Lamont Weekly Report, February 23, 2018

    This week brought unusual swings in local weather, beginning with a snowstorm Saturday evening, the breaking of high-temperature records for the date and the month on Wednesday (, and more seasonal weather at the end of the week. Every roller coaster ride comes to an end.

    On Monday, the R/V Langseth sailed from Dunedin, New Zealand, to begin the South Island, New Zealand, Subduction Initiation Experiment (SISIE), which involves the deployment of 50 ocean-bottom seismometers (OBSs) and the acquisition of multi-channel seismic lines with the ship’s 12.5-km-long streamer across and along the geologically young subduction zone south of New Zealand ( Experiment leaders include Mike Gurnis and Joann Stock from Caltech and Sean Gulick and Harm Van Avendonk from the University of Texas Institute for Geophysics. Sean Higgins wrote on Wednesday, “The team deployed the first line of OBSs and are shooting to them now. The ship party hopes to complete that work and recover those OBSs before heading to the second major OBS line. It’s going to be a weather-challenged cruise, so the ship is likely to work in spurts between fronts coming through that area.”

    Water Research recently posted online a paper by Andy Juhl, Carol Knudson, Greg O’Mullan, and colleagues at Riverkeeper and the Environmental Protection Agency on detailed spatial patterns of concentrations of pharmaceuticals in the Hudson River estuary. The team made measurements of 16 prescribed pharmaceutical products along transects from Troy to the Battery during dry-weather periods in May and July 2016. Six pharmaceuticals were measured at 92% or more of the sites during both periods, and concentrations of individual compounds varied widely. Factors that affected concentration included proximity to wastewater discharge sites, input from tributaries, and tidal mixing. The impact of the measured concentrations on fish and other river wildlife has yet to be assessed. A Kevin Krajick press release on the paper’s findings was posted to our web site on Monday (, and the story was picked up by WNYC ( and other media.

    From Wednesday through today, Lamont hosted a Workshop on Antarctic Surface Hydrology and Future Ice-shelf Stability ( The workshop sought to “bring together scientists with expertise in ice-sheet dynamics, glacial hydrology, climatology and other disciplines in order to move the community toward answering several fundamental questions raised by observations of Antarctic surface hydrological processes,” including questions on surface meltwater generation, transport, and storage and the influence of surface meltwater on ice-shelf stability. Jonny Kingslake, Robin Bell, Indrani Das, and Marco Tedesco served on the workshop organizing committee.

    Yesterday, Scientific Reports published a paper that Mike Kaplan coauthored with colleagues from Chile, Argentina, and New Zealand (and Stanford) documenting the centennial-scale history of southern hemisphere westerly winds and the associated Southern Annular Mode (SAM) that describes the north-south movement of the westerly wind belt. From analyses of sediments deposited over the past 15 thousand years in a lake in southern Chile, the group identified signals of strong westerly winds during the Antarctic Cold Reversal, low winds during the early Holocene, and strong westerlies again over the past 7500 years. The team detected nine positive SAM-like events over the past 6000 years that alternated with cold and wet intervals favorable to glacier expansions. Mike and his colleagues concluded that coherent climate shifts have driven climate change across large portions of the southern hemisphere at centennial and longer timescales.

    In today’s issue of Science magazine, a paper by Chandranath Basak, Bob Anderson, and several German colleagues reported evidence from measurements of neodymium isotopes in marine sediment cores for distinct deep and abyssal waters in the Pacific sector of the Southern Ocean during the Last Glacial Maximum, confirming a previously inferred stratification of the Southern Ocean thought to have facilitated deep storage of carbon dioxide during the last ice age. A widespread change in the neodymium isotope characteristics coincident with the onset of southern hemisphere climate warming during the last deglaciation suggests that there was a climate trigger to the loss of deep stratification of the deep Southern Ocean at that time and the consequent release of sequestered carbon dioxide to the atmosphere.

    In the news this week, Won-Young Kim was interviewed by Susan Hellauer for an “Earth Matters” column about Hudson Valley earthquakes that appeared in Nyack News & Views on Wednesday ( Today’s issue of Science includes a review of Lynn Sykes’s new book, Silencing the Bomb (

    This afternoon’s Earth Science Colloquium will be given by ecoclimatologist Abigail Swann, an Assistant Professor in the Departments of Atmospheric Sciences and of Biology at the University of Washington. Abigail, an M.A. alumna of Lamont and the Department of Earth and Environmental Sciences, will speak on “Quantifying the role that terrestrial ecosystems play in Earth’s climate.” May your own role allow you to leave the ecosystem of your office or lab to join me in Monell for her talk.