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U.S. Geological Survey Open-File Report 2008-1351

USGS Cold-Water Coral Geographic Database—Gulf of Mexico and Western North Atlantic Ocean, Version 1.0


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Click on figures for larger images.
Thumbnail image of Figure 2, geographic distribution map of the database, and link to larger figure.

Figure 2. The USGS Cold-Water Coral Geographic (CoWCoG) Database includes information about cold-water corals from over 1,700 locations, mainly in the Atlantic Ocean off the eastern and southeastern United States, with a few off eastern Canada or in the Caribbean region.  Red dots denote locations listed in the database.

Figure 7A.
Thumbnail image of Figure 7A, screen shot of database showing search window, sample and species window, reference information window, and cruise information widow, with link to larger figure.
Figure 7B. Thumbnail image of Figure 7B screen shot of database showing search window, sample and species window, taxonomy window, and reporter information widow, with link to larger figure.
Figure 7C.
Thumbnail image of Figure 7C, screen shot of database showing search results window, with link to larger figure.
Figure 7D.
Thumbnail image of Figure 7D, screen shot of database showing search results window, search results map, and sample and species view window, with link to larger figure.

Figure 7. These four screen shots show examples of typical search results obtained by using the CoWCoG database. A search for Lophelia pertusa, identified by Waller in the Gulf of Mexico, yields the one record, in the spreadsheet at the top (Figures 7A and 7B).  Clicking on the record number brings up the Sample Data window.  The user can toggle between a map of the selected record (Figure 7A) or a photograph of the actual specimen (Figure 7B) in the Sample Data window.

Additional clicks of highlighted fields in the spreadsheet or the Sample Data window open windows with details about taxonomy (Figure 7B), citation (Figure 7A), cruise (Figure 7A), and reporter (Figure 7B). 

A new search for all records for corals in water depths greater than 2000 m returns 47 records, the partial list shown in Figure 7C.  Clicking on the View Map button brings up the Search Results Map (Figure 7D), where the user can select a point on the map (yellow dot, Figure 7D) and bring up the Sample Data page with a closeup map showing only the selected point (foreground, Figure 7D).

In this example, the locations of six entries were very close to the selected point.  The Sample Data window automatically displays the message in red: “Sample 1 of 6 Selected” and a Next button appears so that the entries can be viewed in rapid succession.
Thumbnail image of Figure 9A, map of Hexacorallia samples, with link to larger figure.

Thumbnail image of Figure 9B, map of Octocorallia samples, with link to larger figure.

Figure 9. Corals from the subclass Hexacorallia (A) occur throughout the study area, whereas corals from subclass Octocorallia (B) appear to be concentrated off the northern United States.  The lack of octocoral data off the southern United States is the result of less research in this region and lack of entries in this database rather than a reflection of the actual distribution of octocorals (see text for further explanation).

The USGS CoWCoG database, like other databases, can never be complete as long as exploration continues because new data will become available.  Also, many publications refer to cold-water coral specimens, but do not give exact locations; some of these data could be included in future versions of the database after obtaining more accurate positional data.  As the global importance of cold-water corals becomes clearer, discoveries of new cold-water coral areas are increasing, and new reports are being published. New versions of the CoWCoG database will be planned for release after a substantial number of additions or software updates have been made.

A quick analysis of the data included in this database (figure 2) shows many areas where corals are apparently absent  These areas may represent an absence of exploration by coral scientists, rather than a true absence of corals.  One example of this is the distributions of hexacoral and octocoral data.  Hexacorals appear to be distributed throughout the study area (figure 9A), whereas octocorals appear to be abundant in the area off the northeastern United States and absent in the Gulf of Mexico (figure 9B).  This pattern results largely because one major source of data for the CoWCoG database was Dr. Les Watling’s deep-water coral database (Watling and others, 2003) which covers the areas off the northeastern U.S. and consists primarily of octocorals (his taxonomic specialty). The pattern in this case is probably a reflection of a particular scientist working in a particular region, rather than a reflection of the true distribution of octocorals. This also highlights a shortcoming of many biological expeditions: the shortage of coral taxonomists to identify specimens or examine video and photographic data.

This dataset also includes only entries for which a particular suite of variables was available, primarily taxonomic data at least down to family and accurate geographical positions.  Many reports are taxonomically or geographically vague, such as “scleractinians” or “soft corals” from the “Gulf of Mexico” or “Bear Seamount.”  These organisms commonly turn out to be bryzoans or other taxa because the scientists on board the collecting cruise may not have been trained in benthic biology. Requiring at least a family name for all data entered (though in fact most entries are identified down to species) helps to ensure that the specimen has been correctly identified at least as either a scleractinian or octocoral. Similarly, standards had to be set for the positional data.  For patterns and processes related to cold-water coral distribution and ecology to be examined, all entries needed to be associated with a latitude and longitude; the name of an ocean basin or a geomorphic feature was not sufficient. Even a seamount can cover a very large area on which the coral could be located, and it would be misleading to assign an arbitrary position to include such an imprecisely located record in the database. Because the quality of oceanic navigation data ranged widely (and has improved greatly over the more than 100 years represented in this database), we assigned accuracy rankings to the data in the database. These rankings can be used to exclude the less accurate coral locations.

The uses of this database are numerous. From examining the complete data plot (figure 2) it is clear that cold-water corals live in a variety of locations, habitats, and water depths. Refining searches to display data relevant only to an individual species is also simple. For example, a manager wishing to find the best site for a marine protected area can quickly plot on a map the locations of all Lophelia pertusa, drop in his or her own .shp file of the U.S. EEZ boundary (or other relevant file), print the map, and export a spreadsheet of locations and references. If the manager needs to know more details about these reefs (for example, when they were visited, on which cruises, were samples collected, and so on), and how accurate the data are, he or she can select these fields to be displayed and exported.

The database can also be searched by taxonomy to reveal biogeographic patterns of cold-water corals.  For example, the CoWCoG Database could be used to investigate whether given species are located only in certain habitats, depths, or regions (see figures 7A, 7B, 7C, and 7D for examples). This database can give essential information for planning coral-collection expeditions or for developing models of cold-water-coral occurrences. The wealth of information available for each sample in the database makes many of these analyses possible.

It must be emphasized that the database does not include data about the absence of coral observations. The lack of records for a particular location does not necessarily mean that there are no corals at that location; it may simply mean that no one has looked or that the data are not available. This issue would be useful, albeit enormously time-consuming, to address in the future by including locations that have been explored and are known to have no corals.

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