SOUTHERN CALIFORNIA BASELINE STUDY AND ANALYSIS …

SOUTHERN CALIFORNIA BASELINE STUDY AND ANALYSIS (1975/1976)

I VOLUME I - EXECUTIVE SUMMARY IPREPARED BY SCIENCE APPLICATIONS, INC.

FOR THE

BUREAU OF LAND MANAGEMENT

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SOUTHERN CALIFORNIA BASELINE STUDY AND ANALYSIS1975-1976

VOLUME IEXECUTIVE SUMMARY

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by: Richard A. Callahanand

Robert Shokes

Science Applications, Inc.1200 Prospect St.

La Jolla, California

Submitted to the Bureau of Landpartial fulfillment of Contract

Management08550.-CT5–52

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FOREWORD

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This program has been performed as a cooperative effort between nine–teen scientists with academic affiliations, three private companiesand an arm of the federal government.

The successful performance of a program of this size and scope is theresult of the hard work and dedication of the ’200 participants.Several individuals however played roles which largely determined thesuccess of this study. These include:

Dr. Isaac Kaplan who originally organized the group and performed aleadership role throughout the program. Drs. Arnold Bainbridge, T.Chow, Osmund Helm-Hansen, Gilbert Jones, Mark Littler and Mssrs.Willard Bascom and M. L. Moberg who ably served on the SteeringCommittee,

Mr. Leonard Cunningham was key to the very successful shipboard opera-tions which characterized this program.

Participation in this program has been a unique and fulfillingexperience largely because of the high aspirations, professionalstandards and performance common to its participants.

R.A. Callahan and R.F. ShokesLa Jolla, CaliforniaMarch 1977

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heavily contaminated with petroleum,trace metals or urban effluents. tlow–ever , the ability of this study todiscern such changes was limited.

- Mainland rocky intertidal sites havefewer organisms and fewer kinds oforganisms than similar island sites.Mainland organisms are also lessvigorous than similar island forms.These changes appear to be due tochemical or physical stresses impactingmainland habitats.

- Crude oil appears to have altered thecomposition of the rocky intertidalplant communities at Coal Oil Point.

- Four communities of microinfauna(foraminifera) live in the SouthernCalifornia OCS. These communitiesoccupy shallow water, slope or basinhabitats.

- All offshore infaunal communities areimpoverished in areas of active sedimenttransport or deposition.

- Seasonal changes in rocky intertidalcommunity structure are slight.

. Animals from locations contaminated withpetroleum or trace metals typicallyincorporate them into their tissues.Information gained during this study wasused to select “indicator” species forsubsequent studies.

petroleum hydroc~rbons cdn be measured atpredevelopment concentrations and crudepetroleum can usually be differentiatedfrom other hydrocarbons, including refinedoils.

The Tanner–Cortes Banks region supports anunusual assemblage of shallow water andopen ocean organisms. At least two uncom-mon organisms occur on these banks; apurple coral and a very primitive molluscof the order Monoplacophora.

Significant improvements were made in thecollection, analyses and interpretation ofpetroleum hydrocarbon and trace metal chem-ical data. These improvements allowed thereliable measurement of predevelopmentconcentrations of hydrocarbons and tracemetals.

– Five devices for collecting uncontami-nated water and uncontaminated andundisturbed sediment samples suitablefor chemical analyses were eitherdeveloped or redesigned from existing“research” devices. The use of suchstate-of-the-art equipment has demon-strated the practicability of obtaininga chemical data base of sufficient sizeand quality to resolve regional differ-ences in the chemistry of the SouthernCalifornia Bight.

- Analytical methodologies were developedwhich allowed the discrimination ofpetroleum type hydrocarbons from otherhydrocarbons.

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LIST OF TABLES

Table w

I-1 Summary of key personnel, affiliation and project area . . . . . . . . . . . . . . . 2

LIST OF FIGURES

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Geological map of sea floor and adjacent land showing complex topography of theSouthern California Borderland . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Southern California Borderland topographical relief . . . . . . . . . . . . . . . . 7

Sources of contamination at sea . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Sediment sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Water sampling. . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Factors influencing the measurement of petroleum in the marine environment . . . . . 12

Southern California Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Existing living foraminiferan communities in the Southern California OCS regiondetermined byclusteranalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

The Southern California OCS showing the intertidal sampling sites . . . . . . . . . 25

Schematic profile of a typical exposed sandy beach . . . . . . . . . . . . . . . . . 32

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1.0 lNTRODUCT1.ON

The “Southern California Baseline Study andAnalysis” is one of several marine environ-mental studies of the Outer ContinentalShelves (OCS) of North America sponsored bythe Department of Interior, Bureau of LandManagement. Selected areas of the SouthernCalifornia OCS are currently being leased bythe Department of Interior to private concernsinterested in discovering and extractingpetroleum reserves.

