*Kerstin Wasson, Susie Fork, John Haskins, Alison Gee & Eric Van Dyke
Elkhorn Slough National Estuarine Research Reserve

LONG-TERM MONITORING SUPPORTS SHORT-TERM RESEARCH AND CONSERVATION STRATEGIES IN THE ELKHORN WATERSHED
The goal of the Elkhorn Slough National Estuarine Research Reserve’s research program is to inform conservation and restoration of coastal ecosystems, with emphasis on the Elkhorn Slough watershed.   Consistently collecting high caliber long-term monitoring data on key indicators of coastal ecosystem health is the highest priority of the Reserve research program.  Using case histories from Reserve data on biological indicators, water quality, and habitat change, we will illustrate how long-term monitoring programs can support and stimulate short-term research, by Reserve staff and moreover by graduate students and other researchers.  Short-term projects are critical for detecting the mechanisms behind trends observed from long-term monitoring, and for informing conservation strategies. For more information on the Reserve’s monitoring programs and to download a list of high priority research projects suitable for student theses, see http://www.elkhornslough.org/research.htm

click here to download the slides from this talk:  Wasson_ResearchESNERR_talk.pdf (1.22MB)

*Joe Needoba1, John Haskins2 & Kenneth Johnson1
1Monterey Bay Aquarium Research Institute
2Elkhorn Slough National Estuarine Research Reserve

OXYGEN DYNAMICS IN ELKHORN SLOUGH
We will discuss the observed patterns of dissolved O2 concentrations within the Elkhorn Slough ecosystem that were determined using autonomous in-situ sensors. Measurements from the Land/Ocean Biogeochemical Observatory (LOBO) and the National Estuarine Research Reserve water quality program were collected hourly in the main channel and the wetlands of Elkhorn Slough. The patterns in oxygen production and removal that result from both biological and physical processes indicate that high productivity occurs year-round. A seasonal gradient in oxygen towards the upper estuary implies that wetlands play an important role in both productivity and respiration throughout the main channel of the ecosystem. Predictable relationships are apparent between the tidal cycle and oxygen dynamics that improve our ability to assess and quantify the primary productivity in Elkhorn Slough and the potential for hypoxia within the main channel of the estuary.

*Kenneth Johnson & Joe Needoba
Monterey Bay Aquarium Research Institute

MODELING BIOGEOCHEMICAL PROCESSES IN ELKHORN SLOUGH
The goals of this project are to develop a numerical model of biogeochemical processes in Elkhorn Slough that can be used to predict ecosystem response to environmental changes.  The processes include benthic and water column photosynthesis and respiration, denitrification,  ammonia flux from sediments, oxygen exchange with the atmosphere and inputs of nutrients from the watershed.   A 13-box model of the Slough (boxes bounded as in E. Dean, 2003, Tidal Scour in Elkhorn Slough, California: A Bathymetric Analysis) with surface water inputs at the Old Salinas River and Carneros Creek was used for all computations.   A simple set of rate laws for biogeochemical processes that control salinity, oxygen, nitrate and ammonia were incorporated in the model.  The rate constants were determined by running the model in a diagnostic mode.  A Simplex optimization procedure was used to find the set of constants (e.g. benthic and water column photosynthesis and respiration) that provide the best fit (least squares) to observations at the LOBO (Land/Ocean Biogeochemical Observatory – www.mbari.org/lobo) L02 mooring near Kirby Park.  Model skill was assessed by comparing predicted values with observations at the remainder of the LOBO moorings.  Rate constants were optimized for each 2 week period during 2005 and 2006.  We are using this set of rates to examine the processes that control plant productivity in the Slough and its sensitivity to oxygen deficiency.  The model can then be run in a prognostic mode to examine the impacts of changes in hydrology on environmental variables such as oxygen concentration.

