Rosenberg Institute Seminar Series at the Romberg Tiburon Center-Abstracts
The Barbara and Richard Rosenberg Institute for Marine Biology and Environmental Science Seminar Series brings leading local, national, and international scientists to a public forum at RTC to speak about the latest advances in science.
See abstracts or brief descriptions for select seminars below.
1/25: Investigating the diet of sea-floor microbes: Clues from isotopic and molecular composition of pore-water dissolved organic matterTomoko Komada, Professor, Department of Chemistry & Biochemistry, Romberg Tiburon Center and San Francisco State University
Marine dissolved organic matter (DOM) is a globally significant carbon reservoir, yet the mechanism of DOM accumulation remains unclear. Microbial processes within the seafloor have long been known to produce DOM, but the significance of this flux is not well understood, because of limited knowledge about the composition and reactivity of DOM generated within the sediments. We address this knowledge gap through isotopic and chemical analyses of pore-water DOM in two California Borderland basins with contrasting depositional patterns. At both sites, pore-water DOM consists of a complex mixture of labile to refractory moieties with variable radiocarbon ages. The composition of bulk DOM varies within and across sites, but the refractory component shows striking similarity regardless of site and sediment depth, and has an older radiocarbon age than bulk DOM. These findings suggest that sediments are important sources of pre-aged DOM that accumulates in the deep sea.
2/8: Shedding light on symbioses: lessons from a bioluminescent vertebrate-microbe associationAlison Gould, Postdoctoral Researcher, UC Berkeley
Virtually all organisms are dependent on symbioses with microorganisms for their success, yet the processes by which these essential interactions are established and maintained over time remain largely unknown. I present a pairwise symbiosis between a coral reef cardinalfish and a luminous bacterium as a model association to investigate the ecological mechanisms that help to maintain symbiont specificity over host generations. To do so, I integrate field studies to define key attributes of the host’s behavioral ecology and life history in Okinawa, Japan with recently developed genomic methods (restriction site-associated sequencing, “RAD-Seq”) to test the hypothesis that the fish’s ecology genetically structures populations of its facultative symbiont over time and space, consequently promoting the specificity of the association. Results indicate that resident populations of adult fish enrich the surrounding reef water daily with their excess luminous symbionts and that larval fish disperse significant distances as a cohort to non-natal reefs and acquire a symbiont from the locally enriched water near their settlement site. Ultimately this study highlights the role of a host animal in structuring natural populations of its bacterial symbiont, thereby promoting the specificity of this bioluminescent vertebrate-microbe symbiosis over host generations.
2/15: Linking sensory neuron plasticity to adaptive, injury-induced behavior in cephalopodsRobyn Crook, Assistant Professor of Biology, San Francisco State University
Most animals will experience sub-lethal injury at least once in their lives. Injured animals incur multiple fitness costs, including increased predation risk, decreased foraging efficiency and reduced reproductive success. Behavioral changes that offsets these costs, even partially, are therefore likely to 1) be under strong selection, 2) be highly conserved and 3) produce measurable adaptive benefits. Although injury-induced behaviors are common and widespread, their neural mechanisms remain poorly understood. Work in my laboratory at SF State aims to identify the mechanisms and functions of injury-induced behaviors in cephalopod molluscs. Cephalopods’ soft bodies are vulnerable to injury, their behavior is highly plastic, and their nervous system is comparably complex (but independently evolved and structurally unique) to that of vertebrates. However, many cellular mechanisms of plasticity are conserved among molluscs and vertebrates. Thus cephalopods are uniquely placed to provide novel insights into strongly selected, highly conserved mechanisms of injury-induced behavior that in mammals may include pain, anxiety and other complex affective states. Recent studies combine electrophysiological manipulations of plasticity in nociceptive input, with measurements of changes to neural signal controlling motor circuits. In behavioral studies, we are looking at the duration and context of injury-induced behaviors that alter defense, foraging and reproduction, to measure the fitness costs of injury and the adaptive value of injury-induced neural and behavioral plasticity.
2/22: Sea-level rise and Pacific coast salt marshes: impacts on plant productivity, community structure, and decompositionChristopher Janousek, Research Associate, Department of Fisheries and Wildlife, Oregon State University and Western Ecological Research Center, USGS
Salt marshes provide valued ecosystem functions and services including food web support, storm protection, nutrient cycling, and carbon sequestration. These functions and services may be threatened by sea-level rise if vertical marsh accretion cannot keep pace with rising water levels. Through observational, experimental, and modeling approaches we are assessing inundation and salinity effects on plant growth, plant fecundity, vegetation composition, and decomposition of plant organic matter across the Pacific coast. Our on-going work suggests the following general conclusions: (i) Inundation and salinity effects on plant growth vary by species, suggesting that marsh vulnerability likely varies spatially and that local marsh species composition may change with relative sea-level rise. (ii) Increasing salinity may interact with rising seas to lower plant productivity and reduce plant diversity. (iii) The cycling of salt marsh carbon through decomposition may be affected by a suite of abiotic and biotic factors including inundation, salinity, plant abundance, and plant composition. Our results help further understanding of how marsh structure and function may be impacted by climate change at local and regional scales along the Pacific coast. Such information is critical for informed tidal marsh management, habitat restoration, and adaptive responses to coastal climate change.