This effort consisted of studies of theOffshore and Intertidal environments. TheOffshore study was designed to provide aninitial descriptive overview of the chemical,biological and sedimentological regimes of theSouthern California OCS. The primary purposeof this overview was to describe this

environment and the association of the variousanimal communities, sediments, chemicalconstituents, water depth, and geographicalareas.

The Intertidal study provided a statisticalanalyses of the floral and faunal communitiesoccupying rocky and sandy beach habitats withemphasis on the associations between organ-isms, petroliferous and other anthropogenicinputs, substrate type, tidal height, geo-graphic area and seasonal fluctuations. Thestudy was conducted during calendar years1975-1976 through a contract to Science Appli-cations, Inc. (SAI) , La Jolla, California.SAI subcontracted nineteen field sampling andanalytical tasks to principal investigatorsfrom universities and two tasks to privateindustries (Table 1–1).

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Table I-1. Summary of key personnel, affiliation and project area.

University California, Berkeley (UCB)

Dr. A. L. Burlingame Hydrocarbon Characterization (GCMS)

Dr. Robert Risebrough (Bodega) Hydrocarbon Analysis - Water, Biota

University California, Santa Cruz (UCSC)

Dr. Kenneth Bruland Trace Metal Analysis - Suspended Particulate

California Institute of Technology, Pasadena (CIT)

●Dr. Claire Patterson

University Southern California (USC)

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Dr.

Dr.

Dr.

Dr.

Dale Straughan

Robert Douglas

Gilbert Jones

Kristian Fauchald

California State University-Northridge (CSU-N)

Dr. Peter Fischer

San Jose State University (SJSU)

Dr. John Martin(Moss Landing)

San Diego State University (SDSU)

Dr. Richard Berry

Analytical Research Laboratory, Inc. (ARLI)

Mr. M. L. Moberg

Escatech, Inc.

Mr. David Hodder

Trace Metal Lab Calibration

Sandy Beach/Slough Sampling and Community Analysis

Microfaunal Sampling and Analysis

Benthic Sampling and Macrofaunal Analysis

Benthic Sampling and Macrofaunal Analysis

Sediment Geochemistry and Characterization

Trace Metal Analysis - Biota

Sediment Geochemistry and Characterization

Hydrocarbon Analysis - Sediments and Biota

Aerial Photography and Kelp Bed Analysis

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3.0 OFFSHORE WATER COLUMN AND BENTHIC STUDIES

3.1 Sampling and Analytical Problems

The acquisition of reliable data which can besuccessfully used by decisionmakers to managethe use of natural resources requires collec–tion and handling techniques which supplyphysically intact, uncontaminated and repre-sentative samples, as well as analyticaltechniques which can generate sensitive data.For example, small changes in the concentra–tions of petroleum or trace metals in themarine environment can not be monitored ifpredevelopment concentrations have not beenreliably estimated. Predevelojnnent concen-trations of petroleum in some areas of theSouthern California OCS were measured to be aslow as 1X10-8 grams per thousand grams ofwater, equivalent to one drop of petroleum in220,000 gallons. Such low concentrationscannot be measured if any contamination of thesample occurs.

At the initiation of this study, especially inthe area of low-level chemical sampling, ade-quate shipboard collection and handling tech-niques had not been applied to a marine pro-gram of this size with similar time con-straints. Extensive efforts were made duringthe first phases of this study to developpractical, cost-effective sampling techniqueswhich would routinely provide reliablechemical data.

tions taken in this program to avoid them.Other precautions for trace metal samplingincluded the use of Teflon-lined, PVC collec–tion bottles, non-metallic line, plasticsheaves, polyethylene-shielded lead weights,Teflon messengers, and an electric/hydraulicwinch with a stainless steel drum. The philo–sophy of excluding contamination when at allpractical was extended to every aspect of thechemical sampling program.