*Nick Welschmeyer*, Lawrence Younan, Sarah Smith, Chris Scianni & Megan Wehrenberg
Moss Landing Marine Laboratories

A NEW UNDERSTANDING OF PLANKTON DYNAMICS WITHIN ELKHORN SLOUGH: THE IMPORTANCE OF MICROBIAL PROCESSES.  
Our goal is to describe the fundamental traits of plankton distributions within Elkhorn Slough; this work is a component of the Sanctuary Integrated Monitoring Network (SIMoN).  Over one hundred sampling cruises have been completed since 2002 providing seasonal coverage of hydrography, nutrients, phytoplankton and bacteria within Elkhorn Slough.  HPLC determination of algal pigments and flow-cytometric analyses of particle types show that phytoplankton of Elkhorn Slough are divided into two communities.  The upper slough is dominated by cryptophytes (tagged by the unique carotenoid, alloxanthin); the lower slough is largely influenced by phytoplankton taxa derived from Monterey Bay.  The biological ‘interface’ between upper and lower plankton communities within the slough is also reflected in changes in bacteria populations and zooplankton species composition.  The horizontal location of the biological interface shifts predictably with tidal forcing; under extreme low-tide conditions the upper slough plankton assemblage spills into Monterey Bay through the harbor jetty and can be detected in the nearshore plume within Monterey Bay.  Analyses of nitrate and phosphate throughout Elkhorn Slough show that the upper section (near Kirby Park) is characterized by uncommonly low N/P ratios (<2 mole/mole), an indication of intense bacterial denitrification.  Dissolved organic matter (DOM) concentrations are also roughly an order of magnitude higher in the upper slough than in the lower slough.  Bacterial processes seem to dominate the upper slough and may play an important role in shaping the selection of species, including invasive species, that characterize the upper reaches of the Elkhorn Slough ecosystem. 

Click here to download the slides from this talk: Welschmeyer_plankton_talk.pdf (754KB)

*John Oliver, Stacy Kim & Kamille Hammerstrom
Moss Landing Marine Laboratories

BENTHIC INVERTEBRATE COMMUNITIES IN ELKHORN SLOUGH
Macro invertebrate communities change with distance into Elkhorn Slough. In the main channel, there is a distinct assemblage in the coarse sands in the Harbor entrance; another assemblage around the rest of the slough mouth; and yet another in the upper slough, which grades through three assemblages from the Dairy to the slough head. There are similar changes in community patterns from the mouth to the slough head on the intertidal mud flats. Intertidal sampling extended into three peripheral wetlands: Parsons Slough, Old Salinas River, and North Harbor. Each had distinct communities, but all three were more similar to the benthos at the slough head, not the mouth. The largest surviving regions of muddy sediment are in the slough head and the peripheral wetlands. The channel at the mouth is covered with coarse sands and gravels and extensive shell deposits, left behind as fine sediment is transported into Monterey Bay. In general, the head of the slough has a very high animal abundance, and a slightly lower density of species. The present communities are significantly different from those sampled in the mid 1970s, especially at the slough mouth. In general, the numerical dominants now are much smaller species that are active more at the sediment surface, compared to the 1970s. One dominant non-native clam was replaced by a native species. In the 1970s, the harbor entrance channel was covered with medium sand with small sand ripples (5cm high, 20cm apart) and an abundant benthos. Today, there are gravel ripples that are 50cm tall and 3-5m apart. Very little can live in these highly mobile deposits that shift direction with the strong tidal currents. The area of shell bottom has spread up and down the slough, and the area of muddy bottom has retreated up slough since the 1970s. 

*Sean Van Sommeran, Josh Laeder, Leon Chen, Callaghan Fritz-Cope, Katie Kent,
& Scot Lucas
Pelagic Shark Research Foundation

ELKHORN SLOUGH NATIONAL ESTUARINE RESEARCH RESERVE:
A CRITICAL HABITAT FOR THORNYBACK RAYS (Platyrhinoidis Triceriatas) AND SHOVELNOSE GUITARFISH (Rhinobatos productus).
A survey of elasmobranch abundance and population structure within the Elkhorn Slough National Estuarine Research Reserve between July 2001 and September 2005 recorded a significant abundance of thornyback rays and shovelnose guitarfishes using these protected waters, including gravid adults and young of the year.  Our results differ from previous research efforts in Elkhorn Slough National Estuarine Research Reserve.

