National Center for Ecological Analysis and Synthesis02-15-2008Sub-Tidal Soft Bottomraster digital dataScience\\ebm\homes\data\marine_threats\data\completed\ecosystems\sub_tidal_soft_bottom\grid\s_t_s_bottomScience02-15-2008A Global Map of human impact on marine ecosystemss_t_s_bottomThe Institute of Arctic & Alpine Research at the University of Colorado at Boulder has collected all available data from benthic substrate point samples, including scientific and industry grab samples, trawls, and core samples, on the rock composition of particular locations around the world as part of the dbSEABED project (http://instaar.colorado.edu/~jenkinsc/dbseabed/). At the time of our purchase of these data (June 2005), the database included 544,543 individual measurements of the percent hard or soft sediment type. The spatial distribution of the data was highly heterogeneous (see Fig. S3), and roughly 65% of the data were 100% soft sediment. Samples with greater than 50% hard substrate were counted as hard; all others were counted as soft. Grid cells were sampled at 2 arc-minutes (~3.7 km, or 13.69 km2 per cell, depending on latitude) and each cell was assigned a binary value of hard or soft substrate. This resolution was used to match the ETOPO2 bathymetry data.
We then used kriging to classify unsampled locations as either soft or hard on the basis of the distribution of substrate types in the surrounding area. Kriging is a statistical interpolation technique for spatial data that uses the spatial variogram of nearby data to assign values to empty cells (S25). Given the vast size of this database, it was not possible to calculate a single variogram for the entire planet, and so we developed variograms for six data-rich regions of the world (Alaska, Florida, Mediterranean, Great Barrier Reef, the North Sea, and New England) and evaluated the kriging solutions that resulted from each of these variograms for indications of poor interpolation, most notably large areas modeled from a single datum and parabolic fan shapes around clusters of points. We used the variogram that resulted in the fewest of these indicators (from the Florida region) and that was from evenly-distributed data that lay along an unbroken swath of coastline with uniform orientation (which reduces clashing trends in the variogram) to produce maps of hard and soft bottom benthic habitats in four different depth ranges - shallow (0-60 m), shelf (60-200 m), slope (200 - 2000 m), and deep/abyssal (>2000 m; Fig. S4. Bathymetry data came from ETOPO2 (2 min. resolution).
Because the distribution of sampling is geographically uneven, some areas of the globe have higher error rates. For example, much of the Southern Ocean is only sparsely sampled in the original point dataset (Fig. S3), and so the kriged data layers for ecosystems in this region have greater errors than for other areas of the globe. In general, shallow and shelf areas are better sampled than continental slopes and deep seafloor, and regions around developed nations (e.g. in North America, Australia and Europe) are better sampled than those around developing nations. In addition, the data may reflect the tendency for trawlers and others sampling the seafloor to avoid hard substrate. Indeed, ~80% of the samples in the original dataset were categorized as soft (~15% mixed-type substrate and 65% entirely soft-sediment), a likely overestimate of the amount of soft substrate on the ocean floor. Accordingly, we anticipate that the distribution of hard substrate will be under-predicted by this method. Given that soft substrates generally tend to be less vulnerable to anthropogenic drivers of change than hard substrates, this method will be conservative with respect to overall impact levels.
What happens in the vast stretches of the world's oceans - both wondrous and worrisome - has too often been out of sight, out of mind.
The sea represents the last major scientific frontier on planet earth - a place where expeditions continue to discover not only new species, but even new phyla. The role of these species in the ecosystem, where they sit in the tree of life, and how they respond to environmental changes really do constitute mysteries of the deep. Despite technological advances that now allow people to access, exploit or affect nearly all parts of the ocean, we still understand very little of the ocean's biodiversity and how it is changing under our influence.
The goal of the research presented here is to estimate and visualize, for the first time, the global impact humans are having on the ocean's ecosystems.
Our analysis, published in Science February 15, 2008, shows that over 40% of the world's oceans are heavily affected by human activities and few if any areas remain untouched.
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Ben HalpernNational Center for Ecological Analysys and SynthesisAssistant Research Scientistsmailing and physical address
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Santa BarbaraCalifornia93101USA(805)-892-2531(805)-892-2510halpern@nceas.ucsb.eduNational Center for Ecologial Analysis and SynthesisMicrosoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.0.1324Raster DatasetRasterGrid Cell1111.0000001.0000008Upper LeftFALSENone1matrix valuesFALSErow and column1.0000001.000000National Center for Ecoogical Analysys and Synthesishttp://www.nceas.ucsb.edu/GlobalMarineDownloadable Data11.28911.28920080213National Center for Ecological Analysis and SynthesisColin EbertGIS AnalystREQUIRED: The mailing and/or physical address for the organization or individual.REQUIRED: The city of the address.REQUIRED: The state or province of the address.REQUIRED: The ZIP or other postal code of the address.805-892-2500ebert@nceas.ucsb.eduhttp://www.nceas.ucsb.edu/GlobalMarine/FGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998local timehttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profileenhttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile{888E5ACE-798D-4CFE-A304-82ACD211E6C6}2008021312251100FALSE20080213153528002008021315352800Metadata imported.C:\DOCUME~1\Ebert\LOCALS~1\Temp\xml92.tmp20080213Microsoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.0.1324s_t_s_bottom-0.50.50.5-0.51ISO 19115 Geographic Information - MetadataDIS_ESRI1.0datasetfile://\\ebm\homes\data\marine_threats\data\completed\ecosystems\sub_tidal_soft_bottom\grid\s_t_s_bottomLocal Area Network00211.289Raster Dataset2111unknown11unknown20080213