ISLANDS OF VARIETY
DATA AND ANALYSIS
TECHNOLOGY FOR BIOLOGICAL INSIGHT
are undersea mountains that rise at least 1,000 meters above the
surrounding seafloor, and even though they dont break the
waters surface, scientists call them islands of biodiversity.
Based on initial studies of 300 seamounts, biologists think many
of the tens of thousands of seamounts worldwide are havens for
unique, locally occurring endemic species. Seamounts may also
serve as stepping stones for transoceanic species dispersal. "There
is a strong parallel with island biogeography, which has a history
dating back to Darwin, and a substantial body of knowledge and
methodology that we can draw on," said biological oceanographer
Karen Stocks, a postdoctoral fellow with a joint appointment at
SDSC and the Scripps Institution of Oceanography (SIO). She and
her colleagues are uniting the sparse and far-flung biological
and environmental data on seamounts into an interactive website.
Through this resource, scientists will be able to gain new insights
into marine biodiversity.
biological diversity of seamounts is evident in these photographs:
antipatharian corals (top) at 580 meters on the Fieberling
Guyot; deep-sea rattail fish and seastar (middle) also on
the Fieberling Guyot; and Gorgonian corals or sea fans (bottom)
at 1,100 meters on the Hoke seamount. Photographs courtesy
of Lisa Levin, whose research was sponsored by ONR.
we want to know is what species occur where, and when," said
Stocks, who is working with SDSC research scientist David Stockwell
and SIO Professor Lisa Levin. "But the marine environment
is tremendously undersampledthere are so many things we
simply dont know about biodiversity in the oceans."
Moreover, the data sets that exist often are spread out, incomplete,
and difficult to access. Stocks and her colleagues are taking
a habitat-specific approach, studying seamounts as a key step
toward building an overall picture of marine biodiversity.
biologists produced museum data sets viewed as having lasting
value. "Then, oceanographic research became hypothesis driven,
and data were seen as important primarily to answer a specific
questiontheir long-term value was often overlooked,"
said Stocks. "But now the pendulum is swinging back, and
people are realizing that regardless of why data sets were sampled,
they can have wider uses."
By combining physical,
chemical, biological, and other oceanographic data, scientists
can build models of species occurrence. Such models will be vital
for managing biodiversity under changing environmental conditions,
whether naturally occurring or human-induced. "People are
waking up to the urgent need to preserve and federate biological
data sets," said Stocks.
considered excellent case studies for understanding patterns in
marine biodiversity," said Stocks. In addition to their high
endemism and possible role in species dispersal, seamounts may
also serve as refuges for species with contracting ranges and
as "hot spots" of speciation. These factors make it
possible to gain deeper insight into patterns of marine biodiversity
by conducting targeted research on seamounts. In addition, seamounts
are productive areas that may support fisheries and coral mining,
and require careful management based on scientific information
to prevent habitat damage.
that make seamounts attractive to study include their wide distribution
(they are found in all ocean basins), their wide range of physical,
geological, and chemical conditions (some are tectonically active
with hydrothermal vents and associated communities), and theyre
discrete, like islands.
of some of the 300 seamountsout of what is believed
to be tens of thousands of seamounts worldwidethat
have been sampled biologically.
DATA AND ANALYSIS
"This is definitely
a case where the whole is greater than the sum of the parts,"
said Stocks. She expects major advances in scientists understanding
of patterns of ocean life to come through integrating data on
the spatial distribution of organisms with environmental oceanographic
data, especially across traditional disciplinary lines.
The initial phase of
the National Science Foundation-funded research involves creating
a multidisciplinary database and linked geographic information
system to compile seamounts data sets that are now dispersed.
Stocks said that the database will be made available on the Web
at SeamountsOnline. This will provide a free resource for searching,
downloading, mapping, and analyzing patterns of biogeography in
the data. SeamountsOnline is part of the Ocean Biogeographic Information
System at Rutgers University, which is part of the 10-year international
Census of Marine Life project. The website is designed both to
facilitate research on seamount ecology and to act as a resource
The second phase of
the research will involve using the database to produce large-scale
maps to reveal patterns of biodiversity and endemism on seamounts.
Finally, the third phase involves applying advanced analytical
tools to test hypotheses about the environmental conditions that
support the species patterns discovered. Based on similar environments,
researchers will test hypotheses that seamount biodiversity decreases
with latitude and that it has a mid-depth maximum.
"One mystery we
would like to probe is that while the biodiversity of seamounts
is generally high compared to surrounding seafloor diversity,
its intriguing that this isnt always true," said
Stocks. "Some seamounts have lower diversity than expected,
and we would like to investigate why."
Like so many things
about the oceans, few seamounts have been sampled biologically
(Figure 2). "There are seamounts off San Diego that Lisa
Levin of SIO has worked on," said Stocks. "Shes
very interested in our project being able to predict species occurrences
that she can then go out and measure."
serve as undersea laboratories for the study of organism response
to hard substrate and strong flows in the deep sea," said
Levin. "They are the reefs of deep water, supporting
a myriad of large, very old, filter-feeding invertebrates, as
well as sandy bottom ecosystems."
an example of modern interdisciplinary research that integrates
data, tools, and knowledge across disciplines and institutions.
"The computing and data management expertise of SDSC combined
with the oceanographic expertise and data collections of SIO make
this an ideal environment for doing this research," said
She is also collaborating
with Professor Hubert Staudigel and researcher Anthony Koppers
of the Institute of Geophysics and Planetary Physics at SIO. Staudigel
and Koppers are building EarthRef.org, which includes an online
seamount database containing such physical information as bathymetric
or depth data (Figure 3). "Were working to link their
physical data with our biological data," said Stocks.
A key aspect of this
research is encouraging people to contribute data sets to SeamountsOnline.
There will be a mix of data entered directly into it, and links
to data curated at the site of origin. "Many people are willing
to participate, but it takes effort to prepare the data,"
said Stocks. "Theres a need for some organized mechanism
to make resources available for this to benefit the whole community."
Depth map of the Ufiata and Pogisa Tokelau Seamounts
will integrate physical datadeep (blue) to shallow
(red/brown)with environmental and species occur-rence
data, enabling analyses and modeling to test hypotheses
and predict the effects of natural and human-induced change
on ocean biodiversity. Image and data from NSF-supported
Earthref.org, courtesy Anthony Koppers, IGPP-SIO, UCSD.
Contour interval 125 m; grid size 100 m; sun azimuth 340°.
TECHNOLOGY FOR BIOLOGICAL INSIGHT
Once data sets are
linked or collected in the database, modern analytical tools may
help discover knowledge never before available. "My background
is in marine-community ecology, and its very exciting to
be able to work with SDSC environmental informatics researcher
David Stockwell," said Stocks.
To go from point data
on where species are found to estimating broader biodiversity
patterns depends sensitively on the number of samples and other
factors. Great care must be taken to use data correctly in order
to reach statistically reliable conclusions.
Stockwell and his informatics
colleagues have developed statistical techniques for analyzing
species-distribution data that are capable of dealing with such
problems as sparse and biased sampling, scale mismatches between
data sets, varying levels of accuracy, and even taxonomic uncertainty.
These tools can help
determine which environmental factors do the best job of predicting
where species will be found. "If we identify which combinations
of environmental factors best predict species occurrence, this
makes possible reliable predictions, which can guide future field
work," said Stocks. Since ship time is expensive, these tools
will make field research more targeted and productive.
applications being incorporated into SeamountsOnline are operated
as free Web services, and theyre also available to the general
biodiversity community," said Stockwell.
The researchers also
want to inform the wider community about these technologies. "Were
planning to show how well these powerful new analytical tools
complement traditional analysis tools that biologists are already
familiar with," said Stocks. Seemingly little things can
make a big difference in the usefulness of a resource like SeamountsOnline,
so Stocks is doing such things as using units familiar to each
tools and analytical research experience that can later be applied
beyond seamounts," said Stocks. "They can help in the
study of other marine ecosystems in more systematic ways than
previously possible." PT
SDSC/Scripps Institution of Oceanography
Scripps Institution of Oceanography
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