Use the filters below to find awards made to CSU faculty members by Program, Campus, Year or Keyword.
COAST Award Program
Joint Meeting of Ichthyologists and Herpetologists/32nd Annual Meeting of the American Elasmobranch Society, New Orelans, LA
Feeling the heat, seasonally acclimated metabolic Q10 of the California horn shark, Heterodontus francisci
With global sea temperature rise, it is unclear how many marine ectothermic organisms will react, particularly elasmobranchs. A better understanding of their metabolic Q10, temperature sensitivity, is needed in order to make realistic predictions as to how some populations will react over time. Oxygen consumption was used as a proxy to measure acclimated metabolic rates of the horn shark, Heterodontus francisci, at winter and summer temperatures (16C and 20C, respectively) typically experienced in a given year and to measure metabolic Q10. Sharks were kept in a large holding tank at one of the desired temperatures for two weeks prior to the trial to allow for physiological acclimation. Trial duration varied among individuals and temperature, trials took up to 12 hours with re-saturation of oxygen occurring when levels reached 80% of starting saturation. Sharks tested to date have ranged in size (37-45cm TL) and weight (0.41-0.679 kg) (n = 8). The resting, pre-prandial metabolic rates of the horn shark at 16C and 20C were 32.6 +/- 9.5 mg O2 kg-1 hr-1 and 44.4 +/- 8.8 mg O2 kg-1 hr-1, respectively. Of the eight horn sharks that we have tested, we estimate a metabolic Q10 of 2.31. These data provide a baseline for understanding the current physiological state of these organisms relative to present sea conditions, but can be modeled to help predict and manage behavioral responses associated with increased sea temperature.
16th International Symposium on Microbial Ecology, Montreal, Canada
Variation of carbon use of microbial communities in different microhabitats
Microbial communities play an important role in the health of ecosystems and changing environmental microbial communities results in altered ecosystem function. The type and abundance of carbon sources affects the demographic rates of the microbes. Culture experiments determined that microbes have differing abilities to breakdown carbon sources and our experiment aims to investigate the response of environmental microbial communities to various carbon compounds. We hypothesize that microhabitats will drive carbon usage, rather than geographic location. We will evaluate our hypothesis by testing samples from two tide pool locations, Ocean Beach and Mission Beach, on three carbon sources; malic acid, cellobiose, and erythritol. From each location we will collect samples from three microhabitats, water column, hermit crabs, and algae. To compare the differences in nutritional abilities based on tide pool location and microhabitat (water, hermit crab or algae), we will grow the microbes on the three carbon sources and identify the proportion of microbes able that grow. The proportional differences across the plate types will be tested using a 2 factorial ANOVA, with microhabitat nested in location. We predict that the samples collected from each microhabitat will have different utilization of the carbon sources and that the sites that we sample from will not affect the usage of carbon sources by these three microhabitats. This data will show that different microhabitats have specific microbial communities, and that each of these microbial communities requires different nutrients. Our findings will describe the nutrient usages of microbial communities in differing environmental conditions and microhabitats.
Western Society of Naturalists Annual Meeting 2017, Monterey CA
The keystone predator Pisaster ochraceus has strong effects on the vertical distribution of the foundation species Mytilus californianus, but the effect of other predators on mussel distribution has rarely been studied in the absence of stars. With the onset of seastar wasting disease (SSWD) and depletion of west coast star populations, investigating how vertical distributions of mussels change when Pisaster is absent will be important for understanding future rocky shore community structure. We examined the effects of crab predation on Mytilus in the absence of Pisaster predation by re-locating stars and transplanting mussels to different tidal heights on a rocky shore in Northern California. When transplanted at low tidal elevations, uncaged mussels showed increased mortality compared to caged mussels at low elevations, and caged and uncaged transplanted mussels at high elevations. Crab attacks on wax snail replicas confirmed mortality on mussels at low elevations were due to crab predation. Both caged and uncaged mussels transplanted to high tidal elevations also experienced mortality, but this was due to disturbance from strong wave forces. Our results suggest that on rocky shores where Pisaster are absent or have been depleted by SSWD, lower limits of Mytilus distributions may be maintained by predatory crabs.
The non-lethal effects of predators on predatory whelk, Nucella lamellosa, shell morphology
Predators not only consume prey , they also non-consumptively affect prey by inducing plastic physical defenses. Such predator induced phenotypic plasticity has been extensively studied in laboratory settings, but its ecological significance in nature is still undetermined. In mesocosms, predatory whelks, Nucella lamellosa, alter their shell shape in the presence of crabs (Cancer productus) and seastars (Pisaster ochraceus). I examined whether these results are reflected in nature by surveying N. lamellosa from 5 rocky intertidal sites in Northern California. I quantified geometric metrics of N. lamellosa shell shape and tested their relationship against three environmental variables: water temperature, wave force, and the densities of crabs and seastars. Responses to predator densities in the field were similar to those reported in mesocosms. Whelks from sites with higher crab density had thicker, wider shells that combat crushing; whelks from sites with higher sea star density had elongate, high-spired shells that combat shell entry. Further research is needed to rule out locally adapted genetic variation between sites; however, N. lamellosa’s plastic response to non-consumptive predator effects in the field parallels the difference in shell shape determined in mesocosm experiments, implying that predator-induced phenotypic plasticity is possibly driving patterns of morphological variation in nature.
