A World Upside Down: The Floating Seafloor of the Urania Basin-April 25th

Ivano Aiello, Moss Landing Marine Labs

Moss Landing Marine Labs Seminar Series - April 25th, 2019

Hosted by The Vertebrate Ecology Lab

MLML Seminar Room, 4pm

Open to the public

Bio: Ivano teaches several graduate courses on different topics and methodologies concerning Marine Geology and cross-disciplinary fields in marine sciences. Ivano's teaching phyilosophy and the research conducted in the Geology Lab are multidisciplinary is the sense that students combine to different degrees geology with a variety of other disciplines in marine sciences (e.g. marine ecology, biology). Ivano's research has also a general interdisciplinary approach: Sedimentology/paleoceanography of upwelling biogenic sediments in Europe and the Pacific Rim (e.g. Monterey Fmt.), eastern equatorial Pacific and Peru Margin (ODP Leg 201), the sub-Arctic (IODP Expedition 323 in the Bering Sea). Relationships between geology and microbial activity in deeply buried marine sediments and other extreme environments. Past evidence of microbial activity preserved by authigenic precipitates in sediments (cold seeps). Geologic/geomorphology of central California rapidly changing costal environments including Elkhorn Slough, beaches and sea cliffs of Monterey Bay. Use of terrestrial laser scanning and 3D data analysis to asses small-scale geomorphologic change.

Abstract:

The Urania Basin (Eastern Mediterranean) is a Deep Hypersaline Anoxic Basin (DHAB) characterized by extreme physical and chemical conditions including very high temperatures (>50ºC), very high salinities (more than 5X seawater) and some of the highest methane concentrations ever recorded in the water column (up to 3.8 mmol/L). Although the Urania Basin is a classic example of DHAB and has been investigated multiple times in the past 30 years, a recent deep-sea expedition made some groundbreaking discoveries both in terms of the physics/geology of the environment as well as concerning occurrence and distribution of microbial life in arguably one of earth's most extreme and inhospitable environments.We found that the lower half of the deep water brine is filled with a very fine (~6µm), high-density (>1.6g/cm3) fluid mud mainly composed of floating modern and fossil species of coccoliths. Because of thermal convection and the very fine size of the coccolith particles, we hypothesized that without accelerating mechanisms (e.g. fecal pellets) the mud could stay in suspension for times longer than the slowest normal pelagic settling creating what looks like an ‘expansion’ of the seafloor several tens of meters into the brine. Based on a  diffusive-convective model, the origin of the Urania Basin stratification has be dated to 1650 years B.P., and may be linked to a major earthquake in the region. This deep-water basin characterized by an expansion of the seafloor into the water column, a 'zero-gravity' environment where particle are capable of staying in suspension for long times, and with a highly diversified microbial life that has more affinity to the deep subseafloor than to the water column could be a model system for life in other planets and moons (e.g. Europa).

 

 

Return of the “age of dinoflagellates”: unusual dinoflagellate dominance in northern Monterey Bay detected with automated imaging flow cytometry-May 2nd

Alexis Fischer, UC Santa Cruz

Moss Landing Marine Labs Seminar Series - May 2nd, 2019

Hosted by The Invertebrate Zoology Lab

MLML Seminar Room, 4pm

Open to the public

Alexis is a Delta Science Postdoctoral Fellow who is interested in the physical, chemical, and biological factors that promote development of blooms, especially harmful algal blooms (HABs). To explore phytoplankton dynamics on daily timescales in the Monterey Bay and San Francisco Bay, she uses an Imaging FlowCytobot (IFCB), an in-situ automated submersible flow cytometer that generates high-resolution images of particles in-flow taken from the aquatic environment. Alexis completed her PhD in Biological Oceanography in the Massachusetts Institute of Technology - Woods Hole Oceanographic Institution Joint Program. Her dissertation focused on cyst dormancy cycling and bloom initiation of Alexandrium catenella, a HAB dinoflagellate that causes paralytic shellfish poisoning.

