Gerald T. Rustic

Publications

• Rustic, G. T., Koutavas, A., Marchitto, T. M., & Linsley, B. K. (2015). Dynamical excitation of the tropical Pacific Ocean and ENSO variability by Little Ice Age cooling. Science, 350(6267), 1537-1541.
  DOI:10.1126/science.aac9937
  Data available at the NCEI data repository.
  Coring cruise KNR195-5 Information
• Suhua Wei, Chuixiang Yi, George Hendrey, Timothy Eaton, Gerald Rustic, et al. (2014). Data-based perfect-deficit approach to understanding climate extremes and forest carbon assimilation capacities. Environmental Research Letters 9:6. iopscience.iop.org/1748-9326/9/6/065002
• Chuixiang Yi, Gerald Rustic, Xiyan Xu, Jingxin Wang, Anand Dookie, Suhua Wei, George Hendrey, Daniel Ricciuto, Tilden Meyers, Zoltan Nagy and Krisztina Pinter (2012). Climate extremes and grassland potential productivity, Environmental Research Letters 7:3. iopscience.iop.org/1748-9326/7/3/035703
• Gerald T. Rustic (2011) Polycyclic aromatic hydrocarbon contamination in and around the Arthur Kill, Staten Island, New York. MS Thesis, Rutgers University. Rutgers MS Theses online

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Selected Presentations

• December 2017 - Central Tropical Pacific Variability And ENSO Response To Changing Climate Boundary Conditions: Evidence From Individual Line Island Foraminifera, American Geophysical Union Fall Meeting 2017
• October 2017 - Measurements, Methods and Motivations: Insights on Mg/Ca from Individual Foramininfera, Geological Society of America Annual Meeting 2017
• October 2017 - El Niño's Response to Background Climate Conditions on Millennial and Interglacial Time-scales: Evidence from Individual Foraminifera, GEOS at the CUNY Graduate Center
• February, 2017 - Means and Extremes: ENSO variability over the last 1000 (and 100,000) years from individual foraminifera, Biology and Paleoenvironment Seminar, LDEO
• December 2015. - Late Holocene Sea Surface Temperature Trends in the Eastern Tropical Pacific, American Geophysical Union Fall Meeting 2015 (Poster).
• December 2014 - Eastern Tropical Pacific Mean State and Variability During the Past 1000 Years, American Geophysical Union Fall Meeting 2014.
• December 2013 - El Niño Southern Oscillation during the Medieval Climate Anomaly, American Geophysical Union Fall Meeting 2013 (Poster).
• December 2012 - Variability of eastern tropical Pacific climate during the last two millennia from δ¹⁸O of individual foraminifera, American Geophysical Union Fall Meeting 2012 (Poster).
• December 2011 - Canopy Photosynthetic Capacity Signature of Extreme Events, American Geophysical Union Fall Meeting 2011 (Poster).

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Research Articles in Preparation

• Late Holocene sea surface temperature trends in the eastern equatorial Pacific
• Differential morphotypic response of eastern equatorial Pacific foraminifera to changing oceanic conditions
• On the variability of paired Mg/Ca — δ¹⁸O measurements from individual foraminifera

Research

Our ability to predict future climate conditions relies on a keen understanding of the climate system and the sources of past climate variability. The brevity of the instrumental record and the time-scale of past climate changes compels us to utilize the geologic record to reconstruct Earth’s climate history. My research focuses on climate variability on timescales relevant to human societies, in particular interannual-decadal scale climate variability and its relationship to different background climate states. Extreme events on these timescales can have major societal impacts, and it remains unclear how strongly this variability is forced by boundary conditions. My current research investigates the behavior of the El Niño Southern Oscillation (ENSO) through the Holocene and late Pleistocene, and I am beginning a project to understand modes of tropical Atlantic variability during the Holocene. I am also extensively involved with developing and testing a novel method for reconstructing variability using geochemical measurements of individual foraminifera.

The El Niño Southern Oscillation - ENSO

The largest source of inter-annual climate variability on Earth is the El Niño Southern Oscillation (ENSO). El Niño and La Niñ events are characterized by significant changes in tropical Pacific sea surface temperatures, with far-reaching effects felt across a wide portion of the globe as a result of the strong ocean-atmosphere teleconnections. The dramatic temperature and precipitation changes that occur during strong ENSO events can affect the health, safety, and food security of millions if not billions of people. Our understanding of the climatic factors that influence the severity and frequency of ENSO is incomplete, in part due to the relative brevity of the instrumental record. To better understand, characterize, and ultimately predict the response of ENSO to future climate conditions, we can look at how ENSO has responded to past changes in global climate. My research explores the mechanisms that affect ENSO variability and the relationship of ENSO to large-scale changes in the climate system which are fundamental to understanding tropical Pacific variability through the Holocene and on longer glacial-to-interglacial time-scales through the late Pleistocene.

