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Articles 1 - 11 of 11

Full-Text Articles in Life Sciences

Assessing Changing Carbon Pool Dynamics And Species Composition In A Pennsylvania Broadleaf Forest Fragment, Kyleigh Levinsky, Jessica L. Schedlbauer Jan 2024

Assessing Changing Carbon Pool Dynamics And Species Composition In A Pennsylvania Broadleaf Forest Fragment, Kyleigh Levinsky, Jessica L. Schedlbauer

Sustainability Research & Creative Activities Grants Reports

Temperate broadleaf forests are pivotal to the global carbon cycle, Representing 37% of the global forest carbon pool (Pan et al 2011). • Maintaining compositional diversity in temperate broadleaf forests, such as the Gordon Natural Area (GNA) is critical to maintaining ecosystem services, such as carbon sequestration. • Pressures from native and non-native herbivores threaten the biodiversity of temperate broadleaf forests in the United States (Ghandi et al. 2010). The introduction of non-native insects such as the emerald ash borer (Argrilus planipennis), as well as the overpopulation of white-tailed deer (Odocoileus virginianus) has led to declines in some tree species. …


Fire History And Long-Term Carbon Accumulation In Hemi-Boreal Peatlands Companion Dataset, Dominic Uhelski, Evan Kane, Katherine Heckman, Rodney Chimner Nov 2022

Fire History And Long-Term Carbon Accumulation In Hemi-Boreal Peatlands Companion Dataset, Dominic Uhelski, Evan Kane, Katherine Heckman, Rodney Chimner

Michigan Tech Research Data

This dataset contains peat property data including location, depth, bulk density, organic matter content, and carbon content, infrared spectra, and radiocarbon dates. Peat cores were collected between 2011 and 2019. Analyses were performed between 2018 and 2021. Samples were collected from peatlands in Michigan, Wisconsin, and Minnesota for the purposes of reconstruction of fire history. The data is associated with a yet-to-be-published manuscript to be submitted to Ecosystems.

A README file is included describing the contents of the dataset and all major spreadsheet files contain a Meta worksheet which describes each column of
data.


Fresh Air For The Mire-Breathing Hypothesis: Sphagnum Moss And Peat Structure Regulate The Response Of Co2 Exchange To Altered Hydrology In A Northern Peatland Ecosystem, Ally O’Neill, Colin Tucker, Evan S. Kane Oct 2022

Fresh Air For The Mire-Breathing Hypothesis: Sphagnum Moss And Peat Structure Regulate The Response Of Co2 Exchange To Altered Hydrology In A Northern Peatland Ecosystem, Ally O’Neill, Colin Tucker, Evan S. Kane

Michigan Tech Publications

Sphagnum-dominated peatlands store more carbon than all of Earth’s forests, playing a large role in the balance of carbon dioxide. However, these carbon sinks face an uncertain future as the changing climate is likely to cause water stress, potentially reducing Sphagnum productivity and transitioning peatlands to carbon sources. A mesocosm experiment was performed on thirty-two peat cores collected from two peatland landforms: elevated mounds (hummocks) and lower, flat areas of the peatland (hollows). Both rainfall treatments and water tables were manipulated, and CO2 fluxes were measured. Other studies have observed peat subsiding and tracking the water table downward when experiencing …


Senescent Trees Stabilize Aboveground Wood Net Primary Production Immediately After Disturbance, Maxim S. Grigri Jan 2020

Senescent Trees Stabilize Aboveground Wood Net Primary Production Immediately After Disturbance, Maxim S. Grigri

Theses and Dissertations

In the United States, forests sequester 17% of national carbon (C) emissions annually (UGCRP, 2018), however shifting forest disturbances threaten the stability of this essential C sink. Unlike the high severity, stand-replacing disturbances that were widespread a century ago, today’s eastern temperate forests experience frequent low-to-moderate severity disturbances from invasive pests and pathogens with mixed effects on net primary production (NPP). Carbon cycling stability after disturbance has been reported, however, the mechanisms underlying immediate NPP stability or decline are not well understood. Through weekly measurements of production in a landscape scale experiment, we show that the sustained growth of senescent …


Rain-Induced Changes In Soil Co2 Flux And Microbial Community Composition In A Tropical Forest Of China, Qi Deng, Dafeng Hui, Guowei Chu, Xi Han, Quanfa Zhang Jul 2017

Rain-Induced Changes In Soil Co2 Flux And Microbial Community Composition In A Tropical Forest Of China, Qi Deng, Dafeng Hui, Guowei Chu, Xi Han, Quanfa Zhang

Biology Faculty Research

Rain-induced soil CO2 pulse, a rapid excitation in soil CO2 flux after rain, is ubiquitously observed in terrestrial ecosystems, yet the underlying mechanisms in tropical forests are still not clear. We conducted a rain simulation experiment to quantify rain-induced changes in soil CO2 flux and microbial community composition in a tropical forest. Soil CO2 flux rapidly increased by ~83% after rains, accompanied by increases in both bacterial (~51%) and fungal (~58%) Phospholipid Fatty Acids (PLFA) biomass. However, soil CO2 flux and microbial community in the plots without litters showed limited response to rains. Direct releases …


Long-Term Nitrogen Addition Decreases Carbon Leaching In A Nitrogen-Rich Forest Ecosystem, X. Lu, Frank S. Gilliam, G. Yu, H. Chen, J. Mo May 2016

Long-Term Nitrogen Addition Decreases Carbon Leaching In A Nitrogen-Rich Forest Ecosystem, X. Lu, Frank S. Gilliam, G. Yu, H. Chen, J. Mo

Frank S. Gilliam

Dissolved organic carbon (DOC) plays a critical role in the carbon (C) cycle of forest soils, and has been recently connected with global increases in nitrogen (N) deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine …


The Linkages Between Photosynthesis, Productivity, Growth And Biomass In Lowland Amazonian Forests, Yadvinder Malhi, Christopher E. Doughty, Gregory R. Goldsmith, Daniel B. Metcalfe, Cécile A.J. Girardin, Toby R. Marthews, Jhon Del Aguila-Pasquel, Luiz E.O.C. Aragão, Alejandro Araujo-Murakami, Paulo Brando, Antonino C.L. Da Costa, Javier E. Silva-Espejo, Filio Farfán Amézquita, David R. Galbraith, Carlos A. Quesada, Wanderley Rocha, Norma Salinas-Revilla, Divino Silvério, Patrick Meir, Oliver L. Phillips Mar 2015

The Linkages Between Photosynthesis, Productivity, Growth And Biomass In Lowland Amazonian Forests, Yadvinder Malhi, Christopher E. Doughty, Gregory R. Goldsmith, Daniel B. Metcalfe, Cécile A.J. Girardin, Toby R. Marthews, Jhon Del Aguila-Pasquel, Luiz E.O.C. Aragão, Alejandro Araujo-Murakami, Paulo Brando, Antonino C.L. Da Costa, Javier E. Silva-Espejo, Filio Farfán Amézquita, David R. Galbraith, Carlos A. Quesada, Wanderley Rocha, Norma Salinas-Revilla, Divino Silvério, Patrick Meir, Oliver L. Phillips

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but …


Large Carbon Release Legacy From Bark Beetle Outbreaks Across Western United States, Bardan Ghimire, Christopher A. Williams, G. James Collatz, Melanie Vanderhoof, John Rogan, Dominik Kulakowski, Jeffrey G. Masek Jan 2015

Large Carbon Release Legacy From Bark Beetle Outbreaks Across Western United States, Bardan Ghimire, Christopher A. Williams, G. James Collatz, Melanie Vanderhoof, John Rogan, Dominik Kulakowski, Jeffrey G. Masek

Geography

Warmer conditions over the past two decades have contributed to rapid expansion of bark beetle outbreaks killing millions of trees over a large fraction of western United States (US) forests. These outbreaks reduce plant productivity by killing trees and transfer carbon from live to dead pools where carbon is slowly emitted to the atmosphere via heterotrophic respiration which subsequently feeds back to climate change. Recent studies have begun to examine the local impacts of bark beetle outbreaks in individual stands, but the full regional carbon consequences remain undocumented for the western US. In this study, we quantify the regional carbon …


