Intern Home Institution Major(s) Project Mentor
Roxana Aguirre-Robertson California State University, Los Angeles - Los Angeles, California Natural Science - Geology

Title: How population density and shrimp size affects the geometry of Upogebia pugettensis burrows in the Yaquina Estuary

Summary: Upogebia pugettensis (the blue mud shrimp) is a thalassanid burrowing shrimp that has been found to occupy more than 80% of the intertidal flats in the Yaquina estuary (DeWitt, et al., 2004). These shrimp are important ecosystem engineers because of their impacts on structure of benthic communities and on biogeochemical cycling of nitrogen and carbon (Dumbauld et al. 1996, DeWitt et al. 2004, DAndrea & DeWitt in prep.). Previously molded casts of their Y shaped burrows reveal considerable variation in the number of openings to the sediment surface, and the distance between openings, which may be dependent on shrimp size or shrimp population density at a site. Knowledge of factors that affect burrow morphology is important for monitoring shrimp populations and modeling the impact of shrimp burrows on decomposition of sediment organic matter (Aller 1988, Welsh 2003, DeWitt et al. 2004, DAndrea & DeWitt in prep.). The purpose of this study is to determine whether burrow geometry differs in response to shrimp body size or population density. To do this, shrimp burrow characteristics of in patches of low, medium, and high shrimp densities in the Yaquina estuary were measured for: a) the number of burrow openings, b) the distance between burrow openings, c) and the burrow-shaft diameter. This was done for approximately 30 randomly selected burrow systems per density class within the Yaquina estuary. The data collected here will also be compared to data previously collected by Dr. DeWitt on existing burrow casts to determine whether the field-measured parameters can predict total burrow length, burrow depth, or total burrow volume.

Ted Dewitt, Ecologist, US EPA-Pacific Coastal Ecology Branch and Brett Dumbauld, Research Ecologist, USDA-Agriculture Research Service
Ariel Camp Hofstra University - Hempstead, New York Biology

Title: Density-dependent habitat selection in juvenile English sole (Pleuronectes vetulus)

Summary: The contribution of nursery habitats to adult recruitment of marine fish depends on the physical qualities of the habitat as well as intraspecifc behavioral interactions, which may be density-dependent. Density-dependent habitat selection (DDHS) was examined in juvenile English sole, found in estuarine nurseries at high densities, and compared to that of northern rock sole which occur at low densities in coastal nurseries and exhibit DDHS. DDHS was hypothesized to be similar between the two species, but would be initiated at higher densities in English sole. Trials were conducted over seven density treatments (0.4, 0.8, 1.5, 3.0, 6.1, 12.2, 18.6, and 23.8 fish m-2) during which fish were given equal access to a preferred sandy habitat and a less-preferred pebble habitat. Low-densities of English sole (0.4-1.5 fish m-2) showed little habitat preference, use of the less-preferred pebble habitat decreased with increasing density up to 3.0 fish m-2 where DDHS initiated and pebble use increased from 30 to 50% with density. This pattern remained even under predation pressure. Initiation of DDHS and The lack of habitat preference at low densities may indicate that English sole perceive conspecifics as indicative of habitat quality. Initiation of DDHS at a higher density (6.1 fish m-2) compared to northern rock sole (1.5 fish m-2) suggests English sole are behaviorally adapted for the greater carrying capacity of estuarine nurseries, although the possible modification of DDHS in response to other factors such as food resources, turbidity and ontogeny remain to be investigated.

Cliff Ryer, Assistant Professor, Fisheries and Wildlife (Courtesy), NOAA Alaska Fisheries Science Center
Emily Colin Colby College - Waterville, Maine

Geology

Chemistry

Title: Paleoproductivity off the coast of southern Chile over the last 30 ky

Summary: Oxygen minimum zones (OMZ) exist between the ocean depths of 500-1000m. The oxygen levels within these regions represent a balance between oxygen supply, provided by well-oxygenated, intermediate waters, and oxygen depletion, caused by bacteria consuming organic matter. The availability vs. dearth of these two factors impact many global climate feedback loops. Productivity and the flux of carbon from the surface layer to deep sea is one of the major factors controlling CO2 partial pressure in the atmosphere and global climate cycles. Here, the paleoproductivity from the southern Chilean margin is reconstructed by normalizing to the flux of 230Th. Results show that over the last 30ky, the height of productivity was found near the last glacial maximum (LGM) (26-20 cal yrs BP). A steady decline is seen in CaCO3 flux from the middle Holocene (~8 cal yrs BP) to present, while opal flux seem to plateau, and organic carbon seems to increase from the late Holocene (~5 cal yrs BP) to present.