3.1.2 Contamination from Sampling Techniques

Three samplers which enable collection ofuncontaminated, representative sediment andwater samples were developed for routine sam-pling. Figure 1-4 illustrates two of thesesamplers and how they work. An importantaspect of these samplers and their associatedtechniques is that they not only minimizecontamination but also maximize standardiza-tion (i.e., sampling reproducibility). Rig-orous standardization of sampling and analy-tical techniques is critical when results willbe used to describe chemical changes in spaceand time.

In addition, an in situ water sampler wasdeveloped which p~mises to allow the quan-titative extraction of a wide range of hydro-carbons directly from sea water, avoiding thenecessity of collecting large quantities ofwater for extraction in the laboratory.

3.1.3 Analytical Methods3.1.1 Contamination from Sampling Platforms

Figure I-3 illustrates some of the sources ofchemical contamination encountered when sam-pling at sea and describes the major precau-

Developing the capability to measure petroleumin the marine environment was an essentialelement of this study. A change in petroleumconcentrations of from one to two drops per

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water can represent aconcentrations at thesampled off Southern

Figure I–5 illustrates the necessity andcomplexity of discriminating between petro-leum-related compounds and other types ofhydrocarbons , and between crude and refinedpetroleum.

Three to four months after initiating thisprogram, the participating scientists and BLMtechnical representatives became aware that

the then-accepted hydrocarbon analyticaltechniques would not provide data suitable forthe needs of this program. The existingmethods lacked the sensitivity to determinethe low concentrations present, as well as theability to repeat the results on the samesample and the qualitative resolution toseparate crude petroleum from other hydro-carbons. A major effort was made to improvehydrocarbon analytical methods by the chemistsin the Southern California OCS study, comple-menting similar efforts initiated in other BIMOCS programs. Substantial progress was madeduring the initial year’s program. The re-sults of these efforts can be seen in theability of this study to discriminate petro–leum from other types of hydrocarbons presentin the Southern California Bight.

3.2 Sampling Design and Results -- Benthicand Water Column

This section summarizes the results of studies

●concerning the sedimentology, chemistry andbiology of the Southern California OCS,touches on the complex regional variations

found in all parameters measured, and whenpossible assesses their biogeochemical rela-tionships.

Benthic sampling was focused within areas ofhigh station density (High Density SamplingAreas , HDSAS) corresponding roughly to areasof high lease interest (Figure I-6). Add i-tional sampling was performed at dispersedstations for broad coverage. This samplingdesign allowed coverage of the five majorsubregions of the Southern California OCS asdefined on the basis of geographical andenvironmental criteria: (1) the inner Shelfregion, (2) the Inner Basin region, (3) theOuter Shelf region, (4) the Outer Basin regionand (5) the Outer Banks region (Figures I-1 toI-2).

3.2.1 Benthic Sedimentology

Three approaches were used to examine thesediment data: (1) Regions were compared bytheir mean sediment parameter values. Indoing so, comparisons between mean grain size,kurtosis and skewness for each sediment sampleprovided easily visualized relationships.(2) Correlational analyses were used to exa–mine trends between certain sediment charact-eristics and depth. (3) Trend surface analy-ses were used to contour the the high densitysampling regions for those variables consid-ered significant.

Sediments from the inner shelves are typicallycoarse, and rich in heavy minerals. Thes esediments are selectively left behind aftertheir finer-grained components have been movedinto the basins by the high energy forces(waves and surf) at work in shallow waters.

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Sampling MethodsThe cnncentmticrns of trace mrmls wrd pe-troleum must be precisely determined in themarine cnvironmem in urder to cstabl ishpredevelopmcn[ conditions. These samemethods will help de[errninc if changes occurthrough time. Marine samples fur chemicalanalysis are often contaminated during sssm-pling. In order k) uvoid [hcse problems newsampling techniques were develuped andexist int? techniques were extensivelymodifiei.

Two ncw sampling devices are illustrated.On the left page is a modified Soutar box corerwhich collects undisturbed and uncontami-nated swrrplcs, from soft bottoms. Thisboxcorer, and u similarly designed Van Veengrab sampler for sandy bo~toms (nut shown),descend through the wsrtcr column as opencylinders. This eliminates surface sedimentdisruption caused by the bow wave andhydraulic pressure within incompletely ventedsystems. Both the corer and grab sirmpler aremade of noncontamimrtirrg materials whichgreatly redurx potential sources of hydrocar-bon and trace meurl contamination. Reproduc-ible subsampling of sediments to uniformdepths was accomplished using a template.The template was pressed into the sample; thesubsamplc was removed from within thetemplate guide using a trowel presel to collectthe desired depth.