Avian use of mudflat habitat prior to living shorelines restoration
Living Shorelines restoration uses the infrastructure that some organisms (e.g., oysters, eelgrass) create to reduce coastal erosion while simultaneously promoting ecological community health. Birds may benefit from living shorelines because restored habitat may increase the amount and diversity of prey species. Bird density and richness increased in response to creation of living shorelines in San Francisco Bay, but this effect has not been evaluated in southern California estuaries. We studied avian use of mudflats at four sites prior to eelgrass and oyster restoration in Newport Bay, CA by conducting scan and focal samples between January-June 2016 at -0.5ft MLLW and lower. Each site consisted of a 130m long x 12m wide mudflat swath, divided into four 20m long treatment plots (control, oyster, eelgrass, oyster-eelgrass) with 10m buffer zones. We found no significant differences in bird density and richness within and among sites. Post-restoration surveys through spring 2017 will examine bird response to eelgrass restoration (completed July 2016) and oyster restoration (planned March, 2017). We predict the largest increase in bird density and richness in treatments that contain both restored eelgrass and oysters, which would support simultaneous oyster- eelgrass restoration as an approach in promoting healthy communities.
Commercial topical sunscreens are detrimental to development of the purple sea urchin, Stronglyocentrotus purpuratus
Commercial sunscreens provide humans protection against ultraviolet radiation. Nevertheless, these sunscreens can dissolve off of human skin during swimming and snorkeling activities and may have detrimental effects of marine organisms. Some of the active ingredients in sunscreens including oxybenzone and titanium dioxide cause the production of hydrogen peroxide in the water column, which causes oxidative stress to marine organisms. One sunscreen company is trying to create less harmful products and asked us to determine whether their zinc oxide-based sunscreen may be safe for marine organisms. We tested effects of this sunscreen on embryos of the purple sea urchin, Strongylocentrotus purpuratus, which are commonly used for toxicology studies. This is also an important organism to marine ecosystems. We hypothesized that any commercial sunscreen may be harmful to embryos of marine organisms and we predict that higher concentrations of sunscreens will be more detrimental. We examined how various concentrations of sunscreen in seawater affect multiple stages of sea urchin development, including the time to first cleavage and the percent normal developmental to the blastula, gastrula, prism and pluteus stages. Exposure of embryos to sunscreen caused developmental abnormalities in both early cleavage and later embryonic development in a concentration-dependent fashion (ANOVA P<0.05).
Joint Meeting of Ichthyologists and Herpetologists/32nd Annual Meeting of the American Elasmobranch Society, New Orelans, LA
Movement of juvenile white sharks in southern California: Predicitng future nursery habitat
The white shark, Carcharodon carcharias, is an apex predator with a circumglobal distribution and a low intrinsic growth rate that is listed as vulnerable by the IUCN. While considerable information is known for adults, there is limited information on the movements, environments, and distributions of juvenile white sharks (JWS). Understanding this life stage is important as JWS experience considerable overlap with human activities and juveniles often have the highest mortality of any life stage. In an effort to quantify JWS movements and understand their distribution in the Southern California Bight, JWS were captured and outfitted with satellite transmitters (SPOT tags: n=20). There was a large amount of variability in number of geopositions rendered (Class 0-3: 645 locations; mean: 36, range: 0-130), with individuals having a higher probability of detection later in the day (1700-2000). Some individuals (n=6) displayed movements south of the United States boarder into Baja California, Mexico. A generalized linear model with a binomial distribution was used as a resource selection function to determine and predict presence of individuals based on depth, distance to shoreline, and daily sea surface temperature (SST). Spatial maps were constructed of changes in depth and SST over a three kilometer window to identify areas of rapidly changing conditions. Sharks were found to significantly select shallow habitats (<3000 m) close to land (<15km) at temperatures between 15.6 and 24.3C. The model predicts sharks to move to Baja California during winter and a higher probability of JWS in southern California during El Nino years.
Joint Meeting of Ichthyologists and Herpetologists/32nd Annual Meeting of the American Elasmobranch Society, New Orelans, LA
Physiological effects of angling and handling stresses on kelp bass (Paralabrax clathratus) in southern California
A common regulatory strategy in the management of gamefish species, including kelp bass (Paralabrax clathratus), is catch and release yet the effects of capture-related stress on fish physiology and behavior are species-specific and remain largely unknown. Quantifying the physiological and behavioral impacts of catch and release will aid in managing the economically and ecologically valuable kelp bass fishery in southern California. Stress hormones and metabolic biomarker levels were quantified in blood samples collected from kelp bass caught on hook and line in the Catalina Island Marine Life Reserve. Baseline biomarker levels were established using blood samples collected in <3 min from time individuals were hooked. To experimentally determine the effects of angling and holding stress on biomarker elevation angled fish were held in coolers for either 10, 15, or 20 min before blood sampling. Glucose and lactate levels were significantly higher in experimental samples than baseline samples and increased significantly with holding duration, which reflects the time it takes for circulating cortisol to influence glucose levels and for lactate buildup in muscle to reach the blood. Recaptured fish were rapidly sampled to assess recovery after varying days at liberty (1-34 d) and in <24 hrs post-release both biomarker levels had returned to baseline. Neither biomarker correlated strongly with angling or handling times, which may be due to lack of sufficient fight duration (22 +/- 0.0001 s) and air exposure (50 +/- 0.0005 s). Cortisol analysis is ongoing and behavioral responses will be evaluated summer 2016.
Examination of the potential association between chronic organochlorine exposure and immunotoxicity in the round stingray (Urobatis halleri)
Chronic organochlorine (OC) exposure has been shown to cause immune impairment in numerous vertebrate species. To determine if local elasmobranchs exhibited a similar effect due to high OC contamination found along the coastal southern California mainland, innate immune function was compared in round stingrays (U. halleri) collected from the mainland and Santa Catalina Island, a reference site. Microscopy and flow cytometry were used to assess proliferation and phagocytosis in splenic and peripheral blood leukocytes. Percent phagocytosis, and mean fluorescence index (MFI) were evaluated by quantifying % leukocytes positive for, and relative amounts of ingested fluorescent E. coli BioParticles. Total cell proliferation differed between sites, with mainland rays having a higher concentration of cells in whole blood. Splenic mean (+/- SE) % phagocytosis (24.7 +/- 4.98 %) was significantly higher in mainland rays compared to Catalina (9.96 +/- 1.18 %). MFI was also greater among the mainland population (2681.74 +/- 410.06 and 1197.1 +/- 146.97). In blood, mainland rays had a significantly higher % phagocytosis (23.44 +/- 2.887 %) compared to Catalina (12.98 +/- 1.58 %), yet no difference was found in MFI. Total PCB and pesticide loads were the most influential factors describing increasing splenic % phagocytosis and MFI, while PCB load alone explained increasing % phagocytosis in blood. Data suggests OC-correlated immunostimulation; however, other site-specific environmental variables may be contributing to the observed effects.
Age structure and growth rates of vermilion rockfish, Sebastes miniatus, along the California coast
Inaccurate information of life histories can be detrimental to stock assessments and management because they may lead to erroneous estimates of population size which could lead to overexploitation. Among rockfish species targeted by recreational anglers, the vermilion rockfish (Sebastes miniatus) is one of the most commonly caught in southern California. Vermilion rockfish populations have declined in size and age in southern California since the 1980s due to fishing pressure. They show low genetic connectivity along their distribution suggesting a presence of subpopulations in regions bordered by biogeographic barriers. Unfortunately, a discovery of a deeper-living cryptic species confounds past assessments. The current study will investigate and clarify the age and growth data of the true vermilion rockfish in California focusing on regions containing identified subpopulations. We will compare populations from four sites along California; Cape Mendocino, Monterey Bay, Santa Barbara, Los Angeles regions. After sampling two sites, we have found smaller individuals in Los Angeles than Santa Barbara. Growth curves between these two sites differ but further investigation is warranted. Further exploitation of vermilion rockfish could reduce genetic diversity and shift demographics of this species. If age and growth rates differ between sites, regional-scale management may help ensure the persistence of healthy and sustainable populations of vermilion rockfish.
Joint Meeting of Ichthyologists and Herpetologists/32nd Annual Meeting of the American Elasmobranch Society, New Orelans, LA
The secret life of baby giants: The recruitment of the endangered giant sea bass
Little is known about the complete life history of giant sea bass (Stereolepis gigas) due to the over exploitation of their fishery in the early 1900's, and depressed populations have prevented much detailed research. This study finally fills in gaps in the early life history of the juvenile giant sea bass by 1) determining distribution and general ecology for the young-of-the-year of S. gigas in the wild, 2) estimating growth rates, based on site aggregations in the wild, and otoliths analysis in the lab, and 3) finally determining pelagic larval duration and general temporal scale of their spawning period. The use of SCUBA transects, video, and lasers allows us to estimate cohort populations, individual sizes, and ecosystem quantifications while in the field, and collecting individuals for otolith analysis helps determine growth rates and planktonic larval duration. These observations have already discovered several previously unknown behaviors, including the "kelping" mimicking behavior, distinct distribution patterns across southern California primarily near underwater canyons, and their annual and daily temporal distribution. These early developmental process are crucial for completing the life history for any species, and this study is the only one of its kind to do so for this endangered species making it a key component to their life history, as well as a baseline for future work on not only S. gigas, but also similar species. Increasing knowledge about current and future populations, will allow us to make increasingly intelligent decisions about current fisheries management policies as well as future conservation efforts.
World Congress of Malacology 2016, Penang, Malaysia
It loves me, it loves me not: Counting species of the "rose petal sea slug", Polybranchia (Mollusca: Gastropoda) with a molecular systems approach
Polybranchia (Gastropoda: Heterobranchia: Sacoglossa) is a pantropical group of herbivorous sea slugs consisting of eight valid species. During field collections, this genus is consistently overlooked because these organisms tend to find shelter under rocks during the day and will become active mainly at night. As a result, these organisms are considered a rare find making the conduction of phylogenetic analyses on this genus a difficult task. This genus has been used in large scale phylogenetic studies where only a few species represent the entire group but a detailed phylogenetic study on Polybranchia has yet to be conducted. This study investigates the disjunct range of Polybranchia viridis and whether the species consists of two populations or two species (one from the Caribbean and another from the Eastern Pacific). Secondly, Polybranchia orientalis is the most commonly found species in the Indo-Pacific but collecting reports are lacking for the five other described species from the Indo-Pacific. Therefore, we hypothesize a species complex from the specimens obtained of P. orientalis. This investigation used nuclear gene H3 and mitochondrial genes COI and 16S. A Bayesian analysis was conducted on the molecular markers to identify clades and misidentified species. Additionally, scanning electron microscopy was used to examine the morphology of the radulae and penis of each clade. Evidence for diversity in obtained specimens was higher than expected.
16th International Symposium on Microbial Ecology, Montreal, Canada
Increased temperature and pCO2 alters the host-associated microbial landscape in a marine foundation macroalgae species: Macrocystis pyrifera
Global climate change is responsible for rising temperatures and increased pCO2 concentrations in the ocean, with potentially deleterious impacts to organisms in nearshore ecosystems. In a four week climate change mesocosm simulation, we measured taxa and functional microbial community changes on the surface of an important foundation species, the giant kelp Macrocystis pyrifera, and the surrounding water column under present day, elevated temperature, elevated pCO2, and future conditions using metagenomics. Water and kelp surface microbial communities were unique (PERMANOVA, p<0.001) and disrupted by climate change stressors (PERMANOVA, p<0.001). Specifically, water column microbial communities were most affected by elevated pCO2 as demonstrated by a significant increase in species richness (ANOVA, p<0.01) and a specific four-fold increase in Rhizobiales. Kelp growth was negatively associated with elevated temperature, with a 2.9 fold increase in microbial diversity and a 3.3 fold increase in Flavobacteriales. Kelp growth was positively associated with future conditions, with a 3.4 fold increase in kelp-associated microbial diversity followed by a 3.5 fold increase in Planctomycetales. In both environments and across stressors, taxonomical composition was more influential than gene function for community differentiation. We demonstrate novel interplay between an important macroalgae host and its microbiome as a result of climate change perturbations.
Sequence binning to improve the quality of environmental genome clusters identified from metagenomes
Metagenomics provides massive amounts of DNA sequencing data that provides a description of the microbial community from an environment. Reconstructing genomes from metagenomic data is complicated due to sample variability and high diversity resulting in genomic clusters of varying quality. In addition, the conserved nature of many genes in microbial genomes makes separating sequences into different taxonomic bins difficult. We are developing a pipeline to extract environmental genome clusters from metagenomes of both high and low diversity. Reads are assembled into contigs with three different assemblers; SPAdes, IDBA and meta-velvet and assembly evaluation will be performed. Assembled contigs are binned based on genome signatures, such as tetranucleotide frequencies and contig coverage. The taxonomy of each environmental genome clusters was identified. Individual clusters are assessed for genome completeness and identification of potential horizontal gene transfers. This pipeline was developed and validated on a low diversity metagenomes collected from the sea water exposed to algae, crustose coralline algae and corals species in Abrolhos Bank, Brazil. Our binning strategy identified 17 distinct bins, in which contigs were similar to Vibrio, Pseudoalteromoas, and Arcobacter genera. The bins were constituent in GC content and tetranucleotide content. Environmental genome clusters containing a high percentage of novel sequences which we can now suggest are part of the genera that was described for each bin. Further development of the pipeline will inform optimal clustering methods for high diversity metagenomes of both microbial and viral fractions to accurately predict the environmental genomes clusters present in different environments.
Genome assembly of rare superheterotrophs from coral reef metagenomes
Seasonal dynamics of a phototrophic mat in an intertidal marine environment
Photosynthetic microbial mats are stratified microbial ecosystems that can be found in a variety of environments including intertidal regions of salt marshes. This study focuses on how seasonally fluctuating environmental factors (salinity, temperature, and pH) influence the composition of an intertidal microbial mat. Using high-throughput sequencing of the 16S rRNA gene and the ITS1 region of fungi, we characterized the microbial communities of the top and bottom layers, and the underlying sediments of a mat system. The top layer of the mat was composed primarily of oxygenic-photosynthetic Cyanobacteria, purple sulfur bacteria, and aerobic heterotrophs, but the relative abundance of each varied seasonally. In the bottom layers of the mat, the depletion of oxygen and filtering of light selected for anaerobic heterotrophs, primarily sulfate reducing bacteria. Fairly consistent conditions within underlying sediments maintained a relatively constant microbial community. Similarly, fungal communities throughout the layers of the mat varied seasonally in the abundance of each lineage. Ongoing seasonal characterization of this mat system will provide foundational data that will allow us to identify factors structuring this mat system and will ultimately lead to a better understanding of how photosynthetic microbial mats contribute to carbon cycling within salt marsh environments.