Major Topics of Research

• Tropical Pacific variability on human time scales
  The last millennium has seen large-scale climate shifts including the Medieval Climate Anomaly and Little Ice Age. We identified a mid-Millennial shift in tropical Pacific dynamics from a low-variability, cool state to a high-variability, warming state using stable isotopes from over 1400 individual foraminifera and Mg/Ca to reconstruct SST. (Rustic et al, 2015)
• The Relationship of the mean state of the tropical Pacific Ocean to global climate states
• ENSO response to climatic boundary conditions on millennial and glacial-to-interglacial timescales
• Modes of Atlantic variability and the impact on African hydroclimate over the Holocene

Paleoclimate Tools and Methods

Studying the large-scale, long-term history of ENSO is done by looking at very smallest things. The geochemical signature of single-celled planktonic organisms called foraminifera, found in deep-sea sediments, can be used to reconstruct past oceanic conditions. These magnificent little geochemists have shells, or tests, made of calcium carbonate (CaCO₃). The oxygen isotope ratio (δ¹⁸O) of the test is related to the calcification temperature and water properties (salinity and δ¹⁸O_sw). As each individual foraminifer has a life-span of roughly one month, careful analysis of the δ¹⁸O from individual shells provides multiple monthly "snapshots" of ocean conditions. With enough of these "snapshots", it is possible to infer not only the mean conditions, but also the variability of the ocean for the time that the foraminifera were alive. This climate information can then be compared to other time intervals to infer changes in ocean's mean state and its variability through time.

In addition to δ¹⁸O, I use other geochemical tools to reconstruct past ocean conditions. Among these tools are the ratios of trace metals, specifically Mg/Ca, in the tests of foraminifera. Mg replaces Ca as a function of calcification temperature, and thus the Mg/Ca ratios relate to the temperature during the foraminifera's lifetime. We can measure Mg/Ca ratios on aggregate samples of multiple crushed and cleaned foraminifera to provide us an estimate of the average temperature from the time interval we are studying. In order to measure the variability of ocean temperatures, we obtain the Mg/Ca ratios from individual foraminifera using laser ablation and inductively coupled mass spectroscopy (LA-ICPMS). This technique allows us to obtain detailed, chamber-by-chamber measurements of various trace metals (Al, Mg, Ca, Mn, Zn, Sr).

I have written software (TrACES - Trace metal Automated Computation and Evaluation Script) to automatically calculate Mg/Ca ratios from the large amounts of raw data generated by LA-ICPMS that detects characteristic changes in the data stream, applies drift correction, detects and flags possible contaminants, and summarizes the data by chamber and by individual. Working with the top-notch laboratory staff at LDEO, I have developed methods for measuring the Mg/Ca ratios in individual foraminifera using solution chemistry techniques and modified chemical cleaning procedures. We have begun using Optical Emission Spectroscopy (OES) ICP-MS to measure individual foraminifera, which will allow for the use of the individual foraminifera method during time periods where oxygen isotopes may be adversely affected by changes in seawater δ¹⁸O from ice volume effects, large scale salinity changes, or other factors.

Current Position

Assistant Professor
Department of Geology
School of Earth and Environment
Rowan University
Glassboro, NJ

Previous Position

Postdoctoral Research Scientist
Lamont Doherty Earth Obsevatory
61 Route 9W, Palisades, NY

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Education

Ph.D. in Earth and Environmental Sciences
City University of New York, Graduate Center, NY, September 2015
Thesis Title: Eastern tropical Pacific climate and El Niño variability during the past millennium
Thesis Advisor: Athanasios Koutavas
Committee Members: Marco Tedesco, Stephen Pekar, Braddock Linsley

Master of Philosophy, Earth and Environmental Sciences
City University of New York, Graduate Center, NY, September 2013

Master of Science, Environmental Science
Rutgers University, School of Environmental and Biological Science, New Brunswick, New Jersey, January 2011
Thesis Title: Polycyclic aromatic hydrocarbon contamination in and around the Arthur Kill, Staten Island, New York.
Thesis Advisor: Lisa Rodenberg

Bachelor of Science, Biology and Geology
University of Rochester, Rochester, NY, May 1995

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Fellowships and Awards

• LDEO Climate Center Grant, November 2015
  Eastern tropical Pacific climate variability during the last glacial termination: How does ENSO respond to changes in climatic boundary conditions?
• CUNY Graduate Center Science Fellowship (partial), 2010-2012
• Rutgers University SEBS Excellence Fellowship, 2009-2010
• Rutgers University SEBS Henry C. Torrey Fellowship Supplement, 2009-2010
• University of Rochester Wilson Scholarship (partial), 1991-1993

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Teaching Experience

College of Staten Island, City University of New York, Staten Island, NY
GEO100 – Planet Earth (Lecture) Fall 2013 - Spring 2015
GEO105 – Environmental Geology (Lecture) Fall 2012 - Spring 2013
GEO103 – Historical Geology Laboratory (Laboratory) Fall 2010 - Spring 2012

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Complete CV and references available upon request.

The El Niño Southern Oscillation (ENSO)

Information about ENSO is coming soon. However, great information about ENSO can be found here at the NOAA ENSO portal.