Zanna Chase, Assistant Professor, College of Oceanic and Atmospheric Sciences
Lauren Colwell Carleton College - Northfield, Minnesota Geology

Title: An Updated Age Progression of the Louisville Seamount Trail and Comparison to the Hawaiian-Emperor Seamount Trail

Summary: Seamount trails are perhaps the most tangible surface expressions of plate motion over upwelling mantle plumes, also known as hotspots. The Louisville seamount trail was generated from one of the longest-lived hotspots in the South Pacific and is comparable to the Hawaii-Emperor seamount trail, as these two trails represent intra-plate volcanism and Pacific plate motion over a similar time interval (~80 Ma to present). In this study we present new 40Ar/39Ar age data that contribute to an updated age progression for the Louisville seamount trail. The inclusion of these new data confirms a systematic (but non-linear) age-progressive trend that, when considered with reference to the most recent absolute plate motion model (WK08G) from Wessel & Kroenke (2008), facilitates a direct comparison to the observed age progression for the Hawaii-Emperor seamount trail. We conclude that the new Louisville age data to the first-order correlate relatively well to WK08G model and the Hawaiian age data. However, toward the older end of the Louisville seamount trail, the measured age data are systematically older than both the WK08G predictions and the Hawaiian seamounts, with offsets ranging up to 6 Myr. Here we report on the implications of these deviations, including plume motion or seawater alteration as possible contributing factors, and the timing and location of morphological bends present in both seamount trails. There appears to be a correlation between the two most prominent bends in both trails, though the ages are not within an appreciable difference of each other. We also observe that magma production ceases for a significant amount of time directly after these prominent bends in the Hawaii-Emperor and Louisville seamount trails, despite a considerable difference in total output for both hotspot systems (1,300 and 130 x 103 km3, respectively).

Anthony Koppers/Bob Duncan, Associate Professor, College of Oceanic and Atmospheric Sciences, Associate Dean, College of Oceanic and Atmospheric Sciences
Joel Craig Georgia Institute of Technology - Atlanta, Georgia Earth and Atmospheric Sciences

Title: Optical Indices of Phytoplankton Dynamics in the Equatorial Pacific

Summary: In situ and satellite measures of various ocean and atmospheric parameters are used to understand ecosystem dynamics. Satellites are limited to the upper waters, buoys are limited in spatial scope and shipboard CTD drops are limited temporally. Lab tests have modeled the response of various wavelengths of light to particulate matter of varying sizes and consistencies in water. Ratios of chlorophyll to carbon change with species and light availability. Optical measures of fluorescence are used to measure chlorophyll. Backscatter and beam attenuation can be used as proxies for particulate organic carbon (POC). Using recently collected equator transect optical data and bottle measures of chlorophyll and particulate organic carbon (POC) concentrations we seek to measure ecosystem dynamics with a less labor intensive approach.

Pete Strutton, Assistant Professor, College of Oceanic and Atmospheric Sciences
Lanaya Fitzgerald Oregon State University - Corvallis, Oregon Environmental Science

Title: Interactions between Jellyfish and Fish: Predation versus Commensalism

Summary: Increasing jellyfish biomass in marine ecosystems around the world may affect many commercially important fish species through increasing predation and competition for food Fishes in the family Gadidae are commercially important, and can be both preyed upon by jellyfish as larvae and early juveniles, and as larger juveniles, adopt a positive commensal association with jellyfish We performed laboratory experiments attempting to mimic fish and jellyfish interactions included larval gadids in the presence of jellyfish, juvenile gadids in the presence of jellyfish and a predator, and a predator in both the presence and absence of jellyfish. In both the absence and presence of a predator, juvenile Pacific tomcod did not display the association behavior that was hypothesized. Predation by jellyfish on larval Pacific cod species was intense, suggesting that increasing jellyfish biomass may have a strong negative effect on the survival of 0-group fish. The absence and presence of jellyfish with a predator experiment illustrated the sensitivity of 2-year Pacific cod to jellyfish stings. After approximately eight stings, predators would learn to avoid contact with jellies. In all, 94.64% of larval gadids were consumed by jellyfish within nine hours. Survival of gadids increased exponentially between larval and juvenile fishes, while the frequency of contact (stings) increased between juveniles and adults. Increased juvenile gadid survival from both jellyfish and larger fish predators may be due to the stronger swimming and avoidance abilities that come with increasing size. Although juvenile cod species were not found to be associating with jellyfish in the laboratory as has been observed in the field, increasing jellyfish biomass may be creating a larger habitat for juvenile 0-group fish seek shelter from larger predatory fish.

Ric Brodeur, Professor, Oceanography (Courtesy), NOAA/NW/NMFS
Rosalinda Fortier University of Rhode Island - Kingston, Rhode Island

Physics

Physical Oceanography

Math

Title: Upwelling Tongues on the Oregon Continental Shelf: a Study using AUV gliders

Summary: Seasonal upwelling on the Oregon continental shelf, particularly over Heceta Bank, is important for commercial fisheries. Understanding the physical processes of this system is important for the local economy and also lends to the understanding of coastal upwelling elsewhere in the world. In this study, year-round high resolution data from three Autonomous Underwater Vehicle Gliders along the Newport Hydrographic (NH) Line (44.65∞) is used to study small scale features of upwelling, called upwelling tongues. The tongues are formed by sub-pycnocline water that has been heated by the sun and sunk along the upwelling front. They seem to appear at the transition to relaxed conditions after a period of upwelling.

Jack Barth, Professor, CEOAS and Kipp Shearman, Assistant Professor, CEOAS
Nicole Goehring Whitman College - Walla Walla, Washington Biology

Title: Interannual Comparison of Juvenile Chinook Growth, Residency, and Diet

Summary: The mechanisms influencing early ocean survival of Chinook salmon are currently poorly understood. In order to assess factors potentially driving interannual disparities within a Chinook population, otolith growth, residency times, and diet were compared between two collections of juvenile Chinook. Samples were taken from the surf zone at Bastendorff Beach, Oregon in the summers of 2006 and 2007. While the 2006 individuals are larger in size than those collected in 2007, the densities were smaller in 2006. The fishs otoliths were extracted and analyzed by mass spectrometer for variations in calcium, strontium, and barium concentrations. Significant increases in strontium, relative to calcium, mark the transition period as the fish move from fresh water to salt water; correspondingly, drops in barium levels indicate fish exiting fresh water systems. These data, coupled with microstructure analysis allowed for the estimation of residency times and growth rates in fresh and brackish/salt water. Stomach analyses revealed species consumed and their relative quantities. Stomach contents were identified to the lowest identifiable taxonomic level and weighed. The traits examined here may serve as a proxy for survival, as studying the condition of fish when they enter the ocean enhances our limited understanding of the factors affecting Chinook salmon survival.

Jessica Miller, Assistant Professor, Coastal Oregon Marine Experiment Station
Sam Kanner Carleton College - Northfield, Minnesota Geology

Title: Quantifying Transport Associated with Internal Waves in Massachusetts Bay

Summary: Previous experiments have shown that large-amplitude internal waves are a significant agent in transporting particles, such as nutrients, larvae and effluent onshore. Surface drifters were deployed in Massachusetts Bay, equipped with GPS devices to quantify the transport associated with these internal wave packets. It was observed that the depth of the drogue below the surface was inversely proportional to the speed at which the drifter moved onshore. This study can be used to make a more comprehensive analysis of where and when the oil from a large-scale offshore spill may reach the shoreline.

