Santa Monica Bay Research Articles

Nitrogen fixation within the water column associated with two hypoxic basins in the Southern California Bight

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 63:193-205 (2011) - DOI: https://doi.org/10.3354/ame01494 Nitrogen fixation within the water column associated with two hypoxic basins in the Southern California Bight M. Robert Hamersley1,*, K. A. Turk2, A. Leinweber3, N. Gruber3,4, J. P. Zehr2, T. Gunderson5, D. G. Capone5 1Soka University of America, 1 University Dr., Aliso Viejo, California 92656, USA 2Ocean Sciences Department, University of California, Santa Cruz, California 95064, USA 3Institute of Geophysics and Planetary Physics, University of California Los Angeles, Los Angeles, California 90965, USA 4Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, 8092 Zürich, Switzerland 5Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, California 90089, USA *Email: rhamersley@soka.edu ABSTRACT: We measured pelagic dinitrogen (N2) fixation by incorporation of 15N2 during regular cruises over 4 yr to deep hypoxic basins in the Southern California Bight, USA. N2 fixation in the photic zone was dominated (80%) by nanoplankton (<10 µm). N2 fixation rates in surface waters were near the upper range measured for nanoplankton in tropical waters, averaging 5.8 µmol m–3 d–1 at the San Pedro Ocean Time Series (SPOTS) station, and 2.4 µmol m–3 d–1 at the Santa Monica Bay Observatory (SMBO) station, with a maximum at SPOTS of 35 µmol m–3 d–1. Quantitative polymerase chain reaction (qPCR) assays and nested PCR-based clone libraries targeting the nitrogenase gene nifH indicate that the uncultivated unicellular cyanobacterial group A (UCYN-A) is an abundant diazotroph in the photic zone. Although N2 fixation rates were highest at the surface, mean N2 fixation averaged 0.07 µmol m–3 d–1 at depths of 500 and 885 m within hypoxic basin waters (<10% O2 saturation). When integrated over the aphotic water column, this deep N2 fixation may account for as much as one-third of the total areal N2 fixation, estimated at 150 µmol N m–2 d–1. These deep hypoxic N2 fixers were an assemblage of heterotrophic bacteria, including Alpha- and Gammaproteobacteria and putative sulfate-reducing bacteria. Our results suggest that N2 fixation could play a role in other hypoxic, high-nitrate waters. KEY WORDS: Nitrogen fixation · Diazotrophy · Southern California Bight · Hypoxic basin Full text in pdf format PreviousCite this article as: Hamersley MR, Turk KA, Leinweber A, Gruber N, Zehr JP, Gunderson T, Capone DG (2011) Nitrogen fixation within the water column associated with two hypoxic basins in the Southern California Bight. Aquat Microb Ecol 63:193-205. https://doi.org/10.3354/ame01494 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 63, No. 2. Online publication date: April 15, 2011 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2011 Inter-Research.

Identification of subwatershed sources for chlorinated pesticides and polychlorinated biphenyls in the Ballona Creek watershed

Santa Monica Bay forms part of the western border of the greater Los Angeles region. The Ballona Creek watershed is highly urbanized and past studies indicate that Ballona Creek is the largest source for most pollutants to Santa Monica Bay. This study evaluates the contribution of subwatersheds to PCB and chlorinated pesticide loading during wet weather flow. Fifteen storm drains from these subwatersheds were sampled during three storms during the 2005–2006 winter rainy season. A series of grab samples were taken over the duration of the storms. The suspended solids were analyzed for polychlorinated biphenyls (PCBs) and chlorinated pesticides. A geographic information system (GIS) was used to calculate the runoff volume from each subwatershed to estimate pollution mass loading. There was no statistical difference among subswatersheds; however, a disproportionate mass of PCB loading came from site 5, which had no obvious sources. No specific subwatersheds were identified as key sources for chlorinated pesticides. These results may serve as a model for other locations with concerns for historic PCB and chlorinated pesticides loadings.

