Spring 2017 Ocean Sciences Seminar

Spring 2017 Seminars

A-340  Earth & Marine Sciences Building
Fridays, 10:40 a.m. - 11:45 a.m. (unless otherwise noted)

Seminar Coordinator: Phoebe Lam pjlam@ucsc.edu

For disability-related accommodations: call (831) 459-4730 or email rrobison@ucsc.edu

    Friday, April 7, 2017

  • Piero Mazzini, Assistant Professor, Romberg Tiburon Center for Environmental Studies

    **Special Location E&MS D250

    **Host Chris Edwards

    The Combined Effect of River Discharge and Wind Forcing in the Coastal Ocean

    Freshwater provided from river discharge influences the dynamics and circulation of most continental shelves around the world. It has profound effects on the transport and fate of materials and substances originated from rivers and estuaries, as well as on the ocean biogeochemistry and marine ecosystems. The effect of buoyancy forcing and its modification by windstress off the Oregon coast are studied here, with an emphasis on the downwelling season (fall/winter). Six years of underwater glider data are used in this study, from 2006 to 2012, bringing unprecedented high-resolution view of the downwelling season, allowing for the first time, the characterization of the Oregon Coastal Current.

  • *Special Seminar* Tuesday, April 11, 2017

  • Claudie Beaulieu, Asst. Professor, Ocean & Earth Science, Univ. of Southampton

    Detection of Climate and Oceanographic Change in the Big Data Era

    Natural variability in all aspects of the Earth system – including the climate system and ecosystems – presents a formidable challenge to the detection and quantification of change forced by industrial activities. Error in detection can disrupt concerted efforts to respond to the challenges of Earth system change, whereas statistically robust quantification informs our understanding of underlying mechanisms of change and helps to improve predictions into the future. The rate of observed climate change results from the superposition of natural and anthropogenic forcing and its robust estimation needs to objectively detect the timing of changes in the trend as well as their magnitude. Quantifying the rate of climate change is further challenged by “memory” within the climate system, which can lead to overconfidence in the detected change. In this talk, I describe a new approach to separate unsteady long-term change from memory, which clarifies a key point in the scientific debate related to the recent “hiatus” in warming.

    Marine ecosystems may also respond to climate change, but detecting these impacts is hindered by the long timescale of memory within the ocean such that time-series analysis of satellite data is still inconclusive as to the sign of change in ocean chlorophyll. Here I show how utilizing both temporal and spatial dependency in the available data reveals the full uncertainty in chlorophyll trends and highlights regions undergoing significant change. More generally, the targeted development of specific statistical techniques is required to process and make full use of the rapidly growing store of Earth system data from models and advancing observational platforms. Space-time modeling in particular is one of my main research directions for the promise it holds to improve detection of climate and oceanographic change in the era of big data. 

  • Friday, April 14, 2017

  • Jed Fuhrman, Professor, University of Southern California

    *Host: Marilou Sison-Mangus

    A Long Term Perspective on Recent Advances in Marine Microbial Ecology

    Over 35 years ago it was discovered that marine bacteria process about half of all the total marine primary productivity (or about a quarter of global productivity) via their uptake of dissolved organic matter and the “microbial loop.” There have been many discoveries since then (often by molecular genetic techniques), including the importance of marine viruses, multiple varieties of non-“extremophile” archaea that sometimes exceed bacteria in abundance locally, incredibly diverse picoplanktonic photoautotrophs, mixotrophs, ubiquitous rhodopsins for solar energy capture, and much more. I’ll briefly go over these historic discoveries and discuss recent work in my lab on seasonality and predictability of microbial populations and its interpretation, surprisingly rapid community changes during and after the spring bloom, the significance of microdiversity, and the need to use standards like “mock communities” in all microbiome analyses.

