Ocean Discovery Lecture Series

 

For over 20 years, the Ocean Discovery Lecture Series (formerly the Distinguished Lecturer Series) has brought the remarkable scientific results and discoveries of the International Ocean Discovery Program and its predecessor programs to academic research institutions, museums, and aquaria. Since 1991, over 1,000 presentations to diverse audiences have been made through the Lecture Series.

 

For the 2020-2021 academic year, an exciting lineup of distinguished lecturers is available to speak at your institution. The topics of their lectures range widely, and include monsoon history, ice sheet dynamics, sediment diagenesis, and more.

The Ocean Discovery Lecturers for the 2020-2021 academic year are:

The chilling effect of mountain growth: Cenozoic insights from the Asian submarine fans

 

 

The uplift of the Himalayan range and associated surface processes have long been hypothesized to have played a role in the long-term global cooling that characterizes the Cenozoic era. Specifically, high erosion rates triggered by a combination of rapid uplift and/or climate forcing such as heavy monsoon precipitations may have enhanced silicate weathering and/or organic carbon burial – two key long-term CO2 sequestration mechanisms. Mechanistic and quantitative reconstructions of silicate weathering rates and organic carbon burial in the sedimentary fans receiving the products of Himalayan erosion are therefore of paramount importance in order to characterize and quantify the impact of Himalayan uplift and erosion on the global carbon cycle and attendant consequences for the Cenozoic cooling.

 

I will present a multi-proxy study of sediment cores recovered by IODP expeditions 354, 355 and 362, providing an unprecedented record of silicate weathering and organic carbon burial in the Bengal, Indus and Nicobar Fans spanning the later part of the Cenozoic Era. Silicate weathering rates remain relatively invariant and comparable (or lower) to modern rates. Meanwhile, abundant accumulations of macroscopic (up to several centimeters in length and diameter) debris of well-preserved wood were discovered within coarse sediment units of the Bengal, Indus and Nicobar Fans. The burial of woody debris in coarse sediments at the base of turbidites rapidly overlaid by thick mud-caps appears to reduce their exposure to oxygen, thereby inhibiting their degradation even in the absence of mineral protection. Furthermore, in the Bengal Fan, organic carbon loading and composition (e.g. degradation state) shows systematic temporal variations. While the burial of wood debris appears to decrease slightly in the later part of the record, the organic carbon loading of turbidite mud caps increases sharply at the Plio/Pleistocene transition. These trends and their implications for the global C cycle will be discussed in the context of variations in the strength of the summer monsoon and related surface processes.

 

Dr. Galy is a tenured Associate Scientist in the Marine Chemistry and Geochemistry department at Woods Hole Oceanographic Institution (MA, USA). He received a master of geological engineering and PhD in geosciences from the Institut National Polytechnique de Lorraine (Nancy, France). His research focuses on multiple aspects of biogeochemistry including carbon cycling in terrestrial and oceanic environments, the long-term evolution of the earth surface and paleo-climate. Valier has worked on deep sea drilling cores since his master thesis, which focused on cores from DSDP Leg 22. In 2015 he sailed as an organic geochemist on IODP expedition 354 to the Bengal Fan.

 

 

 

LECTURE SCHEDULE
  • TBD

Some like it hot! Microbial communities inhabiting hydrothermal systems

 

 

Microbes (including bacteria, archaea, and viruses) are ubiquitous on Earth and have been found under conditions where no animal can survive. Microbes known as extremophiles, inhabit extreme environments such as geothermal hot springs with pH < 3, hypersaline environments with a salinity as high as 35%, and environments with extremely low concentrations of nutrients. One factor that can limit life is temperature; There is currently no known microbe that can tolerate temperatures higher than 122 ˚C. Hydrothermal systems display diverse and unpredictable conditions of extremely high temperatures and acidic pH, offering a range of environments that naturally test the limits of life as we know it. Microbial communities have been found within hydrothermal fluids, microbial mats on basaltic rock and chimneys, as well as within the neutrally buoyant hydrothermal plume, with varying energetic constraints on microbial activity and abundance. Moreover, hydrothermal systems are hypothesized to be the epicenters of the origins of life, making them ideal for studying evolutionary processes. They also display extreme conditions similar to what we could find on other planets.

 

The environmental conditions at Brothers volcano (study site of IODP Expedition 376 Brothers Arc Flux) provided a perfect setting to test the limits and adaptations of life. Preliminary analyses of the borehole fluids revealed temperatures up to 350˚C, pH as low as 1.8, higher salinity than in the upper water column, and very low concentrations of organic nutrients. My research uses a combination of molecular approaches and cultivation to characterize the microbial communities’ diversity and interactions in hydrothermal systems to understand the life of extremophiles.