Occurrence of the Barnacle (Xenobalanus globicipitis) on Coastal and Offshore Common Bottlenose Dolphins (Tursiops truncatus) in Santa Monica Bay and Adjacent Areas, California

Occurrence and distribution of pseudostalked barnacle (Xenobalanus globicipitis) on bottlenose dolphin (Tursiops truncatus) were assessed during a 1997–2007 study in Santa Monica Bay and nearby areas, California. During 425 surveys, 647 individuals were observed to assess presence and prevalence of barnacles; 92 barnacles on 56 individual (8.66%) were observed. On average, one barnacle was found on individuals, usually on top of dorsal fins (97.83%). No significant difference between barnacles' numbers on coastal versus offshore sightings was recorded. A significant difference on their occurrence on dolphins was recorded between seasons and years. Barnacles affect a small portion of the dolphin population in the study area.

Santa Monica Politics: The Left in Charge

THE CALIFORNIA Journal of Politics & Policy Commentary Santa Monica Politics: The Left in Charge Frank J. Gruber* Santa Monica Lookout News This paper is about what happened when the Left took control of the Santa Monica city government after voters enacted one of California’s strictest rent control laws. Its thesis is that once the Left obtained power, progressive politics were turned on their head, and attitudes and policies normally associated with the Right became identified as leftist. Then later, the pendulum swung back. While this paper is largely about events of the past 30 or so years, since Santa Monica voters enacted rent www.bepress.com/cjpp Volume 2, Issue 1, 2010 control (on the second try) in 1979, to understand those events it is necessary to know something about the politics of Santa Monica’s first 100 years. Santa Monica as a city was founded in 1875 by developers who wanted to build the principal port for Los Angeles on the shores of Santa Monica Bay. Before selling any lots on the land they had acquired from Mexican land-grant families, they built a wharf and brought in a railroad from Los Angeles, a railroad they intended to run from Los Angeles up the eastern Sierra to connect with the recently completed (1869) transcontinental railroad. *Since 2000 Frank Gruber has written a weekly column about life and politics in Santa Monica for the Santa Monica Lookout News, a local news website founded in 1998 after the Copley chain closed the Outlook, Santa Monica’s newspaper for more than a century. A collec- tion of Gruber’s columns from 2000 to 2004 has been published in Ur- ban Worrier: Making Politics Personal (Santa Monica, 2009). Before writing the column, Gruber served a year on the Santa Monica Hous- ing Commission and four years on the Planning Commission. Earlier versions of this paper were given as talks at the Santa Monica Public Library and to the California Studies Association’s monthly dinner in Berkeley.

Dirty Water: One Man’s Fight to Clean Up One of the World’s Most Polluted Bays

Review: Dirty Water: One Man’s Fight to Clean Up One of the World’s Most Polluted Bays By Bill Sharpsteen Reviewed by Ryder W. Miller Sharpsteen, Bill. Dirty Water: One Man's Fight to Clean Up One of the World's Most Polluted Bays. Berkeley, CA: University of California Press, 2010. 288pp. ISBN 9780520256606. US$27.50,cloth. Alkaline paper. Los Angeles reporter Bill Sharpsteen presents here in a dramatic telling the somewhat successful efforts by Heal the Bay to clean up and protect Santa Monica Bay. This Los Angeles story with cinematic potential provides an environmental case study which has ramifications for all of the California coast and the oceans everywhere. Even though it was too late to remove the municipal and industrial waste that was pumped into Santa Monica Bay, the tides turned and efforts by activists turned this into a California environmental success story. Though well told, the story is historical, taking place in the mid 1980s and to some extent the accounts are at the mercy of the actor's memories. Sharpsteen also does not spare his criticism, even for some of the heroes of the story, but there is not a lot of self-deprecation here which seems wanted at some points. Some will find Sharpsteen annoying when he questions everybody's verisimilitude. The book does provide fascinating descriptions of the key folks involved. Sharpsteen succeeds at sharing elements of the life stories of the key actors and their motivations. There are the scientists, whistleblowers, concerned citizens, activists, politicians, bureaucrats, legislators, and journalists. Though about pollution, which is often a downer of a subject, the account is compelling and inspirational. At stake was efforts by municipal governments to get a waiver from needing to put all sewage disposed through secondary treatment, a cost which Los Angeles County sought to avoid. Some scientists felt that sewage dumped out to sea would biodegrade and result in more food for sea life, but there was also a lot of DDT discharged before efforts were made not to use it anymore. The sewage also contained assorted dangerous chemicals. Though the battle is over, the clean up is not fully over and the problem is not fully solved. This book would serve as a useful contribution to the study of Los Angeles's environmental history. The book would also be helpful for those studying cceanography, sewage treatment, and toxicology. As a textbook it would also be helpful for beginning students of environmental studies who would like to have a deeper understanding of the roles that they can play. This work can help clarify for students they what part they would like to take in this field if so inclined. This book could also serve as a supplemental textbook for an environmental journalism class. It would help reporters who seek to understand the process of fighting for environmental change. Depicted here are the strengths and motivations of many of the key players involved in the process of fighting for a clean Santa Monica Bay in the 1980s, and can serve as a useful case study. As such it would also be helpful for environmental education students. There is also mention of the roles that journalists play in these efforts. As Sharpsteen points out, it's that symbiotic relationship between protester and reporter that gets the most done (p.89) and recognizing that when all else fails, you must get a reporter to stir the pot (p.112). Whistleblower Dave Brown, probably the biggest hero, the innocent party who lost the most, was to reflect from his experiences: Although years later Brown says he doesn't regret any of what happened, he was briefly stunned by the circus he entered that day (p.130), but “he was just a scientist trying to get the information out (p.131). This upbeat Los Angeles story could make an inspiring movie. The degraded ocean still inspires, as Sharpsteen eloquently writes, If nothing else, all one had to do was turn one's back to the east and face the ocean. One could easily fool oneself into believing nothing else existed. (p.4). Ryder W. Miller , Freelance environmental and science reporter who has been published in Sierra Magazine, California Coast & Ocean, California Wild, and Hydrosphere. Electronic Green Journal, Issue 30, Spring 2010, ISSN:1076-7975

Distributions of putative aerobic methanotrophs in diverse pelagic marine environments

Aerobic methane oxidization in the pelagic ocean serves an important role in limiting methane release to the atmosphere, yet little is known about the identity and distribution of bacteria that mediate this process. The distribution of putative methane-oxidizing marine groups, OPU1, OPU3 and Group X, was assessed in different ocean provinces using a newly developed fingerprinting method (monooxygenase intergenic spacer analysis (MISA)) in combination with pmoA clone library analysis and quantitative PCR (qPCR). The distribution of these three distinct monooxygenase groups, previously reported from pelagic marine environments, was examined in 39 samples including active methane seeps in the Gulf of Mexico and Santa Monica Bay, submarine canyon heads along the California continental margin, an oligotrophic subtropical gyre and areas proximal to a hydrothermal vent in the North Fiji back-arc basin. OPU1 and OPU3 were widely and similarly distributed within the meso- and bathypelagic zone (110 to approximately 2000 m water depth) and showed a >50-fold greater abundance near methane seeps relative to non-seep sites. In contrast, Group X was predominantly recovered from samples along the California margin, at both seep and non-seep sites. All three phylotypes were below detection in the epipelagic zone to depths of 100 m. Several additional deeply branching monooxygenase sequences were also identified in this study, indicating the presence of uncharacterized groups of microorganisms potentially involved in the cycling of methane or ammonium.

Trace organic contaminants and their sources in surface sediments of Santa Monica Bay, California, USA

Spatial distribution of selected contaminants in the surface sediments of Santa Monica Bay (SMB), California was investigated. Sediments were analyzed for DDTs (DDT and metabolites), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs) and coprostanol. Effluent samples from the Hyperion Treatment Plant (HTP), which discharges treated municipal wastewater effluents into SMB, were also analyzed. The inter-correlation in the distribution trends of contaminants was examined. The concentrations of contaminants were interpolated in a geographic information system to visualize their spatial distribution in the Bay. Inventories of the contaminants were also estimated. The concentrations of coprostanol, LABs and PCBs are very high only in the vicinity of the sewage outfall whereas PAHs and DDTs occur widespread in the Bay. The poor correlation of DDTs with LABs, PAHs or coprostanol content confirms the historic origin of DDTs and their absence in the contemporary wastewaters. Moderate correlation of DDTs with PCBs implies historic deposits as a major origin of PCBs. There are hot spots of DDTs at water depths of 60 and 100m and the inventory of DDTs in Bay sediments is insignificant compared to that estimated in the Palos Verdes Shelf which extends from the southern edge of Redondo Canyon around Palos Verdes Peninsula. The concentration of toxic contaminants was examined according to published sediment quality guidelines. About 20 stations contain p, p'-DDE and/or total DDTs above ERM and, PCBs between ERL and ERM indicating potential for adverse biological effects.

Spatiotemporal development of physical, chemical, and biological characteristics of stormwater plumes in Santa Monica Bay, California (USA)

This study characterized stormwater plume development and associated phytoplankton dynamics in a coastal marine ecosystem through shipboard monitoring. We focused on plumes within Santa Monica Bay, California (USA), a coastal system that is subject to rapid pulses of untreated runoff from the urbanized watershed of Los Angeles during the winter rainy season. The physical, chemical, and biological signatures of stormwater plumes were tracked over time after each of 4 precipitation events ranging in magnitude from 1.5 cm to 9 cm. Low salinity surface plumes persisted in Santa Monica Bay for at least 2 to 5 days over spatial scales of up to 15 km. This is consistent with a 6-day residence time for surface water plume parcels, which was estimated from a drifter trajectory in the bay. Shipboard sampling and salinity measurements in the surf zone showed that plumes often persisted even longer nearshore. Plume waters were generally characterized by higher concentrations of dissolved nitrogen, colored dissolved organic matter, and higher light attenuation than non-plume waters. The magnitude of the effect of stormwater runoff on phytoplankton dynamics was dependent on the size of each storm and subsequent residence time of runoff within the bay. Rain events led to increases in primary productivity, phytoplankton biomass, and specifically, increases in diatom biomass, as measured by concentrations of biogenic silica.

Population genetic structure in the redefined vermilion rockfish (Sebastes miniatus) indicates limited larval dispersal and reveals natural management units

Recent studies have revealed that the vermilion rockfish Sebastes miniatus is a cryptic species pair. The splitting of this species impacts stock size estimates and draws attention to the unintended consequences of current management policies. Differences in exploitation level between the species necessitated an evaluation of population structure and connectivity among regional management segments of the fishery. Analysis of gene flow and calculations of larval dispersal values were accomplished using 782 bp of DNA sequence data from the mitochondrial cytochrome b gene of 684 vermilion rockfish sampled from 16 sites between Kyuquot Sound, Canada, and San Quintin, Mexico. Significant genetic heterogeneity was found among sample sites (ΦST= 0.0742, p &lt; 0.001 and FST= 0.0899, p &lt; 0.001). Isolation by distance analysis produced a significant correlation, suggesting low average larval dispersal distance. Analysis of molecular variance showed significant partitioning of genetic variance across the biogeographic boundary at Point Conception (ΦCT= 0.0923, p &lt; 0.001 and FCT= 0.0135, p &lt; 0.001) with additional genetic barriers found at Cape Mendocino, Punta Colnett, Santa Monica Bay, and along the coast of Washington. These genetic barriers conform to oceanographic compartments previously proposed for the California Current Ecological Province and suggest natural management units for this species.

Seabird Observations During Cetacean Surveys In Santa Monica Bay, California

Abstract Seabird occurrence, distribution and behavior were assessed during cetacean surveys conducted between 2006–2007 in Santa Monica Bay, California. Gulls were most sighted year-round (55.63%), followed by brown pelicans (Pelecanus occidentalis; 19.0%), terns (6.61%) and Western grebes (Aechmophorus occidentalis; 6.53%). Gulls, shearwaters, and pelicans were often found foraging with short-beaked and long-beaked common dolphins (Delphinus delphis, D. capensis), and California sea lions (Zalophus californianus) near underwater canyons. Behavioral budget showed a predominance of passing by and floating activities. Feeding was observed in 6.5% of the sightings. This study provides baseline data for future seabird monitoring, conservation and management in the study area.

Diurnal carbon cycling in the surface ocean and lower atmosphere of Santa Monica Bay, California

We investigate the diurnal carbon cycle in the near surface ocean and atmosphere of Santa Monica Bay, California on the basis of hourly measurements of the oceanic and atmospheric partial pressures of CO2 (pCO2oc and pCO2atm) and related parameters from a moored platform. The power spectrum of the data from three deployments during late spring, summer, and fall reveal a strong peak at 1 cycle/day for both oceanic and atmospheric pCO2. While the average diurnal peak‐to‐peak amplitude is about 15 to 20 μatm for pCO2oc and about 10 μatm for pCO2atm, the 10% largest amplitudes exceed 55 μatm and 42 μatm, respectively. The diurnal cycle of oceanic pCO2 is primarily controlled by temperature, but biological processes substantially modify it. The contribution of lateral processes, such as tides, is likely small. For the fall deployment, our data suggest an average net primary production of about 30 mmol C m−2 day−1. The diurnal cycle of atmospheric pCO2 is primarily controlled by the air‐sea breeze. Neglect of the diurnal variations in the flux calculations may result in biases of more than 0.2 mol C m−2 a−1.

Skin Lesions and Physical Deformities of Coastal and Offshore Common Bottlenose Dolphins (Tursiops truncatus) in Santa Monica Bay and Adjacent Areas, California

Skin lesions and physical deformities on coastal and offshore bottlenose dolphins (Tursiops truncatus) were assessed during a photo-identification study conducted between 1997 and 2007 in Santa Monica Bay and adjacent areas in California. During 425 boat surveys, 647 individuals were identified based on marks on their dorsal fins. Of 637 individuals examined for skin lesions and deformities, 79.0% exhibited at least one type of lesion. Offshore animals showed more lesions than coastal animals (offshore: 87.8%, n=209; coastal: 73.4%, n=270). Only one individual showed a physical deformity. Results show that skin lesions affect a large portion of the coastal and offshore dolphin populations in the study area. When considering that lesions and physical deformities can be a sign of disease and may be related to anthropogenic factors, their high presence on dolphins must be a cause of concern.

Ecology and comparison of coastal and offshore bottlenose dolphins (Tursiops truncatus) in California

Populations of coastal and offshore bottlenose dolphins (Tursiops truncatus) are considered to differ ecologically, with implications for their protection and management. We assessed occurrence, distribution and behaviour of coastal and offshore populations of dolphins during a photo-identification study in Santa Monica Bay and nearby areas (1997–2007). Bottlenose dolphins occurred year-round and were encountered on 44.2% of all surveys (n = 425). We photo-identified 647 individuals; of these, 375 (58.0%) were coastal (&lt;1 km from shore), 241 (37.2%) offshore (1–65 km from shore) and 31 were both (4.8%). Dolphins mostly travel (69.0%) and travel-dive (61.5%), with offshore dolphins socialising more (22.6%) than coastal. There were low re-sighting rates for both coastal and offshore dolphins. Low re-sighting rates of coastal individuals provide little evidence of year-round site fidelity, suggesting their range is greater than the study area. Several individuals were re-sighted between and over 1-year periods, often foraging. This suggests that coastal dolphins: (1) are highly mobile within inshore waters, but spend time foraging in the study area, and (2) range &gt;1 km from shore, contrary to what has been previously reported.

Santa Monica Bay Shoreline Monitoring, Data Analysis and Application of Best Management Practices to Meet Bacteria TMDLs

Santa Monica Bay Shoreline Monitoring, Data Analysis and Application of Best Management Practices to Meet Bacteria TMDLs

Abiotic controls of potentially harmful algal blooms in Santa Monica Bay, California

Despite the increasing occurrence of harmful phytoplankton blooms along the North American west coast, records of phytoplankton populations and related environmental conditions are uncommon. In this study, twice monthly measurements in the upper 50 m are used to assess physico-chemical conditions contributing to the growth of potentially harmful bloom taxa over two annual cycles (2004–2005) in the Santa Monica Bay, California. Results were compared to the predictions of the Intaglio model [Smayda, T.J., Reynolds, C.S., 2001. Community assembly in marine phytoplankton: application of recent models to harmful dinoflagellate blooms. Journal of Plankton Research 23, 447–461.] of phytoplankton community assembly. Potentially harmful taxa were present in every surface sample and were numerically dominant during the largest observed blooms, contributing up to 92% of the total phytoplankton abundance >5 μm. Large interannual variation was observed in the dominant taxa and bloom seasonality; Pseudo-nitzschia sp. dominated blooms in early 2004 (February and April), whereas Prorocentrum micans and Lingulodinium polyedrum blooms occurred in May and September of 2005, respectively. The Pseudo-nitzschia sp. blooms were associated with elevated nitrate, dissolved silicon and phosphate concentrations throughout the euphotic zone; the first bloom followed a strong upwelling and the second occurred during the onset of seasonal stratification. In contrast, the blooms of P. micans were associated with highly stratified, low nutrient waters. Multivariate analysis supports the roles of temperature, mixed-layer depth and nutrient concentrations as primary controls of bloom growth, following the conceptual Intaglio model. The strong presence of potentially harmful bloom species in the Santa Monica Bay during this study appears unusual in comparison to limited studies over the last several decades.