  • Friday, April 21, 2017

  • Kelly Benoit-Bird, Senior Scientist, Monterey Bay Aquarium Research Institute

    Resolving the Food Paradox in the Sea

    The average concentrations of biota in the ocean are generally low, a critical problem for ocean consumers. When we examine the biology with new tools guided by the predators themselves, we find that instead of being relatively devoid of life, the ocean is peppered with narrow hot-spots of activity. Small patches of plenty have impacts on ecosystems disproportionate to their contribution to the total biomass, providing the key to solving the experimentally demonstrated feeding paradox as well providing a mechanism for evolution in an apparently isotropic environment where there are no obvious barriers to gene flow, Hutchinson’s “Paradox of Plankton”

  • Friday, April 28, 2017

  • Yui Takeshita, Scientist, Monterey Bay Aquarium Research Institute

    Towards sustained autonomous measurements of net community production and calcification on coral reefs
    Net community production and calcification are fundamental ecosystem properties of coral reefs, yet understanding of the drivers of these key processes is hindered by the lack of methodology to make sustained observations with sufficient temporal resolution. In this talk, I will describe the development of the Benthic Ecosystem and Acidification Measurement System (BEAMS), an autonomous system that is capable of simultaneously measuring benthic net community production and calcification for weeks at 15 minute intervals. 

  • Friday, May 5, 2017

  • Colleen Durkin, Research Faculty, Moss Landing Marine Laboratory

    Linking phytoplankton with sinking particles and carbon export
    When phytoplankton are transported out of the surface ocean they sequester carbon from contact with the atmosphere and fuel deep sea food webs.  This talk will explore the consequences of plankton composition and physiology on carbon export and the mechanisms that lead to vertical transport. Integrating molecular and particle imaging approaches enables resolution of carbon export processes from the upper ocean all the way to the deep seafloor.

  • Friday, May 12, 2017

  • Isabel Reche Cañabate, Professor, Universidad de Granada

    Carbon sequestration in the dark ocean: production of chromophoric dissolved organic carbon and accumulation of transparent exopolymer particles

    During the circumnavigation Malaspina 2010, we explored the transformations of labile dissolved organic matter (DOM) into refractory compounds during the microbial metabolism (microbial carbon pump) using DOM optical properties (absorption and fluorescence). In addition, we quantified the C exports associated with transparent exopolymer particles into the dark ocean. Finally, we estimated the corresponding contributions to carbon sequestration of both processes. 

  • Friday, May 19, 2017

  • Colleen Hansel, Associate Scientist, Woods Hole Oceanographic Institution

    Reactive Oxygen Species in the Cryptic Cycling and Biomineralization of Manganese

    Manganese (Mn) oxides are widely distributed throughout the geologic record and in modern marine sediments and waters. Some microbes oxidize Mn(II) to form Mn oxides through the enzymatic production of the reactive oxygen species superoxide. Yet, while extracellular superoxide production is widespread in microorganisms, this production does not confer the ability to form Mn oxides. Instead, back-reaction between the products, Mn(III) and hydrogen peroxide, formed upon Mn(II) and superoxide reaction inhibits Mn oxide formation. In this way, ROS and Mn cycling are tightly coupled in natural systems, wherein the production and consumption of superoxide and hydrogen peroxide could be mediated by the recycling of catalytic levels of aqueous Mn – a so-called cryptic Mn cycle. The formation of Mn oxides therefore requires breaking this cryptic cycling through the enzymatic consumption of hydrogen peroxide and/or ligand-mediated stabilization of the Mn(III) intermediate. 

  • Friday, May 26, 2017

  • Jim Cloern, Senior Research Scientist, USGS

    Patterns and Processes of Ecosystem Variability in Estuaries: Lessons from Long-term Study of San Francisco Bay

  • Friday, June 2, 2017

  • Andrea Fassbender, Scientist, Monterey Bay Aquarium Research Institute

    Drivers and Sensitivities of Ocean Carbon Uptake

    The ocean is a large sink for anthropogenic carbon through the uptake of carbon dioxide gas across the air-sea interface, which occurs over a backdrop of natural carbon cycle processes. As a community, we are only beginning to understand how these natural processes are responding to persistent ocean warming and chemistry changes and what this means for the future efficiency of the ocean carbon sink and marine ecosystems. This talk will address interconnected chemical, biological, and physical aspects of ocean carbon uptake as well as relevant implications for deciphering signals of change.