Jim Lerczak, Associate Professor, CEOAS; Kipp Shearman, Assistant Professor, CEOAS
Ben Klein Amherst College - Amherst, Massachusetts Geology

Title: Analysis of Organic Carbon in Arctic Shelf Sediments

Summary: The Arctic environment is extremely sensitive to changes in climate. It is therefore essential to closely observe this system to understand how it is affected by current climate change and what the implications of these changes are for the arctic as well as the larger global system. One element of the Arctic that must be studied carefully is the organic carbon cycle. A variety of analyses including Elemental Analysis for Carbon and Nitrogen, surface area analysis and stable carbon and nitrogen isotopes were performed in an effort to quantify the relative contributions of allochthonous and autochthonous sources of organic matter in 14 cores collected on the shelves of the Bering, Chukchi, and Beaufort Seas. The information generated describes current processes and offers insight into shifts in the system during recent history.

Miguel Goni, Professor, College of Oceanic and Atmospheric Sciences
Vivian Lin Scripps College - Claremont, California

Biology

Chemistry

Title: Assessing oxygen flux and physical characteristics of permeable sediments from the Oregon shelf

Summary: Considering recent hypoxic events off the Oregon coast, identifying factors affecting oxygen flux across the shelf is critical to better understanding the ecological and economic impacts of hypoxia. Benthic biological activity may play a significant role in oxygen consumption, but there is a lack of data for benthic oxygen exchange rates in WA-OR shelf permeable sediments. Methods must also be developed for collecting and profiling sand cores. In order to investigate oxygen consumption in coastal sandy sediments, one core was collected from an intertidal location in Yaquina Bay and six cores from a water depth of ~15m on the Oregon shelf off Lincoln Beach. Oxygen microelectrodes were used to obtain high spatial resolution profiles of oxygen consumption rates in these cores via a flow through method. Aerated water was pumped through each sediment core, and the linear decrease in oxygen concentration during short flow-off periods was measured at different depths. Additionally, permeability and porosity of each core were measured to study the relationship between physical characteristics of sands and oxygen consumption rates. Oxygen fluxes calculated by integrating the volumetric oxygen consumption rates to a depth of 4 cm ranged from 42 to 140 mmol m-2 d-1 for Lincoln Beach cores. Permeability and porosity averaged 23◊10-12 m2 and 43.5%, respectively, and were consistent with literature values for other permeable coastal sediments. Estimates of local oxygen consumption by the sediment at Lincoln Beach, according to these oxygen flux values and accounting for depth, suggest rates between 2.8 to 9.3 mmol m-3 d-1; approximating for the Oregon shelf, these values are 0.4 to 1.4 mmol m-3 d-1. In comparison to earlier estimates of oxygen consumption, which placed sediment consumption at 0.1 ± 0.1 mmol m-3 d-1, the benthic contribution to hypoxia may be much more significant than previously estimated.

Clare Reimers, Professor, College of Oceanic and Atmospheric Sciences
Molly Lindle Centre College - Danville, Kentucky

Physics

Mathematics

Title: An Updated Age Progression of the Louisville Seamount Trail and Comparison to the Hawaiian-Emperor Seamount Trail

Summary: Seamount trails are perhaps the most tangible surface expressions of plate motion over upwelling mantle plumes, also known as hotspots. The Louisville seamount trail was generated from one of the longest-lived hotspots in the South Pacific and is comparable to the Hawaii-Emperor seamount trail, as these two trails represent intra-plate volcanism and Pacific plate motion over a similar time interval (~80 Ma to present). In this study we present new 40Ar/39Ar age data that contribute to an updated age progression for the Louisville seamount trail. The inclusion of these new data confirms a systematic (but non-linear) age-progressive trend that, when considered with reference to the most recent absolute plate motion model (WK08G) from Wessel & Kroenke (2008), facilitates a direct comparison to the observed age progression for the Hawaii-Emperor seamount trail. We conclude that the new Louisville age data to the first-order correlate relatively well to WK08G model and the Hawaiian age data. However, toward the older end of the Louisville seamount trail, the measured age data are systematically older than both the WK08G predictions and the Hawaiian seamounts, with offsets ranging up to 6 Myr. Here we report on the implications of these deviations, including plume motion or seawater alteration as possible contributing factors, and the timing and location of morphological bends present in both seamount trails. There appears to be a correlation between the two most prominent bends in both trails, though the ages are not within an appreciable difference of each other. We also observe that magma production ceases for a significant amount of time directly after these prominent bends in the Hawaii-Emperor and Louisville seamount trails, despite a considerable difference in total output for both hotspot systems (1,300 and 130 x 103 km3, respectively).

