Foraminifera, Los Angeles County Outfall Area, California

Foraminifera, Los Angeles County Outfall Area, CaliforniaAuthor(s): Orville L. Bandy, James C. Ingle, Jr. and Johanna M. ResigSource: Limnology and Oceanography, Vol. 9, No. 1 (Jan., 1964), pp. 124-137Published by: American Society of Limnology and OceanographyStable URL: http://www.jstor.org/stable/2833407 .

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FORAMINIFERA, LOS ANGELES COUNTY OUTFALL AREA, CALIFORNIA'

Orville L. Bandy, James C. Ingle, Jr., and Johanna M. Resig Allan Hancock Foundation, University of Southern California, Los Angeles

ABSTRACT

Foraminifera are sparse beneath the sewage field of the Los Angeles County outfall; segments of an abundance aureole are peripheral to the field and contain from 50 to 500 times as many tests as beneath the field. A zone without live specimens occurs beneath part of the sewage field; excepting for the dead zone, hyaline species are more than 8 times as abundant as arenaceous and porcelaneous species in living populations of the entire outfall area. Planktonic/benthic ratios are singularly high in the outfall area; planktonic foraminifera increase in numbers abruptly from very low values on the shelf to about 100/g in the upper bathyal zone; somewhat higher values occur near the outfall. Species thriving within the outfall area include Bulimina marginata denudata, Buliminella elegantissima, and Discorbis columbiensis.

INTRODUCTION

In the continuing investigation of the relationships between ocean pollution and foraminifera, one of the ideal ocean lab- oratory sites is the area of the Los Angeles County outfall at Whites Point, California (Fig. 1). The area represents a portion of the continental shelf of southern California on the south flank of the Palos Verdes Hills, just west of the cities of San Pedro and Long Beach. Along this part of the head- land the shelf is, about 3 km broad; this study embraces a strip of the shelf almost 10 km long. For all practical purposes, the shelf edge near Whites Point is defined by the 100-m contour. Abrupt declivity seaward of the shelf edge is emphasized by the depth increase in less than 1 km to depths of 180 m (Station 5540) and 372 m (Station 4831 ).

The volume of the Los Angeles County outfall is more than 1 x 109 liters per day (275 x 106 gallons), which is about the same as that at Hyperion (Los Angeles City outfall), about 28 km to the north; it is five times the volume of the Orange County outfall, approximately 38 km to the south; and it is 275 times the volume of the Laguna

1 Contribution No. 257 from the Allan Hancock Foundation. This investigation was supported in large part by U.S. Public Health Service Research Grant WP-00158-04, from the Division of Water Supply and Pollution Control.

Beach outfall, about 60 km to the south (Engineering-Science, Inc. 1961). Thus, the Los Angeles County outfall is an important discharge site of the Los Angeles region, and it provides a major contrast, in discharge volume, to the study of the Laguna Beach outfall by Bandy, Ingle, and Resig ( 1964).

Until 1958, the outfall at Whites Point was inadequate, water quality was poor within 10 km of the disposal site, the sea floor was coated with 15 cm of anaerobic sludge within a radius of 6 or 7 km, and noticeable effects were reported as far as 22 km from the outfall (Stevenson 1963). Sediment samples were black with hydro- troilite (FeS) over most of the shelf area, hydrogen sulfide and Chaetopterus variopedatus (a marine polychaete worm with affinity for sediments with a high organic content) were dominant features of the general outfall area, and a coliform bacterial field was reported along much of the shelf (Rittenberg, Mittwer, and Ivler 1958). Since 1958, shore facilities have been improved to remove the greases and sludge from the effluent; one submarine pipe, 229 cm in diameter, was lengthened to a point about 2,440 m offshore in a water depth of 61 m; a second outfall, 183 cm in diameter, extends 2,044 m offshore, ter- minating in depths of about 50 m; and plans now call for an extension of this second outfall. The sewage field can best be en-

124



FORAMINIFERA IN THE LOS ANGELES COUNTY OUTFALL AREA 125

visioned as an elongate ovate body suspended within the water column. Although the position of the sewage field varies slightly in response to changes in tidal phase, current velocity, and thermocline, it commonly rests between depths of 15- 45 m with greatest concentrations at 20- 25 m. The long axis of the elongate ovate field is parallel to the coastline and is cen- tered in an area about 0.8 km inshore from the terminus of the outfalls (personal communication from Mr. Malcolm Whitt, Los Angeles County Design Engineer).