International Society of Microbial Ecology, Montreal, Canada
Low β-diversity in skin microbiome of the Common thresher shark (Alopias vulpinus)
The health of sharks is linked with emergent properties of its microbiome thus determining the structure the skin microbiome of the shark is critical. Shark skin is composed of fluid friction reducing dermal denticles and bioactive mucus. We hypothesized the skin boundary layer of the Common thresher shark (Alopias vulpinus), with its biochemical and biophysical properties, would yield microbial communities distinct from the water column. Shotgun metagenomic libraries were prepared from microbes collected at the base of the first dorsal fin in 6 A. vulpinus individuals in the California Bight. Annotation was conducted with the MG-RAST platform and yielded an average of 577,797 sequences with protein coding motifs per library, but only 2.9 to 8.2 % of those matched known protein sequences in the SEED database. The taxonomic microbiome of the shark was different than to the water column microbial community (PERMANOVA, p < 0.001). Functional composition of microbial communities was also different from the water column (PERMANOVA, p < 0.001). Microbial genera discriminating the skin microbiome from the water column microbial community included Pseudoalteromonas (mean 12.8 %; s.d. 11.4; SIMPER 2.3 %) and Idiomarina (mean 4.2 %; s.d. 3.5; SIMPER 1.2 %) and overrepresented specific gene pathways included heavy metal resistance (mean 2.2 %; s.d. 0.3; SIMPER 3.3 %) and iron acquisition (mean 2.2 %; s.d. 0.2; SIMPER 1.8 %). Highly structured, distinct microbial communities on the skin surface of sharks suggest the presence of processes that are selective towards microbial associates.
Western Society of Naturalists Annual Meeting 2017, Monterey, CA
Spatial differences in life history parameters of a non-fished Pomacentrid, Hypsypops rubicundus, in the Southern California Bight
Life history parameters have generally been accepted to apply to species across their entire range, however recent studies conclude that varying ecological and environmental processes introduce spatial differences in fish life histories. The Southern California Bight (SCB) study area has a unique current circulation pattern which, when coupled with the complex bathymetry, results in strong abiotic gradients and diverse microhabitats. Many prior studies of spatial differences in growth and morphometric parameters for fishes have concentrated on commercially and recreationally exploited species. The Garibaldi (Hypsypops rubicundus) is a protected, non-fished marine damselfish native to the shallow rocky reef habitats in the SCB. During 2013-2016, 435 Garibaldi were collected by divers from seven areas within the SCB: three mainland natural reefs, two mainland manmade reefs, and two sites at Catalina Island (leeward/windward). For this study, morphometric measurements were taken and otoliths were sectioned and aged to determine growth rates and somatic length-weight relationships for Garibaldi collected from each area. It is evident that growth rates differ between island/mainland sites and natural/manmade reefs, indicating that there are significant spatial differences in growth rates between distinct areas within the SCB.
American Geophysical Union Fall Meeting 2016, San Francisco, CA
Development of a tsunami magnitude scale based on DART buoy data
The quantification of tsunami energy has evolved through time, with a number of magnitude and intensity scales employed in the past century. Most of these scales rely on coastal measurements, which may be affected by complexities due to near-shore bathymetric effects and coastal geometries. Moreover, these datasets are generated by tsunami inundation, and thus cannot serve as a means of assessing potential tsunami impact prior to coastal arrival. With the introduction of a network of ocean buoys provided through the Deep-ocean Assessment and Reporting of Tsunamis (DART) project, a dataset has become available that can be exploited to further our current understanding of tsunamis and the earthquakes that excite them. The DART network consists of 39 stations that have produced estimates of sea-surface height as a function of time since 2003, and are able to detect deep ocean tsunami waves. Data collected at these buoys for the past decade reveals that at least nine major tsunami events, such as the 2011 Tohoku and 2013 Solomon Islands events, produced substantial wave amplitudes across a large distance range that can be implemented in a DART data based tsunami magnitude scale. We present preliminary results from the development of a tsunami magnitude scale that follows the methods used in the development of the local magnitude scale by Charles Richter. Analogous to the use of seismic ground motion amplitudes in the calculation of local magnitude, maximum ocean height displacements due to the passage of tsunami waves will be related to distance from the source in a least-squares exponential regression analysis. The regression produces attenuation curves based on the DART data, a site correction term, attenuation parameters, and an amplification factor. Initially, single event based regressions are used to constrain the attenuation parameters. Additional iterations use the parameters of these event-based fits as a starting point to obtain a stable solution, and include the calculation of station corrections, in order to obtain a final amplification factor for each event, which is used to calculate its tsunami magnitude.
Impacts of predator diversity on subtidal red algae-associated invertebrate assemblages
In many temperate reef systems, understory red algae (phylum Rhodophyta) support diverse assemblages of small invertebrates that provide food resources for many organisms. Yet, our understanding of the biological processes that structure these assemblages is limited. Recent surveys of reefs throughout Point Loma and La Jolla, California indicate that temperate reef fishes such as the rock wrasse, black perch, striped seaperch, and California sheephead forage extensively in red algae. California spiny lobsters also forage in this habitat. Surveys of reefs revealed several species of red algae, including Rhodymenia, Gracilaria, Acrosorium, and Plocamium sp. Sampling of these algae indicated a diverse assemblage of invertebrates, including caprellid amphipods, non-caprellid amphipods, gastropods, copepods, and isopods with less common taxa such as cumaceans, ostracods, bivalves, brachyurans, and hydrachnidians. Through development of exclosures and partial exclosures, we will examine whether predator diversity may influence assemblages of red algae-associated invertebrates on southern California rocky reefs.