The third chemical sampling device wasdeveloped to obtain uncontaminated watersamples for hydrocadmn analysis from anydepth desired. The sampler is an extensiveredesign of Woods Hole’s Bodman sampler.The redesign was performed by [he BodegaMarine Laboratory and Ocean Industries, Inc.Moditlcations allow the sssmpler never to beopened on the deck of the ship and to passthrough the air surface interface closed; thesampler opens and closes underwater. BLM “sBodega Bmfrmsn sampler is consh-ucted ofnon-contaminating materials and is equippedwith an automatic bottom closing pilot weigh!release mechanism. A dual pulse-rate pingerchanges frequency when the sampler opens orcloses. Quick disconnect nitrogen purge andsample drainage valves ensure efficientconnection m filtration and storage bottleshoused within a clean room.

Figure I-4b. Water sampling.

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amounts contained within their matrices. Thisapproach was taken in the expectation that anyanthropogenic metal alterations would appearin surface coatings. Both surface and nearbottom particulate and dissolved samples wereanalyzed for hydrocarbons.

3.2.3 Benthic and Water Column ChemistryResults

Metals in Sediments and Water Particulate

In general the metal concentrations of watercolumn particulate and bottom sediments fromthe Southern California OCS reflect the chem-istries of their source materials. The waterssampled between the mainland and first set ofoffshore islands can be expected to contain apreponderance of land-derived materials whosemetal contents have in some cases been af-fected by contact with urban effluents. Sur-face water from these areas usually containsonly fine-grained terrigenous minerals mixedwith smaller proportions of planktonic organ-isms. ‘I’he near-bottom waters tend to re-suspend various assortments of bottom mater-ials ranging from fine-grained to relativelycoarse.

The particulate material suspended in thewaters of the outer areas is somewhat dif-ferent from that found near-shore, being acombination of relatively coarse debris fromthe islands and outer banks (Tanner andCortes) and other bodies of living and deadplanktonic organisms. The planktonic con-tribution is particularly evident in the sur-face waters in the outer edge of the SouthernCalifornia OCS where upwelling supports anunusually high level of primary productivity.

Although particulate suspended in the watercan be considered to be sediments on their wayto the bottom, there are observable differ-ences in the metal concentrations measured insettled and unsettled materials. These dif–ferences occur because the origins of thesesettled and unsettled particulate are dif-ferent. It is interesting to note that bothsurface and deep particulate and suspendedparticulate and deposited sediments differ intrace metal chemistry. In most cases through-out the Southern California OCS there areslight elevations in the metal concentrationsof deep particulate relative to surfaceparticulate. This is caused either by lossof organic matter as the particles sink or bymore extensive adsorption of metals onto thesurfaces of the finer-grained deep samples(especially true in the deep basins). Onlybarium, which decreases in concentration withwater depth, and cadmi~, which is relatively

uniform with depth, depart from this trend.

In most cases, the metal concentrations ofsuspended particulate from near-bottom watersare elevated relative to the deposited sedi-ments lying beneath. In almost every in-stance, the disparity in the chemistries ofthese two phases can be explained by naturalphysical and chemical processes acting on thedeposited sediments and altering their con-centration distributions.

Near-shore sediments tend to be highly vari-able in metal contents, at times exhibitingthe effects of local sources of pollution.The deeper water sediments found in the off-shore basins are normally enriched in metalconcentrations relative to near-shore mater-

ials, but these enrichments are typically

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as compared to other sources. Al though manygeographical areas were represented by onlY afew samples, several generalizations can beinferred from these parameters.

For the inner basins, indications of thepresence of petroleum in bottom sediments aregreatest in samples from Santa Barbara Easin,the northern part of the south coastal basin,and three stations from Santa Monica Basin.For Santa Mrbara Basin the high petroleumlevels are likely the result of natural seep-age from Coal oil Point, whereas those forSanta Monica and northern South Coast Basinscould result from seepage, sewage (includingindustrial discharge), shipping, harbor traf-fic, or any combination of the four. Moderatevalues observed in San Pedro Basin and themajority of the Santa Monica Basin samplessuggest a ‘blend’ of natural and man-derivedcontributory sources.

In the outer basins and slopes the greatestindications of petroleum occur in sedimentsfrom the Tanner-Cortes and San NicolasBasins, as well as in those collected fromsouth of San Miguel Island, south of SantaRosa Island and northwest of Santa CatalinaIsland. Petroleum burdens in most of theseareas can be directly related to known naturalseeps, military activities, or proximity toshipping lanes.

In addition to petroleum-related hydrocarbons,those derived from biological processes (e.g.)productivity) were also found at various con-centrations to some degree in all of the sedi-ments collected in this study. The two mainsources of these biogenic hydrocarbons in mostnear-shore marine areas are (1) run-off from

land contributing the remains and products ofterrestrial vascular plants and (2) metabolicmaterials from marine plankton.

Sediments containing materials from terres-trial plant waxes are distributed throughoutthe Southern California OCS, although ingeneral, locations exhibiting the highestproportions are limited to the near-shoreshelf and adjacent basins. Inputs from otherhydrocarbon sources often ❑ ask the presence ofthe plant wax component in near-shore areas(e.g., Santa Barbara, Santa Monica and SanPedro Basins and adjacent shelves).

Hydrocarbons derived from both living and deadmarine plankton generally increase with dis-tance from the mainland and with coarser sedi-ment grain size. Both of these trends, how-ever, are ultimately related to the charactersof sediments generally found underlying watersof high productivity.

Hydrocarbons in the Water Column

The concentrations of hydrocarbons dissolvedand suspended in marine waters were found tobe very low in all samples not collected inclose proximity to outfalls. Concentrationsas low as 60 rig/liter (sixty billionths of agram per liter) were measured in open waters,while more common dissolved fractions variedfrom 0.15 to 11 pg/1, (eleven millionths of agram per liter) and those associated withparticulate ranged from undetectable to 2.1Pgll. (An exception of one sample off theHyperion outfall which had a particulatehydrocarbon load of 81.0 pg/1.) Typically,10-20 times more dissolved hydrocarbons werepresent than those associated with parti-culate.

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contained materials which are charac~eristi–tally biogenic. Organisms living in basinswere found to have hydrocarbon concentrationssomewhere in the middle to high range.However, their body burdens were of a morebalanced petrogenic/biogenic character thanwere the animals associated with near-shoreseeps and outfalls.

3.2.4 Benthic Biology (Macro and MicroInfauna)

The purpose of the benthic community analysiswas to define infaunal assemblages –- thecommunities of animals that live in the bottomsediments –- throughout the study area. Sincethese animals have very little mobility andlive in a relatively stable environment,studying changes in their community structureover time could provide observable indicationsof the impact of man’s activity on a diversecommunity of marine organisms. Two types ofbenthic infauna were studied, macroinfauna(animals larger than 1.5 mm) and microinfaunaof the class Foraminifera. Foraminifera aresmall calcareous–shelled animals which can betaxonomically classified by the shells (tests)alone. These shell fragments persist inmarine sediments for many thousands of years.Foraminiferal community analyses have beenextensively used to provide information con–cerning environmental conditions in thegeological past.●

The benthic infaunal study included elevenhigh density sampling areas (HDSAS) in whichconcentrated sampling was employed. With oneexception these areas were associated with thefive lease tract areas proposed by the BLM foroffshore resource development (see Figure1-6).

In adcliton to the tIl)S,4’S, more scattered,broad-coverage “survey” stations were sampledthroughout the Southern California (_KS.

8oxcores , augmented by trawls and dredges wereused for the collection of selected macroin–vertebrates for taxonomic and chemical analy–sise Box cores were collected from 711stations; 145 trawl/dredge samples were taken.

Box cores were collected with a standard NavalElectronics Laboratory (NEL) spade corerequipped with a stainless steel sample box of0.063-m2 surface area and an underwater-shutter 35 mm camera designed to photographthe sediment to be sampled just prior topenetration. The photographs were used toobserve the ocean floor around the boxcoresample. All organisms larger than 1.5 mm wereremoved from the sediment and preserved forlater identification in the laboratory.

Three separate types of analyses were con–ducted on the macrobiota collected byboxcoring:

1. Preliminary community analysis(coarse-sort) of all 711 box coresamples ..

2. Rapid Identification Procedure (RIP)of 546 of these samples, and

3. Complete, or detailed, analysis(fine-sort) of lb5 of these samples.

The preliminary analysis, or coarse sort,involved separating those organisms retainedon the screen into five major groups, andrecording the number of individuals and the

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ment of an assemblage indicated more signifi–cant ecological relationships than obtained byunabridged statistics. Estimates of foramini-fera standing crop and species diversity weredetermined by counting live and dead individ-uals.