Click here to download the slides from this talk: VanSommeran_PSRF_talk.pdf (764KB)

*Aaron Carlisle1,2, Richard M. Starr3 & Gregor M. Cailliet2
1 Stanford University
2 Moss Landing Marine Laboratories
3 University of California Sea Grant Extension Program, Moss Landing Marine
Laboratories

MOVEMENTS AND HABITAT USE OF FEMALE LEOPARD SHARKS
IN ELKHORN SLOUGH, CALIFORNIA
The leopard shark (Triakis semifasciata) is one of the most abundant nearshore sharks in California and is commonly found in bays and estuaries.  Elkhorn Slough is a shallow tidal embayment at the edge of Monterey Bay that is extensively utilized by leopard sharks of all ages, and it is believed that the slough functions as a nursery ground.  Since much of the life history of leopard sharks occurs in the slough, understanding how sharks utilize this habitat is important.  From May 2003 to February 2005, 20 female leopard sharks (78 – 140 cm TL) were tagged with acoustic transmitters in Elkhorn Slough, California, and their movements and habitat use were examined using acoustic tracking techniques.  Nine sharks were manually tracked for 20-71.5 h, and 11 sharks were monitored for 4-443 d using an array of acoustic receivers.  Use of different regions in Elkhorn Slough by tagged sharks changed seasonally and was associated with changes in temperature, salinity, and dissolved oxygen.  Sharks used Elkhorn Slough National Estuarine Research Reserve (ESNERR) extensively throughout the year, but especially during the spring and summer.  ESNERR appeared to be important as both a foraging and nursery area, likely due to the abundance of intertidal mudflats.  Movements and habitat use were tidally influenced, and likely were related to the distribution of important prey items in Elkhorn Slough.

Click here to download the slides from this talk: Carlisle_LeopardShark_talk.pdf (1.56MB)

Katie Griffith
Ocean Sciences Department, University of California, Santa Cruz

DISTRIBUTION AND ABUNDANCE OF CUSCUTA SALINA
AT ELKHORN SLOUGH
Cuscuta salina (salt marsh dodder) is a native, parasitic plant that commonly parasitizes Salicornia virginica in Elkhorn Slough’s salt marshes.  C. salina can increase diversity in the salt marsh by preferentially parasitizing S. virginica, and thus creating gaps in the S. virginica monoculture that can facilitate the colonization of other marsh plants in a way similar to disturbance.  C. salina exhibits an extremely patchy distribution at Elkhorn Slough: it is absent from many sites, patchy at others, and almost completely covers large stands of S. virginica at some sites.  The goal of my research is to understand what limits the distribution and abundance of this parasitic plant by testing the following three hypotheses: (1) C. salina is limited by seed recruitment, (2) C. salina is limited by abiotic factors, and (3) C. salina is limited by host (S. virginica) quality.  Seed recruitment surveys (seed traps and wrack collection) suggest that C. salina seeds do not settle along the shoreline border of a marsh but are present in wrack deposits at higher elevations.  Tidal elevation also limits germination success, as shown by deploying seed bags to different elevations in the marsh.  The probability of a C. salina infection increases with increasing distance from the mouth of Elkhorn Slough, with increasing distance from the shoreline, and where host (S. virginica) tissue salinities fall below 70 ppt.  This work suggests that several factors, including seed recruitment, elevation and host salinities may play a role in shaping the distribution and abundance of C. salina at Elkhorn Slough.

Click here to download the slides for this talk: Griffith_Dodder_talk.pdf (416KB)

Suzy Worcester
Division of Science and Environmental Policy, California State University Monterey Bay

SIX YEARS OF CHANGE AT MORO COJO SLOUGH: A REVIEW OF UNDERGRADUATE RESEARCH AT THE CATELLUS AND SEA MIST PARCELS
Many studies have found that undergraduates learn science best when it is an active, hands-on process where they are allowed the opportunity for inquiry-based research projects.  Traditionally such projects are only available to seniors, but at CSUMB we begin these types of projects in the sophomore year in the majors-level introductory biology series.  We have used the two-200 acre parcels of land along the lower Moro Cojo Slough which are owned by the Elkhorn Slough Foundation as living laboratories for Bio 1 students.  These parcels have been under going restoration under the direction of multiple investigators at Moss Landing Marine Labs and the Elkhorn Slough Foundation.  Bio 1 students are given the task of finding a question that relates to the restoration efforts at each site that can be answered with data collected in one three hour lab period.  Through this inquiry-based process students have been able to assess the abundance of plants, aquatic invertebrates, and birds as restoration has proceeded at each site.  By comparing datasets from similar locations between years, students have been able to document significant changes.  As a recent example, this November students were able to observe the first invertebrate colonists in two 3-week old created ponds at the Sea Mist site.  They found that the two ponds were colonized by different invertebrate groups, and that the invertebrates were different from a nearby long term freshwater pond.  In this paper I will provide an overview of the changes the students have documented at the two sites, and the advantages and disadvantages of this approach as a teaching model.  One positive outcome is that one to several students each semester have become interested in wetlands and/or restoration as a result of this experience.