The cellular stress response of Mytilus Edulis to temperature variation and predation risk
This proposal explores how attention to the interactive effects of abiotic (temperature) and biotic (risk of predation) stressors on intertidal mussels Mytilus edulis can enhance qualitative predictions of organismal energetics using a Dynamic Energy Budget model. Moreover, it will identify the physiological pathways affected by these two stressors and how they interact at the subcellular level. The central question of this research is: are predictions of the impacts of environmental change unreliable if natural biotic and abiotic contexts are not considered? The proposed research builds upon a model already parameterized to quantify the effects of temperature and food availability on mussels by examining how predation risk - the "fear of being eaten" - may alter thermal sensitivity under more realistic field conditions where predators are present. By measuring performance metrics (assimilation, respiration, etc.) under different levels of temperature and predation risk, resulting model simulations and outputs from empirical observations will enhance understanding of how organism's perform in a dynamic environment. This approach will be coupled with measurements of cellular stress responses associated with a few key metabolic processes that are likely to be induced by variation in temperature and predation risk and influence prey energetic budgets. Attention to the physiological pathways that are independently and interactively affected by these stressors is key to understanding their role in shaping the whole-organism energetics of this important ecosystem engineer.
Parasite-mediated predator-prey interactions in California coastal fishes
Although their ecological significance is not often recognized, parasites are important components of multiple food webs and can shape host populations, alter competition, and influence trophic interactions. Specifically, parasites and predators may interact in different ways to influence population dynamics of their joint prey. In this study, I have developed an emergence trap to determine the densities of nocturnal parasites that rise above the benthos to feed on fishes (i.e. Gnathiidae and Cirolanidae). I have deployed this trap with three designs (control, lighted, and baited with a live fish) in both embayments and rocky reefs along the San Diego coastline. In using these traps, I will determine the density of emergent parasites by comparing both trap design and differences among habitats. The information derived from this study will be used to inform subsequent experiments on relative infection rates in juvenile fishes to explore whether parasites mediate their predator-induced mortality, which may have important consequences to the population demography of temperate coastal fishes.
Evaluation of a mobile touch tank outreach and tidepool interpretive program to offset visitor impacts on rocky intertidal zones
Rocky intertidal habitats in urbanized settings are heavily perturbed by human visitors (tidepoolers) through the deleterious activities associated with collecting and handling of organisms. To protect rocky intertidal biota, certain locations have been designated as Marine Protected Areas (MPAs), where harming of species is prohibited. Intertidal MPAs are suggested to be ineffective because public compliance and knowledge of regulations has been low. To help increase public knowledge of MPA regulations, two outreach tools have been instituted in Newport Beach, CA: 1) a tidepool interpretive program where educators are on site, and 2) a mobile touch tank, the ISOpod (Interactive Sealife Outreach pod), parked on site for visitors to see and touch organisms in a controlled setting. The goal of this project is to examine the effectiveness of both tools in reducing deleterious activities of visitors. Visitors were discretely observed, counted, and placed into behavior categories (e.g. collecting, handling) during surveys under 4 scenarios based on presence/absence of the ISOpod and tidepool educators. A questionnaire was also conducted with departing visitors to determine if knowledge of MPA regulations increases with outreach programs in place. The percent of visitors engaged in all detrimental activities combined decreased by half when the ISOpod or tidepool educators were present as compared to no outreach program; no combined effect was observed when both outreach programs were in place. The patterns for the individual activities were less consistent. Public knowledge of MPA designation and regulations were relatively high with patterns of higher knowledge when either the ISOpod or educators were in place. Results from this study will elucidate whether these management tools are an effective option to help protect coastal ecosystems.
Low concentrations of large inedible particles reduce feeding rates of echinoderm larvae
Many marine invertebrate larvae must feed in the plankton in order to complete development. The length of time these larvae are in the plankton (planktonic larval duration) can affect larval dispersal and mortality. One factor that can affect planktonic larval duration is larval feeding. Larval feeding rates are commonly measured in homogenous suspensions of edible particles, but natural plankton also contains large inedible (LI) particles that cannot be ingested (e.g. some dinoflagellates and diatoms). Hansen et al. (1991) demonstrated that feeding rates of molluscan veligers are lower when LI beads are present at very high concentrations (1,000-20,000 ml-1). We hypothesized that LI particles at environmentally realistic concentrations reduce feeding rates of echinoderm larvae. Larvae of a holothuroid, two asteroids, and three echinoids were permitted to feed briefly on 6 μm beads alone, or in combination with LI beads at concentrations of 25, 50, 100 or 500 ml-1. Five of the six species had a dose-dependent decrease in larval feeding rate when exposed to LI beads. Specifically, larval feeding decreased by ~50% in treatments of LI beads at 100 or 500 ml-1. In the presence of LI beads, larvae may alter their swimming behavior or engage in particle rejection behavior; either activity might reduce the time larvae would otherwise spend feeding. Our results suggest that larval feeding rates in nature, and perhaps planktonic larval duration, may depend not only on the amount of food particles available in the plankton, but also on the concentration of non-food particles.
