Participating Students - Fernanda Santos

Fernanda Santos
Graduate Center, CUNY
Earth and Environmental Sciences
BART Cohort 2009
Email:FSantos at gc.cuny.edu
Biospheric Mentor: Jeffery Bird
Atmospheric Mentor: Matthew Fraser

Fernanda Santos is a second year Ph.D student in Earth and Environmental Sciences at The Graduate Center, CUNY. In 2004 she received her B.Sc. in Geography from the State University of Rio de Janeiro (Brazil). While majoring in Geography, she did a 3-year internship at the Soil Research Institute of the Brazilian Agricultural Research Corporation, where she worked on different projects involving soil quality and land degradation. In 2006 Fernanda was awarded with a $5,000 scholarship from the Society of Woman Geographers to support her MA research thesis entitled “Quantifying the scales of the land surface heterogeneity”. She received her MA degree in Physical Geography from Hunter College (CUNY) in 2007.

Fernanda is currently working with Dr. Jeffrey Bird from the Department of Environmental Sciences at Queens College (CUNY). Her research aims at understanding the dynamics of charred biomass (black carbon) in temperate forest ecosystems. Fernanda’s research interests also include measurements of soil carbon stocks in tropical environments, and soil microbiology. Outside of her studies, Fernanda enjoys outdoors activities and arts.

Research
An increase in forest fire frequency and intensity, triggered by warmer air temperatures, is likely to increase the contribution of incompletely combusted plant biomass (black carbon) to soil carbon (C) stocks. Black carbon (BC) additions to forest soils also come from atmospheric deposition of BC and soot aerosols produced off-site. While the contribution of BC to soil carbon storage has been well recognized, knowledge of BC dynamics in soil and its response to elevated N deposition in temperate forest ecosystems is limited. In addition, the amount of BC input to soils from the atmosphere via plant-derived sources and fossil fuel emissions is not well known. This proposed research would address two important gaps in our understanding of BC dynamics in temperate forests: (1) the amount and sources of BC deposition from the atmosphere (i.e., fire, fossil fuels); and (2) the in situ degradation rates of BC and wood in soil. Using existing DIRT experimental plots located at the University of Michigan Biological Station, I will track the fate of 13C/15N-enriched Acer rubrum–derived BC (and its precursor wood) added to soil mesocosms within plots that have received zero or elevated NH4-N (20 kg N ha-1 yr-1) since 2004. Labeled BC and wood dynamics will be quantified as the amount of material remaining in soil mesocosms, dissolved organic C (lysimeters), and 13CO2 efflux during 2 years. In addition, the biological degradation and assimilation of BC will be assessed by tracking BC and wood 13C into the phospholipids fatty acids (13C-PLFA) of soil microbes, which will quantify the utilization of added BC and wood by specific microbial groups. The amount of BC deposited annual via aerosols will be quantified at UMBS and will be partitioned into plant biomass-derived BC and fossil fuel-derived BC using isotopic (13C and 14C) and molecular biomarker (Levoglugosan, PAH, BPCA) approaches. This research will provide needed field data on both BC (and wood) decomposition in soil and atmospheric deposition of BC materials, which are critical unknowns in the biosphere-atmosphere C linkage in temperate forests. The results of this study will ultimately contribute to improve models of biosphere-atmosphere BC dynamics.