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Carbon pool trends and dynamics within a subtropical peatland during long-term restoration

Ecological Processes 2017年第1期6卷 449-462页

作者： Paul Julian II Stefan Gerber alan l.wright Binhe Gu Todd Z.Osborne University of Florida Soil and Water Sciences DepartmentFt.PierceFL 34945USA. University of Florida Soil and Water Sciences DepartmentGainesvilleFL 32611USA. South Florida Water Management District Water Quality BureauWest Palm BeachFL 33406USA. University of Florida Whitney Laboratory for Marine BioscienceSt AugustineFL 32080USA.

Introduction:The Florida Everglades has undergone significant ecological change spanning the continuum of disturbance to *** the restoration effort is not complete and the ecosystem continues to experience short duration perturbations,a better understanding of long-term C dynamics of the Everglades is needed to facilitate new restoration *** study evaluated temporal trends of different aquatic carbon(C)pools of the northern Everglades Protection Area over a 20-year period to gauge historic C cycling *** inorganic C(DIC),dissolved organic C(DOC),particulate organic C(POC),and surface water carbon dioxide(pCO2(aq))were investigated between May 1,1994 and April 30,***:Annual mean concentrations of DIC,DOC,POC,and pCO2(aq)significantly decreased through time or remained constant across the Water Conservation Areas(WCAs).Overall,the magnitude of the different C pools in the water column significantly differed between *** of CO2 was dynamic across the Everglades ranging from 420 to 2001 kg CO2 year−***,the historic trend in CO2 flux from the marsh declined across our study area while pCO2(aq)largely remained somewhat constant with the exception of Water Conservation Area 2 which experienced significant declines in pCO2(aq).Particulate OC concentrations were consistent between WCAs,but a significantly decreasing trend in annual POC concentrations was ***:Hydrologic condition and nutrient inputs significantly influenced the balance,speciation,and flux of C pools across WCAs suggesting a subsidy-stress response in C dynamics relative to landscape scale responses in nutrient *** interplay between nutrient inputs and hydrologic condition exert a driving force on the balance between DIC and DOC production via the metabolism of organic matter which forms the base of the aquatic food *** the restoration trajectory as water quality and hydrology continues to improve,it is expect

关键词： Inorganic carbon Organic carbon Carbon dioxide Particulate carbon Hydrology Nutrients

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Soil Enzyme Activities and Organic Matter Composition Affected by 26 Years of Continuous Cropping

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Pedosphere 2016年第5期26卷 618-625页

作者： Fugen DOU alan l.wright Rao S.MYlAVARAPU JIANG Xianjun John E.MATOCHA Texas A&M Agrilife Research Center at Beaumont BeaumontTX 77713(USA) University of Florida Indian River Research&Education CenterFt.PierceFL 34945(USA) University of Florida Soil&Water Science Dept.GainesvilleFL 32611(USA) Southwest University College of Resources and EnvironmentChongqing(China) Texas A&M University Agricultural Research and Extension CenterCorpus ChristiTX 78406(USA)

The study was to determine the long-term effects of subtropical monoculture and rotational cropping systems and fertilization on soil enzyme activities and soil C, N, and P levels. Cropping systems included continuous sorghum(Sorghum bicolor l.), cotton(Gossypium hirsutum l.), corn(Zea mays l.), and cotton/sorghum rotations after 26 years of treatment imposition. Soil under continuous sorghum and continuous corn had 15% and 11%, respectively, greater C concentrations than soil under continuous *** C was 10% higher at 0–7.5 cm than at 7.5–15 cm. Total N followed similar trends with soil depth as organic C. Continuous sorghum had 19% higher total N than other crop species and rotations. With fertilization, continuous cotton had the highest total P at 0–7.5 cm and sorghum had the highest at 7.5–15 cm. Soil total P was 14% higher at 0–7.5 than at 7.5–15 cm, and fertilization increased 15% total P compared to unfertilized soil. Arylsulfatase, alkaline phosphatase, and β-d-glucosidase activity were the highest for sorghum and the lowest for cotton. Rotation increased enzyme activities compared to continuous cotton but not for continuous sorghum. Of all crop species and rotations, continuous cotton generally showed the lowest levels of organic matter and enzyme activities after 26 years. Fertilization significantly increased the yields for all cropping systems, but rotation had no significant effect on either sorghum or cotton lint yield compared to each crop grown in monoculture. long-term cropping did not increase soil organic matter levels beyond short-term gains, indicating the difficulty in promoting C sequestration in subtropical soils.