Wasted sea starts and hungry snails: could disease epidemics have cascating impacts on coastal kelp forests?
In central California kelp forests, sea stars represent the primary predators for a number of macroalgal grazers, including the highly abundant turban snail Tegula spp. If sea star predation is critical in regulating grazing activity, widespread sea star mortality could drive cascading regional losses of algal habitat. Here, we utilized the recent outbreak of wasting disease along the California coast as a unique natural experiment to evaluate the extent of sea star-Tegula interactions in kelp forests off Monterey, Big Sur, and San Luis Obispo. In each study area, we surveyed one reef where local disease impacts were severe, removing all predatory sea stars (SS-), and one nearby control reef where some predators remained present (SS+). Although predator densities at SS+ sites were extremely low (0.05-0.20/m2), distinct differences in Tegula grazing behavior were observed. Approximately 90% of snails at SS+ sites were found grazing on giant kelp (low nutritional content, vertical refuge), while 47-52% of snails at SS- sites were observed on benthic red algae (highly nutritious, vulnerable to predators). Tegula collected from SS- sites also had significantly larger gonads (% body weight) and a larger proportion of ripe gonads compared to SS+ locations. These results suggest that predatory sea stars may play a key role in regulating Tegula grazing activity, as well as determining their local population dynamics. If so, future sea star mortality events could lead to rapid Tegula proliferation and potential depletion of coastal kelp forests.
Japanese Coral Reef Society Annual Conference, Okinawa, Japan
The effects of ocean acidification on the physiology and behavior of brooded coral larvae in Okinawa, Japan
Ocean acidification (OA) is a threat to coral reefs, but little is known of the impacts on the exchange of coral larvae among populations. Integrating larval motility into studies of OA is critical to understanding how OA will influence biodiversity and reef resilience. We hypothesized that, due to the sensitivity of coral larvae to extreme environmental conditions, OA will perturb larval motility (i.e. vertical position in the water). This project focused on behavior and physiology of Pocillopora damicornis larvae using in situ incubations on the reefs of Okinawa, where freshly released larvae were exposed to ambient and elevated pCO2. To test the hypothesis that OA influences larval behavior, larval position was quantified using vertically-oriented, sealed UV-T tubes (4.5 cm ID, 68 cm long) suspended at shallow (0 m) and 3-m depth. Larvae were incubated at ~400 μatm and ~1000 μatm pCO2 and scored for vertical position every 4 h over 24 h. Over 24 h in high pCO2, larval position within these tubes varied among depths and time of day, following a gradual downward migration in shallow tubes and aggregating at ~3.4-m depth in the deeper tubes. Larvae in ambient pCO2 behaved similarly in deep tubes, but did not migrate downward in shallow tubes. Total lipid content of larvae declined 22-25% at high pCO2 but remained constant at ambient pCO2. The decline in lipid content and change in behavior imply that vertical orientation of coral larvae will be altered at high pCO2, which has implications for dispersal of corals among reefs exposed to OA.
Habitat structure and fish foraging: effects of eelgrass epibonts
Seagrass beds provide important habitat for mesopredators such as many juvenile fishes. Seagrass structural complexity (SC) strongly affects predator-prey relationships for mesopredators that utilize these beds for refuge and foraging. SC typically is quantified using metrics like shoot density or the biomass of seagrass blades per unit area. However, seagrass blades often are colonized by epibionts such as algae and bryozoans, which can fundamentally change the quality and amount of habitat structure at small spatial scales. We conducted a lab experiment to determine how adding bryozoan epibionts to eelgrass (Zostera marina) blades affects the foraging success and behavior of juvenile giant kelpfish (Heterostichus rostratus) in San Diego Bay, California. We recorded how increasing eelgrass SC, and increasing eelgrass + bryozoan SC influenced the number of prey detections, attacks, successful captures, and prey escapes. Increasing eelgrass SC and increasing bryozoan SC resulted in decreases in prey detections and attacks by kelpfish, indicating a decrease in foraging ability. Prey escape decreased with increasing bryozoan SC and prey escape was lower with increased eelgrass + bryozoan SC.
Phenotypic variation across the range of the Lined shore crab
Examining patterns of phenotypic variation is an important step in understanding population divergence. The lined shore crab, Pachygrapsus crassipes, has a disjunct range, with two populations found on opposite sides of the North Pacific. These populations have been genetically isolated for approximately 1 million years, but show no previously described phenotypic divergence. We collected crabs from across this range, and analyzed variation in a phenotype – cheliped color – which has not yet been described in this species. We found a lack of variation across the Pacific, but surprising variation in Southern California, which could be the result of introgressive hybridization with the more southern species, Pachygrapsus socius. Next generation sequencing is currently under way to further characterize divergence across the range of this species, and the potential hybrid zone in Southern California.
