Closeup of internal structure of a tropical tree

IsoTropics

Goals

The IsoTropics VIP Team investigates past tropical climate and how trees have responded to environmental changes by analyzing tree rings. They measure stable carbon and oxygen isotopes in the wood to reconstruct past conditions like rainfall, temperature, and atmospheric CO₂ levels, using advanced techniques such as laser ablation and isotope ratio mass spectrometry. 

Despite their critical role in the global climate system and their ability to act as powerful carbon sinks that help slow climate change, the tropics are among the least studied regions when it comes to ecophysiology and past climate change. Our goal is to better understand tropical climates and ecosystems by analyzing the environmental and physiological information preserved in tree rings. We achieve this by measuring the relative abundance of stable carbon and oxygen isotopes in the wood, which allows us to reconstruct the environmental conditions the trees experienced as they grew. These conditions include changes in rainfall, temperature, and atmospheric carbon dioxide levels. In addition to revealing past climate patterns and fluctuations, these measurements also help us understand how trees reacted and adapted physiologically to those changes. Because trees can be long-lived, tree rings provide a unique archive of both short-term and long-term environmental fluctuations driven by natural processes and human activity.

Our ongoing projects include:

  1. Tropical Maya Lowlands: We are developing new oxygen isotopic records from two tree species in the Maya lowlands to capture large-scale circulation patterns in Mesoamerica. By combining these records with others from across Central America, we aim to constrain regional climate dynamics over the past 200–300 years.
  2. Vulnerability and resilience of trees in the Amazon Arc of deforestation: in collaboration with colleagues from Yale University (USA), we are exploring the ecophysiology of Amazonian trees with different carbohydrate storage strategies. The goal is to understand how they respond to environmental stress, particularly in forest edge vs. interior settings by linking isotope measurements in tree rings with metabolic and structural traits.
  3. Tracing the movement of the intertropical convergence zone (ITCZ): In collaboration with colleagues from UNICAMP university (Brazil), we are developing oxygen isotopic records over the last ~ 100 years from a network of Spanish cedars to trace the shifts of the intertropical convergence zone (ITCZ) and associated rainfall pattern. The ITCZ movements (north and south) with the seasons helps shape wet and dry periods in many tropical regions and impacts rainforests, agriculture, and water resources for millions of people.

Issues Involved or Addressed

  • Tropical past climate
  • Tropical atmospheric circulation
  • Tree growth and ecophysiology
  • Atmosphere-biosphere interactions
  • Dendrochronology

Methods and Tech

Our team uses a range of methods to decode the environmental signals stored in tropical wood. One of the advanced techniques we use is laser ablation coupled with isotope ratio mass spectrometry. This cutting-edge approach allows us to measure carbon and oxygen isotopes at incredibly high resolution (down to just 40 microns) across different tree species and locations throughout the tropics. 

  • Dendrochronology
  • Stable isotope mass spectrometry
  • Climate and ecophysiological modeling
  • Spatial data analysis

Academic Majors of Interest

Though open to all majors, we are most interested in students majoring in:

  • Geography
  • Geosciences
  • Ecology and Evolutionary Biology
  • Environmental Sciences
  • Chemistry
  • Natural Resources
  • Plant Sciences
  • Statistics and Data Science
  • Applied Mathematics

Preferred Interests and Preparation

  • Self-motivated and curiosity-driven
  • Basic understanding of and interest in climatology/forestry/ecophysiology/atmospheric sciences.
  • Comfortable working with machines (belt sander, small rotary saw).
  • Comfortable working in a wet chemistry lab
  • Detail-oriented
  • Team-player
  • Openness to learning new techniques

Application Process

To express interest in this team, please complete the VIP Interest Form and select "IsoTropics."

This team accepts students at the start of each semester.

This team recruits students for both credit and federal work-study options for VIP participation.

Team Advisors

Soumaya Belmecheri, PhD
Kevin Anchukaitis, PhD
Ana Isabel Gonzalez-Mendez, MA