Click here to download the slides for this talk: Worcester_MoroCojoChange_talk.pdf (433KB)

*Antonia D’Amore,1, Valentine Hemingway1 & Kerstin Wasson1,2
1Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064, USA
2 Elkhorn Slough National Estuarine Research Reserve

AQUATIC HABITAT AND LANDSCAPE CHARACTERISTICS PREDICT DISTRIBUTION AND REPRODUCTION OF AMPHIBIANS IN THE ELKHORN SLOUGH WATERSHED
Freshwater habitats often host a suite of co-occurring pond-breeding amphibians, which may include both threatened and abundant species, as well as native and invasive species.  Understanding the factors that govern the distribution of different pond-breeding amphibian species is critical for designing conservation and management strategies for freshwater wetlands. We carried out a three-year investigation of amphibian habitat use of over 40 wetlands in the Elkhorn Slough watershed.  How factors influencing distribution differed between a common native species (Pseudacris regilla), a threatened native species (Rana draytoniii), and its invasive congener (Rana catesbeiana) was a primary interest. For each of these species, we assessed presence/absence of key life stages, as well as adult abundance for the two ranid species. For each freshwater habitat, we evaluated various physical and biological variables for the pond itself, as well as parameters regarding the landscape context. We analyzed the resultant dataset using both multivariate and pair-wise analyses.  We found significant statistical relationships between amphibian habitat use and pond and landscape characteristics for all three amphibians, but they differed between species.

Click here to download slides for this talk: DAmore_RegionalFrogs_talk.pdf (625KB)

*Grey F. Hayes1 & Karen D. Holl1,2
1 Elkhorn Slough National Estuarine Research Reserve
2 Environmental Studies, University of California, Santa Cruz

EFFECTS OF CATTLE GRAZING DISTURBANCE AND IMPLICATIONS FOR THE CONSERVATION OF NATIVE PLANTS IN CALIFORNIA COASTAL PRAIRIE
Over the last 250 years, cattle became a dominant component of disturbance regimes in coastal prairie, while exotic plants proliferated.  To investigate the impact of cattle grazing on the native plant community, we combined manipulative experiments examining grazing-related disturbances with field surveys of grazed and ungrazed coastal prairie sites.  We conducted a factorial experiment in winter 1999 through spring 2006 at three coastal prairie sites near Santa Cruz, testing a combination of clipping frequencies and secondary disturbances (litter removal and soil disturbance) on the abundance of native and exotic plant guilds.  While secondary treatments had no effect, increased clipping frequency tended to increase native grass and decrease exotic grass and exotic forb abundance, although the effects were site-specific.  Where cattle grazing was excluded without any disturbance, native grasses have largely disappeared and exotic annual grasses dominate.  During a 2-year field survey, we surveyed cattle grazing impacts in 25 paired grazed/ungrazed sites spanning a 670-km range of coastal prairie plant community, focusing on native annual dicots.  Results suggest native annual dicot species richness and cover was higher at grazed sites, concomitant with decreased litter depth and vegetation height.  Conversely, native perennial forbs decreased and exotic annual species increased in grazed sites.  These results implicate the need for landscape-level planning to target disturbance regime restoration to maintain different guilds of native plants.