Dry atmospheric deposition rates of metals along a coastal transect in southern California

While recent studies indicate atmospheric deposition is a significant source of metals to the Santa Monica Bay and coastal river systems of the Los Angeles area, the spatial extent of the atmospheric source along the entire southern California coast has not been measured in 30 years. This study provides measurements of dry atmospheric deposition of chromium, copper, lead, nickel and zinc at eight sites located along the coast between Santa Barbara and San Diego, and compares these data to historic measurements from the 1970s. Median dry deposition fluxes across sites ranged between 0.23 and 3.6 (chromium), 0.21 and 5.4 (nickel), 0.52 and 14 (lead), 0.89 and 29 (copper), and 4.8 and 160 (zinc) μg m −2 day −1. Differences in metal dry deposition rates observed between sites were dominated by proximity to urban areas and/or other nearby sources, with the highest metal fluxes observed near the Los Angeles Harbor (LAH) and San Diego Bay (SDB) sites. Compared with data from the 1970s, lead fluxes were typically one to two orders of magnitude lower in the present study (2006), indicating atmospheric sources of this metal have decreased over the past three decades in southern California. Chromium fluxes were also lower in 2006 compared with the 1970s, although to a lesser extent than for lead. In contrast, copper and zinc fluxes were typically within the same order of magnitude between the two time periods, with some higher measurements observed in 2006 compared with the 1970s at the LAH and SDB sites. This result indicates atmospheric sources of copper and zinc have not decreased over the past three decades in southern California, and have increased near our harbor/urban sites. Differences in sampling conditions (e.g., Santa Ana winds) and measurement techniques may also explain, in part, the differences observed in metal flux rates for these time periods. However, these limitations were most important for those metals with the smallest difference in flux rates measured in the 1970s vs. 2006 (e.g., chromium).

Effects of Marine Mammals on the Sport Fishery in Santa Monica Bay, California

Marine mammal-sport fishery interactions in Southern California waters are often observed but far less studied than marine mammal interactions with commercial fisheries (Hanan and Read 1989, Beeson and Hanan 1996, NMFS 1997). Older studies (Fiscus and Baines 1968, Miller et al. 1983) show that sea lions rarely interact with fishing activities in and near Santa Monica Bay while, in later investigations, California sea lions (Zalophus californianus) are reported to negatively affect sport fishing (Beeson and Hanan 1996). Previous to our study, no information was reported on interactions between fishermen and other species of marine mammals, except for Miller et al. (1983). The abundance of marine mammals and sport fishermen makes Santa Monica Bay an excellent area to further investigate marine mammal-sport fishery interactions, to compare results with previous findings, and to provide information for future conservation and management decisions linked with the creation of a Marine Protected Area in Santa Monica Bay. The most common marine mammals known to inhabit and feed in the bay year-round include the California sea lion, the bottlenose dolphin (Tursiops truncatus), the short-beaked common dolphin (Delphinus delphis) and the longbeaked common dolphin (D. capensis) (Bearzi 2005a). A survey of sport fishermen was conducted during 1998–1999 to gather general information on the type of interactions existing between marine mammals and fishermen activities and how marine mammals affect sport fishery in Santa Monica Bay. Of 90 interviewed sport fishermen, 30 were selected for the survey in Marina del Rey and Redondo Beach harbors during February–June 2000. The fishermen selected were required to have fished year-round and to have made at least 20 fishing trips per year in Santa Monica Bay (Point Vicente 33u 459 N 118 249 W to Point Dume 33u 599 N 118 489 W, up to 20 km offshore). Further, the fishermen were chosen from both charter boats (n 5 18) and private vessels (n 5 12); this was different from previous investigations where those interviewed were exclusively on charter boats (Miller et al. 1983, Beeson and Hanan 1996). Information about Sport Fishermen and Their Catches Of the selected fishermen, 87% stated they spent 1–3 days per month fishing in the bay and 80% preferred fishing during the summer months (June–August). Most (67%) fished less than 10 km from shore, of which 43% were within 1–5 km and only one fisherman at less than 1 km from shore. In 1998, 38% of the fishermen reported catching mostly ‘‘bass’’ (the term bass is generally used by local fishermen to include any fish species similar to a rockfish) and 36% reported catching mostly yellowtail, Seriola lalandi. In 1999, 47% of the fishermen reported catching ‘‘bass’’ most abundantly while only 13% reported catching yellowtail. Interactions with Marine Mammals All the fishermen observed dolphins in 1998 and 1999. Virtually all (97%) stated that dolphins – generally recognized as ‘‘common dolphins’’ never interfered with their fishing operations; one fisherman reported one Bull. Southern California Acad. Sci. 106(3), 2007, pp. 215–217 E Southern California Academy of Sciences, 2007

