Returning Grads


Ben Grupe (Chief Scientist)

Cruise Role: 

As chief scientist on the second leg of SDCoastEx, Ben will be working to coordinate research and sampling to maximize the scientific objectives accomplished over the seven-day cruise. This includes preparing a balanced cruise sampling plan, deciding when the Melville goes to what stations, and communicating with the captain and resident technicians so that everyone is on the same page. A fifth-year Ph.D. student, this is Ben’s eleventh research cruise, but first opportunity to lead as the chief scientist.

Research: 

Ben has been in Lisa Levin’s lab in the Biological Oceanography program since 2008 and will finish his Ph.D. sometime in 2013. Ben is interested in the ecology of chemosynthetic ecosystems, and has previously researched seep communities off Costa Rica and Oregon. At these sites, he has deployed experimental substrates to see how different aspect of the environment affect the colonizing macrofauna (animals larger than 0.3 mm). He has also used stable isotopes to track food web relationships between different kinds of worms, crabs, snails, limpets, and bacteria that are common at methane seeps.

Ben's science goals on this cruise are mainly related to the seep we discovered 20 miles off San Diego's coastline in July 2012. We will revisit the site to collect sediment cores and describe the geochemistry, microbiology, and invertebrate communities of this particular seep, to place the environment into context with others on the U.S. west coast. We also hope to use the ROV to explore for new methane seeps. We hope that seeps found near San Diego might become long-term research sites, allowing Scripps researchers to venture into these exciting deep-sea ecosystems more easily than in the past.


Christina Frieder

Cruise Role:  

While Ben is away at a conference in New Zealand, Christina will be the stand-in Chief Scientist for the first leg of the journey.  She is a Ph.D. student at Scripps Institution of Oceanography, and has participated in many research cruises that have been as far south as Chile and as warm as Costa Rica. 

Research: 

Christina’s personal research goals on the cruise are to assess biological community responses of animals living within the sediment on the seafloor to sharp changes in oxygen and carbon dioxide.  To do this she will use sediment cores collected with the multicore along a transect through the Oxygen Minimum Zone to investigate macrofaunal (a.k.a animals less than 300 µm) abundance, diversity, biomass and taxonomic composition in relation to the oxygen and carbon dioxide environment. This research will contribute to a global dataset of macrofaunal patterns across OMZs and support her dissertation research that focuses on implications of low oxygen and high CO2 for marine invertebrates.


Alexis Pasulka

Cruise Role: 

Alexis will be working with the Seep Team to locate cold seeps near San Diego using the ROV and collect samples at these sites.

Research: 

Single-celled eukaryotes, also known as protists, are the predecessors to multicellular plants and animals. Animal-like (heterotrophic) protists are important grazers and nutrient recyclers in marine ecosystems; however, we know very little about the distribution, diversity or trophic roles of these protists below the sunlit surface of the ocean. Chemosynthetic ecosystems such as methane seeps are “hot spots” of life on the seafloor and provide a unique environment to study the extent to which protists are adapted to live and interact with other organisms under extreme conditions – dark, low oxygen, high concentrations of toxic chemicals. The overall goal of her dissertation is to provide an understanding of the ecology of heterotrophic protists within methane seep ecosystems. She is interested in examining the distribution and diversity of heterotrophic protists in relation to geochemical (e.g., methane and sulfide concentrations) and biological variables (e.g., prey availability) within methane seep ecosystems. Samples collected during the San Diego Coastal Expedition cruise will enable her to compare protistan communities collected from San Diego seeps with those she has collected from Oregon seeps. Because these seeps exist at different depths and under different oxygen concentrations, she can gain further insight into how variations in chemical (e.g., oxygen concentrations) and physical (e.g., depth) factors influence the composition and diversity of seep protists.


SungHyun Nam

Cruise Role: 

SungHyun will be collecting water samples and data from CTD casts, ADCP, and all the meteorological measurements during the cruise.

Research: 

Better understanding of spatiotemporal variability in hydrography is particularly important for addressing underlying mechanisms that drive changes in biogeochemical parameters like DO, pH, DIC, etc. The question Sungyun will answer on the cruise is: how is the spatiotemporal structure of physical parameters characterized and associated with changes in biogeochemical parameters on the San Diego continental margin? He will use data collected from CTD casts to examine spatial structure and the relationship with biogeochemical parameters. Combined with time series data collected at the Del Mar and other moorings, physical processes at multiple scales affecting the change in biogeochemistry will be addressed. These processes include, but are not limited to, internal waves/tides, sea/land breeze-driven oscillations, temporal upwelling and relaxation, seasonal upwelling, interannual climate events (El Niño/La Niña), and decadal trends.


Michael Navarro

Cruise Role:  

Mike will lead research using the Remotely Operated Vehicle (ROV) for biological surveys along the seafloor of San Diego’s continental shelf.     

Research:  

As the climate changes, the environment of Southern California Current System, including the coastal waters of San Diego, may be becoming less suitable for coastal dwelling organisms including those that we eat (fished species).  More acidic, warmer seawater that holds less oxygen (ocean acidification, warming, deoxygenation, respectively) poses a triple threat for ALL organisms that live here.  The susceptibility of most species to these factors is unknown BUT it is urgently needed to ensure that policies protect valuable natural resources, including those valued economically.  As a starting point, Mike will address his research questions to gather evidence for species that inhabit areas that are exposed to these threats AND that are important economically and ecologically.  Initially Mike will focus work on the market squid, Doryteuthis opalescens, and the spot prawn, Pandalus platycerous.  Both species are valuable commercial fishery species and are known to dwell on the seafloor.  His research questions include: What are the vertical distributions of the market squid and the spot prawn in relation to acidic, deoxygenated seawater (e.g. Oxygen Minimum Shoaling (OMZ))?  Does this relationship change seasonally? 


Yuichiro Takeshita

Cruise Role

Yui will be working with the CTD team to measure pH in the water column. In addition, he will field test the “Deep-Sea Durafet”, a novel pH sensor that can make continuous measurements up to 3000m.

Research: 

Yui is interested in advancing autonomous chemical sensor technology for ocean monitoring applications. Autonomous sensors are devices that run on internal power for extended periods of time without a human operator. He has been heavily involved in the development of the SeaFET and SeapHOx, (chemical sensor packages that measure pH (and dissolved oxygen in the case for the SeapHOx) for months) and over 90 of them have been deployed worldwide. He has helped deployments of the SeapHOx in the kelp forests in La Jolla, moorings off the coast of California, Maui, Palmyra, and the Yucatan peninsula. 


John Ballard

Cruise Role: 

John will be collecting bottle samples from CTD casts for oxygen andcalcium measurements. He is also responsible for earning his sea legs, as this is the second adventure at sea for John and first as an SIO graduate student.

Research: 

John is a first year graduate student interested in developing new ways of measuring the chemical composition of the ocean including the carbonate system, pH, and nutrients. For instance, this cruise will be the first application of a calcium titration system developed earlier this year. Chemical concentrations and changes in space and time provide information about physical, chemical, and biological dynamics in a salty soup of atoms. Cellular respiration requires an electron acceptor, molecular oxygen in aerobic metabolism, to break down organics and produce energy. Many marine organisms form shells and skeletons by combining calcium and carbonate ions. The amount and quality of information that describes the ocean system is ultimately dependent on measurement methods and instrumentation.


Kelley Gallagher

Cruise Role: 

As a part of the OMZ team, Kelley will be collecting core sediment samples using the multicorer. Kelley has participated in a number of field trips to collect sediment samples from diving depths, but the San Diego Coastal Expedition will be her very first cruise. 

Research: 

Kelley is a third year graduate student in Paul Jensen’s lab. She studies a group of bacteria called actinomycetes that live in terrestrial soils and marine sediments. Actinomycetes are an unusual group of bacteria because they dedicate a large amount of energy to the production of complex small molecules. These molecules come in an incredible diversity of structures that are sometimes used as antibiotics, anti-cancer agents, or as a variety of other pharmaceuticals. Although these small molecules are often useful to humans, no one knows why they are useful to the bacteria that make them. For example, they may be acting as warfare agents to kill competitors, or as a part of the chemical language that bacteria use to communicate, or used to survive periods of low oxygen. Although actinomycetes have been found in marine sediments, these environments can vary greatly, and no one knows which sediment environments they prefer. To answer some of these questions, during the cruise Kelley will be looking to see which environmental conditions in the sediments best support actinomycete growth, and in which environmental conditions actinomycetes produce some of these small molecules. In addition, because this cruise will allow her to search sediments deeper than what is commonly sampled for actinomycetes, she hopes to find previously uncultured groups of actinomycetes that will be screened for the production of new pharmaceutically active molecules.


Amanda Netburn

Cruise Role: 


Amanda will be using the ROV to collect visual data on the distributions of animals living in mesopelagic (200-1000 m) depth. These data will be correlated with environmental data collected by the CTD team.

