Below are example projects in each of the faculty labs.
Project: How does climate change affect plant-herbivore interactions in kelp forests?
Much attention has focused on predicting the effects of climate change on the abundance and range of individual species. However, much less is known about how climate change will alter trophic interactions. In marine systems, OA, increasing SST, and nutrient loading may fundamentally alter plant-herbivore interactions by driving changes in consumer metabolism and resource quality. Kelp forests are a model system to explore these effects on trophic interactions because food web dynamics are well understood. REU students will use laboratory experiments to assess how changes to SST and OA would impact feeding behavior and diet choice in several species of sea urchin, the dominant kelp forest herbivores. Urchins would be collected from kelp forests near UCSB and housed in the laboratory to conduct feeding assays across current and future ocean temperature and OA scenarios. Laboratory aquaria would be maintained at 13°C, 16°C, 19°C, or 22°C with 22°C representing summer maxima, which will likely become more frequent under climate change predictions. Urchins will be fed artificially created diets created from dried kelp with low or high nitrogen content to account for the predicted effects of OA on kelp diet quality, with diet quality decreasing with increasing effects of OA on kelp ingestion efficiency will be quantified in each treatment. These feeding assays will be repeated using ranges of temperatures that mimic more extreme climate change scenarios. Ultimately, these assays will assess how the combined effects of climate change on kelp diet quality and urchin metabolism impact the rate of food consumption by urchins and potentially how top-down control metabolism. Sea urchin metabolism, assimilation efficiency, consumption rate, and may be altered under near-future climate change predictions.
Example project: Marine protected areas are increasingly implemented to benefit biodiversity and fisheries. California has implemented one of the largest scientifically designed networks of MPAs in the world and our lab has several projects related to understanding the effectiveness of the network. We have shown that community structure differs in and out of protected areas, abundances and biomass of targeted species are greater in MPAs. How this altered community structure affects food web dynamics remains to be explored. We will use a combination of stable isotope analysis and good old-fashioned gut contents to explore the trophic relationships of kelp forests animals inside and outside of MPAs. Growth rates and parasite load will also be measured. REU students in my lab can choose to develop a project based on their interests and fit with ongoing work in the Caselle lab.
Climate change is impacting marine biodiversity worldwide through alterations in ocean temperature, dissolved oxygen, pH and salinity levels. These environmental stressors rarely act in isolation and can interact to additively, antagonistically or synergistically influence an animal’s performance. Phenotypic plasticity, the ability of an organism to alter its phenotype in response to environmental change, is one mechanism that can allow populations to buffer some of the negative effects of climate change. The REU student working with the Eliason research team will develop a project to assess the effect of climate change stressors on the physiological performance of marine critters in the Santa Barbara Channel.
A main research question in our group centers on how eggs are “activated” to begin development at the time of fertilization. We use several marine invertebrates as model systems to address this process, which is highly conserved across all multicellular species, including mammals. Some of our projects focus on specific proteins and signaling pathways, others are more discovery-based. Undergraduates can contribute in several ways. First, students can learn how to evaluate large, information-rich data sets and search public databases as we compile and annotate the thousands of proteins that undergo changes in phosphorylation state or exhibit dynamic interaction complexing in the first few minutes post fertilization. Students can also assist in validation and characterization of candidate proteins. Finally, we are initiating a transcriptome assessment using deep sequencing in order to gain even further insight into the changes occurring in the egg to embryo transition and students will participate directly in mRNA isolation, library construction, and sequence analyses. All undergraduates in the lab assist with husbandry of marine invertebrates in seawater aquaria, learn to collect gametes, and to set and culture embryos.
Projects in the Hofmann lab would come in three varieties, depending on what someone wants to learn. First and foremost, REU students would get experience in doing research in ocean acidification and how to set up and design experiments (e.g., seawater chemistry, creating tanks with controlled pH and temperature). In addition, students would learn about patterns of natural variation in pH in our local marine ecosystem, the kelp forest, and how this variation might impact marine organisms that live in this environment. We have projects that examine transgenerational effects in sea urchins, projects that would assess the metabolism of organisms in response to these changes, and projects that have molecular ecology approaches such as measuring gene expression changes or changes in DNA methylation in order to study an epigenetic mechanism. All of the projects are couched in a ocean global change context and would introduce an REU student to this integrated field of research. Specially, there is a coupling of the oceanography (e.g., what is the pH of water in the kelp forest or in a seagrass bed) and organismal performance, with an eye to how this relationship will play out into the future in an ocean change context.
Project: How does OA and cooling affect the physiology and diversity of coccolithophores?
This project will investigate the extent to which OA and cooling affect the diversity and physiology of a group of marine phytoplankton that produce calcium carbonate: the coccolithophores. The rationale for this study is to elucidate the consequences of increased upwelling intensity and frequency on the population structure and functional properties of phytoplankton. Coccolithophores are particularly relevant to these studies because (a) they are susceptible to changes in pH and temperature; (b) there are limited studies of these organisms in upwelling regions; and (c) there are almost no physiological studies of non-bloom coccolithophore populations despite these being biogeochemically more relevant than the conspicuous bloom populations observed with remote sensing techniques. So far, the OA research community has focused efforts on the synergistic effects of OA and ocean warming, but the combined effect of cooling and acidification remains an open question. The student assigned to this project will make observations in the field to assess the diversity of calcifying types under different upwelling conditions using flow cytometry. The student will also conduct laboratory incubation experiments using the cosmopolitan species Emiliania huxleyi to lab-test field observations. Flow cytometry observations will reveal the diversity of species, and the diversity of calcifying cell types. Scanning electron microscopy will confirm morphotype abundance and diversity and will enable the identification of any corrosion of the biomineral. The student participating in this research project will use samples from the Plumes and Blooms program (PI: Prof. David Siegel, UCSB) and will have the opportunity to analyze samples and discuss results in a broader context, using physio-chemical data collected during cruises
Project: Reconstructing shark communities on coral reefs
Historical reports from explorers, naturalists, and ship logs tell tales of seas swarming with sharks, yet accurate shark population assessments began after the initial degradation of marine ecosystems. Our team extracts and identifies shark dermal denticles (tooth-like scales) preserved in modern and ancient coral reef sediments to reconstruct quantitative pre-human shark baselines and assess how shark communities have changed over time. Denticles can reveal the ecology and taxonomy of the sharks from which they were shed, helping us to answer important questions about the abundance and diversity of sharks inhabiting reefs over time. With this information in hand, we can begin to better understand how losses of sharks have affected coral reefs and what baseline goals should be set for shark conservation.
