A comparison of reef fish assemblages inside and outside of a marine reserve at Santa Catalina Island, California

Froeschke, John T. and Larry G. Allen*, Nearshore Marine Fish Research Program, California State University, Northridge.

The fish assemblage of the rocky reef kelp forest habitat of Santa Catalina Island, California was compared inside and outside of a marine reserve. Two sites inside and out of a marine reserve were sampled approximately quarterly using visual census on SCUBA at depths of six and 12 meters from October 2002 to February 2004. On each sampling date, divers swam a 2 m wide * 50 m long transect counting all conspicuous fishes within the 100m2 area and assigning each fish to one a five size classes (adult, sub-adult, juvenile, young of year or recruit). Twenty-three species from 14 families were observed on transects during this period. The assemblage was dominated by warm temperate and subtropical species including pomacentrids, gobiids, labrids and serranids. Species richness was similar at all sites however, the relative abundance of some species differed between reserve and non-reserve sites. Densities of adult sheephead (Semicossyphus pulcher) and kelp bass (Paralabrax clathratus) were significantly higher inside the marine reserve. There were no strong seasonal patterns of abundance in the assemblage of fishes. Overall, these data indicate that a small marine reserve may effectively protect some recreationally important species from harvest and ultimately may lead to enhanced stocks of these fishes at non-reserve locations through larval export and/or adult emigration.

Acanthogobium flavimanus: Does the San Francisco Bay Population Show Evidence for Population Genetic Bottleneck?

Beck, A.R., E.M. Gallardo and R.R. Wilson, Jr. California State University, Long Beach.

Yellowfin goby, Acanthogobius flavimanus, is an estuarine fish with a native distribution in northeastern Asia. The species was evidently introduced into San Francisco Bay (SFB) and the harbors and estuaries of southern California during the 1960's and 1970's, and has since established populations in those locations. We collected data on the frequencies of microsatellite alleles of both native and introduced populations to test the hypothesis that post-invasion gene flow exists between northeast Asia and California. We sampled the SFB populations in 4 consecutive years (2001 - 2004), a sample from the historic SFB population collected in 1966-1967, and the Japan populations in the summer of 2003. Based on Rhost and the M statistic of Garza and Williamson (2001), the hypothesis of gene flow between SFB and Tokyo Bay cannot be rejected (p>0.05). Neilson and Wilson (2005) calculated the haplotype singleton ratio for these populations based on mtDNA control region sequence, and found evidence for a population bottleneck in the SFB population. The M statistic of Garza and Williamson (2001) has a parallel structure to that of the haplotype singleton ratio in that both methods compare the observed number of alleles (or haplotypes) to the number expected in a population that has not experienced a population genetic bottleneck. Our results indicate that these two methods agree about the presence of a population genetic bottleneck caused by the invasion of A. flavimanus into SFB.

Spatially Explicit Mean Field Models for The Dynamics of Predation in Intertidal Communities.

Robert A. Desharnais, Carlos Robles, Megan Donahue, and Ling Cao. California State University at Los Angeles, Department of Biological Sciences, Los Angeles, CA, 90032.

Spatially-structured dynamics are an important consideration when local interactions among individuals of a sedentary species are intense. Intertidal communities often display intense local interactions among individuals, and the dense populations, small spatial scale, and striking distribution patterns of the communities suggest that this system is especially apt for investigations of spatially-structured dynamics. Mean field approximations of a cellular automata model were developed to investigate the dynamics of the intertidal mussel Mytilus californianus and its predators. The models incorporate open recruitment, growth, and the size-dependent consumption of prey and predator immigration and emigration with emigration rates that are inversely proportional to the overall per capita rate at which predators consume prey. The observation that predators are more likely to forage in areas with large numbers of smaller prey is incorporated as a spatially explicit mean field effect. For a range of reasonable parameter values, the mean field model exhibits alternate stable states: a low density of small mussels or a high density of large mussels. When mean field patches are linked with rates of recruitment, growth, and predation are modified to simulate a tidal height gradient, these alternate stable equilibria are manifested as a sharp lower boundary in the distribution of prey. When model parameters are modified to account for varying wave energy, the changes in the prey size and spatial distributions resemble overall patterns found in real mussel beds. In this paradigm, mussel bed boundaries are a balance between prey productivity and predation mediated by environmental factors. Field tests of this hypothesis are in progress.

Spatial models of mussel beds: environmental gradients, neighborhood effects, and temporal dynamics.

M. Donahue, R. Desharnais, C. Robles, C. Garza. California State University, Los Angeles.

Intertidal mussel beds have been a model system for marine and community ecologists for decades. The intertidal landscape is unique because of the pronounced environmental gradients that occur over small spatial scales. Strong trophic interactions play out on these environmental gradients and are known to structure mussel bed communities; however, previous conceptual models have oversimplified these interactions. Using a cellular-automata approach, our model produces realistic mussel bed structure as a dynamic equilibrium between mussel settlement and growth and seastar predation. Key features of the model include strong environmental gradients in tidal height and wave exposure and neighborhood effects in seastar predation. Here, we investigate how gradient steepness and neighborhood scale interact to influence mussel bed structure. This model has produced specific predictions about the response of the mussel bed to change in predator density; these predictions are unique to the dynamic equilibrium view of the mussel bed structure and are not predicted by previous conceptual models. In preparation for testing these predictions in the field, we have used the model to investigate the time-course of change in response to predator augmentation and reduction.

Salinization of surface water and groundwater, Hueco Bolson and Mesilla Valley, New Mexico, Texas and Chihuahua: sources of sulfate as indicated by stable O, H and S isotopes.

Chris Eastoe1, Jason Dadakis2, Barry Hibbs3. (1) SAHRA/Dept. of Geosciences, University of Arizona (2) Orange County Water District (3) -CREST, Dept. of Geological Sciences, California State University, Los Angeles.

Salinity and d34S values in Rio Grande water increase in the Hueco Bolson, with sharp increases in El Paso and near Fabens at times of low flow. Fluctuations at El Paso reflect input of high-d34S salty groundwater from the Mesilla Valley upstream. Near Fabens, addition of water with d34S > 9 ‰, [SO4] > 300 mg/L and Cl/SO4 near 1 is required. Such water can be derived from the Hueco Bolson aquifer, but not from urban effluent or agricultural drainage. Sulfate d34S and d18O values are consistent with Hueco Bolson groundwater as the source of high-d34S sulfate. Sulfate geochemistry and salinization mechanisms differ in pre-dam (pre-1916) or post-dam river water now present as groundwater. Pre-dam groundwater in Hueco Bolson and Mesilla Valley has increased in salinity relative to contemporaneous river water as a result of addition of salty basin water with d34S > 9 ‰; and Cl/SO4 > 1 in the Hueco Bolson. Post -dam groundwater salinity in the Hueco Bolson has increased by addition of sulfate with d34S commonly lower than values in present-day river water, and can be explained by oxidation of sulfide in alluvium, but not by addition of urban wastewater, or of gypsum and sulfuric acid as agricultural amendments.

Born and raised in Southern California: Developmental evolution and cryptic speciation in the sea slug genus Alderia.

Ryan Ellingson and Patrick Krug, Department of Biological Sciences, Cal State Los Angeles.

Variable development within a single species (poecilogony) is a rare phenomenon, and empirical examples often turn out to comprise cryptic species. The sacoglossan genus Alderia contains a single recognized species in north Atlantic and Pacific estuaries; it produces feeding larvae (planktotrophy) throughout its distribution except in California, where both planktotrophy and lecithotrophy (non-feeding larvae) are expressed. Molecular, morphological and developmental evidence indicate that populations south of Bodega Harbor comprise a true poecilogonous species, distinct from the strictly planktotrophic congener A. modesta. Northern populations (Bodega to Vancouver) consist of large adults with a smooth dorsum that produce planktotrophic larvae; those from Tomales Bay south consist of smaller adults with a raised dorsum that seasonally toggle between planktotrophy and lecithotrophy. Sequences of the mitochondrial COI gene were obtained from 204 individuals from 14 populations. Northern and southern haplotypes formed reciprocally monophyletic clades differing by 16-20%, including fixed differences at 36 of 480 sites. Molecular clock calibration indicates the species have diverged since the early Pleistocene (1.4 million years ago! ). The northern species is absent from the south of Tomales Bay yet common only 4 km away; population dynamics may reflect differential colonization of regionally distinct strains of the host algae Vaucheria spp.

Early life history, growth, and reproduction of captive weedy sea dragons, Phyllopteryx taeniolatus.

Kristy Forsgren, M.S. Graduate Student, Biological Sciences, California State University Long Beach.

The developmental stages, somatic and reproductive growth, and the reproductive behavior of weedy sea dragons, Phyllopteryx taeniolatus, were described using a captive population. Development was categorized into 4 periods: incubation, larval, juvenile, and subadult. The von Bertalanffy growth parameters generated from the length-at-age data of known age animals were L8 = 285 ± 3 mm length and k = 2.20 ± 0.05 yr-1. Gonosomatic index of both sexes was very low (<0.003%). Courtship involved a tail curling behavior, where males would approach and curl its tail away from females. Females also curled their tails away from males if they were preferred. Breeding occurs when the pair swims upward in the water column with the female transferring eggs to the male's brood patch. Females (251-322 mm TL) ovulated an average of 110 eggs per spawning and males (310-328 mm) successfully incubated an average of 91 eggs per clutch. Male brood patch size limits the number of eggs that could be accommodated by the male; therefore, limiting the reproductive success of the pair. In addition to improving our understanding of the life history, this information can be used to estimate demographic parameters and assist in better classifying this species' threatened status.

Fracture Trace Analysis of Structural Geology at the Sierra de Presidio and its Relationship to Hydrogeochemistry.

Alfredo Granados-Olivas (CIG-UACJ); Barry Hibbs (CalState-LA); John Hawley (NMSU); Chris Eastoe (UofA).

Water, the liquid of life, is the most important natural resource on the Paso del Norte Region (Southwest US- North central MX), where more than 2 million people supply their basic water needs mostly on the availability of ground water resources of the region. Twin-cities expand along the transboundary Hueco Bolson where pumping on this aquifer system has depleted the depth to static water table averaging from 10 to 55 m in the last 100 years (1902-2000). The temporal evolution of water quality has been deteriorating, where concentrations of TDS and other ions have been manifested on some of the municipal wellfields. The Bandejas area, a transboundary watershed tributary to the Rio Bravo-Rio Grande, has unconfined layers conforming the aquifer formation which have been considered as unviable to bring into production to mitigate the demands of the major city on the region, Ciudad Juarez, Chihuahua. In this paper, the headwaters of the Bandejas watershed (Sierra de Presidio) are evaluated on its structural geology seeking for potential fracture traces that might be related to recharge zones an its spatial correlation with the hydrogeochemistry monitored on the study area. This process was done while using ASTER satellite imagery and GIS coverages, fracture traces and faults where mapped with GPS units and geophysical vertical electric soundings (VES) where taken at these geomorphic features to identified lithologic contacts where fault was inferred. Results show a geospatial correlation of hydrogeochemistry and the mapped lineaments and faults, which extend into the floodplain of the Rio Bravo/Rio Grande where most agricultural wells (<1000 TDS) are located.

Age and growth of the round stingray, Urobatis halleri, at Seal Beach, California.

Loraine Hale, M.S. Graduate Student, Biological Sciences, California State University Long Beach.

The round stingray, Urobatis halleri, is the most common nearshore elasmobranch in southern California and is particularly abundant at Seal Beach, California, where they cause 200-500 round stingray-related injuries each year. Because of the desire to reduce the number of round stingray-related injuries, knowledge of the age and growth of this species is important for management. Stingrays were collected monthly in beach seines at Seal Beach, California in 2003 and 2004 (n=171). Vertebral centra were sectioned and age was estimated by two readers. The parameters estimated by the von Bertalanffy growth model were a L8=348 mm for males and 251 mm for females, k= 0.06 year-1 for males and 0.11 year-1 for females, and t0= -4.61 for males and -5.38 for females. The age structure of the population of round stingrays at Seal Beach consists of mostly mature males and females. Age at maturity (150 mm disc width) corresponded to an average age of 3.8 years for females and 3.75 years for males with a maximum estimated age was 14 years old. Males were more numerous than females throughout the year with the highest frequency of occurrence in August; however from May through September females outnumbered males.

Digital hydrogeologic-framework model of the binational Western Hueco Bolson area, Texas and Chihuahua.

John W Hawley and John F Kennedy. New Mexico Water Resources Research Institute, New Mexico State University

Basin-fill aquifer systems of the binational, Hueco Bolson-Paso del Norte region collectively form a major trans-boundary groundwater resource. This paper summarizes progress on development of a new digital hydrogeologic-framework model of the western Hueco Bolson. The study area includes the El Paso-Ciudad Juárez Metro-district, adjacent parts of El Paso County, Doña Ana and Otero Counties (NM), and the Rio Grande/Bravo Valley of Texas and Chihuahua. Research to date is part of a multi-institutional/disciplinary project: "Hydrogeologic and Water Quality Study of the Hueco Bolson Aquifer," including the New Mexico Water Resources Research Institute, under terms of a NSF Glue-Grant agreement with California State University-Los Angeles (CEA-CREST). A hydrogeologic map and eight preliminary cross sections have been completed to date. Special emphasis is on development of conceptual models of hydrogeological-hydrogeochemical systems in areas of nested piezometers and detailed hydrogeochemical research in Lower Valley areas between Paso del Norte and Fabens (TX). GIS methodology (e.g. ARC/INFO®) integrates hydrogeologic elements such as aquifer-system lithology and stratigraphy, basin (bedrock) boundaries and internal basin structure. The digital "template" for the hydrogeologic-framework model is 3-dimensional and has a combined map-fence-diagram format (1:100,000 map-scale, 10x cross-section vertical exaggeration, and base elevation of 0-300m above msl).

Irrigation return flows or cross-formation leakage from the Hueco Bolson Aquifer as the dominant source of salinity in the Rio Grande Alluvium? - inorganic and isotopic tracers tell a story.

Barry Hibbs (1), Mercedes Merino (1), Scott Reinert (2), and Chris Eastoe (3);
(1) California State University, Los Angeles, (2) El Paso Water Utilities, (3) University of Arizona

The Rio Grande alluvial floodplain aquifer between El Paso/Juarez and Fort Quitman, Texas has been intensively tilled and irrigated since 1910. Almost since that time, the Rio Grade and its interconnected alluvial aquifer have had excessive salinity problems. Presently, salinity of surface water and groundwater increases from 800-2000 mg/L total dissolved solids (TDS) near El Paso,Texas to 2500 to 7500 mg/L TDS near Fort Quitman, Texas, approximately 115 km downstream. We investigated the "San Elizario Island" portion of the alluvial floodplain aquifer near Fabens, Texas, about 45 km downstream of El Paso. Salinity in groundwater in this 95 square-km reach of alluvial floodplain varies substantially from about 1000 mg/L TDS to 6000 mg/L TDS. This represents one of the largest salinity variations across such a small section of the floodplain. Approximately 40 groundwater samples have been collected from the Rio Grande floodplain aquifer in the San Elizario Island area. Two distinct water types are identified. The first water type is a relatively dilute groundwater type containing 1000 to 1750 mg/L TDS, 250 to 600 mg/L chloride (Cl), and chloride/bromide (Cl/Br) weight ratios of 550 to 900. The second water type is a relatively saline groundwater type containing 2000 to 6000 mg/L TDS, 900 to 2100 mg/L Cl, and Cl/Br weight ratios of 1200 to 2000. Previously it had been thought that these salinity contrasts were due to variable agricultural practices and local variations of soil lithology in the floodplain soils. However, this paper show that the more saline groundwater type in San Elizario Island is demonstrably attributed to cross formational leakage from the underlying Hueco Bolson aquifer. Isotopic and inorganic tracers show that leakage occurs from a very saline water bearing unit in the Hueco Bolson, directly beneath the floodplain aquifer.

Groundwater recharge and riparian sustainability in the San Pedro Basin AZ.

James Hogan1, Matthew Baillie1, Arun Wahi1, Chris Eastoe2, Brenda Ekwurzel1. (1) Hydrology and Water Resources, University of Arizona (2) Geosciences, University of Arizona.

Groundwater managers in the semiarid Southwest U.S. must balance the demands of growing populations against the needs of riparian ecosystems. We employed a suite of geochemical measurements, including isotopic tracers and noble gases, to improve our conceptual and quantitative understanding of recharge processes and water sources, information which can aid groundwater management. Most precipitation in this region falls during either summer monsoons or winter frontal storms. Each source has a distinct stable isotopic composition allowing us to determine the dominant season for recharge. Groundwater in the basin has a narrow range of stable isotope compositions, 62-72% winter precipitation. Detectable tritium and 14C values > 100 pMC from springs and groundwater from wells in mountain canyons and along the mountain front indicate decade-scale residence times. Away from the mountain front 14C values rapidly decrease, reaching 12.3 pMC near the river. This suggests total basin residence times greater than 10,000 years, consistent with past measurements. Within the riparian corridor groundwater is a mixture of basin groundwater and locally recharged monsoon runoff, varying from 20-90% basin groundwater. The water source correlates well with independent classification of river reaches as either gaining (basin) or losing (monsoon). Likewise river baseflow varies from 40-100% monsoon precipitation, and is closer to basin groundwater in gaining reaches.

Hueco Bolson Hydrogeology, Management, and Modeling.

Bill Hutchison, P.G., Hydrogeology Manager. El Paso Water Utilities.

The Hueco Bolson is a deep alluvial groundwater basin that underlies portions of New Mexico, Texas and Chihuahua. Fresh and brackish groundwater occurrence is a function of tectonics, geomorphology, and sedimentology.

El Paso has relied on the Hueco Bolson as a major water supply source since 1903. As a result of high pumping, groundwater levels in the Hueco have declined and brackish groundwater has intruded into areas that historically yielded fresh groundwater. El Paso Water Utilities (EPWU) began reducing its Hueco pumping in 1989. This action was made possible by a variety of water management initiatives including increased water conservation, increased surface water diversions, and increased reclaimed water use. The reduction in pumping has resulted in stabilized groundwater levels in many areas. However, brackish groundwater intrusion remains an issue. A 27.5 mgd desalination plant is currently under construction that will result in reductions in brackish groundwater intrusion, and allow EPWU to better utilize its fresh groundwater wells during droughts.

Short- and Longer-term Stress Effects of "Catch & Release" in Marine Gamefish-Catalina Island Studies.

Kevin M. Kelley. Marine Biology Program, Dept. Bio-Sci, California State University, Long Beach.

In California sheephead, white seabass, jack mackerel, and other marine fish, stressors such as catching or handling induce rapid and profound (>50-fold) surges in blood plasma concentrations of the hormone, cortisol. Cortisol levels will be sustained under most circumstances in which presence of stressor(s) remains, returning to baseline at a rate that differs among species and is dependent upon activity of synthetic and metabolizing enzymes. Elevated cortisol results in key physiological changes adaptive for survival through a stressful period. These include fuel mobilization from stores (for increased energy demands) and inhibition of energy-expensive processes such as growth and repair. Prolonged stress, however, becomes deleterious, particularly because important physiological systems cannot be inhibited for extended periods without serious consequences. Our work on stressed fish indicates that a blood protein, IGFBP-1, is increased by cortisol and serves to inhibit tissue synthetic activity and body growth. IGFBP-1 is considered an effective biomarker for stress impacts on growth. Recent experiments also demonstrate that IGFBP-1 remains elevated in serum even after subsidence of a cortisol surge, suggesting its impacts may be prolonged. [www.csulb.edu/depts./endo; funded by CA Sea Grant College Program NOAA NA06RG042 2002-03, project # R/F-192, & NSF grant # IBN0115975]

What Lakes in Southern California's Arid Environment Tell Us About Past and Future Climate Variability.

Matthew E. Kirby1, Steve P. Lund2 , Michael Anderson3 , Broxton W. Bird1, Christopher Poulsen4. (1) Cal-State Fullerton, Dept. of Geological Sciences (2) University of Southern California, Dept. of Earth Sciences (3) University of California, Riverside, Dept. of Environmental Sciences (4) University of Michigan, Dept. of Geological Sciences

Arid environments, such as Southern California, are vulnerable to catastrophic droughts and severe floods. Understanding their future impact is dependent on a thorough knowledge of past activity. Therefore, it is critical to locate and develop archives that record past hydrologic variability, such as the under-studied lakes of Southern California. Lake Elsinore is Southern California's largest, non-playa natural lake. Recently acquired drill cores from the lake's deepest basin reveal a thick, continuous Holocene (10,000 year) record of hydrologic variability. Multi-proxy analyses indicate a first-order Holocene drying trend in response to changing insolation. Superimposed on this trend is decadal-to-multi-centennial scale variability, which reflect a variety of external forcings such as complex ocean-atmosphere interactions in the Pacific sector (e.g., ENSO, PDO). There is also compelling evidence that the early Holocene was characterized by more frequent, severe storms. Conversely, the mid-to-late Holocene is characterized by a lack of evidence for severe storm activity. Rather, the mid-to-late Holocene is characterized by larger amplitude climate variability, possibly in response to the initiation of modern El Nino-Southern Oscillation dynamics. In response to this mid-to-late Holocene climate change, the occurrences of long-lived droughts have increased through present day. On-going research on lakes from Southern California will continue to develop a more complete picture of Holocene climate variability from which we can assess better the dynamics of future climate change in our arid environment.

Effects of Wildfire on Flow Paths in San Bernardino Mountain Watersheds: Evidence from Hydrograph Separation and Geochemistry.

Helen Kong1, Sheila Morrissey2, Rose Santilena2, Terri Hogue1, Laura Rademacher2, Tom Meixner3. (1) Department of Civil and Environmental Engineering - University of California, Los Angeles. (2) Department of Geological Sciences - California State University, Los Angeles. (3) Department of Hydrology and Water Resources - University of Arizona.

This study investigates the hydrologic and geochemical changes to the City Creek watershed, which burned in the October 2003 Old Fire. City Creek is located in the San Bernardino Mountains in the eastern part of the Los Angeles basin. Organic compounds from vegetation are vaporized during intense fires and settle in the soil, forming a hydrophobic layer. The increased hydrophobicity changes hydrologic flowpaths by increasing overland flow and decreasing infiltration to the subsurface. The City Creek stream flow can be divided into two components: overland flow (new water) and soil and groundwater flow (old water) using hydrograph separation and observed 18O isotope concentrations. Preliminary hydrograph separation results indicate that the overland flow contribution is greater in the early post-fire runoff. Precipitation in February 2004 results in more overland flow compared to a precipitation event during April 2004. Much of the City Creek vegetation was burned during the Old Fire, resulting in decreased transpiration and an increase in baseflow to the creek during the summer of 2004 when compared with the pre-fire summer baseflow. The NETPATH geochemical model was used to calculate geochemical reactions from precipitation to pre- and post-fire summer baseflow. Increased overland flow and decreased uptake by vegetation also resulted in increases in nitrogen, sulfur, potassium and carbon in City Creek during the first few months after the fire.

Water Budget Analysis - A Story of Two Arid Region Groundwater Basins.

Laton, W.R., Department of Geological Sciences, California State University, Fullerton.

Este Hydrologic Sub-basin lies within the southern edge of the Mojave Desert region, at the base of the San Bernardino Mountains. This area receives little to no rain and until recently had experienced substantial groundwater level declines. Since 1994 however, the water levels have reached a more stable condition, allowing for a water budget analysis in which recharge equals discharge. For the purpose of developing a detailed water budget, the Este Hydrologic Sub-basin was divided into two different type basins, the Lucerne Valley and Fifteenmile Valley; closed and open basins, respectfully. Basins were based in part on the surface water and groundwater boundaries. The resulting water budgets suggest that Lucerne Valley is within 300 acre-feet of balancing, while the Fifteenmile Valley water budget analysis showed an excess of approximately 7,000 acre-feet of water. This excess of water could be attributed to movement of groundwater from the basin into the adjacent basin.

Stabilizing Responses by a Keystone Predator ,Pisaster ochraceus, of Mussel Communities.

Alan Martinez, Dr. Carlos Robles. California State University, Los Angeles.

Recent studies suggest that Pisaster ochraceus have the capacity to adjust their densities to changing prey availabilities. Such numerical responses are among a group of possible predator responses believed to effect stable regulation, but the operation of the various responses is poorly understood. I will investigate Pisaster's developmental and functional responses to understand how these component responses, along with the numerical response, integrated as the total predator response. The experiment consists of 6 replicates dispersed over a 10 km2 area of Barkley Sound, British Columbia. Each replicate consists of three sites: one assigned sea stars removals, another assigned sea star augmentation, and the third designated as unmanipulated (control) site. The manipulations "force" the densities to artificial levels, nullifying the numerical response and establishing new predator/prey abundance ratios. Changes in sea star growth rates, movement patterns and diets are then compared between treatments and controls. Preliminary data on size frequency suggests that sea stars shrink or grow depending on abundance of food supply. Additional responses that have yet to be analyzed are diet, net alongshore movement, and growth of sea stars. The study will provide information about whether sea stars possess behavioral and physiological mechanisms thought essential for stabilizing populations of their prey.

Marine Protected Areas and Marine Protected Area Processes: An Overview and an Update

Steve Murray, California State University, Fullerton.

Marine Protected Areas (MPAs) are being offered as promising tools for improving protection of coastal populations and communities. Because MPAs are space-based, they have the potential to be significant tools for implementing ecosystem-based management, a practice strongly promoted in the recent report by the US Commission on Ocean Policy. In this presentation, I will review MPA principles, disucss predicted scientific outcomes, and then examine the status of MPA protection in Southern California, including the role of the Catalina Marine Science Center Marine Life Refuge. I will then briefly describe the status of three MPA processes with the potential to significantly affect Southern California coastal ecosystems: 1) the Channel Islands National Marine Sanctuary; 2) the Marine Life Protection Act; and, 3) Federal Advisory Committee and MPA Center work on developing a framework for creating a national system of MPAs.

Oceanic structure and variability: setting the stage for biological populations

Rick Pieper, Director, Southern California Marine Institute

Assessing successes of MPA's on biological populations is complicated by many factors. As on land, oceanic structure and variability sets conditions that allow some populations to survive, grow and reproduce better than others. It has often been difficult to define and understand these oceanic conditions and, thus, the normal variability in observed marine populations. Vertical structure includes an upper mixed layer where light allows for phytoplankton growth. Upwelling may brings nutrients (often lacking during the summer) to this upper zone. Fine scale structures (thin layers on the order of centimeters) often define areas of high concentrations of food and animals. Temporal variability and impacts range from seconds and minutes, to hourly (diel or diurnal changes), to daily (storms and wind events), to multi-month (seasons), to one-five years (El Niño Southern Oscillations) to tens of years (inter-decadal oscillations). Only recently have we begun to understand these longer scales of oscillation. Biological populations from phytoplankton to whales, including kelp beds and their communities, all respond to these variations in oceanic conditions. Different scales will be discussed, along with their potential impacts on marine populations. Measurement techniques will also be discussed and biological examples from local water, including Catalina Island, will be used whenever possible.

A large-Scale Field Test of Equilibrium Dynamics in an Archetypal Predator-Prey System

C.D. Robles, M. Donahue, R.A. Desharnais, and C. Garza CEA-CREST California State University at Los Angeles.

Predation by sea stars Pisaster ochraceus on intertidal populations of sea mussel Mytilus californianus has been the subject of several experimental tests of classic ecological theory. Until now the theory of how the predators regulate the prey has been couched in verbal explanations without regard to equilibrium dynamics, and the tests of theory have been "press experiments", which seek to determine only whether predation is a factor in processes setting spatial limits of the prey. The cellular automaton of Robles and Desharnais (2002), in contrast, numerically describes boundaries as the result of an abrupt shift in equilibria between predation and prey production, which occurs predictably over continuous environmental gradients. Test of this hypothesis a large scale field experiment is described wherein the rates and direction of prey population change indicate the operation of the equilibria. In a break with past approaches, manipulations are planned that can reveal asymmetries in how initial conditions affect the rates at which the experimentally induced equilibria will be established. It is hoped that a new unified methodology of field tests will arise form this work.

Shallow Surf Riders: Small-scale Larval Distribution in Estuarine Waters

Demian A. Willette, Patrick J. Krug. Dept of Biological Sciences, California State University, Los Angeles.

Larval supply to settlement sites strongly affects the distribution of marine organisms, but it is unclear how physical properties of the water column influence larval abundance at small spatial scales. We measured the near-bottom concentration of larvae over shallow mudflats in Newport Bay and the Cabrillo Wetland, San Pedro. For 12 months, larvae were sampled 1-10 cm above the substratum over a 3 hr flood tide for 3 consecutive days per month per site. Larvae were sorted live, grouped by taxon and identified to genus or species by DNA sequencing. Day-to-day variance in larval abundance was unexpectedly high, and concentrations were often radically skewed between the 2 heights on a given day, but evenly or reverse-distributed the next day. Such changes in small-scale distribution were observed for all major taxa, although spionid and barnacle larvae were consistently more abundant at 5 cm. Overall abundances at Newport were 3x higher for veligers, 17x higher for spionids, and 31x higher for pediveligers than at Cabrillo, whereas barnacle nauplii were 5x more abundant at Cabrillo. Flow measurements were recorded near the bed using an Acoustic Doppler Velocimeter (ADV) during sampling, revealing complex oscillatory flows; hydrodynamics may cause near-bottom fluctuations in larval abundance.

Development of an amylose-iodide method for the determination of phosphite in natural waters.

R.A. Barco, D. Patil, T.M. Salmassi, G. Hanrahan. California State University, Los Angeles.

Recent developments in the field of microbiology and research on the origin of life have suggested a possible significant role for reduced, inorganic forms of phosphorus (P) such as phosphite [H3PO3, P(+III)] and hypophosphite [H3PO2, P(+I)] in the biogeochemical cycling of P. In order to confirm the importance of reduced forms of P, we need to develop new and better methods for the detection of these compounds in the environment. To this end, a new method has been developed based on the oxidation of phosphite to phosphate [P(+V)] by a mixed-iodide solution containing tri-iodide (I3-) and penta-iodide (I5-). Free I5- and I3- subunits in the solution react with the amylose content in starch to form a blue complex, which has a ëmax of 580 nm. We were able to detect phosphite in the 1-10 uM range with reproducible linearity. Interference studies show that low arsenite concentrations can also be determined by this method. To fully understand the importance of reduced P, ultimately, we hope to develop the starch iodide method into an in situ detection technique for measuring phosphite directly in natural waters where sensitive and reliable field-based methods of analysis are needed.

San Joaquin Marsh as a Natural Treatment System for Excess Trace Elements and Nutrients.

Carole Bartel, Barry Hibbs, Humberto Nation, Mercedes Merino, Diane Martinez. California State University, Los Angeles.

The San Joaquin Marsh in Irvine, California serves a dual function as a natural treatment wetland and bird sanctuary. During about a 10 day residence period between inlet and outlet flows from San Diego Creek through the marsh, selenium is reduced by an average of 36% from a mean of 17 ug/L to 11 ug/L and total nitrogen by 74%. These pollutants can get sorbed to marsh sediments undergo denitrification and plant uptake processes which releases dimethyl selenide gas. However, arsenic and total phosphorus increase in concentration from the inlet to the outlet. ! Groundwater baseflows account for most of the trace element loading from upstream sources, while runoff dilutes them. Temporal variations of trace element and nutrient concentrations at San Joaquin Marsh show two major patterns: seasonal and weekly variations. Seasonal changes show a slight increase due to low in chemical and biotic processes in the marsh during late summer and early fall. Weekly variations show a peak during the weekend due to a decrease in runoff during the end of the week. Removal processes inside of the marsh (reduction/oxidation reactions, sediment sorption, transformation to gases, and plant uptake) are now being studied to assess pollutant reduction and removal processes.

Isolation of PAH degrading bacteria from urban soils

C. Beaty, P. Wong, T.M. Salmassi, C.K. Khachikian, California State University, Los Angeles.

Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant, organic contaminants found in various environments. Bacteria are known to degrade these compounds and researchers have found relationships between concentrations of PAH and abundance of PAH-degraders. Some researchers have isolated and identified the microbes responsible for mineralizing the PAHs. A few studies have examined the abundance of PAHs and their degraders in urban soils. In March 2005, soil samples were collected between train tracks and a road on the corner of Valley Boulevard and Mariana Avenue in Los Angeles. The soil was collected at the surface and at a depth of 20 cm from the surface. We hypothesized that PAHs generated from combustion accumulate in surface soils and expected to find PAH degraders in these samples. The goal of this experiment is to isolate and identify PAH-degraders by cultivation and molecular techniques. The cultivation of microbes was conducted using minimal media amended with one of three types of PAHs (pyrene, phenanthrene, and anthracene). Several different types of colonies were observed with distinct clear zones (suggesting degradation of the PAH) for plates containing phenanthrene (4 mg/ml). These suspect PAH degraders were purified and identified by molecular methods. In future studies, we hope to correlate the abundance of PAH degraders with distance from the source of these contaminants (e.g., freeways).

Evaluating ecological function in urban stream restoration.

Brunelle, S., Audia, S.M., Gamon, J.A., California State University, Los Angeles.

Urban areas such as Los Angeles face challenges in restoring degraded urban streams and surrounding riparian areas, since multiple interests and goals must be considered in addition to ecological function. When restoring an urban stream as mitigation for the destruction of a natural riparian region, it is important to consider whether the restored stream functions comparably to the natural stream that was removed. This study examines a specific example of a restored urban stream (lower Arroyo Seco in Pasadena, CA) as mitigation for the loss of a natural stream canyon (Sunshine Canyon Landfill). The restoration was considered successful due to the initial survival and growth of vegetation along with improved aesthetics and recreational opportunities in a degraded urban corridor. Consequently, this mitigation project has been declared a model to be replicated elsewhere in the Los Angeles region. However, our initial findings have found a decrease in the survival of the vegetation after the five year monitoring period, indicating this may not be a sustainable plan. Criteria for successful mitigation should include more indicators of ecosystem function such as long term sustainability of the community, enhancement of water quality, and wildlife usage. We propose that urban stream restoration should be coupled with long-term monitoring that evaluates these criteria.

A Mathematical Model of Mussel Bed Boundary in Response to Predation

Ling Cao, Robert Desharnais Ph.D., Megan Donahue Ph.D.. California State University, Los Angeles.