 

Research: 


In all of the world’s oceans, there exists a deep aggregation of unusual fishes, crustaceans and gelatinous organisms that live suspended in the water column. This layer is often referred to as the “deep scattering layer (DSL),” because it was first revealed by the strong scattering of sound reflected from active sonar systems. Many of the DSL animals are essential prey to organisms with commercial and conservation interest, such as tunas, sharks and whales, yet little is known about their population dynamics and susceptibility to anthropogenic changes to the oceanic environment. Amanda's advisor, Dr. J. Anthony Koslow, recently initiated a midwater sampling program in the waters offshore of San Diego. Our lab uses trawl nets and active acoustics to sample the animals. The trawl nets are efficient at capturing many of the fishes and crustaceans, however many fragile gelatinous organisms are destroyed in the nets. On the SDCE cruises, Amanda will use the ROV to get a complete picture of the finescale vertical structure of the midwater ecosystem at the boundary of the continental margin.  Along with measurements of environmental variables, the visual surveys will provide her with data to help understand how environmental factors shape the vertical habitat space for deep open ocean animals. Further, patterns discerned through data collected on this cruise will contribute to our understanding of how the predicted deoxygenation, acidification and warming may affect open ocean ecosystems.



Kirk Sato


Cruise Role


Kirk will investigate the relative abundance and distribution of benthic megafauna and demersal fishes on the continental shelf and slope. He will co-lead the Shelf team 
with Mike Navarro during otter trawl sampling and on ROV benthic operations. 

 

Research: 


Kirk is a PhD student in Dr. Lisa Levin's lab at Scripps.  The ocean interior is experiencing a rapid decrease in dissolved oxygen and these oxygen limited zones are expanding to shallower depths. What does this mean for benthic taxa and populations that conduct aerobic metabolism? Does the oxygen concentration in the surrounding water limit certain species distributions? If so, which species and at what oxygen concentration?  Kirk’s research questions are motivated by the need to consider these metabolic thresholds, in addition to CO2 stress and pH stress, in structuring low oxygen communities, especially as OMZs expand in future decades.


Jillian Maloney

Cruise Role: 

As a member of the Methane Seeps Team, Jillian will be assisting with the collection, processing, and interpretation of multibeam bathymetry and sub-bottom sonar data. With these data, Jillian will help identify features on the seafloor that may indicate the presence of methane seeps.

Research: 

Jillian is a Ph.D. student at Scripps Institution of Oceanography studying tectonic and sedimentary processes, and their impact on biological communities. In addition to helping find methane seeps, the geophysical data collected during the cruise will be used by Jillian for her research on the tectonics of the California Continental Borderlands region. This offshore region has a complex tectonic history, but the slip rates and recency of faulting on offshore faults remain poorly understood. This research will help to understand better the tectonic framework offshore San Diego, and to assess the geohazard posed by offshore faults on the densely populated San Diego region.

Lisa Levin

Cruise Role:

As faculty mentor for this cruise, Levin will be available to all students for consultation on matters ranging from event scheduling and sample processing to cruise reporting. She will try to help students acquire skills needed for cruise leadership,  assist with OMZ sampling, provide seep expertise, and mentor her grad students to optimize their cruise outcomes.

Research:


A professor at Scripps Institution of Oceanography (SIO), Lisa Levin studies the animals on the deep and shallow seafloor.  Levin received her PhD from SIO, conducted postdoctoral studies at Woods Hole Oceanographic Institution, taught for nine years at North Carolina State University, and returned to SIO as a faculty member in 1992. Much of Levin’s deep-sea research focuses on the structure and function of continental margin ecosystems , including habitats such as methane seeps and oxygen minimum zones. She is currently addressing climate change consequences for deep-sea systems and promoting stewardship of the deep ocean.  Levin has been active in the  Census of Marine Life Continental Margin Ecosystems (COMARGE) and Chemosynthetic Ecosystem Science (ChEss) programs and the international follow on SYNDEEP and INDEEP programs. She has participated in more than 35 cruises in the Pacific, Indian and Atlantic Oceans,  many as chief scientist. Back at Scripps, she also investigates aspects of populations connectivity, ocean acidification and deoxygenation, and wetland ecology and restoration.



Carlos Neira

Cruise Role:

Carlos Neira as part of the OMZ team will be collecting sediment samples from a multicorer to study the metazoan meiofauna of the OMZ and other settings such as methane seeps.

Research:

Carlos, an associate project scientist at Levin Lab, is interested in the continental margin meiofauna, primarily those of the eastern Pacific OMZs. Present knowledge of meiofaunal ecology along the EP OMZ is not commensurate with the crucial role this group plays in the benthic ecosystem. As oceanic oxygen levels decline globally and OMZs expand, meiofauna are likely to displace macro- and megafauna, with likely consequences for essential ecosystem functions. The set of samples collected during this cruise together with meiofaunal samples previously collected along the eastern Pacific margin (Chile to Oregon) will be used to examine in what extent low oxygen/high organic matter conditions within the OMZs select for specific meiofaunal patterns of abundance, taxonomic composition, diversity, biomass, feeding modes. The research will fill a major gap in the knowledge of meiofaunal ecology and contribute to a better understanding of the influence of hypoxia thresholds on marine biodiversity, of growing importance in the face of current OMZ expansion due to climate change.   


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