Characterizing how the loss of canopy forming algae effects patterns of net community production on temperate rocky reefs
In many coastal regions in the Eastern Pacific, temperate rocky reefs are undergoing regime shifts associated with lowered production and diversity in benthic flora cover, and an increase in grazing invertebrates. While the transition from kelp forests to areas characterized by less diverse algal cover along the west coast of the United States has been addressed, linkages between the loss of primary producers and patterns in productivity along a latitudinal gradient have not been established. The goal of this study is to quantify differences in algal diversity and net community production (NCP) on temperate rocky reefs, and how these differences vary across a latitudinal gradient. Using sensors that measure dissolved oxygen (DO) and photosynthetically active radiation (PAR), paired with diver surveys, we are estimating in situ community rates of production and respiration in kelp forests and adjacent ecosystems that have undergone a disturbance. Five rocky reefs from Central California to Baja California, Mexico have been chosen to address this knowledge gap. Preliminary results indicate that in Stillwater Cover, Monterey, there are clear differences in NCP between rocky reefs dominated by canopy forming kelps (5.61 O2 mg L-1 hr-1 ±0.01), and adjacent urchin barrens (8.16 O2 mg L-1 hr-1 ±0.03). Assessing how the processes that govern kelp forests vary along a latitudinal gradient can enhance our understanding of larger patterns of variability in ecosystem functioning, and prove crucial to predicting how kelp forest communities will persist in the future.
Salt marsh response and recovery to coseismic subsidence
Salt marshes worldwide are under increasing stress from eustatic sea level rise. Along the tectonically active west coast of North America, some salt marshes are also vulnerable to abrupt increases in relative sea level rise (RSLR) resulting from coseismic subsidence. Elevation zonation of sub-environments within a marsh provides the opportunity to interpret the sedimentary record in marshes to infer past earthquakes, which may improve understanding of regional seismic hazards and ecosystem response to increases in sea level. Our study area is the Seal Beach Wetlands (SBW), an ~3 km2 salt marsh straddling the seismically active Newport-Inglewood fault zone in southern California. A previous study of the SBWidentified sedimentary evidence of three coseismic subsidence events. Here, our goals were to identify coseismic subsidence events preserved in SBW stratigraphy and to quantify marsh recovery following an earthquake to assess marsh resiliency to rapid RSLR. To do this, we focused on one core collected near the fringe of the SBW and applied a suite of sedimentary and geochemical analyses. Our results indicated that the SBW may preserve sedimentary evidence of four potential coseismic subsidence events. Events were distinguished in the stratigraphy by a sharp upper contact interpreted as an abrupt shift in marsh depositional sub-environments, from a vegetated marsh, to an intertidal mudflat or a subtidal environment. This stratigraphy suggests that the marsh rapidly subsided, preserving the evidence of the vegetated marsh as a peat deposit overlain by a low-organic mud or muddy-sand layer. A typical marsh accretion facies succession occurred above each earthquake event in the core, suggesting full marsh recovery. From the core data, we also observed that the net average rate of marsh recovery, i.e., marsh accretion, was consistent. Estimated recovery rates between 0.6 and 1.1 mm/yr were comparable to the overall accretion rate and regional late Holocene RSLR rate of 0.8 mm/yr. These results suggest that following a coseismic subsidence event the marsh recovery rate is relatively constant. Therefore, marsh resiliency to rapid increases in sea level depends on the rate of RSLR relative to the rate of recovery, which in this case is controlled by the amount of subsidence per event, and the frequency of events.
Examining the major histocompatibility complex class I functional diversity in the Rainwater killifish (Lucania parva)
California’s dynamic coastline: a geomorphologic study of the Salinas sub-cell during and after the 2015/16 El Niño
Facilitating sediment accretion and biotic recovery in a salt marsh restoration site
Characterizing the role of DNA methylation patterns in the California mussel, Mytilus californianus
Habitat use and mercury loads of western gulls (Larus occidentalis) at three California colonies
Movement patterns and site fidelity of giant sea bass (Stereolepis gigas) on Santa Catalina Island, California
Effects of short-term high pCO2 exposure on enzymatic activity and gene expression in juvenile rockfish (Sebastes spp.)
Linking foraging behavior and energy balance in California sea lions
Characterization of the detoxification enzyme Glutathione S-Transferase in the marine gastropod, Tritonia diomedea
Evaluating spatial and temporal variability of vessel traffic in San Francisco Bay for more informed spatial risk assessments in a large, urbanized estuary
Determining the relationship of protein metabolism and phenotypic plasticity in larvae of the sand dollar, Dendraster excentricus
Key habitat and recruitment of green abalone (Haliotis fulgens)
The effect of ocean acidification and hypoxia on the behavior and physiology of juvenile temperate reef fish
Diversity and origins of the nudibranch genus Flabellina in California and the Northeastern Pacific
Effects of habitat edge type on eelgrass community structure and relative survival
Effects of maternal age on offspring behavior and storage efficiency in Northern elephant seals (Mirounga angustirostris)
Investigating the mechanism by which southern sea otters (Enhydra lutris nereis) facilitate the invasion of an exotic fouling bryozoan
The roles of acclimation and food availability on the physiology and survival of the California mussel (Mytilus californianus) in response to ocean acidification
Short term impact of sediment augmentation on vegetation and invertebrate communities in a Southern California coastal wetland