Forty-six samples in the Whites Point area (Fig. 1) were collected as a part of a general sampling program of the entire shelf area of southern California between 1957 and 1962. Thus, the sampling period spans the interval from a time of inadequate sewage treatment to the much improved conditions at present. Samples were collected with a Hayward Grab sampler; por- tions for foraminiferal study were preserved in isopropyl alcohol and stained with rose bengal, a protein-specific stain.

Planktonic and benthic groups of foraminifera (marine protozoans), together with their characteristic test or shell, combine to make an ideal parameter for recording characteristics of the water column (planktonic group) and the substrate (benthic group) by the nature and distribution of the hard parts left behind after the death of the organisms. Abundances of foraminifera are recorded in numbers of specimens per gram of dry sediment, the foraminiferal number; counts of about 200 or 300 specimens per aliquot conduce to a high degree of dependability in values for occurrence.

This investigation was supported in large part by U. S. Public Health Service Re- search Grant WP-00158-04, from the Di- vision of Water Supply and Pollution Control. The writers wish to express their gratitude to Dr. R. E. Stevenson, who de- veloped the offshore program; to Captain G. Allan Hancock and members of the crew of the Velero IV, who made possible the shipboard operation; to Richard Ander- son, R. A. P. Gaal, Robert Lessard, Ger-

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FiG. 1. Los Angeles County outfall area, show- ing stations and bathymetry in meters.

trude Mahn, William Poiski, Kurt Rott- weiler, Detlef Warnke, Mary Wittington, and R. K. Stouffer for technical assistance; to Dr. Donn S. Gorsline and Kelvin S. Rodolfo for a critical reading of the manu- script; to Barbara Lidz for drawing the foraminiferal figures; and to Maynard T. Smith for editorial assistance and typing. A number of the samples used in this study was collected as a part of the field program of a project supported by the California State Water Pollution Control Board.

GEOLOGIC SETTNG

The geologic setting for the mainland shelf in the Whites Point area is described in a number of reports by Emery ( 1952, 1958, 1960), Moore (1954),. Wimberley (unpublished data), and in a current report on facies trends in San Pedro Bay (Bandy, Ingle, and Resig, in press). San Pedro Shelf and the shelf in the Whites Point area were carved out of the flank of the positive faulted anticlinal Palos Verdes Hills uplift., which separates the Los An- geles., San Pedro., and Santa Monica basins markedly. Residual and relict sediments, reported from San Pedro Shelf to the east, are not significant in the area of this report.

The age of the mainland shelf at Whites Point is Late Quaternary (Bandy,et al.., in press). Shepard and Suess (1956) have



126 ORVILLE L. BANDY, JAMES C. INGLE, JR., AND JOHANNA M. BESIG

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45'45 I 0 1 2 3 0 1 2

-4 KILOMETERS KILOMETERS

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SAND

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SEDIMENT MAP IN SEDIMENT 33?_ 3t 33 ? ' 33' 39, ~ I I 1 39' 39 I I 39 118'24 22 20 2 5 SA 11R824'2 20' R8

118 24' 22' 20' Il818 _ 3I3S

! ~~~~~~~~~~~~~~~~~~~~. .? !2........._

PERCENT NITROGEN IN SEDIMENT

II11124' 22' 20' 1181 > S 2

FIG. 2. Characteristics of the substrate. A. Sediment distribution. B. Percentage of calcium carbonate in sediment. C. Percentage of nigrogen in sediment.

documented a rise in sea level from minus 50 m to the present level during the past 12,000 years; Emery (1960) reports ages of 17,000-24,000 years for samples of fossil calcareous algae from depths of over 100 m off the Palos Verdes Hills. Sea level must have stood only slightly above the line of occurrence of calcareous algae at the time they were alive.

SUBSTRATE AND OCEANOGRAPHY

Sediments of the shelf, bounding the southern part of the Palos Verdes Hills, are

mostly olive green silty sands on the inner shelf and olive green sandy clayey silts on the outer shelf, with a zone of sandy silts in between (Fig. 2A); black sediments are dominant in the outfall area. This pattern accords with that described by Stevenson, Uchupi, and Gorsline (1959). Calcium carbonate values, determined gasometri- cally, exceed 10% in samples of the inner shelf area and also in those along the outer edge of the shelf (Fig. 2B). Values are much reduced on the outer half of the shelf in the region of the outfalls where less




than 2% CaCO3 was recorded for Station 5103. This contrasts with values of from 5 to more than 10% near the outfall at Laguna Beach (Bandy et al. 1964), and agrees with values of about 29 over much of the nearby San Pedro Shelf (Bandy et al., in press).

The percentage of nitrogen in a sediment varies directly with the amount of original organic matter present and consequently should reflect any artificial organic enrich- ment due to debouchment of sewage. Ni- trogen percentages (determined by micro- Kjeldahl method of Kabat and Mayer 1961, p. 476-483) in the vicinity of the outfall at Whites Point range between 0.05 and 0.30. In contrast, nitrogen values in sediments near the small-volume Laguna Beach outfall range between 0.04 and 0.089. No major outfall is present on the San Pedro shelf, and nitrogen values there average much less than 0.059 over almost the entire shelf area. Thus, a positive relationship exists between volume of sewage released and per cent nitrogen in proximate sediments.

Average temperatures of surface waters of the Whites Point area are similar to those of Santa Monica Bay and San Pedro Bay, ranging from a low of about 13C in winter to about 22C in summer (Zalesny 1959); water temperatures at 100 m are about 9- lOC and are between 8 and 9C at 200 m throughout the year (Emery 1960). As in San Pedro Bay and Santa Monica Bay, the salinity variation in surface waters is between values of about 33.6 and 33.4%oo; at depths of 200 m the value is about 34.1%oo

(Zalesny 1959). As water leaves Santa Monica Bay to

the north, it sweeps around Palos Verdes Point, and a landward flow or eddy, usually less than 1 km/hr, results (Stevenson 1963). Pollution effects which characterize the water mass over the shelf at Whites Point include the following: 1) according to Rittenberg, Mittwer, and Ivler (1958), coliform bacteria are concentrated in the water and on the sea floor in outfall areas which discharge unchlorinated sewage such as this one (bacteria number more than 10,000/cm2 in contrast to values of 250 or

less where chlorination is practiced); 2) suspended solids reduce the water trans- parency (Stevenson and Polski 1961); 3) low salinity effluent dilutes the seawater by about 5% directly over the discharge points; 4) phosphate and fixed nitrogen in the effluent are about 1,000 times their normal concentrations in surface seawater; 5) heavy metals are relatively abundant in effluent; and 6) the oxygen demand is about 70 times that of normal seawater (Emery 1960). At Whites Point, there has been a marked decrease in the abundance of kelp, attributed to sewage discharge (Dawson 1959), but more recently some kelp beds have again populated the shallow inshore waters.

RELATION OF FORAMINIFERA

TO OCEAN POLLUTION

General relationships Studies of the sewage field off Whites

Point define it as ovate in horizontal section, funnel-shaped in vertical section; it is suspended at depths of from 15-45 m above the sea floor and extends for several kilometers along the shelf throughout most of the year, coming to the surface or near the surface for restricted periods in the spring and fall (personal communication from Mr. Malcolm Whitt, Los Angeles County Design Engineer). Thus, the pollution field extends over the sea floor in the general region of the central shelf and causes depositional effects over much of the central and outer shelf areas. Los Angeles County effluent is untreated in contrast to that at Laguna Beach, which is chlorinated. Chlorination is employed at Whites Point only when the sewage field comes near the surface of the sea.

General foraminiferal parameters show a striking relationship to the area affected by the primary sewage field. Foraminiferal abundance (specimens/g of dry sediment) generally increases offshore in most areas (Bandy and Arnal 1960); at Whites Point less than 1/g occurs under the sewage field, but the abundance increases to 100, 500, and more off the edge of the shelf and in three inshore locations near the



128 ORVILLE L. BANDY, JAMES C. INGLE, JR., AND JOHANNA M. RESIG

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LIVE BENTH IC FORAMI N IFE RA FORAMINIFERAL NUMBER PER GRAM

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LIVE /DEAD RATIOS NUMBER OF LIVE BENTHIC FORAMINIFERA SPECIES OF FORAMINIFERA

39 _/_ 33- l 33e _ _33e 39' 41' 49' ,. 49' L3 3

33'"2 33'2, 18 118'24' 22' 20' 118'18 SC 184'2'0'II9 3D

FIG. 3. General foraminiferal parameters. A. Total foraminiferal tests/g of dry sediment. B. Number of live benthic foraminifera/g of dry sediment. Area without live specimens is assumed to be a dead zone. C. Live/dead ratios of benthic foraminifera. Areas with values higher than 0.05 are crosshatched. D. Isopleths based upon number of live benthic species per station.

edge of the sewage field (Fig. 3A). Live specimens are completely absent from an elongate band covering some 8% of the shelf area of this study (Fig. 3B), which is approximately beneath the suspended sewage field. Values increase to about three or more specimens/g away from the "dead" region.

Live/dead ratios and live/total population ratios have been used for evaluating depositional rates (Phleger 1960). Ratios

are greater away from the Whites Point outfall area laterally and along the edge of the shelf (Fig. 3C). In this instance, these values reflect the lack of live specimens near the sewage field rather than relative depositional rates. As with number of live specimens per gram, plots of the number of live species found at each station show a "dead" zone extending along the shelf in the general area of the sewage field (Fig. 3D). Numbers of live




species increase to 10 in the upper bathyal zone and in three restricted localities of the inner shelf. Although foraminifera are not living on part of the sea floor beneath the sewage field, the marine polychaete worm Chaetopterus variopedatus is abundant there (Rittenberg et al. 1958).

Arenaceous-porcelaneous-hyaline groups Smaller benthic foraminifera may be

grouped into three categories for conve- nience: those with agglutinated tests of sand, those with porcelaneous imperforate tests of calcium carbonate, and those with perforate calcareous tests, referred to as hyaline. The calcareous tests are secreted by the animal, whereas the arenaceous tests are made of foreign particles selected by the foraminifer from the substrate. Using the trigon method of multivariate analysis of Krumbein (1954), a 1/8 ratio contour is added for the hyaline group be- cause of its dominance over all others; thus, trends are brought out within the area so dominated. Further, it is especially important to distinguish between dead and living population patterns since the live specimens may be assumed to be in situ and adjusted to their environment, whereas the dead population, or thanatocoenosis, is often a mixture of transported, reworked, and redeposited specimens.

A striking feature of arenaceous- porcelaneous-hyaline relationships is the contrast between dead and living patterns (Figs. 4A, 4B1): arenaceous specimens dom- inate the dead population under much of the sewage field, whereas the hyaline cate- gory is more than 8 times as abundant as all others in the live population throughout the region of the sewage field, excepting for the dead area. Considering the porcelaneous and arenaceous categories as accessories to the dominant hyaline group, it is noteworthy that the porcelaneous specimens are the important adjunct in the shallow inshore areas, whereas the arenaceous specimens comprise the important ac- cessory group over much of the shelf in the dead population. In previous works, arenaceous species have often been cited

as being the dominant groups near southern California outfall areas (Zalesny 1959; Resig 1960; Watkins 1961); note that in the Whites Point area (Figs. 4C, 4D) highest percentages of the dead arenaceous population occur in the central shelf area, under the sewage field, whereas in the live population lowest values are under the sewage field and with a distinct increase to 10 and 20% of the live population, both inshore and offshore, away from the outfall area. This does not support the idea of living arenaceous species dominating in outfall areas. A high organic content in the shelf area contributes to reduced pH values which would result in destruction of calcareous tests as opposed to arenaceous tests; thus, dead populations would reflect high arenaceous values as a secondary phenomenon.