Abstract:

Monterey Bay is the largest open embayment along the U.S. West Coast and is subject to intense autumn dinoflagellate blooms, many of which are harmful algal blooms. During 2004–2007 these blooms were so dominant that it was called the “age of dinoflagellates”. In 2018, after a decade absence, these conditions returned with an abundance of dinoflagellates documented at the Santa Cruz Municipal Wharf (SCW) using an Imaging FlowCytobot (IFCB). The IFCB combines video and flow cytometric technology to capture images with chlorophyll fluorescence above a trigger threshold. A phytoplankton image training set was amassed and used to train a 28-category random forest classifier that has 90% overall accuracy. The dominant dinoflagellate was Akashiwo sanguinea, exceeding 40 cells mL-1 and 500 cells mL-1 in March and May, respectively – a time of year when dinoflagellates are characteristically rare. Also abundant were Prorocentrum spp., Ceratium spp., and Gymnodinum spp. – all “upwelling relaxation” dinoflagellate taxa (Smayda 2002). During the winter and spring, pulses of increased dinoflagellates were associated with wind reversals, relaxation of upwelling, water column stability, and river discharge, which would have created a retentive, nutrient-rich region at SCW. These daily dynamics were also reflected in interannual drivers of anomalous dinoflagellate abundance at SCW. A partial least-squares regression was applied to a 7-year de-seasonalized weekly SCW timeseries. Winds from the west and south, increased river discharge, and negative NPGO and ENSO anomalies could explain 80% of anomalous dinoflagellate chlorophyll from January through May. High-frequency IFCB sampling and our coastal phytoplankton classifier will continue to improve our understanding of harmful dinoflagellate bloom development and better inform monitoring decisions.

New laser-imaging technology elucidates form, function, and ecological impact of deep sea, giant larvacean mucus houses -May 9th

Kakani Katija, MBARI

Moss Landing Marine Labs Seminar Series - May 9th, 2019

Hosted by the Ichthyology Lab

MLML Seminar Room, 4pm

Open to the public

Kakani received her PhD in Bioengineering at the California Institute of Technology and specializes in biological fluid mechanics and in situ imaging methods. She is currently a Principal Engineer and Principal Investigator at MBARI, with funding provided by the Packard Foundation, National Geographic Society, NOAA, and NSF-OTIC/IDBR. Kakani has been named a National Geographic Emerging Explorer in 2011 and a Kavli Research Fellow in the National Academy of Sciences in 2013.

Abstract:

The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet remains one of the least explored. Little-known marine organisms that inhabit midwater have developed life strategies that contribute to their evolutionary success, and may inspire engineering solutions for societally relevant challenges. Although significant advances in underwater vehicle technologies have improved access to midwater, small-scale, in situ fluid mechanics measurement methods that seek to quantify the interactions that midwater organisms have with their physical environment are lacking. Here we present DeepPIV, an instrumentation package affixed to a remotely operated vehicle that quantifies fluid motions from the surface of the ocean down to 4000 m depths. Utilizing ambient suspended particulate, fluid-structure interactions are evaluated on a range of marine organisms in midwater (and the benthos). Initial science targets include larvaceans, biological equivalents of flapping flexible foils, that create mucus houses to filter food. Little is known about the structure of these mucus houses and the function they play in selectively filtering particles, and these dynamics can serve as particle-mucus models for human health. Using DeepPIV, we reveal the complex structures and flows generated within larvacean mucus houses, and elucidate how these structures function. Future technologies (currently in the development pipeline) that will enable study of organismal ecomechanics in the deep sea will also be discussed.

 

 

KELPRR: Guiding kelp restoration actions in Northern California through multidisciplinary science and community engagement-March 28th

Cynthia Catton, CA Fish & Wildlife

Moss Landing Marine Labs Seminar Series - March 28th, 2019

Hosted by The Ichthyology Lab

MLML Seminar Room, 4pm

Open to the public

Dr. Cynthia Catton has studied kelp forest ecosystems, including important marine invertebrate fishery species and climate-change impacts, for over 15 years in California. She received a BS in Zoology with a Marine Emphasis from the University of Washington, and a PhD in Marine Biology from Scripps Institution of Oceanography. Dr. Catton is an Environmental Scientist with the California Department of Fish and Wildlife and a Research Associate at the UC Davis Bodega Marine Laboratory.

Dr. Catton will be talking about her current work to form a strong multi-institutional and community-engaged collaborative research program (KELPRR) to support kelp forest restoration in northern California.

Watch Cynthia’s MLML Seminar Presentation Below: