruct past ecological
conditions.
The discovery of new crustacean species in unexpected places
underscores the scope of the ongoing biodiversity crisis for
freshwater ecosystems.
The research was supported by the Biodiversity Program of the
Presidium of Russian Academy of Sciences, the Russian Science
Support Foundation, the Russian Foundation for Basic Research, the
Smithsonian Institution Office of Fellowships and the National
Science Foundation.