This just in: Claire Garfield, Stony Brook undergraduate extraordinaire, has been awarded the prestigious 2020 Marshall Scholarship! Claire has a deep interest in science and the environment, and continues to inspire us with all of her achievements. Congratulations, Claire!
You can read more about Claire’s amazing accomplishments at Stony Brook University News, including her recent DAAD-Rise Fellowship and Barry Goldwater Scholarship.
Friend of the lab, polymath, and all around great guy, Prof. Gordon Taylor’s work on microplastics and Raman microspectrometry was recently featured by SBU News. Check out the full article and a short video here! To learn more about the amazing instrumentation used in these studies, check out Stony Brook University’s NAno-RAMAN Molecular Imaging Laboratory (NARMIL) website.
What happens when wave-generated air bubbles burst at the ocean surface? Radiocarbon (14C) measurements suggest that they grab hold of some of the oldest organic molecules in the sea and throw them into the air. Read all about it in our team’s latest paper, published online this week in Science Advances :
Beaupré, S. R., D. J. Kieber, W. C. Keene, M. S. Long, J. R. Maben, X. Lu, Y. Zhu, A. A. Frossard, J. D. Kinsey, P. Duplessis, R. Y. W. Chang, and J. Bisgrove (2019), Oceanic efflux of ancient marine dissolved organic carbon in primary marine aerosol, Science Advances, 5(10), doi:10.1126/sciadv.aax6535.
Abstract: Breaking waves produce bubble plumes that burst at the sea surface, injecting primary marine aerosol (PMA) highly enriched with marine organic carbon (OC) into the atmosphere. It is widely assumed that this OC is modern, produced by present-day biological activity, even though nearly all marine OC is thousands of years old, produced by biological activity long ago. We used natural abundance radiocarbon (14C) measurements to show that 19 to 40% of the OC associated with freshly produced PMA was refractory dissolved OC (RDOC). Globally, this process removes 2 to 20 Tg of RDOC from the oceans annually, comparable to other RDOC losses. This process represents a major removal pathway for old OC from the sea, with important implications for oceanic and atmospheric biogeochemistry, the global carbon cycle, and climate.
Outstanding scientist and colleague, Dr. Amanda Frossard, explains how to generate marine aerosol with a forced-air Venturi in our team’s latest paper, published online this week in JGR-Atmospheres:
Frossard, A. A., M. S. Long, W. C. Keene, P. Duplessis, J. D. Kinsey, J. R. Maben, D. J. Kieber, R. Y. W. Chang, S. R. Beaupré, R. C. Cohen, X. Lu, J. Bisgrove, and Y. Zhu (2019), Marine aerosol production via detrainment of bubble plumes generated in natural seawater with a forced‐air venturi, Journal of Geophysical Research: Atmospheres, doi:10.1029/2019jd030299.
Abstract: During September–October 2016, a marine aerosol generator configured with forced‐air Venturis was deployed at two biologically productive and two oligotrophic regions of the western North Atlantic Ocean to investigate factors that modulate primary marine aerosol (PMA) production. The generator produced representative bubble size distributions with Hinze scales (0.32 to 0.95 mm radii) and void fractions (0.011 to 0.019 Lair Lsw‐1) that overlapped those of plumes produced in the surface ocean by breaking wind waves. Hinze scales and void fractions of bubble plumes varied among seawater hydrographic regions, whereas corresponding peaks and widths of bubble size distributions did not, suggesting that variability in seawater surfactants drove variability in plume dynamics. Peaks in size‐resolved number production efficiencies for model PMA (mPMA) emitted via bubble bursting in the generator were within a narrow range (0.059 to 0.069 μm geometric mean diameter) over wide ranges in subsurface bubble characteristics, suggesting that subsurface bubble size distributions were not the primary controlling factors as was suggested by previous work. Total mass production efficiencies for mPMA decreased with increasing air detrainment rates, supporting the hypothesis that surface bubble rafts attenuate mPMA mass production. Total mass and Na+production efficiencies for mPMA from biologically productive seawater were significantly greater than those from oligotrophic seawater. Corresponding mPMA number distributions peaked at smaller sizes during daytime, suggesting that short‐lived surfactants of biological and/or photochemical origin modulated diel variability in marine aerosol production.
Find out more in our latest publication in Environmental Science & Technology, led by outstanding scientist and collaborator, Dr. Amanda Frossard.
Frossard, A., V. M. F. Gerard, P. Duplessis, J. D. Kinsey, X. Lu, Y. Zhu, J. Bisgrove, J. R. Maben, M. S. Long, R. Chang, S. R. Beaupre, D. J. Kieber, W. C. Keene, B. Noziere, and R. C. Cohen (2019), Properties of seawater surfactants associated with primary marine aerosol particles produced by bursting bubbles at a model air-sea interface, Environmental Science & Technology, 53(16), 9407-9417, https://doi.org/10.1021/acs.est.9b02637.
The National Ocean Sciences Accelerator Mass Spectrometry facility (NOSAMS) at the Woods Hole Oceanographic Institution presented Steven Beaupré with the Robert J. Schneider-CFAMS Award on Thursday, June 13. This prize was created by Dr. Robert Schneider, one of the founders of NOSAMS, to recognize the development of new continuous flow AMS (CFAMS) applications and novel radiocarbon methodologies, with applications to Earth, Ocean, and Environmental Sciences. The Beaupré Lab thanks Dr. Schneider and the entire NOSAMS staff for their generosity, hospitality, and many years of friendship.
If you’re in Winnipeg and love isotopes, then please come to Dr. Brett Walker’s presentation at 12:10 pm in room 223 of the Wallace Building at the University of Manitoba. It’s all part of the fun at this year’s Advances in Stable Isotope Techniques and Applications (ASITA) Conference.
Brett D. Walker, Steven R. Beaupré, Sheila Griffin, Jennifer Walker, Ellen Druffel, Xiaomei Xu. (2019) A Novel Sealed-tube Method for δ13C Analysis of CO2 via a Gas Bench II Continuous Flow IRMS at UC Irvine. Advances in Stable Isotope Techniques and Applications (ASITA) Conference. Winnipeg, Manitoba, Canda.
Abstract: The oxidation of environmental samples to CO2 and subsequent isotopic analysis on a Gas Bench II continuous-flow isotope ratio mass spectrometer (IRMS) can present many analytical challenges. In off-line applications, such as UV photochemical oxidation of aqueous DOC, only 1 sample is prepared per day. Therefore, long-term storage (months-years) of equilibrated sample CO2 splits is desirable, in order to accumulate a sufficient number of samples to warrant a day of isotopic measurements. Here we present our sealed-tube sample preparation technique for the measurements of CO2 via a Gas Bench II IRMS at UC Irvine. We also present several years of IAEA and UC Irvine isotope standards showing the robustness of this method for accurate δ13C isotope analysis of small sample gas splits (10-35 μgC). We also discuss the evolution of the technique and several pitfalls to avoid during its implementation to minimize sample loss (<1% failure rate) and to maximize efficiency and measurement precision (less than ±0.1‰). This technique is an alternative method for δ13C analyses of samples of samples where off-line isolation isolation and long-term storage are desired, but also higher sample throughput than a traditional dual-inlet cracker setup.
Xi Lu, our graduate student extraordinaire, just published a surprisingly simple method for obtaining the most precise measurements of CO2 gas abundances for routine radiocarbon dating. Aside from a capacitance diaphragm gauge (CDG) and a good vacuum line, all that you really need to improve your measurements are air, a love of Boyle’s Law, and the right sized reference flask. That’s it. Familiarity with the virial equation doesn’t hurt, either. Read all about it in the journal, Radiocarbon (and don’t forget to check out the Supplemental Materials!):
Lu, X. and Beaupré, S.R. (2019), Optimized volume determinations and uncertainties for accurate and precise manometry, Radiocarbon, doi:10.1017/RDC.2019.43.
Have questions about ancient carbon in aerosols generated by bursting bubbles from breaking waves? Then come to the hotel Scandic Lerkendal in beautiful Trondheim, Norway on Tuesday, June 6, at 2 pm for my talk at the 2018 Radiocarbon Conference:
Radiocarbon (14C) constraints on the fraction of refractory dissolved organic carbon in primary marine aerosol from the Northwest Atlantic
Steven R. Beaupré, David J. Kieber, William C. Keene, Michael S. Long, Amanda A. Frossard, Joanna D. Kinsey, Patrick Duplessis, Rachel Chang, John R. Maben, Xi Lu, Yuting Zhu, John Bisgrove
Nearly all organic carbon in seawater is dissolved (DOC), with more than 95% considered refractory based on modeled average lifetimes (~16,000 years) and characteristically old bulk radiocarbon (14C) ages (4000 – 6000 years) that exceed the timescales of overturning circulation. Although this refractory dissolved organic carbon (RDOC) is present throughout the oceans as a major reservoir of the global carbon cycle, its sources and sinks are poorly constrained. Recently, RDOC was proposed to be removed from the oceans through adsorption onto the surfaces of rising bubble plumes produced by breaking waves, ejection into the atmosphere via bubble bursting as a component of primary marine aerosol (PMA), and subsequent oxidation in the atmosphere. To test this mechanism, we used natural abundance 14C (5730 ± 40 yr half-life) to trace the fraction of RDOC in PMA produced in a high capacity generator at two biologically-productive and two oligotrophic hydrographic stations in the Northwest Atlantic Ocean during a research cruise aboard the R/V Endeavor (Sep – Oct 2016). The 14C signatures of PMA generated day and night from near-surface (5 m) and deep (2500 m) seawater were compared with corresponding 14C signatures in seawater of near-surface dissolved inorganic carbon (DIC, a proxy for recently produced organic matter), bulk deep DOC (a proxy for RDOC), and near-surface bulk DOC. Results constrain the selectivity of PMA formation from RDOC in natural mixtures of recently produced and refractory DOC. The implications of these results for PMA formation and RDOC biogeochemistry will be discussed.
Dr. Middelburg is the Chair in Geochemistry and Director of Research in the Department of Earth Sciences at Utrecht University, and a member of the Royal Netherlands Academy of Arts and Sciences. His interests are broad, spanning from rivers to the deep sea, microbes to benthic animals, compound specific isotope analyses to models of bulk organic matter degradation, and more. Please visit his homepage for more information: https://www.uu.nl/staff/JBMMiddelburg.