摘要
为了揭示水盐梯度对河口湿地土壤有机碳组分的影响,对闽江河口不同淹水环境和盐度下短叶茳芏(Cyperus malaccensis)湿地土壤活性有机碳含量进行了测定与分析.结果表明,无论半咸水湿地还是淡水湿地,土壤微生物生物量碳(MBC)含量均随淹水频率增加而增加,增幅分别为67.8%和38.8%.半咸水湿地高低潮滩的土壤MBC含量均低于淡水湿地,高低潮滩降幅分别为52.9%和43.1%.半咸水湿地高低潮滩土壤可溶性有机碳(DOC)含量均高于淡水湿地,增幅分别为56.7%和105.6%.2种湿地土壤易氧化有机碳(EOC)含量均随淹水频率增加而降低,半咸水湿地高低潮滩间降幅18.0%,淡水湿地降幅50.1%.半咸水湿地高低潮滩土壤EOC含量均高于淡水湿地,增幅分别为20.2%和97.4%.微生物熵以及DOC和EOC占SOC的比值分别为0.42%~1.76%、0.39%~0.85%和20.14%~36.49%.微生物熵随盐度增加而降低,土壤DOC和EOC的分配比例随盐度的增加而增加.相对于淹水环境变化,土壤TN含量和电导率对SOC及其活性组分含量影响的贡献更大.土壤DOC、EOC与SOC显著正相关,土壤MBC与SOC、EOC和DOC均呈负相关,暗示底物的有效性和土壤MBC周转速率是影响土壤微生物活性和碳库积累的重要因子.淹水频率增加提高了土壤微生物的数量,但土壤微生物对淹水环境有一定的适应机制.盐度增加可提高土壤DOC、EOC含量,但降低土壤MBC含量.土壤氮含量和盐度是影响闽江河口湿地生态系统土壤碳库演变的重要限制性参数.
In order to reveal the effects of hydrologic and salinity gradients on soil organic carbon composition in estuarine wetlands, the contents of soil organic carbon fractions along the hydrologic gradient within a freshwater Cyperus malaccensis marsh and a brackish C. malaccensis marshes in the Min River Estuary were measured. Soil microibial biomass carbon（MBC） contents raised with increasing flooding frequency both in brackish-water marsh（67.8%） and freshwater marsh（38.8%）, respectively. For both high tidal flat and low tidal flat, the MBC content in brackish-marsh was lower than that in freshwater marsh, and declining ranges were 52.9% and 43.1% high tidal flat via low tidal flat, respectively. Soil dissolved organic carbon（DOC） content in brackish marsh was higher than that in freshwater marsh, and increasing range were 56.7% and 105.6% high tidal flat via low tidal flat. Soil EOC content declined with increasing flooding frequency, and declining ranges were 18.0% and 50.1% brackish marsh via freshwater marsh, respectively. Soil EOC content in brackish marsh was higher than that in freshwater marsh, increased by 20.2% in high tidal flat and 97.4% in low tidal flat, respectively. The percentages of soil microbial entropy, DOC and EOC in SOC were 0.42% - 1.76%, 0.39% - 0.85% and 20.14% - 36.49%, respectively. Microbial entropy declined with increasing flooding frequency, while the proportions of soil DOC and EOC in SOC increased with increasing flooding frequency. Compared with the varied flooding environment, soil TN content and conductivity had a greater contribution on the SOC contents and its active components. Soil DOC and EOC contents were positively correlated with SOC content, and soil MBC content was negatively correlated with SOC, EOC and DOC contents, which implied substrate availability and soil MBC turnover rate exerted important impacts on controlling soil microbial activity and soil carbon pool accumulation in estuarine tidal marsh. Soil microbes increased with increasing flooding fr
出处
《中国环境科学》
EI
CAS
CSSCI
CSCD
北大核心
2017年第10期3919-3928,共10页
China Environmental Science
基金
国家"973"项目(2013CB430401)
中国博士后科学基金(2017M611337)
国家自然科学基金资助(41371127)
关键词
盐度
淹水环境
土壤有机碳
活性组分
闽江河口
salinity
flooding environment
soil organic carbon
active fractions
Min River Estuary
