Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the 

U.S. Government

This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters 

and between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and 

proportions may not be true on plots of this map.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS

Digital files available at http://pubs.usgs.gov/sim/3302/

Suggested Citation: Dieter, B.E., Greene, H.G., Endris, C.A., Erdey, M.D., and Golden, N.E., 2014, Potential marine benthic habitats, 

Offshore of Coal Oil Point map area, California, sheet 7 in Johnson, S.Y., Dartnell, P., Cochrane, G.R., Golden, N.E., Phillips, E.L., 

Ritchie, A.C., Kvitek, R.G., Dieter, B.E., Conrad, J.E., Lorenson, T.D., Krigsman, L.M., Greene, H.G., Endris, C.A., Seitz, G.G., Finlayson, 

D.P., Sliter, R.W., Wong, F.L., Erdey, M.D., Gutierrez, C.I., Leifer, I., Yoklavich, M.M., Draut, A.E., Hart, P.E., Hostettler, F.D., Peters, K.E., 

Kvenvolden, K.A., Rosenbauer, R.J., and Fong, G. (S.Y. Johnson and S.A. Cochran, eds.), California State Waters Map Series—

Offshore of Coal Oil Point, California: U.S. Geological Survey Scientific Investigations Map 3302, pamphlet 57 p., 12 sheets, scale 

1:24,000, http://dx.doi.org/10.3133/sim3302.

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3302

US Army Corps

of Engineers

EXPLANATION

Approximate modern shoreline—Defined as

Mean High Water (MHW) (+1.33 m), North

American Vertical Datum of 1988 (NAVD 1988)

! Video observation

# Sample locality

3-nautical-mile limit of California’s State Waters

Bathymetric contours—Derived from modified

10-m-resolution bathymetry grid. Contour

intervals: 0–100 m water depth, 10 m; 

>100 m water depth, 50 m

Habitat interpretation outline

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120°0' 119°55' 119°50'

34°25'

Figure 1. Map showing video-observation locations and sample localities for Offshore of Coal Oil Point map 

area.

34°30'

CALIF.

0 4 8 Nautical Miles

Kilometers 0 5 10

120° 119°40' 119°20' 119°

34°

34°20'

MAP LOCATION

Ventura

Santa Barbara

Anacapa

Island

Santa Cruz Island Santa Rosa Island

Area of

Map

Santa Barbara Channel

Limit of California’s

State Waters

100

Sh_a-p

Shm_a-s*(q)

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Ssm_a/u*(q)

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Ss(s/m)h_e/u

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DESCRIPTION OF MAP UNITS

UNCONSOLIDATED CONTINENTAL SHELF SEDIMENTS

Soft, unconsolidated sediment (sand and mud), predominantly rippled

Pockmarks or depressions, in soft, unconsolidated sediment (sand and mud)

Soft, unconsolidated sediment (sand), rippled

Terrace, or possibly delta or fan, composed of soft, unconsolidated sediment (sand), 

predominantly rippled 

Hummocky mounds of soft, unconsolidated delta sediment

Mound of coarse-grained, soft, unconsolidated sediment (cobbles and pebbles) 

MIXED SUBSTRATE ON CONTINENTAL SHELF

Hydrocarbon-seep depression, in soft, unconsolidated sediment

Mixed habitat of soft, unconsolidated sediment, overlying hard, consolidated 

sedimentary bedrock

Mixed habitat of soft, unconsolidated sediment, overlying hard carbonate substrate

Mixed habitat of soft, unconsolidated sediment, overlying hard tar deposits; inferred

HARD SUBSTRATE ON CONTINENTAL SHELF

Hard mound made up of carbonate rock

Hard, exposed tar mound

Differentially eroded sedimentary-bedrock outcrop

Deformed and differentially eroded sedimentary-bedrock outcrop

Hard boulders or pinnacles of exposed asphalt; inferred

UNCONSOLIDATED CONTINENTAL SLOPE SEDIMENTS

Landslide scarp, in soft, unconsolidated sediment

Soft, unconsolidated sediment (sand and mud), rippled

Pockmarks or depression, in soft, unconsolidated sediment (sand and mud)

HARD SUBSTRATE ON CONTINENTAL SLOPE

Deformed and differentially eroded sedimentary-bedrock outcrop

ANTHROPOGENIC FEATURES

Trawl grooves and marks, in soft, unconsolidated sediment (sand and mud)

Oil-platform-generated shell hash mound mixed with soft, unconsolidated sediment 

Linear depression, in soft, unconsolidated sediment overlying hard anthropogenic 

feature (pipeline)

Oil-platform structural-foundation framework (legs and pipes) and shell mound

Hard anthropogenic feature (pipeline)