Planktonic relationships

Limited data provide some evidence of phytoplankton abundances in cells/liter for a portion of the shelf (Fig. 5A). An abundance of more than 9,000 cells/liter at the outfall area may be significant; however, larger values than this were recorded in the water column over the nearby San Pedro Shelf (Bandy et al., in press), with no associated outfalls. Arenaceous-planktonic-calcareous benthic relationships reveal a dominance of calcareous benthic specimens on the shelf generally, with a central elongate region of arenaceous abundance (Fig. 5B). As accessories within the area of calcareous benthic dominance, planktonic foraminiferal tests are more abundant than arenaceous tests over the inner shelf area and in the upper bathyal zone. Only one limited area of dominant planktonics appears, and this is somewhat inshore from the outfall areas. Planktonic/ benthic foraminiferal ratios are highest along the outer edge of the shelf and in one area just inshore the Whites Point outfalls (Fig. 5C); this small area may repre- sent higher productivity of planktonic foraminifera in the overlying water or it may be an area of high mortality, or both. The higher ratios at the edge of the shelf and




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PERCENT ARENACEOUS PERCENT ARENACEOUS IN DEAD FAUNA IN LIVE FAUNA

39' I 39' 319 ' I I I 39' 118'24' 22' 20' 11,1 118"2 22' 20' l1B18 4

FIG. 4. Distributional relationships of foraminiferal groups based upon wall structure. A. Multivari- ate analysis of arenaceous-porcelaneous-hyaline groups in the dead population. Note arenaceous dominance in the outfall area. B. Multivariate analysis of arenaceous-porcelaneous-hyaline groups in the live population. Note the dominance of hyaline types and the dead zone. C. Distribution of arenaceous specimens in the dead population. Dominant occurrences are in the midshelf area. D. Distribution of arenaceous specimens in the live population. Dominant occurrences are inshore and offshore.

in deeper waters are due to more living space in the longer water column; a number of planktonic species are zoned according to depth, those occurring deeper being necessarily excluded from shallow waters over the shelf (Bandy 1963a; Casey 1963). As in the region of the San Pedro Shelf, planktonic foraminiferal specimens/g of

dry sediment reflect a prominent seaward increase from about 10-100 along the outer edge of the shelf (Fig. 5D); somewhat higher values surround part of the outfall region on the shelf although the immediate outfalls and much of the area under the sewage field are dominated by very low values.




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FiG. 5. Planktonic relationships. A. Cells of phytoplankton/liter, total for water column. Data collected during 1957 and 1958. Note high values at the outfall. B. Multivariate analysis of arenaceous- planktonic-calcareous benthic foraminiferal groups. Note abundance of planktonic tests midway between the end of the outfalls and shore. C. Planktonic/benthic foraminiferal ratios. Note the highest values midway between the outfall area and the shore, also along the outer edge of the shelf. D. Distribution of planktonic foraminifera based upon specimens/g of dry sediment.

Bathymetric groups Referring to bathymetric ranges of Resig

(1963), it is possible to select dominant species that have optimum depths of 0-150 m (Buliminella elegantissima group), 20- 120 m (Bulimina marginata denudata group), and 20-70 m (Trochammina pacifica group); these groups are progressively

more restricted, and the third (20-70 m) is composed exclusively of agglutinated species (Table 1, Figs. 6A, 6B). Evaluation by the trigon method shows that the dead population has a dominance of two of the three groups: the Trochammina pacifica group is dominant in large areas of the central and inner shelf, the Bulimina mar-




TABLE 1.-Foraminiferal species comprising bathymetric groups, Los Angeles County outfall area,

California

0-150 m, Buliminella elegantissima group Bolivina vaughani Natland Buccella frigida (Cushman) Buliminella elegantissima (d'Orbigny)

20-120 m, Bulimina marginata denudata group Bulimina marginata denudata Cushman and

Parker Nonionella miocenica stella Cushman and

Moyer Nonionella scapha basispinata (Cushman

and Moyer)

20-70 m, Trochammina pacifica group Eggerella advena (Cushman) Gaudryina arenaria Galloway and Wissler Goesella flintii Cushman Haplophragmoides advenum Cushman Reophax communis Lacroix Reophax scorpiurus Montfort Trochammina pacifica Cushman

ginata denudata group is dominant on the outer half of the shelf and along the inner shelf to the northwest (Fig. 6A). In contrast, live populations reveal a dominance, more than 8 times as much as the other groups, by the Buliminella elegantissima group along the inner shelf and under

the inner half of the sewage field (Fig. 6B); the Bulimina marginata denudata group is the most abundant assemblage on much of the central and outer shelf areas and is dominant under the outer portion of the sewage field; the Trochammina pacifica group remains dominant in but two or three small restricted central shelf posi- tions away from the outfall area.

Trends of species and species groups

In a recent study of paralic foraminiferal faunas of southern California (Bandy 1963b), dominant members of beach or intertidal populations were found to be Rotorbinella lomaensis, Cibicides fletcheri, and miliolids. Off the Palos Verdes Hills, this group comprises less than 10% of the live assemblage deeper than about the 10-m contour and about 20% or more of the population shallower than this (Fig. 7A); plots of values in the total live/dead population show the 10% isopleth displaced slightly seaward and no evidence for a 20% isopleth. On the basis of existing data, pollution conditions do not affect these inshore populations; this agrees with mea- surements of the bacterial field by mem-

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33- -RATIOS OF BATHYMETRIC GROUPS_ 33- 33- RATIOS OF BATHYMETRIC GROUPS_ 33- 394 44 1 39 39' _ I I 41

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FIG. 6. Multivariate analysis of mainland shelf foraminiferal groups based upon bathymetric group- ings: Buliminella elegantissima group, 0-150 m; Bulimina marginata denudata group, 20-120 m; and the Trochammina pacifica group, 20-70 m. A. Dead population. B. Live population. Note that the Tro- chammina pacifica group is dominant around the outfall areas in the dead population and is replaced by the Bulimina marginata denudata group in the hve population,




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---PERCENT TOTAL POPULATION

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39

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FIe, 7, A-D. Distribution of individual species and species groups. A. Distribution of Rotorbinella group (1. Cibicides fletcheri Galloway and Wissler, 2. Qtinqueloculina akneriana, and 3. Rotorbinella lomanensis [Bandy] ). Note restriction to inshore zone. B. Distribution of Elphidium spp. ( I. Elphidium poeyanum translucens Natland). Note restriction to inshore zone, especially in the live population. C. Distribution of Discorbis columbiensis Cusbman. Note affinity for insbore area, excepting in the outfall region. D. Multivariate analysis of the occurrences of Bulimirna marginata denudata, Buliminella elegantissinwa, and Trochammina pacifica in the dead assemblage. Trochammina dominates much of the outfall area.

bers of the Los Angeles County Sanitation engineering staff, which show that the sewage field dissipates before reaching the inshore areas (personal communication from Mr. Malcolm Whitt, Los Angeles County Design Engineer). Renewed development of kelp beds along the inshore

areas is also a possible reflection of the absence of inshore pollution.

Two forms, also dominant in the inshore area, are Elphidium spp. and Discorbis columbiensis (Figs. 7B, 7C); both increase from very rare on the shelf to more than 5% (Elp'hidium) and 20% (Discorbis) of




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FIG. 7, E-G. Distribution of individual species and species groups. E. Multivariate analysis of the occurrences of Bulimina marginata denudata, Buliminella elegantisrsima, and Trochammina pacifica in the live population. Bulimina marginata denudata is most abundant in the ouffall area, excepting in the dead zone. F. Multivariate analysis of Bulimina marginata denxudata, Buliminella elegantissima, and Nonionella spp. ( 1. Nonionella miocenica stella Cushman and Moyer, 2. Nonionella scapha basispinata [Cushman and Moyer]l) in the dead population. G. Multivariate analysis of the same species as in F in the live population. Note the reduction in Nonionella spp. from the dead to the live analysis.

the living benthic population in the inshore areas. Occurrences of these two forms in the total population (as opposed to live population relationships) are aligned generally with those values for living populations. A remarkable feature of Discorbis columbiensis is the extension of its area of abundance into the central shelf region

near the outfall area where it appears to be dominant in deeper waters and on a differ- ent kind of substrate under the sewage field, as opposed to its normal occurrence.