Classifying environmentally significant urban land uses with satellite imagery

We investigated Bayesian networks to classify urban land use from satellite imagery. Landsat Enhanced Thematic Mapper Plus (ETM +) images were used for the classification in two study areas: (1) Marina del Rey and its vicinity in the Santa Monica Bay Watershed, CA and (2) drainage basins adjacent to the Sweetwater Reservoir in San Diego, CA. Bayesian networks provided 80–95% classification accuracy for urban land use using four different classification systems. The classifications were robust with small training data sets with normal and reduced radiometric resolution. The networks needed only 5% of the total data (i.e., 1500 pixels) for sample size and only 5- or 6-bit information for accurate classification. The network explicitly showed the relationship among variables from its structure and was also capable of utilizing information from non-spectral data. The classification can be used to provide timely and inexpensive land use information over large areas for environmental purposes such as estimating stormwater pollutant loads.

Dye dispersion in the surf zone: Measurements and simple models

To examine the spatial and temporal effect of low-volume land-based runoff on beach contamination, discrete batches of dye were released at the shoreline at three beaches in Santa Monica Bay in 2000 (Malibu Creek, Santa Monica Canyon and Pico–Kenter drain). Dye concentration was measured at the shoreline 25, 50 and 100 m alongshore from the dye release point for up to 40 min after dye release. The shoreline concentration time series are characterized either by approximately exponential decay in concentration after passage of the dye patch maximum concentration or by persistent low concentration up to 30 min after passage of the initial dye patch front. In the absence of detailed measurements of physical conditions, several simple advection–diffusion models are used to simulate shoreline concentration time series for an idealized surf zone in order to probe the roles of alongshore current shear and rip currents in producing the observed characteristics in dye concentration time series. Favorable qualitative and quantitative comparison of measured and simulated time series suggest alongshore current shear and rip currents play key roles in generating the observed characteristics of nearshore dye patch dispersion. The models demonstrate the potential effects of these flow features on the extent and duration of beach contamination owing to a continuous contamination source.

Habitat quality and endoparasitism in the Pacific sanddab Citharichthys sordidus from Santa Monica Bay, southern California

Prevalence, mean abundance and mean intensity of the most common endohelminths infecting Pacific sanddab Citharichthys sordidus were compared among six trawl stations in the Santa Monica Bay. These trawl stations varied in their distance from the 8 km effluent of the Hyperion treatment plant which is situated adjacent to Santa Monica Bay. Juvenile stages of Anisakis sp., Corynosoma sp., Lacistorhynchus dollfusi and Tetraphyllidean plerocercoids were found infecting Pacific sanddabs. Significantly higher prevalence and mean intensity of L. dollfusi and Anisakis sp. were seen at the non‐outfall stations compared to outfall stations either immediately surrounding or in the vicinity of the outfall. These differences appeared to be related to changes in invertebrate population densities in response to the presence of contaminants. Canonical analysis of discriminance using parasite abundance data discriminated non‐outfall from outfall stations. The cestode L. dollfusi explained most of the variability in discriminant scores generated from the analysis and appears to warrant further investigation as a potential bioindicator of pollution exposure in its fish host.