A mussel bed forms a distinct sharp boundary in the mid-intertidal. One of the traditional explanations for the abrupt lower boundary of the mussel bed is that the bed is a spatial refuge from predatory sea stars imposed by tidal exposure. Observations of sea stars feeding above this boundary at high tide demonstrate that the refuge explanation is inadequate. I used a mathematical model to explain this boundary formation. We developed a model of mussel zonation which includes dynamic processes such as mussel settlement and growth, predation, and predator migration. An ordinary differential equation (ODE) model referred to as the "basic model" describes mean-field predator-prey interactions without any environmental gradients. The basic model results in two stable equilibria of mussel size. For this study, I simulated an array of basic model "patches," in which patch position represents tidal height and attack rate decreases linearly with tidal height. I compared two cases: (a) where predators respond to mussel densities in individual patches, and (b) where predators respond to local mussel density (a patch and its immediate neighbors). In both cases, I found a distinct lower boundary to the mussel bed. When predators respond to local mussel density, the boundary shifts higher (lower) in response to increased (decreased) predation. I have also been developing a two-dimensional "quilt model" where patches vary across both gradients of tidal height and wave exposure.

Development of a novel molecular recognition probe for the detection of phosphite in natural waters

Alex Carlton1, John A. Moss2, Marc M. Baum2, and Grady Hanrahan1. (1) Department of Chemistry & Biochemistry, California State University, Los Angeles, Los Angeles, CA 90032, (2) Department of Chemistry, Oak Crest Institute of Science, 2275 E. Foothill Blvd, Pasadena, CA 91107

Recent evidence suggests a significant role for reduced inorganic phosphorus (P) species in metabolic processes and raises interesting questions regarding the biogeochemistry of these species in the environment. It is possible that reduced P compounds such as phosphite [H3PO3, P(+III)], are important in the cycling of P, but that their lifetimes are too short to measure significant concentrations hours or even days after removing the samples from their natural environments for laboratory analysis. This presentation describes the initial development of a phosphite detection method based on a molecular recognition probe for the in situ determination of phosphite in natural waters. The probe assembly consists of a recognition unit, which undergoes a chemical change in the presence of phosphite, coupled to a reporter complex, which exhibits a subsequent change in fluorescence behavior in response to the physiochemical interaction at the recognition unit.

Modeling Evapotranspiration and Carbon Uptake with Vegetation Reflectance Indices in a Dynamic Chaparral Ecosystem.

Helen Claudio, John Gamon, Yufu Cheng, Dan Sims, Walt Oechel, Hongyan Luo. California State University, Los Angeles.

We compared vegetation reflectance indices with CO2 and water fluxes (evapotranspiration) in a chaparral-dominated ecosystem in southern California. This study focused on data gathered between January 2001 and July 2003, where the vegetation spectral data were collected with a 100-meter tram system and the flux data were collected at an adjacent eddy tower. Simple and multiple regressions were taken with the fluxes as the dependent variable and the normalized difference vegetation index (NDVI), water band index (WBI), and photochemical reflectance index (PRI) as the independent variables. The study period was also divided into pre-drought, drought, and recovery to determine extent drought had on the relationships between the fluxes and optical indices. Through the overall study period, CO2 flux was most strongly correlated with NDVI and PRI, while evapotranspiration was most strongly correlated with NDVI and WBI. During the drought, the evapotranspiration-optical relationship strengthened but weakened with recovery. However, the CO2 flux-optical relationship weakened during the drought and rebounded with recovery. These results help identify key optical features related to CO2 and water fluxes and provide the first steps in constructing a CO2 uptake and evapotranspiration models driven from remote sensing data.

Geochemical Classification Groundwater Salinization in the Northern Hueco Bolson Aquifer

Jennifer Druhan1, Chris Eastoe1, James Hogan1, Barry Hibbs2, Bill Hutcheson3. (1) University of Arizona (2) California State University, Los Angeles (3) El Paso Water Utilities.

Multiple discrete vertical zone samples of groundwater from recently constructed well fields in the northern Hueco Bolson provides a unique opportunity to identify recharge zones and the dynamics of salinization in the aquifer. Oxygen and hydrogen isotopes were used to delineate mountain front and inter-basin flow as the two primary recharge mechanisms in the northern section. Incorporation of anion ratios and S isotope data with that of these recharge zones indicates multiple sources of salinization. Values characteristic of deep saline waters appear at depths greater than 300 meters, with S isotope values higher than 9\permil and Cl/Br ratios greater than 10,000. Mixing trends of these highly saline deep waters appear at the lowest intervals of some wells above 300 meters, indicating upward movement of deep saline groundwaters as a possible source of increased salinity. Additionally, data from shallower well intervals show a range of anion and sulfur isotope signatures distinct from those of the deep saline waters, with Cl/SO4 ratios of 200-8000 and a wide range of S isotope values. These anion and sulfur isotope distributions with depth suggest multiple salinity sources in addition to deep saline waters, as well as some evidence of bacterial sulfate reduction at shallow intervals.

Agent-Based Models for Population Dynamics in a Benthic Community

Jian Liu, Robert Desharnais. California State University, Los Angeles.

For more than five decades, population dynamics in intertidal community have been intensively studied by marine biologists. Theories and associated mathematical models have been proposed to explain the interaction between predators and prey. Most of these mathematical models have been built using differential equations, are oversimplified, and have inherent weaknesses. Agent-based models (ABM) are individual-based models, which comprise agents (e.g. prey, predators) and infrastructure (e.g. time and space), and eliminate most of explicit and/or implicit assumptions imposed by other models. ABM's are a more powerful and realistic tool for studying population dynamics in a benthic community because they can model space and time as continuous and can incorporate the behavior of individuals. I will present an agent-based model implemented in the computer programming language C++. I will present results from simulations of the interaction between prey and predator in an explicitly spatial context that show the effects of environmental gradients on the structure of the prey population in intertidal zone.

Optimization Of The Batch Method For The Determination Of NO3 + NO2 - N In Natural Waters.

Kent Miller, Ai Yuasa, Grady Hanrahan. California State University, Los Angeles.

A glass column, tightly packed with copperized cadmium granules, has established itself
as a useful tool in reducing NO3 to NO3 + NO2. Specifically, employing this method, the NO2 in NO3 + NO2 forms an intense pink azo dye color when complexed with sulfanilamide and N - (1-naphthyl) ethylenediamine dihydrochloride. Quantitatively, the optimum ratios of reagent and standard of reduced NO3 + NO2 was found which made it possible to determine low level concentrations of NO3 + NO2-N in natural waters from Hot Creek in Mammoth, California. The research describes our strategy for optimizing a procedure to detect low level concentrations of NO3 + NO2-N in natural waters using the batch method with a copperized cadmium column.

Inorganic Phosphorus Stability in Variable Matrices.

M. Mc Dowell, T. Salmassi, K. Foster.California State University, Los Angeles.

As one of the six necessary elements for the growth of organisms, phosphorus (P) is the least studied with respects to reduced species biochemical cycling. Generally, phosphorus' group V neighbor's arsenic (As) and nitrogen (N) are also found in the fifth (V) oxidative state within the environment. Despite the wealth of literature available on the chemical cycling of Group V elements such as nitrogen and arsenic, there is limited information available on the redox cycling of phosphorus even though there is evidence of reduced phosphorus in biological systems. Traditionally, phosphorus is characterized in the phosphate (HPO4 2-) form. However, in addition to phosphate there are three other reduced forms of phosphorus including phosphorus acid (H3PO3, P(+III)), hypophosphorus acid (H3PO2, P(+I)) and various forms of phosphides (P(-III)). In this study, an ion chromatography method was used to determine the stability of reduced phosphorus in microbial media designed to support the growth of heterotrophic bacteria isolated from geothermal waters. Preliminary results showed that the reduced forms of phosphorus were stable for at least 7 days. Further studies will implement the methods developed in isolating and identifying phosphite dependent bacterial organisms that may reside within hot springs at Hot Creek near Mammoth Lakes, CA.

Sulfate levels in groundwaters and its relationship to levels of both chloride and bromide in the Rio Grande Alluvium Aquifer.

Mercedes Merino1, Barry Hibbs1, Chris Eastoe2 and Eric Bangs3. (1) California State University, Los Angeles (2) University of Arizona

Chloride, bromide and sulfate concentrations in surface and groundwater were calculated for a portion of the Rio Grande alluvium Aquifer in the San Elizario Island region in Fabens, Texas. The results showed a link between Cl/Br ratios and isotopic data with sulfate concentrations in the region. A linear relationship was established to allow chloride and bromide data to be used to estimate sulfate concentrations. Concentrations were obtained from measurements taken at water wells, springs and surface water, and the data was analyzed using Cl/Br ratios and isotopes of oxygen and hydrogen. Both solutes showed significant increases in concentration for all samples having low Cl/Br ratios. However, there was no significant difference in isotopic signatures. Both surface water and groundwater samples had sulfate levels above the standard of 250 mg/L, and most of the samples had chloride concentrations above 250 mg/L. Some factors that could be contributing to high sulfate and chloride levels in this portion of the alluvium aquifers include possible seepage of saline water from the deep Hueco Bolson aquifer and/or irrigation return flow.

The Effects of Moisture on the Surfaces of Montmorillonite and Silica Gel.

Antonino Monterrosa, Dr. Crist Simon Khachikian. California State University, Los Angeles.

A key factor in the uptake and release of contaminants in soils is the amount of water adsorbed to the soil particles. It is hypothesized that the decrease of surface area is caused by a coating of water molecules on the surface of soil particles. Additionally, contaminants may condense within pores of the solids, effectively reducing their pore areas as well. To our knowledge, these processes have not been studied in detail. In our experiments, we incubated four different solids (i.e., 2 silica gels, kaolinite, and montmorillonite) in three different controlled environments (i.e., with relative humidity values of 16%, 76%, and 86%) at ambient temperatures. Our results indicate that moisture significantly affects the surface areas of all solids, except for kaolinite. For example, the surface area of one of the silica gel samples incubated for 443 days at 16%, 76%, and 86% were 271.1 m2/g, 237.5 m2/g, and 218.1 m2/g, respectively. Moreover, long-term incubation of samples results in a decrease in surface areas for Montmorillonite at 86% RH compare to 76%RH (i.e., surface area of montmorrillonite at 76% RH changes from 2.95 to 7.10 m2/g upon incubation for 442 days but at 86% RH it only changes to 6.03 m2/g).

Tests of Three Hypotheses and Differential Settlement in Mytilus galloprovincialis and M. californianus.

Paul Moya and Carlos Robles. California State University, Los Angeles.

Three alternative hypotheses ("mechanical settlement", "competition settlement", and "gregarious settlement") predict different patterns of mussel larvae settlement on rocky shores, depending on community interactions of the juveniles and adults. The mechanical settlement hypothesis (Caceres 1994) explains that that larval settlement is solely a physical process in which secreted mucus threads become entangled on irregular substrates. The competition settlement hypothesis (Peterson 1984) states that competitively dominant species settle randomly in regards to its congener, whereas competitively subordinate species avoid the dominant species. The gregarious settlement hypothesis (Petraitis 1974) maintains that each species of larvae attain adaptations to recognize cues to settle preferentially on adult conspecifics. Field experiments were conducted to evaluate the hypotheses applied to Mytilus galloprovincialis and M. californianus in Southern California. Differences in settlement rates of the two species with respect to varying types of collector are consistent with the mechanical settlement hypothesis. Additionally, wave exposure gradients appeared to cause differential settlement between the two species that paralleled alongshore differences in the relative abundance. These findings are part of a growing body of evidence that settlement processes are inextricably linked to post-settlement population and community processes.

Spatial and Mechanistic Characterization of Differential Selenium Immobilization and Remobilization via Groundwater Into the San Diego Creek Watershed, Irvine California.

Humberto E. Nation, Mercedes M. Merino, Barry J. Hibbs, Carole M. Bartel, Alejandra Lopez. Department of Geological Sciences. California State University, Los Angeles.

Recent studies in San Diego Creek Watershed have shown moderate to high selenium loading into surface water via groundwater source loading. Groundwater often contains between 25 to100 ug/L selenium in areas where groundwater baseflows account for as much as 90% of the surface flows in the watershed. Remobilization of sequestered selenium in groundwater occurs through oxidation conditions within soils above and below the water table. Differential accumulation of selenium occurred in the reducing sediments within the 15,000 acre area occupied by what was known in predevelopment times as the "swamp of the frogs marsh." Remobilization of selenium due to contemporary oxidizing conditions in shallow groundwater following drainage of the marsh has been shown to be the source of higher than normal concentrations of this trace element in groundwater.
The present study has identified spatial differences in selenium concentration in groundwater and yielded information about the mechanisms of immobilization (in predevelopment times) and remobilization (in modern times), supporting the hypothesis of reduction/oxidation controls on selenium concentrations in subsurface water that changed as land conditions changed from swampy marsh to agricultural landscapes.

Examination of Naturally Occurring Arsenic and Chromium in Aquifers Underlying the Western Mojave Desert.

Curtis P. Plotkin1, Crist Khachikian1, John Izbicki2, Laura Rademacher1. (1) California State University, Los Angeles. (2) U.S. Geological Survey, Water Resources Division.

Recent studies by the USGS suggest that chromium in aquifers underlying parts of the Mojave Desert are released naturally from aquifer materials. To understand the desorption kinetics of chromium and arsenic in this aquifer, batch and column studies were performed. Core material was collected from the Sheep Creek fan near Victorville, CA. Chromium was leached in batch experiments under pH 2, 7, and 9 conditions for both ambient and heated samples. Chromium was released in all samples, with greater release in lower pH conditions. Temperature increased release in all samples except for those at pH 2. Column experiments were also performed using glass columns 1.5 cm by 15 cm. The columns were packed with unpulverized core material. Water at pH values of 2, 7 and 11 were pumped through the columns and the effluent was collected and analyzed using an ICP-MS. Chromium concentrations decreased with increasing pore volumes passing through the columns. On the other hand, arsenic concentrations remained high for approximately 10 pore volumes before dropping to background levels. The column experiment demonstrated a direct relationship between vanadium and arsenic and an inverse relationship with manganese and iron. Currently geochemical modeling is underway using PHREEQCI to better understand the geochemical relationships that are occurring.

Bacterial Community Diversity in Soils With Elevated CO2 at Mammoth Mountain, CA.

Carolina Reyes, Dr.Tina Salmassi, Dr. Khachikian, Roman Barco, Christine Ammons, Pauline Wong, Christina Ung, Mesfin Gewen, Gavin Chan. California State University, Los Angeles.

In 1988, a series of earthquakes triggered the release of CO2 from the subsurface of Mammoth Mountain, California, a dormant volcano, into the surrounding soil killing ~170 acres of pine trees. Past CO2 flux measurements in the tree kill areas have been recorded to account for 20-90% (vol %) and 1% or less in the adjacent undisturbed forest soil. Additionally soil pH is low and vegetation mortality high, thus, organic acid composition is low and aluminum silicate dissolution high in these soils. As atmosphere, pH and free metal ions influence microbial growth, we hypothesized that bacterial communities at this field site, would differ in overall number and composition based on soil CO2 levels. Therefore the aim of this study was to assess the effects of elevated soil CO2 on composition and diversity of bacterial communities in these soils by most probable number (MPN) analysis and by 16S rDNA analysis. Based on MPN analysis there appear to be more aerobic heterotrophs in the control area and more aluminum resistant bacteria in the CO2 area. Preliminary sequence analysis of 16S rDNA, a universally conserved gene region in bacteria, suggests there is less diversity in the CO2 area.

Preference for nutrient-enriched coral reef algae (Acanthophora spicifera and Gracilaria sp.) by an important benthic herbivore (Diadema setosum).

Valerie Rodriguez, Peggy Fong, Department of Ecology, Evolution and Biology, University of California, Los Angeles.

Sea urchins have the ability to distinguish between types of algae and their
palatability; however, it is not known whether sea urchins can differentiate between conspecific algae varying in nutritional quality. This study tested whether the tropical sea urchin Diadema setosum fed preferentially on enriched algae cultured with nitrogen and phosphorus versus ambient controls grown without added nutrients. This study uses Acanthophora spicifera and Gracilaria sp. to test the ability of urchins to distinguish between nutritional types of these palatable red algal species. Given that nitrogen and phosphorus are nutrients that cause rapid growth of algae and are also by-products of eutrophication, it is crucial to understand the foraging choices of herbivores, and whether they specifically consume nutrient-enriched algae. Diadema setosum distinguished between nutrient-enriched and control algal treatments, and consumed significantly greater amounts of nutrient enriched A.spicifera. Urchins did not distinguish between nutritional types of Gracilaria sp. These results suggest herbivores may play a pivotal role in sustaining coral reef systems in the face of competition with fast-growing algae.

The Applications of Wave Dynamometers in Rocky Intertidal Community Ecology

Neshan Sarkisian, Carlos Robles. California State University, Los Angeles.

When researching rocky intertidal communities, water flow speeds seem to play a key role in shaping almost every ecological process. A simple and economical device often used for measuring maximum flow speed is a dynamometer or "drogue" (Bell and Denny, 1994). Data from drogues can be used to study how ecological processes are affected by wave action. The basic functioning structure consists of a tension spring, a "whiffle" ball, and a rubber marker which shows how far the water dragged the ball under the tension of the spring. Drogues however, have their limitations; they can only give readings of the maximal wave speed encountered in an area of roughly one-square foot, over a certain period of deployment. Multiple measurements must be taken per study site in order to attain an accurate mean representation of the maximum water velocity encountered in those sites. The measurements are made by recording the displacement of the marker after a certain period of deployment. This measurement can then be incorporated into a formula which takes into account spring constants and drag constants to attain the maximum wave velocity encountered. These principles are illustrated with field data from British Columbia.

Effect of wildfire on chaparral light-use efficiency detected by optical pigment assays

Jose Alfonso Silva Sepulveda, John Gamon, Evelyn Lima, Yufu Cheng. California State University, Los Angeles.

Studies have demonstrated that wildfire in California chaparral increases nutrient availability for plants, presumably enhancing photosynthetic light-use efficiency. Leaf optical assays provide useful tools for understanding pigment and photosynthetic responses to different nitrogen levels. To learn more about the effect of fire on chaparral species, this study explored the xanthophyll to chlorophyll (X:Chl) ratio change for chaparral species, chamise (Adenostama fasiculatum) and red shank (Adenostoma sparsifolium), before and after fire. The photochemical reflectance index (PRI) and a modified normalized difference vegetation index (NDVI) were used to analyze pigment concentrations. PRI and NDVI were correlated with the X:Chl ratio, which was determined using high performance liquid chromatography (HPLC). Our results indicated that after a fire, chaparral species have a higher PRI and NDVI, but a lower X:Chl ratio. These results indicate that wildfire increases the photosynthetic light use efficiency of chaparral due to a high nitrogen concentration.

A PCR-based Method for Identifying Larvae of Taxonomically Diverse Invertebrates

Demian A. Willette, Patrick J. Krug. Dept of Biological Sciences, California State University, Los Angeles.

Taxonomic identification is problematic for invertebrate larvae that lack species-specific morphological characters. We developed a molecular method for identifying gastropod, barnacle, and bivalve larvae to species or genus. Larvae (130-300 um) were sampled from local estuaries, sorted by gross morphology, photographed and frozen. Genomic DNA was extracted from individuals or pools of 2-10 morphologically identical larvae. Sequences of the mitochondrial cytochrome oxidase 1 gene, widely used in genetic studies of invertebrates, were amplified by polymerase chain reaction (PCR) and compared to the NCBI database. Larval species was determined by 99-100% sequence identity over 380-560 nucleotides; an 83-92% match identified the likely genus while indicating that the exact species was missing from the database. Sequences were obtained from 63% of veligers, half of which were confidently identified to species, including the bubble shell Bulla gouldiana, Crepipatella lingulata, and Crepidula onyx. Fewer pediveliger and nauplii samples yielded sequences. The most abundant pediveliger in Newport Bay was the invasive mussel Musculista senhousia (1,696 + 614 larvae per m3 in Sept). All nauplii sequences had a 99-100% species match, accurately identifying Chthamalus fissus, C. dalli and Balanus glandula. This method provides information on reproductive seasonality and larval abundance of invasive bivalves, important for wetland preservation.

Effects of land use on deposition impact to an urban river.

Newton Wong, John Gamon. CEA-CREST, California State University, Los Angeles.

As water quality standards are being enforced, cities are pressured to meet EPA's TMDL (total maximum daily load) in waterways to avoid legal actions. Various land use practices along urban waterways contribute different levels of pollution, nutrients, and bacteria. In this study, we explored the possibility that airborne pathogens and particulates are worsening water quality and that different land uses cause different depositional effects in urban streams. We compared two different types of land uses adjacent to the Arroyo Seco (tributary of the Los Angeles River). Airborne bacteria and particulates were collected along the river at a horse stable and a revegetated region that was part of a river restoration. The stream region by the horse stable had more particulates and bacteria than the revegetated region. These results suggest that cities should plant vegetation buffer zones along urban streams to trap particulates and reduce bacterial contamination of waterways.