Agricultural Conversion Without External Water And Nutrient Inputs Reduces Terrestrial Vegetation Productivity, William Kolby Smith, Cory C. Cleveland, Sasha C. Reed, Steven W. Running Jan 2014

Agricultural Conversion Without External Water And Nutrient Inputs Reduces Terrestrial Vegetation Productivity, William Kolby Smith, Cory C. Cleveland, Sasha C. Reed, Steven W. Running

Ecosystem and Conservation Sciences Faculty Publications

Driven by global population and standard of living increases, humanity co-opts a growing share of the planet's natural resources resulting in many well-known environmental trade-offs. In this study, we explored the impact of agriculture on a resource fundamental to life on Earth: terrestrial vegetation growth (net primary production; NPP). We demonstrate that agricultural conversion has reduced terrestrial NPP by ~7.0%. Increases in NPP due to agricultural conversion were observed only in areas receiving external inputs (i.e., irrigation and/or fertilization). NPP reductions were found for ~88% of agricultural lands, with the largest reductions observed in areas formerly occupied by tropical forests …


Iron Oxidation Stimulates Organic Matter Decomposition In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver Jul 2013

Iron Oxidation Stimulates Organic Matter Decomposition In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver

Steven J. Hall

Humid tropical forests have the fastest rates of organic matter decomposition globally, which often coincide with fluctuating oxygen (O2) availability in surface soils. Microbial iron (Fe) reduction generates reduced iron [Fe(II)] under anaerobic conditions, which oxidizes to Fe(III) under subsequent aerobic conditions. We demonstrate that Fe (II) oxidation stimulates organic matter decomposition via two mechanisms: (i) organic matter oxidation, likely driven by reactive oxygen species; and (ii) increased dissolved organic carbon (DOC) availability, likely driven by acidification. Phenol oxidative activity increased linearly with Fe(II) concentrations (P < 0.0001, pseudo R2 = 0.79) in soils sampled within and among five tropical forest sites. A similar pattern occurred in the absence of soil, suggesting an abiotic driver of this reaction. No phenol oxidative activity occurred in soils under anaerobic conditions, implying the importance of oxidants such as O2 or hydrogen peroxide (H2O2) in addition to Fe(II). Reactions between Fe(II) and H2O2 generate hydroxyl radical, a strong nonselective oxidant of organic compounds. We found increasing consumption of H2O2 as soil Fe(II) concentrations increased, suggesting that reactive oxygen species produced by Fe(II) oxidation explained variation in phenol oxidative activity among samples. Amending soils with Fe(II) at field concentrations stimulated short-term C mineralization by up to 270%, likely via a second mechanism. Oxidation of Fe(II) drove a decrease in pH and a monotonic increase in DOC; a decline of two pH units doubled DOC, likely stimulating microbial respiration. We obtained similar results by manipulating soil acidity independently of Fe(II), implying that Fe(II) oxidation affected C substrate availability via pH fluctuations, in addition to producing reactive oxygen species. Iron oxidation coupled to organic matter decomposition contributes to rapid rates of C cycling across humid tropical forests in spite of periodic O2 limitation, and may help explain the rapid turnover of complex C molecules in these soils.


Long-Term Nitrogen Addition Decreases Carbon Leaching In A Nitrogen-Rich Forest Ecosystem, X. Lu, Frank S. Gilliam, G. Yu, H. Chen, J. Mo Jun 2013

Long-Term Nitrogen Addition Decreases Carbon Leaching In A Nitrogen-Rich Forest Ecosystem, X. Lu, Frank S. Gilliam, G. Yu, H. Chen, J. Mo

Biological Sciences Faculty Research

Dissolved organic carbon (DOC) plays a critical role in the carbon (C) cycle of forest soils, and has been recently connected with global increases in nitrogen (N) deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine …