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Visualization of Spatial Data in Marine Biogeographic Information Systems. Steven Perry and Daphne G. Fautin Department of Ecology and Evolutionary Biology, & Natural History Museum and Biodiversity Research Center. ABSTRACT
Visualization of Spatial Data in Marine Biogeographic Information Systems
Steven Perry and Daphne G. FautinDepartment of Ecology and Evolutionary Biology, & Natural History Museum and Biodiversity Research Center
One difficulty with using ArcIMS to visualize the distributions of marine species is that it splits generated maps at the 180° meridian (around the International Date Line). This is an impediment to the visualization of distribution patterns for many marine taxa including corals.
In the study of marine biodiversity, remote sensing techniques are used to collect the physical oceanographic data that are often incorporated into biogeoinformatics databases. This includes bathymetric data, sea surface temperatures, salinity, and water chlorophyll concentrations.
When studying the distribution of marine organisms, it is often not possible to use remote sensing techniques to gather data directly. This is due to the fact that most of the organisms under study are either too small or live too deep in the water to be sensed remotely.
A major exception to this general rule are the coccolithophores, single-celled phytoplankton that are covered with microscopic calcite (limestone) scales. Blooms of coccoliths can number in the trillions and cover large geographic areas. In addition to the fact that blooms are large phenomena, the scales of coccoliths yield a characteristic signal to spectroradiometers.
However, coccolithophores are not characteristic of most marine species, which must be directly sampled in the field.
This is a major issue being addressed in planning for GOOS, the Global Ocean Observing System. GOOS will attempt to develop new systems for remote sensing of marine life including networks of data collecting buoys and floats.
Traditional remote sensing techniques are useful mainly for the collection of physical oceanographic data such water salinity.
Distribution of Acropora digitifera generated by the OBIS mapper: Acropora is the largest genus of reef-forming corals.
Two-Dimensional Visualization Problem
Geographic Information Systems are designed to collect, transform, and display geographic data. Traditionally geographic data have consisted of latitude and longitude pairs. While this is sufficient for most users of GIS
technology, scientists who study marine biodiversity are faced with the problem of extremely dense datasets where multiple species observations can occur at the same latitude and longitude, but at different depths. This is an impediment to the visualization of marine biogeographical information using current GIS tools.
Most GIS software packages can load and display information from DEMs (Digital Elevation Models). DEMs are designed to model continuous topographical surfaces. Many consumers of GIS technology that model terrestrial systems can use DEMs to provide a type of two-and-a-half dimensional view of their data. When modeling marine environments DEMs can be used to convey information about the sea floor including trenches and sea mounts. However, since they model only a single surface, DEMs are of no use when modeling the kind of truly three dimensional data involved in the collection of marine biodiversity observations.
Traditional two-dimensional GIS visualization systems are useful in the study of marine biodiversity, but good three dimensional GIS technology would make it easier to find significant depth-related patterns in the data.
A remotely sensed Emiliania huxleyi (coccolithophore) bloomoff Alaska in April 1998 (from the NASA SeaWIFS Project)
Biogeographic information systems that allow for the collection and visualization of marine biodiversity data are faced with peculiar challenges that are not encountered by those that are focused on terrestrial organisms. Many marine populations are distributed across the international date line, making visualization with traditional GIS mapping tools problematic. Two and two and a half dimensional GIS visualization systems do not provide the ability for researchers to easily examine the rich three dimensional patterns of marine species distribution. Finally, traditional remote sensing techniques, while useful for oceanographic data collection, are not well suited to the study of most marine organisms.
Marine species are distributed in three dimensions. This makes visualization of marine biodiversity patterns difficult with traditional GIS.
Development of “Hexacorallians of the World” was funded by US National Science Foundation grants DEB95-21819 and DEB99-78106 in the program PEET (Partnerships to Enhance Expertise in Taxonomy) and supplements in the REU program (Research Experience for Undergraduates) and OCE00-03970 in NOPP (through the National Oceanographic Partnership Program).
Remote Sensing Problem
Many databases of geographical information incorporate remote sensing data. Remote sensing data allows users of GIS technology to extract information about large-scale geographical features or patterns. In most cases it is quicker and more efficient to use remote sensing data than to send researchers out into the field to take small-scale measurements of the phenomena under study.
Global distribution of all Hexacorallian observations in “Hexacorallians of the World”