Seminars

Watch the Live Stream here or here

Abstract:

Biological dinitrogen (N2) fixation is a critically important component of the marine N cycle, as it supplies readily-available nitrogen (N) and can support primary productivity. N2 fixation is mediated by some Bacteria and Archaea, referred to as diazotrophs. These specialized single-celled organisms convert nitrogen gas from the atmosphere and convert it to biologically available nitrogen via nitrogen fixation. Marine nitrogen-fixing microbes inhabiting the well-lit surface ocean have diverse physiologies, from free-living autotrophs to particle-bound heterotrophs to symbiotic associations with eukaryotes, and few cultivated marine nitrogen-fixers are available to study in isolation. Their distributions and nitrogen-fixing activities are controlled by a complex interplay between physical and chemical controls and biological interactions that vary from species to species. My research uses cultivation-independent techniques and biogeochemical rate measurements to advance our understanding of the environmental drivers behind the distribution and activity of some of the most enigmatic nitrogen-fixing taxa. Today I will talk about some recent research centered on the importance of enigmatic marine nitrogen-fixing symbioses in both oligotrophic and coastally-influenced ecosystems.

Bio:

Kendra is a marine microbial ecologist studying specialized microbes that convert nitrogen gas into bioavailable nitrogen, which is a vital process supporting oceanic primary productivity. Her research focuses on understanding the ecophysiology of poorly understood nitrogen-fixing microbes, an effort fundamental for improving our ability to predict the magnitude and distribution of nitrogen fixation in contemporary and future oceans. Many nitrogen-fixers have yet to be isolated in culture, so Kendra’s research relies on extensive field work and applying cultivation-independent techniques to detect and study these cryptic microbes. Kendra’s uses single-cell rate measurements, targeted molecular techniques, metagenomics, and biogeochemical rate measurements to enable integration across huge spatial scales in the ocean.

Watch the Live Stream here or here

Abstract:

Cal Poly Humboldt has a culturally diverse student body that has led its faculty and staff to pursue the creation of a culturally sustaining environment. In order to achieve this goal, Humboldt first partnered with ESCALA, a professional development organization, to transform our instructional culture to benefit Latinx and Hispanic students, and then, developed an internal program called Creando Conciencia (Create Awareness, in Spanish) to continue this effort. Besides these university-wide efforts, in our lab we have partnered with tribal nations, and city, state and federal institutions in order to provide our diverse students with the best learning environment possible. In this presentation, I will discuss two projects describing the status of Night Smelt and Redtail Surfperch in sandy beach surf zones in Humboldt and Del Norte counties, that our students are currently carrying out. These two fish species are of cultural, commercial and ecological importance, who despite inhabiting the same habitat appear to be experiencing opposite population trends. Finally, I will briefly introduce a new program funded by a University of California Office of the President California Climate Action Seed grant that will allow us to expand our collaborations to five coastal tribal nations and will provide capacity building and priority species research in marine and estuarine habitats.

Bio:

I am originally from Guayaquil, Ecuador where I obtained a B.Sc. in Biology at the University of Guayaquil. Thanks to a Fulbright Scholarship, I moved to Charleston, Oregon to pursue a M.Sc. in Marine Biology at the University of Oregon’s Oregon Institute of Marine Biology. I then moved two hours north, to Newport Oregon, where I obtained a Ph.D. in Fisheries Science from Oregon State University’s Hatfield Marine Science Center. After finishing my Ph.D., my family and I moved to Mount Pleasant Michigan, where I was a postdoctoral fellow at Central Michigan University, and Guayaquil, Ecuador, where I was a research and teaching fellow at Escuela Superior Politecnica del Litoral. Before joining Cal Poly Humboldt, I worked at the Charles Darwin Research Station (CDRS) in Galapagos, Ecuador, as a Senior Fisheries Ecologist. During that time, I was also the interim science coordinator for CDRS for nine months, and participated in the sharks, seabirds, seamounts and climate change programs. These experiences have led me to pursue research geared towards high-use and/or low-information/data-limited fisheries species, and towards the provision and analysis of vital early and adult life history data of fishes and crustaceans, especially with respect to impacts from local fishery pressures and climate change. In order to achieve this goal, I use a combination of field, laboratory analysis and numerical modeling approaches.