关键词： C sequestration fertilization monoculture rotation subtropical soil

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Autotrophic and Heterotrophic Nitri?cation in a Highly Acidic Subtropical Pine Forest Soil

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Pedosphere 2016年第6期26卷 904-910页

作者： FAEFlEN J.Sarwee lI Shiwei XIN Xiaoping alan l.wright JIANG Xianjun College of Resources and Environment Southwest UniversityChongqing 400715(China) Everglades Research&Education Center University of FloridaBelle Glade FL 33430(USA)

The occurrence of nitri?cation in some acidic forest soils is still a subject of ***?cation of main nitri?cation pathways in acidic forest soils is still largely *** yellow soil(Oxisol) samples were selected to test whether nitri?cation can occur or not in acidic subtropical pine forest *** contributions of autotrophs and heterotrophs to nitri?cation were studied by adding selective nitri?cation inhibitor *** NH^+_4-N concentrations decreased,but NO^-_3-N concentrations increased signi?cantly for the no-nitrapyrin control during the ?rst week of incubation,indicating that nitri?cation did occur in the acidic subtropical *** calculated net nitri?cation rate was 0.49 mg N kg^(-1)d^(-1)for the no-nitrapyrin control during the ?rst week of *** amendment resulted in a signi?cant reduction of NO^-_3-N *** nitri?cation rate averaged0.28 mg N kg^(-1)d^(-1)and the heterotrophic nitri?cation rate was 0.21 mg N kg^(-1)d^(-1)in the ?rst ***-oxidizing bacteria(AOB) abundance increased slightly during incubation,but nitrapyrin amendment signi?cantly decreased AOB amo A gene copy numbers by about 80%.However,the ammonia-oxidizing archaea(AOA) abundance showed signi?cant increases only in the last 2weeks of incubation and it was also decreased by nitrapyrin *** results indicated that nitri?cation did occur in the present acidic subtropical pine forest soil,and autotrophic nitri?cation was the main nitri?cation *** AOA and AOB were the active biotic agents responsible for autotrophic nitri?cation in the acidic subtropical pine forest soil.

关键词： acidic yellow soil ammonia-oxidizing archaea ammonia-oxidizing bacteria net nitrification rate nitrapyrin nitrification inhibitor

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Evaluation of nutrient stoichiometric relationships among ecosystem compartments of a subtropical treatment wetland. Do we have “Redfield wetlands”?

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Ecological Processes 2019年第1期8卷 267-287页

作者： Paul Julian II Stefan Gerber Rupesh K.Bhomia Jill King Todd Z.Osborne alan l.wright Matthew Powers Jacob Dombrowski Soil and Water Sciences Department University of FloridaFt.PierceFL34945USA Soil and Water Sciences Department University of FloridaGainesvilleFL 32611USA South Florida Water Management District Water Quality Treatment TechnologiesWest Palm BeachFL 33406USA Whitney laboratory for Marine Bioscience University of FloridaSt AugustineFL 32080USA.

Background:Evaluation of carbon(C),nitrogen(N),and phosphorus(P)ratios in aquatic and terrestrial ecosystems can advance our understanding of biological processes,nutrient cycling,and the fate of organic matter(OM)in these *** of aquatic ecosystems can change the accumulation and decomposition of OM which can alter biogeochemical cycling and alter the base of the aquatic food *** study investigated nutrient stoichiometry within and among wetland ecosystem compartments(i.e.,water column,flocculent,soil,and aboveground vegetation biomass)of two subtropical treatment wetlands with distinct vegetation *** flow-ways(FWs)within the network of Everglades Stormwater Treatment Areas in south Florida(USA)were selected for this *** evaluated nutrient stoichiometry of these to understand biogeochemical cycling and controls of nutrient removal in a treatment wetland within an ecological stoichiometry ***:This study demonstrates that C,N,and P stoichiometry can be highly variable among ecosystem compartments and between *** law slopes of C,N,and P within surface water floc,soil,and vegetation were significantly different between and along ***:Assessment of wetland nutrient stoichiometry between and within ecosystem compartments suggests unconstrained stoichiometry related to P that conforms with the notion of P limitation in the *** in N:P ratios between floc and soil suggest different pathways of organic nutrient accumulation and retention between *** nutrient stoichiometry was highly variable and decoupled(or close to decoupled as indicated bylained variation between parameters),in particular with respect to *** hypothesize that decoupling may be the imprint of variability in inflow nutrient ***,despite active biogeochemical cycles that could act to restore nutrient stoichiometry along the FW,there was little evidence that such balancing occurred,as the