Analytical methods focused on the possiblerelationships between changes in the physicalenvironment and in the communities understudy. Plots of liveldead ratio, standingcrop, species diversity, number of species andnumber of individuals as functions of waterdepth, various sediment characteristics andother physical environmental factors wereemployed. Besides cluster analysis, multipledescriminant analysis was applied.

3.2.5 13enthic Biology Results

Macrofauna

The HDSAS could be separated into three dis-tinct macrofaunal groups: a nearshore group(Huntington Beach-Laguna Beach, Point Dume,Coal Oil Point), an island group (San Migueland Santa Rosa Islands) and an open watergroup (Santa Catalina Island, Santa RosaRidge, Santa Cruz Basin, and Tanner-CortesBanks) . The communities within each groupwere generally found not to be statisticallyinterelated. Only the Point Dune and Coal OilPoint HDSAS were found to be statisticallysimilar. Individual stations tend to be simi–lar across geographic groupings on a depth-related basis. However, this relationship isby no means clearcut. Similarly no communityalterations could be shown to exist at Coal

oil Point stations where sediments are rich inpetroleum. However, this survey was notdesigned to detect such alterations.

Many new and a few possibly rare species werefound, including a snail-like molluscan of theclass Monoplacophera, an ancient class of“living fossils”’. Tanner and Cortes banks,located approximately 210 km west of San Diego(Figure 1-1 and 1-2) appear to constitute anunusual environment where near-shore and openocean species form unusual associations.

The spatial distribution of benthic macrofaunain the Southern California Borderland is mostclearly associated with bathymetry. Howeversome associations also exist between thebenthic macrofauna and sediment characteris-tics. Few cause and effect relationships maybe discerned because they are obscured by thecomplexity of interactions between the biotaand their physio–chemical environments. It isextremely difficult to separate the effects ofsediment type and bathymetry on benthic assem–blages because they are so interdependent.

Some overall patterns of biotal and sedimentdistributions, however, are apparent. Forexample, a particular sea cucumber dominateswhere there are fine sediments with littleshell debris in shallow water. Where there ismore shell debris, a species of brittle staris co–dominant or dominant. In slightlydeeper water with the same sedimentcharacteristics, sea urchins are dominant.

In shallow areas where the ocean bottomconsists of soft silts and clays, threefamilies of amphipod crustaceans predominate.Shallow areas with gravel and boulder-strewn

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Figure I-7. Existing living foraminiferan communities in the SouthernCalifornia OCS region determined by cluster analysis.

23

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Figure I-8. The Southern California OCS showing the intertidal sampling sites.

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Biology

In all, 477 taxa were identified at the 10sites. Over half of the plant species werered algae and most of the animals weregastropod molluscs (snails).

Three intertidal zones are consistently foundon Southern California rocky shores: an upperzone dominated by blue–green algae, a middlezone dominated by barnacles, and a wet, lowerzone covered by coralline algae, red algae andkelp. All three of these zones were clearlyrecognizable at all study sites having con-tinuous rocky slopes.

Seasonal trends were generally lacking exceptfor a general reduction in biomass standingcrop during the winter.

Assemblages of organisms were found to bespecific to site. This distinctiveness cangenerally be attributed to variations insubstrate material, substrate stability,upwelling exposure, wave exposure, watertransparency, natural and man-made disturb-ances , and available nutrients.

The sites tend to fall into two groups:island sites and mainland sites. This overalltrend appears to be due to a lower level ofhuman-induced stress on the island sites.Island sites tend to have higher biomassstanding crop than mainland sites. Thisdifference is primarily due to the brown algalstanding crops which are more sparse andpatchy at the mainland sites. The datasuggest that reduction in brown algal biomassmay be associated with sewage-induced stress.

in addition LO the differences in the brownalgae, red algal turf communities tend to bemade up of larger and ❑ ore robust specimens atthe island sites. Mainland turf communitieswere generally found to be lower, more com-pact, and more epiphytized (plants growing onother plants). Ocean Beach (a mainland site)provided is an important illustration of thischaracterization. It appears to have receivedlittle environmental stress over the last 30years, since its present biota closely resem-ble those found in the area in 1947. Inter–estingly, the turf communities in both cases(1947 and present) resemble the present islandturf communities. The observation also sug–gests that a compact, highly epiphytized turfmorphology is characteristic of a “stressed”community.

other parameters which appear suppressed atmainland sites as compared to island sites arenumber of taxa, richness, evenness and macro-invertebrate species diversity. Macrophytecover was found to be about the same at eachtype of setting.