Anthony Koppers, Associate Professor, College of Oceanic and Atmospheric Sciences and Bob Duncan, Associate Dean, College of Oceanic and Atmospheric Sciences
Kiva Oken Carleton College - Northfield, Minnesota

Mathematics

Biology

Title: The Effect of Hypoxia on Fish Larvae and other Mesoplankton Populations on the Oregon Shelf

Summary: A nearshore hypoxic zone was first detected along the Oregon shelf in 2002 and has occurred every year since. The upwelling of hypoxic, nutrient-rich Arctic waters drives the now-annual event. Many factors impact how fishes respond to hypoxia, but studies in semi-enclosed ecosystems have shown that most mobile life forms avoid habitats low in oxygen, and earlier life stages are more susceptible. Using a multinet with an attached CTD, we sampled the mesoplankton population throughout the Oregon shelf at different depth intervals during the upwelling season. We found that total biovolume is inversely proportional to dissolved oxygen, and that the hypoxia does not significantly affect fish larvae. We suspect the unexpected results are due to a combination of sunlight avoidance, species-specific responses, and sampling methods.

Lorenzo Ciannelli, Assistant Professor, College of Oceanic and Atmospheric Sciences
Samuel Peterson Oregon State University - Corvallis, Oregon

Physics

Mathematics

Title: Investigations on the Coastal Undercurrent off Cape Blanco

Summary: In this project we used computer simulations of velocity fields and lagrangian label fields to explore the undercurrent along the coast of Cape Blanco during august of 2001. We found that a large proportion of the undercurrent north and south of Cape Blanco is discontinuous from one another (in a sense to be explained). Later work will be on obtaining trajectories of water parcels in this undercurrent system.

Alex Kurapov, Assistant Professor, College of Oceanic and Atmospheric Sciences
Laura Poppick Bates College - Lewiston, Maine Geology

Title: The growth and lifespan relationship in the Pacific Geoduck

Summary: Growth rate and lifespan were compared within and among two Pacific geoduck populations in order to determine if early-life growth ultimately predicts longevity. The dendrochronological technique of crossdating was employed to age and measure the first fifteen annual growth increments in acetate peels of geoduck hinge plates. Significant differences in growth rate among geoducks of various ages were determined with linear regression. Analysis from both sites showed a significant decrease in growth rate during the first three years of life as age increased. Individuals that grew fastest during the first three years also had the highest measured meat weights. Because meat weight positively correlates with reproductive output, a possible tradeoff of fast growth may be the opportunity to be more fecund while ultimately living a relatively short life. The inverse growth and lifespan relationship described here may represent a common biological concept.

Bryan Black, Assistant Professor (Sr Res), OSU/Hatfield Marine Science Center
Megan Pros Monmouth College - Monmouth, Illinois Biology

Title: The hypoxia phenomenon on the Pacific coast: Can copepod (Calanus marshallae) eggs hatch in extremely low levels of dissolved oxygen?

Summary: Despite the growing concern about the hypoxia phenomenon on the Oregon shelf, little research has been invested on the effects of hypoxia on zooplankton, an important link between phytoplankton and the rest of the ocean food web. If hypoxia on the Oregon shelf becomes an increasing occurrence and more intense, it will be important to explore the kinds of effects it will have on local sea life, especially the base of the food chain. We investigated the effects of hypoxic water conditions on the eggs of the copepod Calanus marshallae. Adults are mobile, and are likely able to move away from areas of hypoxic water, but we question if their eggs, which sink in the vertical water column, can still hatch and develop if they sink into hypoxic water. We collected water off of the Oregon, Washington, and California coasts during biweekly day cruises and during a ten day cruise on the National Oceanic Atmospheric Administrations (NOAA) research ship, the McArthur II. We filled biochemical oxygen demand bottles (BOD) with water collected from Conductivity-Temperature-Density (CTD) instrument casts and placed between fifteen and thirty eggs in each bottle. The eggs were preserved after five days. We found that eggs do not hatch as well in concentrations of low oxygen compared to higher oxygen concentrations above hypoxic values. Our results also show that the nauplii that do hatch have slowed development in hypoxic water. This work suggests that hypoxic water does have some negative effect on egg hatching and nauplii development, which could have a negative impact on all the important species that feed on them if the hypoxia conditions on the shelf increase. More data is needed to further clarify the repeatability and significance of these results.