Click here to download slides for this talk: Hayes_PrairieDisturbance_talk.pdf (447KB)

*Carolee Bull1, K Martin2, G Vellicer3 & M Singer4
1USDA/ARS, 1636 E. Alisal St., Salinas, CA 93901
2William Paterson University, 300 Pompton Rd., Wayne, NJ 07470
3Max-Planck Institute for Developmental Biology, Tübingen, Germany
4University of California Davis, Department of Microbiology. Davis, CA 95616

Eric Van Dyke
Elkhorn Slough National Estuarine Research Reserve

THE ESNERR AERIAL IMAGERY ARCHIVE: A POWERFUL TOOL FOR REGIONAL LAND COVER AND HABITAT CHANGE ANALYSIS
The ESNERR Research Program maintains an archive of vertical aerial photographs covering Elkhorn Slough and its watershed that spans more than three-quarters of a century and comprises more than 60 separate flight dates totaling approximately 2000 individual images.  A substantial portion of the archive has been digitally processed and georeferenced for compatibility with geographic information systems.  This collection, assembled in collaboration with the California Department of Fish and Game, Elkhorn Slough Foundation, Moss Landing Marine Laboratories, UCSC Library Map Room, and several other organizations, offers an unparalleled base for geospatial and quantitative studies of historic and contemporary wetland and upland habitats at a variety of scales from local ecosystems to the regional landscape.  In this overview presentation, Eric will survey the scope of the collection and then provide examples from several aerial photo-based land cover classification and habitat change studies.

*Gage Dayton1,2, Melissa Apdodaca1,2, Ross Clark2,3, Adam Wiskind1,2 & Sara Tanner1
1 Moss Landing Marine Laboratories
2 Central Coast Wetland Working Group
3 California Coastal Commission

Cleaning water by restoring wetlands: Water quality in the Moro Cojo Watershed
The Moro Cojo watershed receives non-point source pollution from agricultural and urban runoff.  We measured nitrate concentration in water samples collected from agricultural runoff at multiple locations along the Moro Cojo Slough.  Our sampling design was set up to examine changes in nitrate levels as water passed through wetland habitat.  We found that nitrate concentration decreased considerably as water traveled away from the input source.  Preliminary results suggest that wetlands adjacent to agricultural fields in the Moro Cojo Slough may function as “biological filters” and help improve water quality before it flows into Monterey Bay.

Click here to download this poster: Dayton_WaterQuality_poster.pdf (171KB)

Nora Grant
Moss Landing Marine Laboratories

FLUME TESTS OF FLOW IN ZOSTERA MARINA CANOPIES
Seagrass beds are known to alter hydrodynamics of the water column. Flow can be altered by dampening flow within the bed, increasing current velocity over the bed, and increasing turbulence within the bed. These processes can have both positive and negative effects on the plants and animals of the Seagrass assemblage. A salt-water flume was used to test flow conditions in Zostera marina (Linneaus) canopies at three densities and four flow velocities. Flourescein dye was introduced in front of the canopy and tracked over time using video analysis. Velocity of dye was calculated from the change in X,Y coordinates over time, diffusivity within the bed was measured by change in area of the dye, and bending of the canopy was measured at the front of the canopy to estimate deflection of flow. Anticipated results of the tests were; flow dampening inside the canopy would be greatest at high shoot density, dye would be diffused most at higher shoot density, and angle at the front of the Zostera canopy will increase with flow velocity. Velocity was dampened at low and medium densities, diffusivity was greatest at slow flow in the high density bed, and canopy angle was most extreme at high flow velocity for all densities tested. Patterns seen in the data are used to speculate on the ecological function of hydrodynamics in Z. marina canopies.

Click here to download this poster: Grant_Eelgrass_poster.pdf (679KB)

Rikk Kvitek & Carrie Bretz
California State University Monterey Bay, Seafloor Mapping Lab

HABITAT MAPPING AND CHANGE DETECTION
IN ELKHORN SLOUGH
Habitat change and loss due to anthropogenic and natural factors is the major environmental problem facing many coastal and estuarine resource management agencies. The primary goal and challenge of most coastal environmental change detection programs however, is the ability to detect trends early enough to take appropriate management action before too much “loss” has occurred. Harbor creation has led to increased tidal scour that is rapidly eroding the banks, salt marsh and main channel of Elkhorn Slough, destroying freshwater wetlands, and inundating an active railroad line. Multibeam and singlebeam sonar surveys of the Elkhorn Slough, combined with high accuracy GPS terrestrial surveys, were used to quantify variation in the rates of habitat change compared to previous baseline data from the 1990s and 1980s. The results from the bathymetric time series provide clear evidence for continued high and accelerating rates of erosion and habitat loss since 1993.

*Joji Muramoto, Stephen Gliessman1, Steven Koike2, Carol Shennan1, Danniel Schmida3, Robert Stephens4 & Sean Swezey1
1 University of California, Santa Cruz
2 University of California Cooperative Extension, Salinas
3 Sandpiper Farms
4 Elkhorn Ranch

MAINTAINING AGROECOSYSTEM HEALTH IN AN ORGANIC STRAWBERRY/VEGETABLE ROTATION SYSTEM
Continued growth of organic strawberry and vegetable production in California faces two challenges: soil-borne disease management without use of synthetic chemical fumigants, and fertility management to optimize fertility input use while ensuring protection of surrounding vulnerable habitats. The goal of this project is to demonstrate effects of diverse organic strawberry/vegetable rotations and integrated ecological practices on agroecosystem health. In 2001, we initiated a replicated on-farm trial at Moss Landing, California with number of years between strawberry crops as main plot (5 levels) and strawberry cultivar as sub-plot (2 levels). Ecological practices such as biofumigation with broccoli or mustard residues, compost application, use of vegetables that do not host Verticillium dahliae (spinach and broccoli) as rotational crops, and choosing strawberry cultivars that are less sensitive to disease are used in an integrated manner. While the main-treatment effects will be tested after the fifth year, soil health indicators (Verticillium dahliae propagule number, soil inorganic N, and other physicochemical indicators) and agroecosystem health indicators (yield, disease incidence, and N loss) will be monitored during all five years. In the first four years, strawberries, vegetables and cover crops had moderate yields and no major disease problems. No significant differences were found between any treatments in yields of any crops during this period. Broccoli residue incorporations consistently reduced Verticillium dahliae propagules in soils, whereas mustard incorporations did not. Even in the continuous strawberry-cropping plot, fruit yield has been consistent probably due to the effect of broccoli incorporations under low soil-borne disease pressure. The N monitoring in strawberries suggested: 1) the maximum N-loss during the rainy season reached 214 kg/ha, and 2) adjusting basal/supplemental N rates and pre-plant plastic mulch application can reduce N-loss during the rainy season to less than 20 kg/ha, while maintaining fruit yield. Results from the final year will also be presented.

*Nicholas Nidzieko1, James Hench1, Joseph Needoba2, Kenneth Johnson2,
& Stephen Monismith1
1Environmental Fluid Mechanics Laboratory, Stanford University
2Chemical Sensor Laboratory, Monterey Bay Aquarium Research Institute

CIRCULATION IN ELKHORN SLOUGH
As researchers work to understand biogeochemical processes within the slough, there is a pressing need to improve our understanding of the contribution of hydrodynamics to these processes. Our research is focused on circulation mechanisms in Elkhorn Slough at tidal, seasonal, and estuary-wide scales. At the tidal timescale, we are investigating how turbulence and stratification interact to influence lateral circulation generated by curvature (bends) and lateral density gradients. On the seasonal timescale, we are studying how annual shifts in estuarine gravitational circulation from classical to inverse affect the residence time throughout the estuary. Finally, a numerical study presently underway is improving our understanding of temporal and spatial variations in longitudinal mixing and how these affect the dispersion and residence time of nutrients, such as nitrate, in Elkhorn Slough. This numerical study is specifically focused towards integrating measurements from the LOBO observatory.
Click here to download the poster: Nidzieko_Hydrology_poster.pdf (3.9MB)

Rikke Kvist Preisler1,2
1Ecology and Evolutionary Biology, University of California, Santa Cruz
2Elkhorn Slough National Estuarine Research Reserve