Example project: Macroalgae are important primary producers in shallow marine ecosystems, and many species coexist on reefs along our coast. We are interested in whether key traits of these species can be used to predict their distribution in space. A student could measure and describe algal species traits such as nutritional value, toughness, and light absorption qualities and relate them to abundance with depth in the intertidal or subtidal environment. Students with AAUS diving certification can potentially pursue a project that includes underwater fieldwork. Past REU students have conducted studies on kelp detritus production, stable isotope dynamics in organisms, and diet studies of kelp forest species.
Typical REU project: Students can choose projects based on their interests and the types of skills they would like to develop. For example, a student with more mathematical and conservation interests may choose to work on models of fisheries economics as fish stocks shift in response to climate change. A student who is more interested in microbial ecology and would like to gain experience in the lab may prefer to work with our experimental systems, culturing ciliates and testing hypotheses about how prey types affect growth and photosynthetic rates.
Example project: Population genetics of Pisaster ochraceus during the Sea Star Wasting Disease (SSWD) Epidemic.
The sea star wasting disease (SSWD) event of 2013-2014, one of the largest known marine disease epidemics, is responsible for unprecedented large-scale declines in Pisaster ochraceus populations ranging from Alaska to Baja California, Mexico (http://seastarwasting.org). In many locations, this outbreak correlated with warmer sea surface temperatures. A relationship between thermal tolerance and the expression of the elongation factor 1-α (EF1α) has been identified in other metazoans. Furthermore, previous work suggests that an insertion mutation in an intron of EF1α is lethal when homozygous, but is maintained in the population through apparent overdominance. That is to say, heterozygous individuals were less likely to develop SSWD. An REU student will use standard molecular biology approaches to student the impacts of SSWD on the genetic diversity at the EF1α locus and its possible relationship to disease resilience.
Global climate change causes a shift in ocean surface temperature, carbonate system, light regimes and nutrient stoichiometry. These changes synergistically influence phytoplankton – the base of the marine food web – in a manner that is not fully understood. We are in the process of assessing this synergistic influence on phytoplankton in a series of experiments that focus on population dynamics and photochemistry of phytoplankton cultures. Potential REU projects would be designed as independent, hypothesis-driven experiments that would tie in with this work. While we are open to new ideas for the REU projects, we also have a few of our own that we could work on. For example, one project could involve assessment of photosynthesis in stressed cultures using well-established techniques, and compare the results with newer, faster, and high throughput techniques that enable rapid assessment of photochemical aspects of the cultures. A second example is an assessment of lipid content and lipid metabolism in phytoplankton cultures under different stressed conditions. Lipids are a good proxy for the nutritional content of a cell, and cells under different stresses may have the same quantity, but may not be of similar quality. Phytoplankton quantity under different environmental stressors may be the same, but the nutritional quality of these cells may not be the same. Consequently, consumption of this biomass by grazers in the ocean could have consequences that ripple through the marine food web. Using techniques in lipid staining, fluorometry, and flow cytometry, we could investigate how lipid profiles change in cells under different stresses. Skills gained from either of these experiments include phytoplankton culturing and manipulation of these cultures, flow cytometry, microscopy, fluorometry, photochemistry, and data analyses to address hypothesis-driven questions. Furthermore, the findings from these experiments would feed into our current experiments, and enable a comprehensive understanding of how the base of the marine food web is realistically impacted by a rapidly changing world.”
Typical REU project: Studies examining the impact of environmental stress have historically emphasized the critical effects of changes in the average environment on the physiology and ecology of single species. Yet many ecosystems are likely to experience changes in variability in these key environmental drivers as well as changes in the central tendency. However, little remains know about how variability in the environment can alter physiological, ecological, or ecosystem processes. The REU participant will lead a study to examine how changes in the mean and variability in temperature and oxygen will a key predator-prey interaction betweenCalifornia spiny lobster (Panulirus interruptus) and the purple urchin (Strongylocentrotus purpuratus).
An example of a project for REU participants in the Wilbanks lab could work with is our ongoing focus on the role of the microbes in controlling nutrient flux within the giant kelp forests of the Santa Barbara Channel. Giant kelp (Macrocystis pyrifera) forests are diverse and productive marine ecosystems that are important both ecologically and to key ecosystem services from fisheries to pharmaceuticals. UCSB is home to the Santa Barbara Coastal Long Term Ecological Research project (SBC LTER), an interdisciplinary program investigating the processes shaping the structure and function of the giant kelp forest ecosystem. Marine macroalgae are known to host dense, epiphytic biofilms composed of bacterial communities that are both distinct from that in surrounding water column and specific to individual species of macroalgae. We are broadly interested in the role of microorganisms in altering the flux of nutrients both into and out of kelp fronds. Potential REU projects could involve both field and laboratory studies of the examining the effect of elevated temperature and/or pCO2 on the flux of organic carbon and microbial community structure.