Bill Peterson, Professor, College of Oceanic and Atmospheric Sciences (Courtesy); NOAA Northwest Fisheries Science Center
Shayna Rogers Oregon State University - Corvallis, Oregon Environmental Science

Title: Corvallis Ozone and Aerosol Experiment (COAX)

Summary: Air pollution can have serious implications for environmental health. High levels of particulate and gaseous matter in the lower atmosphere have been linked to the onset of respiratory distress, cardiovascular dysfunction, and ocular irritation in humans. Concentrations of these compounds are controlled by a variety of complex factors, including emission sources, transport and mixing, transformation, and removal (Ko, 1992). Using aerosol and ozone gas as indicator species, this study investigates the interplay of these factors at two sites in Corvallis, Oregon. It incorporates information about weather patterns, including data on temperature, relative humidity, surface and aloft winds, and mixing height to examine environmental controls on pollution. This project will increase understanding of how human exposure to contaminants can vary spatially and temporally on a local scale.

Rick Vong, Associate Professor, College of Oceanic and Atmospheric Sciences
Kether Scharff-Gray University of New England - Biddeford, Maine Marine Biology

Title: Sources and Fate of Organic Carbon in the Oregon Coastal Upwelling Regime

Summary: During the summer months, wind from the north blowing along the coast causes water to be transported offshore via Ekman Transport, which leads to the upwelling of deep, dense, nutrient rich water. This study aims to better understand the sources and fate of the carbon in this system. Elemental analysis will be conducted to measure the concentration of particulate organic carbon and particulate nitrogen in water samples collected along two transects off the Oregon coast. Analysis of this information will clarify the sources of organic carbon and nitrogen in the water. The information derived from this study will add to the understanding of the oceans role in the global carbon budget.

Miguel Goni, Associate Professor, College of Oceanic and Atmospheric Sciences
Norma Vazquez California State University, Monterey Bay - Seaside, California Earth System Science and Policy

Title: Evaluation of MHC Diversity as a Means to Study Mate Choice in Quillback Rockfish (Sebastes maliger)

Summary: The use of odor cues has been proposed as one method by which rockfish of the genus Sebastes recognize conspecifics and select mates. The major histocompatibility complex (MHC) is known to have primary function in the immune system in vertebrates but is also proposed to play a role in mate recognition within species and in mate selection in other organisms. One hypothesis is that females maximize the heterozygosity of their offspring at MHC loci through choosing mates that maximize their collective MHC diversity. The goal of this project is to evaluate the MHC genetic diversity within a single species of the genus Sebastes. The MHC class 2 beta gene family was studied in quillback rockfish (Sebastes maliger). We used degenerate primers and standard PCR protocols to amplify MHC sequences from 19 quillback rockfish. Six to eight clones were selected from each individual for sequencing and analyzed for sequence differences. In 227 sequences obtained, there were 97 distinct exon 2 sequences (79 coding sequences and 18 pseudogenes) and a range of 3-7 repeats of the intron 1 minisatellite. With phylogenetic analysis, clusters of monophyletic Sebastes maliger sequences were found among other clades that were blended with MHC sequences from Aguilar and Garza (2005). Pseudogene sequences were scattered throughout the tree. Our results primarily demonstrate the high MHC variability in S. maliger. For future directions, MHC or other candidate genes will be studied in different rockfish and examined in captive-bred rockfish larvae for evidence of non-random mating based on MHC.

Michael Banks, Director, Cooperative Institute for Marine Resources Studies
Hannah Waters Carleton College - Northfield, Minnesota Biology

Title: The effects of time-lag and ocean conditions on common murre (Uria aalge) productivity

Summary: The diet composition of top predators in marine ecosystems affects their reproductive output through availability (abundance and accessibility) and variation in the energy values of prey species. I studied a colony of common murres (Uria aalge) to determine reproductive success, dominant prey species, the age-classes of these prey species, and evaluated these data using PDO indices to identify if a time-lag exists between murre productivity and ocean conditions. Pacific herring, pacific sand lance (Ammodytes hexapterus) and smelt (Family Osmeridae) were the dominant prey species, composing over 50% of chick diet in each year. Sand lance were predated primarily as YOY age-class, herring as 1-year olds, and smelt as 1- and 2-years. PDO and copepod biomass showed strong correlations with reproductive success, as well as with reproductive success time-lagged 1 and 2 years. These results indicate that a time-lag exists between murre productivity and ocean conditions at Yaquina Head, and suggest that studying ocean conditions and copepod biomass from the present year alone do not account for differences in prey quality by species and age-class, which affect top predator health and reproductive success. Additionally, top predator reproductive success can be used as an indicator, as it reflects multiple trophic levels and ocean conditions.

Rob Suryan, Assistant Professor (Sr Res), OSU/Hatfield Marine Science Center
Caitlin White Lawrence University - Appleton, Wisconsin

Biology

Environmental Science

Title: Bopyrid isopod parasite recruitment and growth in Upogebia pugettensis and Neotrypaea californiensis

Summary: High prevalence of the introduced bopyrid isopod parasite OrthIone griffenis, Markham 2004 appear to limit populations of native mud shrimp, Upogebia pugettensis in eastern Pacific estuaries, even though they infest only reproductive sized shrimp and do not directly increase mortality. In contrast, all sizes of the co-occurring ghost shrimp, Neotrypaea californiensis are vulnerable to infestation by its native bopyrid isopod parasite Ione cornuta, Bate 1864 and only 0.5% of most ghost shrimp populations are infested. Thus, Neotrypaea populations are not limited by Ione. We compared processes by which the cryptoniscan stages of OrthIone and Ione appear to recruit and develop, grow and interact with the mud shrimp and ghost shrimp in Yaquina Bay, Oregon to resolve, in part, which processes control host vulnerability. Only the small male Ione grow on hosts in the absence of females, while isolated male OrthIone of all sizes grow uniformly. The host conditions that result in first cryptoniscan invasions were not discovered. OrthIone infestations did not occur by direct experimental exposure over the entire mud shrimp molt cycle. Ione and OrthIone cryptoniscans were not attracted to their respective available shrimp hosts and would not settle or remain in host branchial chambers when experimentally injected. The mechanisms of host vulnerability to cryptoniscan infestation appear to be more complex than previously supposed.

John Chapman, Research Associate, Department of Fisheries and Wildlife and Brett Dumbauld, Research Ecologist, USDA-Agriculture Research Service
Kiya Wilson Lewis and Clark College - Portland, Oregon Earth Science

Title: Using an Array of NE Pacific Margin Sediment Cores to Establish a Provenance Record and Link Land-Ocean Responses to Climate Variability

Summary: A major challenge in climate studies is attempting to couple continental and marine records. This can be overcome by looking at both signals in the same marine sediment core. The continental fraction of these sediments, including pollen and rock fragments, reflects the effects of regional climate change on continental runoff, ice extent, vegetation and surface ocean circulation. The transport of this terrigenous materiel to the ocean, and how this transport changes over time, must be understood in order to relate vegetation (pollen) and erosion (rock) changes to specific river catchments. This project examines this question by studying provenance in an array of surface sediment cores along continental margin of the Pacific Northwest. Provenance is determined using bulk sediment 40Ar/39Ar radiometric dating of sediment cores, for comparison with bulk sediment 40Ar/39Ar ages of major rivers in the Pacific Northwest reported by VanLaningham et. al (2006).

Nick Pisias, Professor, College of Oceanic & Atmospheric Sciences and Bob Duncan, Associate Dean, College of Oceanic and Atmospheric Sciences