BIOGEOGRAPHIC INVESTIGATION OF VARIATION IN INVASION SUCCESS OF THE EUROPEAN GREEN CRAB
Many studies of species’ invasions focus on the impact of invasive species, or quantify to which degree an area is invaded by many species. The focus of my study is to quantify the invasion success of a single species, the European green crab, Carcinus maenas, and to investigate variation in invasion success indicators at a biogeographic scale. In order to quantify patterns of spatial variation in abundance, habitat use, and species interactions of a global invader, I have begun sampling the European green crab in its native and invaded ranges. I am examining aspects of the invader and the invaded community that can contribute to invasion success, such as green crab relative abundance, fecundity, habitat use, and interspecific interactions. Long term monitoring in Elkhorn Slough has shown that while relative abundance of a native crab has been declining since 2001, relative abundance of the European green crab has been increasing. While not implying any causal relationship, this pattern is intriguing, and the potential of species interactions affecting abundance or size structure of other species will be investigated at a biogeographic scale. This study will allow us to provide specific information about one of many factors that may regulate crab populations at various locations at local and global scales. Our study will provide valuable insights to community ecologists and coastal managers on how to prioritize prevention, management, and eradication of invasive species.

Click here to download this poster: Preisler_GreenCrab_poster.pdf

Smith, Sarah, Chris Scianni & Nick Welschmeyer
Moss Landing Marine Laboratories

FLOW CYTOMETRIC ANALYSIS OF BACTERIA AND PHYTOPLANKTON IN ELKHORN SLOUGH
The primary goal of this investigation is to characterize the planktonic microbial community of Elkhorn Slough using flow cytometry.  Phytoplankton pigment analyses of seawater from a series of ten stations from the mouth of the slough to just past Kirby Park indicate that that along this gradient there is a predictable and dramatic shift in the major constituents of the phytoplankton community; cryptophytes dominate the upper reaches of the slough.  Data from flow cytometric analyses (Becton Dickson,  FACSort) support these findings, as there is a shift in both cell counts and particle fluorescence characteristics from the mouth of the slough to Kirby Park.  Cryptophyte algal constituents were easily separated cytometrically on the basis of their unique fluorescent pigment composition which includes phycobilins.  The bacterial community was assessed with the use of the fluorescent nucleic acid stain, Syto-13 (Invitrogen), in conjunction with flow cytometry.  Vital stains, SYTOX and CTC, were also used to determine the fraction of both bacteria and phytoplankton cells that were alive and therefore potentially active in the system.  Preliminary results suggest that up to 75% of total bacterial cells may be dead.  While many of these objectives may also be achieved with traditional microscopic analyses, the microscopic approach is laborious and subject to user investigator bias.  The advantages of flow cytometry include rapid and accurate quantification of different populations of cells in a seawater sample.  Flow cytometric analysis of viability conditions in bacteria and phytoplankton may provide explanations for the apparent development of distinct plankton species assemblages within Elkhorn Slough.

Click here to download this poster: Smith_Phytoplankton_poster.pdf

Teela Williams
Environmental Studies, University of California, Santa Cruz

THE EFFECTIVENESS OF BACILLUS SPHAERICUS  IN REDUCING MOSQUITO LARVAE IN WILDLIFE GUZZLERS AT ESNERR
 Bacillus sphaericus is an organic pesticide; a target specific bacterium that when ingested by certain mosquito species causes mortality by destroying stomach lining cells. The use of this pesticide could be useful in controlling mosquito populations in the ESNERR and possibly lead to the removal of Mosquito fish (Gambusia affinis), which through previous studies have been shown to have a negative effect on tadpole growth(Booth 2005).  This ongoing experiment was designed to test the effectiveness of this pesticide on reducing mosquito larvae populations in the wildlife guzzlers at ESNERR.  This experiment was defined from the need of the ESNERR to effectively and safely reduce populations of the West Nile Virus carrying mosquito while ensuring the health of the ESNERR wildlife, especially the federally threatened California Red Legged frog. This experiment design also allows for close and frequent observation of the 18 wildlife guzzlers distributed in the ESNERR. These guzzlers are breeding grounds for Pacific Tree Frog and resident sites for California Red Legged frogs. Observations thus far suggest a strong correlation between vegetation, temperature and water toxicity with both tadpole and mosquito breeding and growth patterns.  Guzzlers surrounded by oaks have presented higher number of mosquito larvae than other guzzlers. These guzzlers are shaded, cooler and lack aquatic vegetation. Pacific Tree frogs can be found in these guzzlers but they exist in fewer numbers and are slow to mature and emerge than in guzzlers that are not shaded and have dense aquatic vegetation.

Click here to download this poster: Williams_BacterialMosquitoControl_poster.pdf