The 2,386th Meeting of the Society

January 5, 2018 at 8:00 PM

Powell Auditorium at the Cosmos Club

Presidents' Lecture

Taking the Pulse of the Ocean in a Changing World

Margaret Leinen

Vice Chancellor for Marine Science, UC San Diego
Director, Scripps Institution of Oceanography

Sponsored by Millen, White, Zelano & Branigan, PC

About the Lecture

The revolution in engineering that resulted in miniaturization, autonomy, and biological sensing made its way rapidly to ocean observation. When oceanographers started using the constellation of new sensors, platforms and systems made possible by this engineering revolution, they found that the ocean is even more dynamic than previously understood, and that it is changing rapidly.

Some changes are associated with climate, for example the changes in ocean oxygenation with time. Time series observations of the heat content of the ocean allowed scientists to determine the extent of ocean warming and the way it is distributed globally in the oceans. Some changes are part of large natural oscillations in the state of the oceans, such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Natural changes like these have large physical effects on the oceans, changing sea levels for instance, and they have dramatic biological effects as well, including dramatic changes in the distribution of fish species.

Other changes clearly are brought about by human activities on the oceans such as over-fishing and the systematic removal of large segments of the food chain in the ocean. The impact of the removal of primary predators on the nature and abundance of the ecosystems of which they are a part is dramatic and changes due to physical and chemical pollutants are readily and frequently observed as well.

It is sobering to recognize that human activities can dramatically affect the oceans, and to dramatically alter the largest ecosystem on the planet. We have to wonder, what are the implications of these changes for us, perhaps the most vulnerable community depending on the oceans?

About the Speaker

Margaret Leinen is the Director of Scripps Institution of Oceanography and Vice Chancellor for Marine Science of the University of California, San Diego (UCSD). She also is a Science Envoy for the US Department of State for Latin America and the Pacific, and she is Vice-Chair of the Research Board of the Gulf of Mexico Research Initiative started in response to the Deepwater Horizon oil spill.

Before coming to UCSD, Margaret served as Vice Provost for Marine Sciences at the Harbor Branch Oceanographic Institute of Florida Atlantic University, as Vice Provost for Marine Programs at Rhode Island University’s Graduate School of Oceanography, and as Assistant Director for Geosciences at the National Science Foundation (NSF).

Among many notable scientific undertakings, Margaret served on the Steering Committee of the Joint Global Ocean Flux program of the International Geosphere Biosphere Program (IGBP) that defined the relationship between ocean carbon fluxes and ocean ecosystems. She was co-chair of the seven cruise NSF study of the equatorial Pacific Ocean to define the relationship between carbon flux and El Nino conditions there. And she served as Vice-Chair of the IGBP effort of the International Counsel for Science to foster interdisciplinary studies of atmospheric, terrestrial and oceanic carbon fluxes and their relationship to climate.

While at NSF she co-chaired the first US government interagency plan for ocean research and she served as Chair and Vice-Chair of the US Global Change Research Program. She was instrumental in NSF’s funding the R/V Sukuliaq, it’s first ice-strengthened oceanographic ship, and to transforming the ocean drilling program to a fully internationally activity,

She has served as President of the American Geophysical Union and as President of The Oceanography Society, and chaired the Atmospheric and Hydrospheric Section of the American Association for the Advancement of Science.

Margaret’s research focuses on paleo-oceanography, paleo-climatology and biogeochemistry of the ocean. She was among the first to identify the importance of biogenic and eolian contributions to the trace element geochemistry of deep sea sediments. She also worked on deep sea hydrothermal systems and discovered the first hydrothermal vents on the Juan de Fuca Ridge, where the National Science Foundation (NSF) now operates a regional cabled ocean observatory.

Margaret is a Fellow of the American Association for the Advancement of Science, the Geological Society of America and the California Academy of Sciences, and she has been awarded Distinguished Alumni awards by the University of Illinois, Oregon State University and the University of Rhode Island,, all three of the institutions where she studied.

She earned a BS in Geology from the University of Illinois, an MS in Geological Oceanography from Oregon State University and a PhD in Oceanography from University of Rhode Island.


President Larry Millstein called the 2,386th meeting of the Society to order on January 5, 2018 at 8:07 PM in the Powell Auditorium of the Cosmos Club in Washington, DC. He announced that this was the annual Presidents’ Lecture. He then announced the order of business, noted that the meeting was being live-streamed on the internet, and welcomed new members to the Society.

Corresponding Secretary Robin Taylor read excerpts from the Anniversary Address of the first president of the Society, Joseph Henry. The Address, given in the year of the Society's founding on November 18, 1871 is published in Volume I of the PSW Bulletin. In the Address, Henry stated the purposes of the Society and discussed the challenges to doing good science and communicating it to the public. He warned the Society not to be under the influence of amateurs and politicians.

President Millstein then introduced the speaker for the evening, Margaret Leinen, Director of the Scripps Institution of Oceanography and Vice Chancellor for Marine Science at the University of California, San Diego. Her lecture was entitled “Taking the Pulse of the Ocean in a Changing World.”

She began her talk by noting that recent technological advances and the capture and analysis of large data sets have transformed the field of ocean science and our understanding of the ocean. She noted that the measurement of ocean temperatures and fluctuations in them, of great concern recently, are areas that have benefitted from these advances. Historically, scientists relied upon ships traversing the ocean to make occasional measurements to chart ocean temperatures. The ships were only able to provide several hundred samples per year. But, starting in the year 2000, scientists have been able to deploy autonomous floats that collect better data and transmit every five days. There are now over 4,000 such floats operating around the globe. This technological advancement has allowed scientists to comprehensively identify both warming and cooling patterns in the oceans, and to measure ice melt and ocean salinity.

With respect to sea level, from the 1880s until around 1990, scientists principally relied upon tide gauge measurements to track sea level. Then in the 1990s, satellite altimetry provided scientists with dense enough data for scientists to map sea levels and identify their uneven distribution around the globe. The data generated from this technology allows scientists to better predict the specific effects of sea level rise on different parts of the world.

Technology which allows for consistent sampling has also revealed dramatic ocean changes. For example, sampling for surface ocean acidity, which is linked to increased CO2 levels in the water, shows that the oceans are 30% more acidic than they were in 1850.

In the mid-2000s, scientists began to understand the impact of ocean acidification on the ocean’s biota. Research on terapods, which are ocean snails, shows that they have become less able to make pristine shells. Scientists believe this is due to ocean acidification which decreases the availability of carbonate ions.

In addition to increasing acidification, the increase of carbon in the ocean, along with rising ocean temperatures, has led to an increase in biota growth and consumption of oxygen. This has resulted in ocean deoxygenation, which has caused some ocean life, such as fish, to be displaced. Further effects are still being studied.

Technological advancements have also led to an increase in the quality and quantity of deep sea field research. This is important because laboratory work cannot account for all of the factors necessary to fully understand ocean life and to answer questions about how that life will cope with ocean change.

In sum, Dr. Leinen said large data sets allow scientists to explore new ways of doing ocean science. Much of 20th century scientific thinking was deductive hypothesis testing, using a sampling strategy designed to answer those specific questions. This methodology often precluded other insights. In contrast, the availability of larger and denser data sets has allowed scientists to identify trends and reach conclusions, largely by induction. Dr. Leinen said she encourages scientists and funders of science to continue adding to existing data sets and to conduct more science in the field.

President Millstein then invited questions from the audience.

One member asked how ocean deoxygenation affects zooplankton migration. Dr. Leinen said that during the night zooplankton reside on the ocean surface and migrate down into the ocean during the day. She said there is data suggesting zooplankton are not migrating as deeply into some deoxygenated zones.

A livestream viewer asked whether scientists have considered the effects of carbon in deep ocean water that is now mixing with surface waters. Dr. Leinen said that scientists have considered the matter, but lack the data to reach any conclusions at this time.

After the question and answer period, President Millstein thanked the speaker, made the usual housekeeping announcements, and invited guests to join the Society. At 10:05 p.m., President Millstein adjourned the 2,386th meeting of the Society to the social hour.

Attendance: 103
The weather: Clear
The temperature: -9.5°C
Respectfully submitted,

James Heelan
Recording Secretary