EXPLANATION OF MAP SYMBOLS

Contact

Area of “no data”—Areas near shoreline not mapped owing to insufficient highresolution seafloor mapping data; areas beyond 3-nautical-mile limit of California’s 

State Waters were not mapped as part of California Seafloor Mapping Program

3-nautical-mile limit of California’s State Waters

Bathymetric contour (in meters)—Derived from modified 10-m-resolution bathymetry grid. Contour intervals: 1–100 m water depth, 10 m; >100 m water depth,

50 m

DISCUSSION

This map shows “potential” marine benthic habitats in the Offshore of Coal Oil Point map area. Marine 

benthic habitats represent a particular type of substrate, geomorphology, seafloor process, or any other attribute 

that may provide a habitat for a specific species or an assemblage of organisms. Such maps are based largely on 

seafloor geology, and this map integrates seafloor geology (sheet 10) with information depicted on several other 

thematic maps of the Offshore of Coal Oil Point map area: high-resolution bathymetry (sheet 1); shaded-relief 

imagery (sheet 2); backscatter (sheet 3); seafloor character (sheet 5); and ground-truth information (sheet 6). This 

map also uses information from the usSEABED bottom-sampling compilation by Reid and others (2006). The 

combination of remotely observed data (for example, multibeam bathymetry and backscatter, seismic-reflection 

profiles) and directly observed data (for example, camera transects, sediment samples) translates to higher 

confidence in the ability to interpret broad areas of the seafloor. 

To avoid any possible misunderstanding of the term “habitat,” the term “potential habitat” (as defined by 

Greene and others, 2005) is used herein to describe a set of distinct seafloor conditions that in the future may 

qualify as an “actual habitat.” Once habitat associations of a species are determined, they can be used to create 

maps that depict actual habitats, which then need to be confirmed by “ground-truth” surveying using in situ 

observations, video, and (or) photographic documentation. 

Marine benthic habitats are classified using the Benthic Marine Potential Habitat Classification Scheme, a 

mapping-attribute code developed by Greene and others (1999, 2007). In this map series, habitat-classification 

codes are based on the deepwater habitat-characterization scheme developed by Greene and others (1999), which 

was created to not only easily distinguish marine benthic habitats but also to facilitate ease of use and queries 

within GIS and database programs. The code, which is summarized in chapter 6 in the accompanying pamphlet, 

is derived from several categories of the Benthic Marine Potential Habitat Classification Scheme (Greene and 

others, 1999, 2007), and it can be subdivided on the basis of the spatial scale of the data. 

High-resolution, multibeam-sonar data, converted to bathymetric depth grids (seafloor digital elevation 

models; sheet 1), are essential to development of the habitat map. Shaded-relief imagery (sheet 2) allows for 

visualization of seafloor terrain, providing a foundation for interpretation of submarine landforms. Areas of 

seafloor bedrock exposures are identified by their common sharp edges and high relative relief; these may be 

contiguous outcrops, isolated parts of outcrop protruding through sediment cover (pinnacles or knobs), or 

isolated boulders. High backscatter is further indication of “hard” bottom, consistent with interpretation as rock 

or coarse sediment. In many locations, areas within or around a rocky feature appear to be covered by a thin 

veneer of sediment, identified on the habitat map as “mixed” induration (in other words, containing both rock and 

sediment). Broad, generally smooth areas of the seafloor that lack sharp and angular edge characteristics are 

mapped as “sediment” and are further defined by various sedimentary features such as erosional scours and 

depressions, as well as depositional features such as dunes, mounds, or sand waves. Low backscatter, indicative 

of a “soft” bottom, also significantly aids identification and classification of sedimentary habitats.

The Offshore of Coal Oil Point map area contains 24 potential marine benthic habitat types within two 

megahabitat settings: Shelf (continental shelf), and Flank (basin flank or continental slope). On the shelf, these 

habitat types range from predominantly soft, unconsolidated sediment (sand and mud to cobbles and pebbles) to 

areas of hard bedrock exposures, including flat carbonate substrate and differentially eroded, well-bedded 

sedimentary-bedrock outcrops. Some sedimentary-bedrock outcrops are partly covered with soft, unconsolidated 

sediment to produce a hard-soft mixed habitat type. Pockmarks, tar mounds, and carbonate mounds complete the 

variety of habitats identified on the continental shelf in the map area. Significant anthropogenic features associated with oil production, such as platforms, pipelines, and shell mounds beneath platforms, as well as remnant 

mounds from past seafloor-exploitation activity, all produce artificial habitats for rockfish (Sebastes spp.). In the 

narrow band of basin-flank or continental-slope megahabitat, macro- and mesohabitats of predominantly soft, 

unconsolidated sediment with numerous pockmarks have been mapped. This suggests a very “leaky” area where 

gas and fluids associated with hydrocarbon reservoirs at depth have been escaping from the seafloor. 

The soft, unconsolidated sediment habitat on the Shelf megahabitat, which includes pockmarks and inferred 

sediment-covered tar flows (see sheet 11, this report), covers 78.13 km2

 of the total 109.65 km2 area mapped, 

representing 71.3 percent of all of the potential habitat types identified. Sediment-covered bedrock on the 

continental shelf, which includes the mixed hard-soft habitat type, covers 5.17 km2, about 4.7 percent of the 

potential habitats mapped. Hard bedrock exposures on the continental shelf cover 14.41 km2 (13.2 percent), 

whereas anthropogenic features on the shelf cover almost 0.1 km2, only a fraction of habitat area. On the Flank 

megahabitat, soft, unconsolidated sediment habitat covers 10.3 km2, representing 9.4 percent of all habitats 

mapped in the Offshore of Coal Oil Point map area; hard bedrock exposures at the top of the slope cover 1.5 km2, 

representing 1.4 percent of all habitat types mapped.

Fluid flow to the seafloor from petroleum reservoirs at depth resulted in the formation of hard, carbonatecemented sediment substrate, carbonate mounds, pockmarks, and asphalt (tar) mounds. Sheet 11 of this report 

shows detail of seafloor hydrocarbon seepage and related asphalt and tarball accumulations. Exposed carbonate 

mounds and hard ground, locally covered with sediment, provide potential habitat for sessile organisms. This mix 

of potential marine benthic habitat types provides the varied relief, in addition to the rugosity and substrate 

hardness, that may contribute to the concentration of a diverse marine ecosystem within an otherwise homogeneous, soft, unconsolidated sediment habitat.

REFERENCES CITED

Greene, H.G., Bizzarro, J.J., O’Connell, V.M., and Brylinsky, C.K., 2007, Construction of digital potential 

marine benthic habitat maps using a coded classification scheme and its application, in Todd, B.J., and 

Greene, H.G., eds., Mapping the seafloor for habitat characterization: Geological Association of Canada 

Special Paper 47, p. 141–155. 

Greene, H.G., Bizzarro, J.J., Tilden, J.E., Lopez, H.L., and Erdey, M.D., 2005, The benefits and pitfalls of 

geographic information systems in marine benthic habitat mapping, in Wright, D.J., and Scholz, A.J., eds., 

Place matters: Portland, Oregon State University Press, p. 34–46.

Greene, H.G., Yoklavich, M.M., Starr, R.M., O’Connell, V.M., Wakefield, W.W., Sullivan, D.E., McRea, J.E., 

and Cailliet, G.M., 1999, A classification scheme for deep seafloor habitats: Oceanologica Acta, v. 22, p. 

663–678.

Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED—

Pacific Coast (California, Oregon, Washington) offshore surficial-sediment data release: U.S. Geological 

Survey Data Series 182, available at http://pubs.usgs.gov/ds/2006/182/.

1

Moss Landing Marine Laboratories, Center for Habitat Studies;

2

U.S. Geological Survey 

Potential Marine Benthic Habitats, Offshore of Coal Oil Point Map Area, California

By

Bryan E. Dieter,1 H. Gary Greene,1 Charles A. Endris,1 Mercedes D. Erdey,2 and Nadine E. Golden2

2014

ONE MILE = 0.869 NAUTICAL MILES

BATHYMETRIC CONTOUR INTERVAL 10 AND 50 METERS

1 .5 0 1 KILOMETER

1000 0 1000 2000 3000 4000 5000 6000 7000 FEET

1 1/2 0 1 MILE

SCALE 1:24 000

APPROXIMATE MEAN

DECLINATION, 2014

MAGNETIC NORTH

12 / ° 1 2

TRUE NORTH

Potential marine benthic habitats mapped by Bryan E. Dieter, Charles 

A. Endris, and H. Gary Greene, 2011. Bathymetric contours by Andrew 

C. Ritchie, 2011

GIS database and digital cartography by Nadine E. Golden, Charles A. 

Endris, and Mercedes D. Erdey

Edited by Taryn A. Lindquist

Manuscript approved for publication June 2, 2014

Onshore elevation data from NOAA Coastal Services Center (data 

collected by EarthData International in 2002-2003) and from U.S. Army 

Corps of Engineers (data collected by Fugro Pelagos in 2009). 

California's State Waters limit from NOAA Office of Coast Survey

Universal Transverse Mercator projection, Zone 11N

NOT INTENDED FOR NAVIGATIONAL USE

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119°50'

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119°55'

119°55'

120°

120°

34°30'

34°25'

34°25'

Scientific Investigations Map 3302

Sheet 7 of 12

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey