Welcome Back Students!

The undergrads who work in our lab are awesome!  Currently we have 10 students working on a diverse range of projects this semester.  There are students sieving and germinating seeds from cores taken from a marsh in Maryland. These seeds will help us assess how the sedge Schoenoplectus americanus, has evolved over the past 100 years in response to changes in CO2, temperature, salinity and flooding regimes.  We have students entering Public Land Survey data from the 1800s to help us recreate the composition, density, and biomass of historical forests of Indiana and Illinois.  Other students are working on a different tree project that involves counting tree rings from 100-200 year old trees in oak savannas compared to those in woodlands to examine the trees’ response to climate change through time.  This project also involves cutting up the tree rings to run isotope analyses to asses the water use efficiency of the trees throughout the trees’ lives and in the different conditions.  Finally, we have a student working on a project that will use the ecosystem model Linkages within the PEcAn tool to improve predictions of tree growth.

Our undergrads work hard, but they also have lots of fun and they make the lab fun!

Look at this huge old tree undergrads Emily Miller, Alec Helmke and Erin Nguyen found while taking the summer course at Notre Dame’s field station, UNDERC!
All 3 students have entered an extensive amount of historical Public Land Survey tree data for the lab. Even when students aren’t in the lab, they can’t get away from thinking about old trees.

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Welcome Megan Vahsen

The McLachlan lab welcomes new graduate student Megan Vahsen!

Megan is joining us to work on the marsh evolution and ecology project. See this page to learn more about Megan and the project.

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Quant Camp

Jason coordinated Quant Camp, an optional full emersion short course on quantitative skills for early career BIOS grad students from all disciplines.

The goals of the course were to provide hands on practical experience in problem solving, to introduce best practices in scientific computing, overview of scientific workflows and project management, integrating models, theory, & data and basic concepts in statistics and probability.

Students learned about random variable, data distributions & disease on Day 1, state space models and ecosystem measurements on Day 2, and uncertainty and cancer on Day 3.  They also worked in groups to develop their own independent projects where they applied the quantitative skills they learned.

Other course instructors were Beth Archie, Alex Perkins, Stuart Jones and a call-in by Zach Schafer.  Incoming McLachlan graduate student Megan Vahsen was the TA for the course.

Here are some pictures from the course.

 

 

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New NSF Funding! Coastal Marsh Response to CO2

We’ve been awarded a new grant from NSF (DEB- Ecosystem Studies)  for our project on Eco-evolutionary dynamics of coastal marsh responses to rishing CO2!

Here’s the overview of our proposed work:

Current projections of coastal marsh ecosystem responses to global environmental change (i.e., rising atmospheric carbon dioxide, sea level rise) assume static relationships between climate-related stressors and plant performance. However, the performance of ecologically dominant plants can rapidly evolve in response to climate-related stressors, which suggests that evolution could be driving ecological change in coastal marshes. Utilizing a 100+ year seed bank of the foundational sedge Schoenoplectus americanus (formerly Scirpus olneyi), we aim to examine the evolutionary dimensions of coastal marsh responses to environmental change. Building on preliminary findings, our goal is to determine whether ecosystem processes that regulate surface elevation are shaped by heritable responses of S. americanus to salinity, inundation, and carbon availability. To do so, we will first propagate and genotype modern and “ancestral” cohorts of plants from seeds retrieved from Chesapeake Bay marsh sediment cores. Taking ecological interactions into consideration, we will then conduct fully crossed exposure experiments with contemporary and ancestral cohorts to measure heritable, non-heritable and environmental contributions to plant traits, growth, and surface elevation. We will assess the aggregate importance of evolution to carbon and sediment accumulation (and allied processes) through a mechanistic model that accounts for data and model uncertainty. We will validate model predictions against independent estimates from sediment core profiles, and we will use a Bayesian assimilation framework to integrate all data streams (i.e., experiments, paleo observations, model predictions, prior studies) to determine the extent to which a century of evolution has affected Chesapeake Bay marshes, and how further data collection and model improvements might strengthen predictive forecasting.

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Website Revisions and Link

It’s time for a change! The McLachlan lab has transferred to this new website. We are currently in the process of updating our website content, so please excuse our dust for a little bit.

 

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