Three important shelf species, dominant members of the bathymetric groups in pre- ceding discussions, are Bulimina marginata denudata, Buliminella elegantissima, and




Trochammina pacifica. Although Bulimin- ella elegantissima ranges from 0-150 m, it is an abundant constituent with the inshore populations of Rotorbinella, Elphi- dium, Discorbis, etc. (Bandy 1963b); Buli- mina nwirginata denudata is a unique bimodal form, being abundant on the open shelf and also in many lagoonal areas; and Trochammina pacifica is a dominant shelf inhabitant. These three species comprise the bulk of the foraminifera occurring on the shelf near Whites Point. The trigon method shows that in the dead population Bulimina marginata denudata dominates the outer shelf and Bulimitnella elegantissima the inner shelf, with central areas of abundant Trochammina pacifica (Fig. 7D). In the living assemblage (Fig. 7E), the central area and the region beneath the sewage field show an abundance of Bulim- inella marginata denudata, with Bulimin- ella elegantissima most abundant in the inner shelf area and in some locations along the outer shelf. Significantly, there is a major change between dead and live population abundances and patterns in this outfall area in contradistinction to the absence of important changes in analogous plots for the populations of San Pedro Shelf to the east, an area without major outfalls (Bandy et al., in press).

Species of Nonionella appear to be important in dead populations of outer por- tions of the shelf in the Whites Point region; they are also important constituents on the central and outer parts of San Pedro Shelf in both live and dead populations (Bandy et al., in press), and they are important in many parts of the Tertiary marine section of California. Evaluation of Nonionella with Buliminella elegantissima and Bulim- ina marginata denudata, by multivariate analysis, shows a marked increase in the abundance of Bulimina marginata denudata in the outfall area, from dead to live populations, and only small restricted localities show an abundance of Nonionella in the live plots in contrast to the patterns on San Pedro Shelf (Figs. 7F, 7G). It is suggested that Nonionella cannot tolerate the outfall conditions, whereas Bulimina marginata

denudata and Buliminella elegantissima can thrive in close proximity to the affected area.

SUMMARY AND CONCLUSIONS

Los Angeles County outfalls contribute more than 1 x 109 liters of effluent daily to the sea off Whites Point. Sediments of the inner shelf are silty sands, those of the outer shelf are sandy silts; sediments, temperature gradient, and water depth change with increasing distance from shore. Faunal changes controlled primarily by one or more of these factors should reflect such controls. Although most of the sediments are olive green in color, those near the outfalls are black (FeS) owing to hydro- troilite and an abundance of sulfides. Cal- cium carbonate values are low in the outfall area, under the sewage field; they increase inshore and offshore to maxima of more than 40%. Nitrogen values are high in the general region of outfalls, ranging from slightly less than 0.05 to more than 0.30%.

Living foraminiferal distribution patterns show a marked decrease in values under the Whites Point sewage field. Segments of an abundance aureole occur 1 or 2 km away from the outfalls and border the edges of the pollution field. This contrasts with the general and progressive increase in foraminiferal abundance offshore in other unaffected areas (Bandy and Arnal 1960). A zone of dead and rare living foraminiferal specimens occurs beneath the general area occupied by the sewage field; however, abundant specimens of Chaetop- terus variopedatus, a marine polychaete worm, occur in the zone. Live/dead ratios are primarily affected by the absence of live specimens in the dead zone under the sewage field; they do not serve to evaluate depositional rates in this area.

Agglutinated species of foraminifera are most abundant in the outfall region and the central shelf in dead populations, whereas calcareous foraminifera are dominant in the outfall region in living populations. Phytoplankton cells and planktonic foraminifera tests are abundant near the outfalls




off Whites Point; they may reflect greater productivity resulting from abundant nu- trients in the outfall area. Planktonic/ benthic foraminiferal ratios attain values of more than 0.5 under the sewage field alone in the sediments off Whites Point; high values of this kind usually are restricted to the bathyal zone here and especially along the San Pedro Shelf nearby. Plots of planktonic foraminifera/g indicate a central depression zone in the immediate outfall area and something of an abundance aureole surrounding this.

A bathymetric group, with optimum depths between 20 and 70 m and composed of agglutinated species, is the most abundant dead foraminiferal group in the outfall area and beneath the sewage field of the central shelf region; Buliminella elegantissima and Bulimina marginata denudata are completely preponderant in the outfall region in the living population analyses.

Prevalent inshore populations include a Rotorbinella group, Elphidium spp., Dis- corbis columbiensis, and Buliminella elegantissima. There is no evidence of pollution reflected in these inshore populations. The return to "natural" conditions is cor- roborated by the renewed development of kelp beds in the inshore zone. Buliminella elegantissima and Discorbis colunmbiensis also expand markedly into the outfall region in living population studies; both transgress sediment, depth, and temperature boundaries in doing so. Species of Nonionella, so numerous on the central and outer part of San Pedro Shelf nearby, are relatively rare in the Whites Point area. It is suggested that Nonionella cannot tolerate the pollution environment, in contrast to Buliminella elegantissima, Bulimina marginata denudata, and Discorbis columbiensis.