The number of macrophytes (large plants suchas kelp) unique to the islands is much higherthan the number found only on to the mainland.Also, there are many more macroinvertebratesunique to the islands than to the mainland.These observations suggest that the plant andanimal communities on the mainland have beenreduced due to environmental stress althoughthey are predicated on the assumption that atsome previous time, the island and mainlandenvironments had similar biological composi–tions.

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Because of the broad-brush samplingapproach, it cannot be stated withcertainty that there are no seasonalvariations , only that none wereobservable.

The sampling and analysis of only afew individuals of any given specieswas found to result in chemical dataof high variability. One hundredpercent variation from the mean wasfound in some cases. These data areof limited use in the establishmentof well-defined *’baseline*’ condi-tions; however, they do provideinitial indications of the chemicalconcentrations and variations to be

anticipated in subsequent monitoringsurveys.

● Comparison of trace metal dataderived in this study with thosefrom previous studies of similarsystems is in general agreement.Some noticeable differences, such aslower lead concentrations found insome cases in this study, more thanlikely are the result of utilizingimproved sampling and analyticalmethods which have significantlyreduced sample contamination.

● Only the California mussel could begeographically compared along themainland coast for its metal con-tents, and they appear relativelyconstant except for noticeableelevations of lead at Pales Verdesand Corona del Mar. Only cadmiumshowed significant variation in

tissues Orlglllating f r om Lhe

islands, being elevated at islandsites in both kelp and mussels.Chromium showed some evidence ofelevation at mainland sites relativeto island sites in the tissues of asmall marine snail.

● Relatively large variations werefound in body tissue concentrationsof hydrocarbons, in rocky intertidalorganisms. These variations are duein part to evolving changes andimprovements in the analyticalmethodologies , and in part to themore complex pathways by whichthese materials are incorporatedinto tissues, as compared to heavymetals assimilation.

Bivalves collected at PlatformHeidi, an active rig near Coal OilPoint, were found to have relativelylow petroleum-type hydrocarbonconcentrations with a high fractionof their total hydrocarbons derivedfrom plankton.

● In general, all organisms collectedat Coal Oil Point contained signifi-cantly higher petroleum-relatedhydrocarbon burdens than did theircounterparts from other mainland andisland sites. Unfortunately, themost thoroughly sampled rocky inter-

tidal plant, the Giant Kelp does notoccur at Coal Oil Point. For thisorganism, the highest petroleumhydrocarbon concentrations werefound in samples collected at Santa

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Sampling along the single-line transectswas accomplished by excavating cores atregular intervals from high to low tidelevels. Sand was ranoved in stages to studythe distribution of species by depth. Exca-vated sand was analyzed at each depth formoisture , grain size, and organic carboncontent. At each site, three of the cores(designated upper, middle and lower) hadadditional sediment samples collected fortotal organic carbon analysis. During the1976 summer quarter, sediment samples wereremoved from these same quadrats at C)ceanBeach (San Diego) and Coal Oil Point forhydrocarbon and trace heavy metal analyses.

Slough environments were sampled differentlythan were the exposed sandy beaches due to theunique characteristics of these estuarinesites. A single sampling technique was usedcombining coverage aspects of both the profileline and random quadrat approaches. Thisprocedure better accommodated the largerspecies, such as the sand dollar, found inestuarine sites.

Sandy Beach/Slough Sedimentology

In conjunction with the biological and chemi-cal sampling performed at the 17 sandy beachslough sites (see Figure I–8), beach sedimentswere collected for substrate characterization.The goals of this effort were to (1) provide asedimentological survey and description of thesandy beaches throughout the Southern Califor-nia OCS, (2) provide substrate characteriza-tion for correlation with biological communitydistributions and (3) provide correlatablesedimentary data for aiding the interpretationof chemical (hydrocarbon and trace heavymetal) measurements.

During the study, grain size distributions,clay mineral characterizations , and calciumcarbonate and total organic carbon determina-tions were performed on sediment samplesselected from eleven mainland and six islandbeach sites.