3/1: Restoration of native species in highly modified estuariesChela Zabin, Smithsonian Enviromental Research Center
Restoration frequently occurs in habitats that have been dramatically altered by human activities, including the introduction of non-indigenous species (NIS). NIS can pose threats to native species as competitors, predators, or ecosystem engineers. When eradication of NIS is not tractable, one potential tool for restoration practitioners is to take advantage of environmental conditions that alter the impacts of NIS on species targeted for restoration. I’ll discuss investigations of this option for native oyster (Ostrea lurida) restoration in three California bays and implications for restoration design.
3/8: Indigenous Knowledge of Marine Systems from Coastal Tribes and Canoe Cultures
Melissa K. Nelson, Ph.D., Associate Professor of American Indian Studies, SFSU
Pacific Ocean Tribes from the Coast of California to the Islands of Hawaii and around the Pacific Rim have long-term ecological knowledge and marine management systems. They harvest fish, seafood, and seaweed for food, navigate their canoes through coastal waters, and hold a deep cultural and spiritual connection to the Ocean through intergenerational practices based in ethical values imbedded in oral traditions. This talk will highlight coastal environmental changes and share tribal responses to climate disruption with particular attention to the iconic abalone, access to seaweed, and revitalization of canoe traditions.
3/15: The economics of sea level rise: A case study in southern Monterey BayPhilip King, Ph.D., Associate Professor in Economics at San Francisco State University
A brief overview of the issues involved in any economic analysis of sea level rise, followed by a specific application in southern Monterey Bay. The study examines the benefits and costs of differing adaptation strategies over four reaches in southern Monterey Bay. The economic benefits include recreation, ecological value and protection of private and public property. Under a wide range of plausible scenarios and assumptions, we find that coastal armoring is not cost effective. In most cases, retreat is the best option.
4/5: Ocean acidification: Science, solutions, and stepping out of our comfort zones
Tessa Hill, UC Davis
Recent work has focused on the potential consequences of reduced ocean pH that result from ongoing influx of anthropogenic carbon dioxide (CO2) into seawater (termed 'ocean acidification', or OA). Research along the West Coast has brought into sharp focus the potential local consequences of highly acidified seawater for aquaculture operations and California ecosystems more broadly. In response, states have mobilized in developing policy and science recommendations, with research efforts shifting to defining strategies for coping with this issue. For example, seagrass beds have been highlighted as potential "OA refugia" for their capability to buffer acidified waters. These ecosystem services are based upon the assumption that seagrasses fix carbon through photosynthesis, thereby effectively reducing the CO2 load in seawater, and that seagrass beds can also 'trap' carbon in below-ground sedimentary reservoirs.In this talk, I will review some of the science of OA, potential local solutions including the role of vegetated habitats, and provide a call for marine scientists to step out of our 'comfort zones' in addressing problems of major societal significance.
Sherry Tamone, Professor of Biology, University of Alaska Southeast
4/26: Applications of endocrinology to the management of commercially important crustaceans in Alaska
Commercially important crustaceans in Alaska include but are not limited to red king crab, snow crab, Dungeness crab, Tanner crab and Northern spot shrimp. Crab fisheries are size selected male only fisheries while all sexes of shrimp may be harvested. The Tanner crab (Chionoecetes bairdi) and northern spot shrimp (Pandalus platyceros) both undergo male specific sexual differentiation that is important to their life history and to the fishery, and these life history events can be studied through their endocrinology. Molting hormones (ecdysteroids) regulate growth in all crustaceans. In crabs such as Tanner and snow crabs, these hormones can be used in association with morphometrics to distinguish terminally molted male crabs, a life history stage distinguished by an allometric increase in chelae size. Sexual differentiation of male crustaceans is mediated by the insulin-like androgenic gland hormone (IAG), a product of the androgenic gland (AG). The role of this hormone is to promote the male phenotype during the life history of the animal. For gonochoristic species such as C. bairdi, and protandric species such as P. platyceros, IAG is thought to be the hormone responsible for promoting spermatogenesis and secondary sexual characteristics (such as the large claw morphology of C. bairdi). In protandric shrimp, in which functional males become functional females, the mechanism for transition from male to female is hypothesized to be the degeneration of the AG; thus elimination of IAG. Professor Tamone will present data on our current understanding of the endocrine basis for sexual differentiation in Tanner crab and spot shrimp.
The Seminar Series is supported by generous contributions from the Barbara and Richard M. Rosenberg Institute at the Romberg Tiburon Center, San Francisco State University