REFERENCES

BANDY, 0. L. 1963a. Cenozoic planktonic foraminiferal zonation. Micropaleontology, 9: in press.

. 1963b. Dominant paralic foraminifera of southern California and the Gulf of Cali- fornia. Contrib. Cushman Foundation Foram- iniferal Res., 14: 127-134.

, AND R. E. ARNAL. 1960. Concepts of foraminiferal paleoecology. Bull. Am. Assoc. Petrol. Geologists, 44: 1921-1932.

, J. C. INGLE, JR., AND J. M. RESIG. 1964. Foraminiferal trends, Laguna Beach outfall area, California. Limnol. Oceanog., 9: 112- 123.

, AND In press. Facies trends, San Pedro Bay, California. Bull. Geol. Soc. Am.

CASEY, D. 1963. Studies on the ecology of planktonic foraminifera and radiolaria off the southern California coast. J. Paleontol., 37: 977.

DAWSON, E. Y. 1959. A primary report on the benthic marine flora of southern California, p. 169-264. In Oceanographic survey of the continental shelf area of southern California. Publ. 20, Calif. State Water Pollution Control Board.

EMERY, K. 0. 1952. Continental shelf sediments of southern California. Bull. Geol. Soc. Am., 63: 1105-1108.

. 1958. Shallow submerged marine ter- races of southern California. Bull. Geol. Soc. Am., 69: 39-60.

* 1960. The sea off southern California. John Wiley and Sons, Inc., New York. 366 p.

ENGINEERNG-SCIENCE, INC. 1961. Report on col- lation, evaluation, and presentation of scien- tific and technical data relative to the marine disposal of liquid wastes, prepared for Calif. State Water Pollution Control Board. Engi- neering-Science, Inc., Arcadia, Calif. 105 p.

KABAT, E. A., AND M. M. MAYER. 1961. Experi- mental immunochemistry. 2d ed. C. C Thomas Co., Springfield, Ill. 205 p.

KRUMBEIN, W. C. 1954. The tetrahedron as a facies mapping device. J. Sediment. Petrol., 24: 3-19.

MOORE, D. G. 1954. Submarine geology of San Pedro Shelf. J. Sediment. Petrol., 24: 162- 181.

PHLEGER, F. B. 1960. Ecology and distribution of Recent foraminifera. Johns Hopkins Press, Baltimore. 297 p.

RESIG, J. M. 1960. Foraminiferal ecology around ocean outfalls off southern California, p. 104- 121. In Waste disposal in the marine environment. Pergamon Press, London.

1963. Foraminifera around southern California ocean outfalls. Report submitted to Division of Water Supply and Pollution Control, U.S. Public Health Service. 29 p.

RITTENBERG, S. C., T. MiTTrwER, AND D. IVLER. 1958. Coliform bacteria in sediments around three marine sewage outfalls. Limnol. Ocean- og., 3: 101-108.

SHEPARD, F. P., AND H. E. SUESS. 1956. Rate of postglacial rise of sea level. Science, 123: 1082-1083.

STEVENSON, R. E. 1963. Sewage disposal and




the sea in southern California. Part 2. Water Sewage Works, 110: 49-51.

, AND W. POLSKI. 1961. Water transpar- ency of the southern California shelf. Bull. Southern Calif. Acad. Sci., 60: 2.

, E. UCHUPI, AND D. S. GORSLINE. 1959. Some characteristics of sediments on the mainland shelf of southern California, p. 59-109. In Oceanographic survey of the continental shelf area of southern California. Rept. sub-

mitted to Calif State Water Pollution Control Board by Allan Hancock Foundation, Univ. Southern California.

WATKINS, J. G. 1961. Foraminiferal ecology around the Orange County, California, ocean sewer outfall. Micropaleontology, 7: 199- 206.

ZALESNY, E. 1959. Foraminiferal ecology of Santa Monica Bay, California. Micropaleon- tology, 5: 101-126.



Documents

Foraminifera, Los Angeles County Outfall Area, California