Sandy Beach/Slough Chemistry (Sediments andBiota)

beach sands were collected by plastic orstainless steel push cores at seven of themainland and five of the island sandy beachsites (Figure 1-8) for the measurement ofambient levels of petroleum-type hydrocarbonsand the several trace heavy metals. Con-current with these collections , sand crabswere also taken for measurement of theseconstituents .

Samples were apportioned over several of thebeaches in such a way as to provide someinformation on seasonal, tidal height, andsediment depth effects on chemical distribu-tions. Coal Oil Point , which receives naturalpetroleum input from nearby seeps, was com–pared to Ocean Beach (San Diego) which wasconsidered a “petroleum-free” control.

4.2.2 Sandy Beach/Slough Results

Biology

All beaches sampled had distinctive biologicalcommunities and no single species was found atall sites. A total of ’240 species wereidentified at the 17 sites; of these, 53 werefound at mainland beach sites, 119 at islandbeach sites and 68 at slough sites. Of the119 species found on island sites, 96 werefound at Twin Harbors and 45 of those wereunique to that site.

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sites were sampled often enough to establishsuch trends. ALSO> it must be realized thatthese observed seasonal peaks were usually

dominated by increases in a single species, asopposed to prevalent changes in a location’ scharacteristic biological make–up.

Sedimentology

Based on data from this initial year’s survey,most intertidal sites follow expected sedi-mentological trends. Selected sites, however,exhibited unique patterns of variation betweenseasons and tidal levels. For example, gen-eral trends observed for decreasing tidallevels were a decrease in grain size, an in-crease in calcium carbonate, and a decrease inorganic carbon. Also, the mainland sites werefound to have carbonate comprising less than3% of the sample weight with a slight increasefrom north to south. The island beaches con–tain much more carbonate (average 16%) thanthe mainland sites due to lower availabilityof terrigenous sediment.

The general tendency for beaches to erodeduring the winter and acrete during the summerwas observed at most of the sites. Thedepartures from this trend which were foundduring the 1975-1976 sampling period appearparadoxical relative to site locations.During the summer the Southern California WSreceives swells from southern storms and anysummer errosion cycle which might occur shouldbe expected to focus on beaches facing south.This did not appear to be the case. In1975-76 the only two island beaches facingsouth exhibited summer accretion and othersfacing west and north were characterized byerosion. These observations may be explainedby one of the following factors:

● the 1975-1976 da~a are atypical,

● sand movement at the island sites iscontrolled by the nearshore submar-ine topography rather than by gen-eral wave patterns alone,

e beach erosion is controlled byseasonal variations in the direc-tions and strengths of the prevalentcurrent systems operating off South-ern California during the different“oceanographic seasons” character-istic of the area.

Chemistry

The relationship between patterns of communityvariability and levels of trace metals andhydrocarbons in sediments and tissues is ofprime interest to this program. The marineenvironment of the Southern California OCS isby no means pristine, having been subjected torelatively large inputs of domestic and indus-trial effluents as well as natural and man–induced oil sources. The general increases inlevels of pollutants in this environment hasbeen implicated in the documented declines inthe number of species and biomass of variousgroups of organisms.

As anticipated, beach sands from Coal OilPoint contain generally higher total amountsof hydrocarbons than those of Ocean Beach (SanDiego) . The elevated hydrocarbon levels atCoal Oil Point do not, however, appear to havehad inhibitory effects on the development ofits sandy beach fauna. Moreover, samples ofsand crabs from Coal Oil Point did not showelevated hydrocarbons levels in their tissues

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5.0 CONCLUSIONS AND RECOMMENDATIONS

The initial year of this environmental base-line program was generally successful in itsmain purpose of describing the chemical,physical and biological assemblages in theSouthern California OCS. Significant progresswas made in identifying improvements whichwould enhance future program designs and re–finements in sampling and analytical tech–ni ques . Programs suggested from the exper-ience of this initial effort promise tofurther clarify the ambient distributions ofchemical and biological constituents in thearea.

Information useful LO Lhe management of OCSresources includes estima~ions of the inherent‘“natural” variations which characterize localbiological and chemical parameters. Reliableestimates of these parameters will provide formaking sound decisions regarding environmentalprotection.

An intensive program to study the biology andchemistry of Tanner–Cortes Banks, an unusualhabitat, was also recommended and included inthe second years program.

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