Spring 2019

Spring 2019 Seminars

A-340  Earth & Marine Sciences Building
Fridays, 10:40 a.m. - 11:45 p.m. 

Seminar Coordinator: Jerome Fiechter   fiechter@ucsc.edu

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

    April 5

  • Dr. Brian Wells, Fisheries Ecology Division, NOAA Southwest Fisheries Science Center

    “Process studies to quantify ecosystem dynamics and inform Ecosystem-Based Fishery Management in the central California Current”

    A decade of work on ocean ecology of California salmon is used to build a conceptual model of how salmon are influenced by climate variability and change, the abundance and distribution of their predators and prey, and fisheries. This conceptual model is used to identify critical gaps in understanding and research activities and technical approaches needed to fill them. I then discuss emerging risks and vulnerabilities facing salmon fisheries and propose analysis frameworks for evaluating and communicating risks and tradeoffs to decision makers. Research in this area is expected to develop tools and information products that can be used operationally in salmon fisheries management, and ultimately form a central part of the adaptive management system needed to improve resilience of salmon populations and the fisheries they support.

  • April 12

  • Dr. Lisa Schwarz, UC Santa Cruz, Department of Ecology and Evolutionary Biology

    "Environmental Variability To Predict Population Changes For Marine Mammals: Beyond Climate Change"

    Many studies have shown that marine mammals respond behaviorally to single anthropogenic disturbance events. In addition, exposure to multiple disturbances that cause seemingly minor behavioral changes could lead to reduced reproduction and lower survival of individuals. Man-made disturbances that reduce foraging success (reduce energy input) are of particular concern, and individuals may not be able to compensate for lost energy intake, especially if foraging is limited in space or time. Several methods have emerged to address disturbances that reduce foraging. Broad, long-term marine mammal studies can use inter-annual environmental variability as the source of a natural experiment to help quantify the links between environment, prey availability, and health and demographics. In addition, Stochastic Dynamic Programming models are an effective way to characterize the end points of natural selection (lifetime reproductive success), linking environment, physiology, and metrics of fitness. Several case studies provide insights in to the successes and challenges of such approaches.  

  • April 19

  • Dr. Juhee Lee, UC Santa Cruz, Department of Statistics

    Bayesian Sparse Multivariate Regression with Asymmetric Nonlocal Priors for Microbiome Data Analysis”

    We propose a Bayesian sparse multivariate regression method to model the relationship between microbe abundance and environmental factors for micro- biome data. We model abundance counts of operational taxonomic units (OTUs) with a negative binomial distribution and relate covariates to the counts through regression. Extending conventional nonlocal priors, we construct asymmetric non- local priors for regression coefficients to efficiently identify relevant covariates with their effect direction. We build a hierarchical model to facilitate pooling of information across OTUs and achieve parsimonious models with improved accuracy. We present simulation studies that compare variable selection performance under the proposed model to those under Bayesian sparse regression models with asymmetric and symmetric local priors and two frequentist models. The simulations show the proposed model does a good job of identifying important covariates and yields coefficient estimates with favorable accuracy compared with the alternatives. The proposed model is applied to analyze an ocean microbiome dataset collected over time to study the association of harmful algal bloom conditions with microbial communities.

  • April 26


  • May 3

  • Dr. Nyssa Silbiger, California State University Northridge, Department of Biology

    "pH"ingerprinting coastal oceans: connecting climate change, natural 
    variability, and biological feedbacks

    Coastal ecosystems persist in a highly dynamic environment, especially 
    with respect to pH. This high spatiotemporal variability of pH is driven 
    by complex physical and biological processes that complicate climate 
    change predictions. Using coral reefs and rocky intertidal ecosystems as 
    examples, I discuss several case studies that highlight how pH, in 
    combination with other anthropogenic stressors, affect ecosystem 
    functioning. Specifically, I focus on how ecosystem function is affected 
    by natural pH variability across multiple spatial scales, biological 
    feedbacks, and how a local stressor (nutrient enrichment) affects 
    biologically-driven pH dynamics. Understanding the natural variability 
    of coastal ecosystems and how organisms both drive and respond to 
    changes in pH is necessary to project how ecosystem functioning will 
    change in the future.

  • May 10

  • Dr. Tom Connolly, Moss Landing Marine Laboratories

    "Physical dynamics and biogeochemical impacts of poleward flow in the California Current System"

    Seasonal coastal currents in the California Current System transport water with diverse physical and biogeochemical characteristics from across the North Pacific. Currents flowing northward (or poleward) like the California Undercurrent carry warm and salty water from equatorial sources. This equatorial water strongly influences seasonal variations in nutrients, dissolved oxygen, and pH throughout the region. Although a great deal of past research has been devoted to characterizing this part of the ocean, the physical mechanisms that drive seasonal currents remain elusive. This presentation will compare patterns of seasonal variability throughout the California Current System, discuss potential forcing mechanisms, and highlight the biogeochemical impacts of water from different origins. These regional dynamics are also linked to surface currents associated with wind relaxation events, which are shown to influence variability of nearshore chlorophyll in Monterey Bay.

  • May 17

  • Dr. Andrew Hein, NOAA Southwest Fisheries Science Center

    Inferring ecological interactions in marine ecosystems

    Marine ecosystems consist of large numbers of species coupled to one another through ecological interactions. While we have a wide range of methods for determining which species are present in a given ecosystem, measuring the links between them is more challenging. New technologies for tracking and observing marine organisms in the field and generating realistic environments in the lab provide an opportunity to study these ecological interactions directly. In this talk, I will discuss methods that we are developing to infer ecological interaction rules from behavioral data, and emerging opportunities and challenges in applying these techniques to build a data-driven understanding of ecological interactions in oceans and rivers.

  • May 24

  • Dr. Mercedes Pozo Buil, UC Santa Cruz & NOAA Southwest Fisheries Science Center

    Forecasting California Current System Variability on Decadal to Centennial Timescales

    Given the strong recent interest in forecasting ocean conditions a decade or more in advance, it is critical to identify dynamics that drive ocean variability and predictability on these timescales. At  decadal timescales, observational data show that the advection of subsurface water mass anomalies can be exploited for decadal predictability in the California Current System (CCS). Using an ensemble of eddy-permitting model simulations, I establish the robustness of these previous results and estimate the predictable components controlling the propagation of the subsurface anomalies. For centennial timescales, I present a regional modeling framework, based on statistical and dynamical downscaling techniques, to generate climate projections for the CCS. I then describe projected physical ocean conditions for the CCS in the high-resolution regional downscaled projections, and compare them with the coarse-resolution global climate model outputs. Ultimately, these forecasts of ocean conditions are intended to provide decision-makers with information needed to develop effective long-term ecosystem and fishery management strategies.

  • May 31

  • Dr. Trond Kristiansen, Norwegian Institute for Water Research