Watch the Live Stream here or here

Abstract:

Due to the public health risks of wastewater contamination of coastal waters worldwide, there is a need for rapid tracking of sewage-laden flows. Fluorescence-based submersible sensors have been used for monitoring organic contaminants in natural waters; however, their potential to serve as a real-time warning of high bacteria concentrations and wastewater pollution under estuarine conditions with tidal influence remains to be evaluated. The Tijuana River Estuary has been plagued by decades of cross-border sewage flow that poses major public health risks for beach goers, Navy Seals, and border patrol agents, and has resulted in long-term beach closures on both sides of the US-Mexico border. This study assessed the use of submersible, in-situ tryptophan-like (TRP) and humic-like (CDOM) fluorescence sensors for tracking fecal indicator bacteria (FIB) concentrations in real-time in the Tijuana River Estuary during three conditions: 1) dry weather without cross-border sewage flow, 2) dry weather with cross-border flow, and 3) wet weather with cross-border flow. FIB concentrations of samples collected during scenario #2, dry weather with cross-border flow, were most significantly correlated with submersible TRP and CDOM sensor fluorescence. TRP and CDOM fluorescence were also measured using a benchtop, scanning fluorometer with instrument corrections, which yielded significant correlation (p < 0.001) with FIB concentrations under all hydrologic conditions, reflecting the superior performance of the benchtop instrument. Regular maintenance conducted weekly or fortnightly was required to minimize sensor fouling. Also, the presence of high strength wastewater resulted in an inner filter effect, which requires post-processing corrections or data flagging as part of quality control efforts. Overall, we conclude that TRP and CDOM sensors are currently able to provide real-time warning of sewage contamination. However, quantifying the magnitude of contamination is not yet possible in real-time, and efforts are underway in our research groups to achieve this goal.

Watch the Live Stream here or here

Dr. Liz Alter is a marine evolutionary biologist, Assistant Professor of Biology at California State University, Monterey Bay and a Research Associate at the American Museum of Natural History in New York. Her research focuses on understanding how biodiversity is generated and maintained, particularly in oceans, estuaries and rivers, using the tools of genomics. Dr. Alter serves as a Commissioner on the Fish and Wildlife Advisory Commission of Santa Cruz County, as well as the Scientific Advisory Board of the Billion Oyster Project, which seeks to restore coastal ecosystems while training high school students in marine science. She holds a PhD from Stanford University’s Hopkins Marine Station, and an MS from UC Berkeley.

Watch the Live Stream here or here

Danielle Haulsee is the Chief Science Officer at Hubbs-SeaWorld Research Institute, specializing in fisheries oceanography and the spatial and behavioral ecology of marine animals. She obtained her Ph.D. in 2017 from the University of Delaware's College of Earth, Ocean, and Environment, focusing her doctoral work on characterizing the movement ecology and social dynamics of a coastal top predator found along the East Coast of the U.S., the sand tiger shark. A key feature of her research is integrating advanced bio-logging (using tags carried by animals to record information), remote sensing and underwater robots to study the impact of a dynamic ocean on the occurrence and distribution of marine fish and sharks. Using these technologies, Danielle focuses her research on tackling applied research questions, contributing to bycatch reduction strategies, impact assessments of offshore wind development, and working towards more effective dynamic ocean management strategies. Her work spans multiple oceans, from studying the movement ecology of sharks and sturgeon in the Atlantic, to the fisheries ecology of billfish in the Eastern Tropical Pacific, to the oceanography of the White Shark Cafe in the Central Pacific and off the Nansen Ice Shelf in Antarctica.

Watch the Live Stream here or here

Natalia Llopis Monferrer is a postdoctoral fellow at the Carbon Flux Ecology Lab at MBARI. She received her PhD in Chemical Oceanography at the “Université de Bretagne Occidentale” (France). Natalia is a motivated biogeochemist with a passion for understanding how plankton influences the cycling of certain elements in our oceans, working to improve our knowledge of ocean biogeochemical cycles. Her research focuses on the ecology of silicifying Rhizaria, which are eukaryotic, mostly heterotrophic single-celled organisms, globally distributed, dwelling chiefly in the open ocean, from the surface down to bathypelagic depths. The goal of her postdoctoral project at MBARI is to characterize the silicification process in Rhizaria by combining different techniques: (i) exploration of genomic data to characterize the SITs of Rhizaria at different environmental conditions, (ii) targeted collection and maintenance of these delicate protists using cutting-edge technologies (e.g., remote operated vehicles, microfluidics) and, (iii) state-of-the-art imaging techniques, based on optical, fluorescent and electron microscopy, to examine silica deposition at a cellular level. This project will shed light on the little-known ecology of individual Rhizaria, and their ultimate role in relation to diatoms in the global plankton ecosystems and biogeochemical cycles.

Watch the Live Stream here or here

Kyle Cavanaugh is an Associate Professor in the Department of Geography at University of California, Los Angeles and Vice Director of the UCLA Marine Center. He received his PhD in Marine Science from the University of California Santa Barbara in 2011 and then completed a postdoc at the Smithsonian Institution. His research involves using satellite imagery to study the drivers and consequences of changes in coastal foundation species such as giant kelp forests and mangroves.

Watch the Live Stream here or here

Dr. Tom Turner received his Ph.D. in population biology from UC Davis in 2008. After finishing his postdoc at the Gregor Mendel Institute in Vienna, Austria, he became an assistant professor at UC Santa Barbara in 2009 and in 2015 began work as an associate professor. His work focuses on the diversity, systematics, and ecology of California sponges, particuarly the description of new species in shallow-water ecosystems such as kelp forests.