 

Dr. Labonté received her B.S. and M. Sc. from Laval University, and her Ph.D. from the University of British Columbia. She was a post-doctoral researcher at Bigelow Laboratory before heading to Texas A&M University at Galveston, where she currently is an Assistant Professor. Her research focuses on determining the role of viruses and their hosts in aquatic environments, from the surface to below the seafloor, through the characterization of their relationships. Dr. Labonté participated as a shipboard scientist on IODP Expedition 376 Brothers Arc Flux and worked on cores from Expeditions 337 Juan de Fuca Ridge-Flank Hydrogeology and 357 Atlantis Massif Serpentinization and Life.

 

 

 

LECTURE SCHEDULE
  • TBD

Magmatism at rifted margins: the story from drilling in the South China Sea

 

Our understanding of the magmatic response to rifting and continental break-up as recorded at passive continental margins was revolutionized in the 1980s and 1990s through ocean drilling and seismic data, largely from the North Atlantic margins. This led to a broad classification of rifted margins as either ‘magma-rich’, characterized by seaward dipping reflector sequences of stacked basalt lava flows and significant magmatic underplate, or ‘magma-starved’, characterized by hyper-extended continental crust and exhumed serpentinized mantle prior to igneous oceanic crust formation. In this talk, I will summarize results from IODP Expeditions 367/368/368X in 2017 and 2018 that drilled a sequence of basement holes in a transect across the highly extended northern rifted margin of the South China Sea marginal basin. Contrary to expectations, results from the recovered cores revealed rapid initiation of Mid-Ocean Ridge basalt-type magmatism from normal temperature mantle. Thus, the northern South China Sea rifted margin appears to be an ‘intermediate’ case, where there is a relatively sharp transition from thinned continental crust to steady-state seafloor spreading and development of typical thickness oceanic crust.

 

David Peate is Professor and Chair of the Department of Earth and Environmental Sciences at the University of Iowa. He is an igneous geochemist primarily interested in how basaltic rocks record details of mantle sources and melt generation & differentiation processes in different tectonic environments. He sailed as a petrologist on ODP Leg 163X to the East Greenland rifted margin and IODP Expedition 368 to the South China Sea rifted margin.

 

 

 

LECTURE SCHEDULE
  • TBD

 

Hunting the magnetic field through ocean drilling

 

Earth’s magnetic field has been the target of scientific investigation for over four centuries yet the basic fact that the field switches polarities, though suspected for over a century was not proven until the early sixties.  This fact was key to the plate tectonic revolution and part of the rationale to begin drilling the ocean floor with the Deep Sea Drilling Project over fifty years ago.  And the study of the Earth’s magnetic field has remained an integral part of ocean drilling throughout the history of endeavor.

 

In addition to flipping polarity, the Earth’s magnetic field changes both direction and strength on time scales from decades to millennia.  Human observations of field directions provide constraints for field behavior since the age of maritime exploration starting in the fifteenth century but field strength measurements only started in the 19th century, so understanding of the geomagnetic field requires the use of “accidental” records such as sediments and igneous rocks.  Because 70% of the surface of the Earth is covered by ocean, marine records are essential to get a global view of history of the Earth’s magnetic field and records beyond a few million years  require ocean drilling.

 

The International Ocean Discovery Program maintains cores from fifty years of drilling.  Magnetic measurements on these cores continue to provide clues as to the timing and nature of magnetic reversals, attempted reversals (excursions), and the rise and fall in field strength since the Jurassic.  Prof. Tauxe will share paleomagnetic results not only from her most recent experience on IODP Expedition 382 to the “Iceberg Alley” in the Scotia Sea but also from previous expeditions since DSDP Leg 73.

 

Dr. Lisa Tauxe is Distinguished Professor of Geophysics at the Scripps Institution of Oceanography, University of California, San Diego.  She received her PhD from Columbia University and participated in her first expedition (Leg 73) while a graduate student. She has sailed on a total of five expeditions (Legs 73, 108 and Expeditions 318, 355 and 382).  

 

 

 

LECTURE SCHEDULE
  • TBD

 

Waxing and waning of an ice sheet: Records from the Amundsen Sea, Antarctica

 

 

Today, Antarctica is covered by an ice sheet that, if it were to melt, has the capacity to contribute on the order of nearly 60 m to global sea-level rise.  Most of that ice is relatively stable, and is expected to be so long into the future, but parts of the West Antarctic Ice Sheet, particularly Thwaites and Pine Island glaciers, may be susceptible to sudden retreat, or even “collapse.”  In the past, the ice was significantly expanded, reaching the continental shelf break around most of the margin.  As the ice sheet retreated to its modern extent, the shrinking ice left behind a sedimentary signature of deglacial history.  Over repeated cycles of glacial advance and retreat, sedimentary deposits of alternating glacial and interglacial periods have built up on the continental shelf and slope.  Because the stability of the Antarctic Ice Sheet is strongly influenced by the ocean, the sedimentary deposits from the ice-ocean margin are the ideal place to study the controls on stability or instability of the ice.

 

This talk will focus on the sedimentary record from the West Antarctic margin, by combining geophysical survey data, including 3.5 kHz profiles, seismic data, and multibeam swath bathymetry, with both gravity and drill cores, to map the past extent of the ice, determine the chronology of glacial cycles, and develop an understanding of the controls on glacial stability.  Data will be presented from three different time periods.  To begin, data from IODP Expedition 379, which drilled deep-water sites beyond the glacial limit and thus not susceptible to erosion, will be presented.  These drill cores contain continuous records of glacial cyclicity since the Neogene, allowing correlation to global sea-level records.  Next, we will examine records of retreat since the last glacial maximum, at the end of the Pleistocene, where the difference in timing of retreat in individual drainage basins can be determined.  Finally, we will look at the sedimentary records from where Thwaites Glacier has retreated over just recent decades, allowing an examination the factors influencing the ice today and how they differ from past periods.

 

Dr. Julia Wellner is Associate Professor in the Department of Earth and Atmospheric Sciences at the University of Houston. Her fields of expertise include stratigraphy and sedimentology, with an emphasis on Antarctic Ice Sheet history and climate since the Eocene. She was a co-chief scientist on IODP Expedition 379 to the Amundsen Sea in 2019.

 

 

 

LECTURE SCHEDULE
  • TBD

 

Development of modern ocean circulation during the Cenozoic

 

 

During the Neogene, our planet’s polar regions evolved from being largely ice-free into having bi-polar ice sheets.  As the cryosphere grew in size, compressed temperature gradients invigorated wind and ocean circulation.  Large sediment drifts in the North and South Atlantic show dramatic changes signaling the onset of more vigorous circulation, which is the hallmark of today’s ocean-atmosphere-cryosphere system.  A spectacular array of depositional features can develop within sediment drifts, the largest of which can be imaged seismically.  The sediment drifts deposited under the influence of North Atlantic Deep Water show a rich history of deep current activity during the Neogene.  High-resolution images of the large drifts along the Argentine margin similarly reveal a dynamic record of Southern Ocean derived deep currents during the Cenozoic. It is not surprising that surface ocean currents responded in kind.  Shallow (<750m) sediment drifts in the Florida Straits (subtropical western North Atlantic) and Maldives (equatorial Indian Ocean) record a coeval increase current controlled deposition in these tropical locations.

 

Scientific ocean drilling has targeted several deep-sea sediment drifts, providing chronologies and therefore a means to establish linkages and identify large-scale common forcing. The dramatic changes in drift accumulation in shallow and deep-water regions in these far-flung regions document that our global ocean-atmosphere system is well integrated, showing that its main components developed during the latter part of the Neogene when the polar Antarctic Ice Sheet was established.  I was fortunate to have sailed on ODP Leg 166 (Bahamas) and IODP Expeditions 303 (North Atlantic) and 359 (Maldives) as well as on a recent seismic cruise to the Argentine margin, allowing recognition of connections among their individual drift histories.

 

Wright is a professor in the Department of Earth and Planetary Sciences at Rutgers University. He received his MS from the University of South Carolina working on Indian Ocean planktonic foraminifera during the Neogene and his PhD from Columbia University where he focused on reconstructing Neogene deep-water circulation patterns. Building on his graduate studies, Jim has continued his interest in Neogene climate and ocean circulation and has sailed on five expeditions aboard the RV JOIDES Resolution

 

 

 

LECTURE SCHEDULE
  • TBD

 

Host A Lecture

 

The application period to host a lecturer for the 2020-2021 academic year is now open through May 15, 2020. The application form can be found here. USSSP will work with the lecturers to try to develop broad scheduling priorities for the year. Applicants can expect to hear from lecturers over the summer to initiate the institutional scheduling process. Although every effort will be made to accommodate all requests, in some cases this may not be possible. When necessary, preference will be given to smaller institutions, or to those with a limited history of involvement with IODP.

 

USSSP will provide support for the lecturer’s travel to your institution, while hosting venues are responsible for housing, meals, and local transportation.

 

 

Nominate a Lecturer

 

Participation of researchers in the USSSP-IODP Ocean Discovery Lecture Series is essential to the program’s goal of bringing scientific results and discoveries to the geoscience community. The nomination period for the 2020-2021 period has closed.

 

 

Ocean Discovery Lecturer Specifications

 

  • Six Ocean Discovery Lecturers are chosen for each academic year.
  • Each Ocean Discovery Lecturer is required to give six lectures during the academic year. Due to the popularity of the program, many lecturers, however, agree to give more.
  • The lecture topic should focus on results of IODP research. Synthesis lectures on broad topics associated with IODP’s scientific objectives (environmental change, processes, and effects; climate change; deep biosphere and the subseafloor ocean; and solid Earth cycles and geodynamics) are strongly encouraged.
  • Lectures should be aimed at a broad geoscience audiences consisting primarily of graduate and undergraduate students and the scientifically literate public.
  • USSSP will fund the speaker’s transportation expenses to and from each institution; host institutions will provide housing, meals, and local transportation for the speaker.
  • After completion of the required lectures, USSSP will provide a small honorarium for the speaker’s participation.

 

 

Previous Distinguished Lecturers

 

Information on current and previous Ocean Discovery Distinguished Lecturers can be found here.