Chen Min

No Thumbnail Available
Last Name
Chen
First Name
Min
ORCID

Filters

2007 - 2009 1 2010 - 2014 3
3 1
4
Reset filters

Settings

Search Results

Now showing 1 - 4 of 4
  • Article
    The impacts of recent permafrost thaw on land–atmosphere greenhouse gas exchange
    (IOP Publishing, 2014-04-06) Hayes, Daniel J. ; Kicklighter, David W. ; McGuire, A. David ; Chen, Min ; Zhuang, Qianlai ; Yuan, Fengming ; Melillo, Jerry M. ; Wullschleger, Stan D.
    Permafrost thaw and the subsequent mobilization of carbon (C) stored in previously frozen soil organic matter (SOM) have the potential to be a strong positive feedback to climate. As the northern permafrost region experiences as much as a doubling of the rate of warming as the rest of the Earth, the vast amount of C in permafrost soils is vulnerable to thaw, decomposition and release as atmospheric greenhouse gases. Diagnostic and predictive estimates of high-latitude terrestrial C fluxes vary widely among different models depending on how dynamics in permafrost, and the seasonally thawed 'active layer' above it, are represented. Here, we employ a process-based model simulation experiment to assess the net effect of active layer dynamics on this 'permafrost carbon feedback' in recent decades, from 1970 to 2006, over the circumpolar domain of continuous and discontinuous permafrost. Over this time period, the model estimates a mean increase of 6.8 cm in active layer thickness across the domain, which exposes a total of 11.6 Pg C of thawed SOM to decomposition. According to our simulation experiment, mobilization of this previously frozen C results in an estimated cumulative net source of 3.7 Pg C to the atmosphere since 1970 directly tied to active layer dynamics. Enhanced decomposition from the newly exposed SOM accounts for the release of both CO2 (4.0 Pg C) and CH4 (0.03 Pg C), but is partially compensated by CO2 uptake (0.3 Pg C) associated with enhanced net primary production of vegetation. This estimated net C transfer to the atmosphere from permafrost thaw represents a significant factor in the overall ecosystem carbon budget of the Pan-Arctic, and a non-trivial additional contribution on top of the combined fossil fuel emissions from the eight Arctic nations over this time period.
  • Preprint
    An analysis of the carbon balance of the Arctic Basin from 1997 to 2006
    ( 2010-06-18) McGuire, A. David ; Hayes, Daniel J. ; Kicklighter, David W. ; Manizza, Manfredi ; Zhuang, Qianlai ; Chen, Min ; Follows, Michael J. ; Gurney, Kevin R. ; McClelland, James W. ; Melillo, Jerry M. ; Peterson, Bruce J. ; Prinn, Ronald G.
    This study used several model-based tools to analyze the dynamics of the Arctic Basin between 1997 and 2006 as a linked system of land-ocean-atmosphere C exchange. The analysis estimates that terrestrial areas of the Arctic Basin lost 62.9 Tg C yr-1 and that the Arctic Ocean gained 94.1 Tg C yr-1. Arctic lands and oceans were a net CO2 sink of 108.9 Tg C yr-1, which is within the range of uncertainty in estimates from atmospheric inversions. Although both lands and oceans of the Arctic were estimated to be CO2 sinks, the land sink diminished in strength because of increased fire disturbance compared to previous decades, while the ocean sink increased in strength because of increased biological pump activity associated with reduced sea ice cover. Terrestrial areas of the Arctic were a net source of 41.5 Tg CH4 yr-1 that increased by 0.6 Tg CH4 yr-1 during the decade of analysis, a magnitude that is comparable with an atmospheric inversion of CH4. Because the radiative forcing of the estimated CH4 emissions is much greater than the CO2 sink, the analysis suggests that the Arctic Basin is a substantial net source of green house gas forcing to the climate system.
  • Article
    Bathymetric zonation of deep-sea macrofauna in relation to export of surface phytoplankton production
    (Inter-Research, 2010-01-28) Wei, Chih-Lin ; Rowe, Gilbert T. ; Hubbard, G. Fain ; Scheltema, Amelie H. ; Wilson, George D. F. ; Petrescu, Iorgu ; Foster, John M. ; Wicksten, Mary K. ; Chen, Min ; Davenport, Roe ; Soliman, Yousria ; Wang, Yuning
    Macrobenthos of the deep, northern Gulf of Mexico (GoM) was sampled with box cores (0.2 m2) along multiple cross-depth transects extending from depths of 200 m to the maximum depth of the basin at 3700 m. Bathymetric (depth) zonation of the macrofaunal community was documented for 6 major taxa (a total of 957 species) on the basis of shared species among geographic locations; 4 major depth zones were identified, with the 2 intermediate-depth zones being divided into east and west subzones. Change of faunal composition with depth reflects an underlying continuum of species replacements without distinct boundaries. The zonal patterns correlated with depth and detrital particulate organic carbon (POC) export flux estimated from remotely-sensed phytoplankton pigment concentrations in the surface water. The Mississippi River and its associated mesoscale eddies, submarine canyon, and deep sediment fan appear to influence the horizontal zonation pattern through export of organic carbon from the ocean surface and the adjacent continental margin. On the local scale, near-bottom currents may shape the zonation pattern by altering sediment grain size, food availability, and larval dispersal. This study suggests a macroecological relationship between depth, export POC flux, and zonation; parsimonious zonal thresholds need to be tested independently for other continental margin ecosystems.
  • Article
    An assessment of the use of sediment traps for estimating upper ocean particle fluxes
    (Sears Foundation for Marine Research, 2007-05) Buesseler, Ken O. ; Antia, Avan N. ; Chen, Min ; Fowler, Scott W. ; Gardner, Wilford D. ; Gustafsson, Orjan ; Harada, Koh ; Michaels, Anthony F. ; Rutgers van der Loeff, Michiel M. ; Sarin, Manmohan M. ; Steinberg, Deborah K. ; Trull, Thomas W.
    This review provides an assessment of sediment trap accuracy issues by gathering data to address trap hydrodynamics, the problem of zooplankton "swimmers," and the solubilization of material after collection. For each topic, the problem is identified, its magnitude and causes reviewed using selected examples, and an update on methods to correct for the potential bias or minimize the problem using new technologies is presented. To minimize hydrodynamic biases due to flow over the trap mouth, the use of neutrally buoyant sediment traps is encouraged. The influence of swimmers is best minimized using traps that limit zooplankton access to the sample collection chamber. New data on the impact of different swimmer removal protocols at the US time-series sites HOT and BATS are compared and shown to be important. Recent data on solubilization are compiled and assessed suggesting selective losses from sinking particles to the trap supernatant after collection, which may alter both fluxes and ratios of elements in long term and typically deeper trap deployments. Different methods are needed to assess shallow and short- term trap solubilization effects, but thus far new incubation experiments suggest these impacts to be small for most elements. A discussion of trap calibration methods reviews independent assessments of flux, including elemental budgets, particle abundance and flux modeling, and emphasizes the utility of U-Th radionuclide calibration methods.