关键词： Decomposition Mineralization Everglades Treatment wetlands

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Redox-driven shifts in soil microbial community structure in the drawdown zone after construction of the Three Gorges Dam

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Soil Ecology letters 2019年第3期1卷 114-125页

作者： Shuling Wang Sarwee J.Faeflen alan l.wright Xia Zhu-Barker Xianjun Jiang College of Resources and Environment Southwest UniversityChongqing 400715China Indian River Research&Education Center University of FloridaFort PierceFL 34945USA Department of land Air and Water ResourcesUniversity of California DavisCA 95616USA

Soil redox is a critical environmental factor shaping the microbial community structure and ultimately alters the nutrient ***,the response of soil microbial community structure to prolonged or repeated redox fluctuations is not yet *** study the dynamic effects of prolonged redox disturbances to the soil microbial community structure,soil samples experiencing 8,5 and 0 alternating oxic-anoxic cycles within approximately 6 months each year were collected and the microbial community structure were evaluated using phospholipid fatty acid analysis(PlFA)*** redox disturbances had significant effects on soil physiochemical properties and soil microbial community *** relative abundance of straight chain saturated PlFAs,cyclopropyl,and terminal-and mid-branched chain saturated PlFAs increased due to prolonged redox disturbances,but there was a consistent decrease in linear monounsaturated PlFAs and polyunsaturated PlFAs in the fluctuating *** redox disturbances had a negative impact on the total PlFA content(a proxy for biomass).Both the fluctuating zone(8-cycle and 5-cycle plots)and the never flooded zone(0-cycle plots)were dominated by Gram-positive bacteria and a low content of fungi,actinomycetes and *** fungi and protozoa abundance decreased significantly with an increase in the occurrence of alternating flooding-dry events,suggesting that the prolonged redox disturbance leads to high stress on the fungi and protozoa ***,total organic matter(TOC)and C:N ratio,environmental factors that can be influenced by recurring redox fluctuations,also influenced the microbial community structure.

关键词： Water fluctuation zone Redox disturbance Microbial community structure Phospholipid fatty acids(PlFA) Three Gorges Reservoir

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Oxygen availability,rather than ammonia,plays an important role in niche differentiation between comammox Nitrospira and canonical ammonia oxidizers in a neutral purple paddy soil

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Pedosphere 2023年第2期33卷 381-384页

作者： Shuling WANG Zhihui WANG Yongpeng ZHAO alan lwright Xianjun JIANG College of Resources and Environment Southwest UniversityChongqing 400715(China) Indian River Research&Education Center University of FloridaFort Pierce FL 34945(USA)

Dear Editor,Nitrification,the only process linking the oxidation and reduction of N in natural ecosystems,plays a vital role in maintaining global N *** oxidation is the first and rate-limiting step of aerobic nitrifi... 详细信息

关键词： paddy soil ammonia

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Heterogeneously integrated silicon-conductive oxide MOSCAP microring modulator array

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Photonics Research 2025年第1期13卷 187-193页

作者： WEI-CHE HSU SAEED ABDOlHOSSEINI HAISHENG RONG RANJEET KUMAR BERND ZECHMANN alan X.WANG Department of Electrical and Computer Engineering Baylor University School of Electrical Engineering and Computer Science Oregon State University Intel Corporation Center of Microscopy and Imaging Baylor University

In pursuit of energy-efficient optical interconnect, the silicon microring modulator（Si-MRM） has emerged as a pivotal device offering an ultra-compact footprint and capability of on-chip wavelength division multiplexing（WDM）. This paper presents a 1 × 4 metal-oxide-semiconductor capacitor（MOSCAP） Si-MRM array gated by high-mobility titanium-doped indium oxide（ITi O）, which was fabricated by combining Intel's high-volume manufacturing process and the transparent conductive oxide（TCO） patterning with the university facility. The 1 × 4 Si-MRM array exhibits a high electro-optic（E-O） efficiency with Vπ· l of 0.12 V · cm and achieves a modulation rate of（3 × 25 + 1 × 15） Gb/s with a measured bandwidth of 14 GHz. Additionally, it can perform on-chip WDM modulation at four equally spaced wavelengths without using thermal heaters. The process compatibility between silicon photonics and TCO materials is verified by such an industry-university co-fabrication approach for the MOSCAP Si-MRM array and demonstrated enhanced performance from heterogeneous integration.

关键词： Modulation Optical interconnects Optical signals Silicon modulators Silicon photonics Wavelength division multiplexing

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Progress in carbon dioxide separation and capture: A review

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Journal of Environmental Sciences 2008年第1期20卷 14-27页

作者： Hongqun Yang Zhenghe Xu Maohong Fan Rajender Gupta Rachid B Slimane alan E Bland Ian wright Department of Chemical and Materials Engineering University of Alberta EdmontonABT6G2G6 Canada School of Materials Science and Technology Georgia Institute of Technology Atlanta GA 30332 USA Gas Technology Institute Des Plaines IL 60018 USA Western Research Institute Laramie Wyoming 82072 USA Oak Ridge National laboratory P.O. Box 2008 Oak Ridge TN 37831 USA

This article reviews the progress made in CO2 separation and capture research and engineering. Various technologies, such as absorption, adsorption, and membrane separation, are thoroughly discussed. New concepts such as chemical-looping combustion and hydrate-based separation are also introduced briefly. Future directions are suggested. Sequestration methods, such as forestation, ocean fertilization and mineral carbonation techniques are also covered. Underground injection and direct ocean dump are not covered.

关键词： coal flue gas carbon dioxide sorbent absorption adsorption membrane separation sequestration

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Combinatorial genetics methods for discovering high-order regulatory combinations and engineering genetic drivers for neural differentiation

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Neural Regeneration Research 2021年第12期16卷 2403-2404页

作者： Dawn G.l.Thean alan S.l.Wong laboratory of Combinatorial Genetics and Synthetic Biology School of Biomedical SciencesThe University of Hong KongPokfulamHong Kong Special Administrative RegionChina Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong Kong Special Administrative RegionChina

Diving into the search for effective cell differentiation factors:Researchers are still striving to find better therapeutics to revert or slow down the progression of neurological disorders such as Parkinson’s disease,Alzheimer’s disease,and Huntington’s *** disorders are the result of neuronal cell death in different parts of the *** or treatments used to relieve the symptoms in patients have not been well *** do not recover the damaged neural tissues and can result in unwanted side effects.

关键词： Huntington neural Alzheimer

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Downscaling future climate scenarios to fine scales for hydrologic and ecological modeling and analysis

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Ecological Processes 2012年第1期1卷 109-123页

作者： lorraine E Flint alan l Flint U.S.Geological Survey Placer Hall6000 J St.SacramentoCA 95819USA

Introduction:Evaluating the environmental impacts of climate change on water resources and biological components of the landscape is an integral part of hydrologic and ecological investigations,and the resultant land and resource management in the twenty-first *** of both climate and simulated hydrologic parameters on ecological processes are relevant at scales that reflect the heterogeneity and complexity of *** present,simulations of climate change available from global climate models[GCMs]require downscaling for hydrologic or ecological ***:Using statistically downscaled future climate projections developed using constructed analogues,a methodology was developed to further downscale the projections spatially using a gradient-inverse-distancesquared approach for application to hydrologic modeling at 270-m spatial ***:This paper illustrates a methodology to downscale and bias-correct national GCMs to subkilometer scales that are applicable to fine-scale environmental *** scenarios were chosen to bracket the range of future emissions put forth by the Intergovernmental Panel on Climate ***-scale applications of downscaled datasets of ecological and hydrologic correlations to variation in climate are ***:The methodology,which includes a sequence of rigorous analyses and calculations,is intended to reduce the addition of uncertainty to the climate data as a result of the downscaling while providing the fine-scale climate information necessary for ecological *** results in new but consistent data sets for the US at 4 km,the southwest US at 270 m,and California at 90 m and illustrates the utility of fine-scale downscaling to analyses of ecological processes influenced by topographic complexity.

关键词： downscaling climate change spatial scale scenarios

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