Temporal and spatial dynamics of enzyme activities and organic carbon in sediments of Caohai wetland of Guizhou Plateau
LI Yang1, XIA Pin-hua2, GE Hao1, GUO Guang-xia3
1. College of Life Science, Guizhou Normal University, Guiyang 550001, China;
2. Guizhou Key Laboratory of Mountainous Environment Information System and Eco-Environmental Protection, Guizhou Normal University, Guiyang 550001, China;
3. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
The present study focused on the investigation on the contents of organic carbon and the activities of extracellular enzymes as well as the related environmental factors in the sediments of different water level gradients in Caohai County,Guizhou Provincewere,from March to Decemberin 2015 with an interval of one month.The results showed that the organic carbon content in the sediments of the grassland ranged between 243.03~37.35g/kg.Along with the declining of water level,the wetland was degraded,organic carbon was largely reduced and the soil carbon pool was lost.Polyphenol oxidase (PPO) exhibited a low activity in the Yanzicai wetland of profundal zone,and this enzyme activity increased with the decline of water level.However,the activities of hydrolases,such as invertase,urease and phosphatase,were not elevated,which is not totally consistant with the "enzyme lock" mechanism hypothesis.Moreover,a strongly negative correlation was observed between the PPO activity and organic carbon content in sediments,and a certain negative correlation between PPO activity and phosphatase activity.No significant correlation existed between PPO activity and invertase or urease.The temporal and spatial dynamics of enzyme activity could be well explained by phytomass and soil physio-chemical indicators (TN,TP,pH,SMC).Based on the above results,it is suggested that the increase of PPO activity caused by the water level declining could be an important mechanism underlying carbon pool loss in sediments of grassland wetland.
黎杨, 夏品华, 葛皓, 郭光霞. 高原湖泊湿地草海沉积物胞外酶与有机碳的时空动态[J]. 中国环境科学, 2017, 37(7): 2723-2730.
LI Yang, XIA Pin-hua, GE Hao, GUO Guang-xia. Temporal and spatial dynamics of enzyme activities and organic carbon in sediments of Caohai wetland of Guizhou Plateau. CHINA ENVIRONMENTAL SCIENCECE, 2017, 37(7): 2723-2730.
Gorham E. Northern Peatlands:Role in the Carbon Cycle and Probable Responses to Climatic Warming[J]. Ecological Applications, 1991,1(2):182-195.
[2]
Limpens J, Berendse F, Blodau C, et al. Peatlands and the carbon cycle:from local processes to global implications a synthesis[J]. Biogeosciences, 2008,5(6):1475-1491.
[3]
Mclatchey G P, Reddy K R. Regulation of organic matter decomposition and nutrient release in a wetland soil[J]. Journal of Environmental Quality, 1998,27(5):1268-1274.
[4]
Laiho R. Decomposition in peatlands:Reconciling seemingly contrasting results on the impacts of lowered water levels[J]. Soil Biology & Biochemistry, 2006,38(8):2011-2024.
[5]
Freeman C, Ostle N, Kang H. An enzymic ‘latch’ on a global carbon store[J]. Nature, 2001,409(6817):149.
[6]
Freeman C, Ostle N J, Fenner N, et al. A regulatory role for phenol oxidase during decomposition in peatlands[J]. Soil Biology & Biochemistry, 2004,36(10):1663-1667.
[7]
Saraswati S, Dunn C, Mitsch W J, et al. Is peat accumulation in mangrove swamps influenced by the "enzymic latch"mechanism?[J]. Wetlands Ecology & Management, 2016:1-10.
[8]
Mayer A M. Polyphenol oxidases in plants and fungi:going places? A review[J]. Cheminform, 2006,67(21):2318-2331.
[9]
Luo L, Gu J D. Seasonal variability of extracellular enzymes involved in carbon mineralization in sediment of a subtropical mangrove wetland[J]. Geomicrobiology Journal, 2015,32(1):68-76.
Romanowicz K J, Kane E S, Potvin L R, et al. Understanding drivers of peatland extracellular enzyme activity in the PEATcosm experiment:mixed evidence for enzymic latch hypothesis[J]. Plant & Soil, 2015,397(1/2):1-16.
Fenner N, Freeman C. Drought-induced carbon loss in peatlands[J]. Nature Geoscience, 2011,4(12):895-900.
[24]
Calvert G A, Bullmore E T, Brammer M J, et al. Activation of auditory cortex during silent lipreading[J]. Science, 1997, 276(5312):593-596.
[25]
Ayuso S V, Guerrero M C, Montes C, et al. Regulation and spatiotemporal patterns of extracellular enzyme activities in a coastal, sandy aquifer system (Do~nana, SW Spain).[J]. Microbial Ecology, 2011,62(1):162-176.
[26]
Boavida M J, Wetzel R G. Inhibition of phosphatase activity by dissolved humic substances and hydrolytic reactivation by natural ultraviolet light[J]. Freshwater Biology, 1998,40(2):285-293.
[27]
Sinsabaugh R L, Lauber C L, Weintraub M N, et al. Stoichiometry of soil enzyme activity at global scale[J]. Ecology Letters, 2008,11(11):1252-1264.
[28]
Toberman H, Evans C D, Freeman C, et al. Summer drought effects upon soil and litter extracellular phenol oxidase activity and soluble carbon release in an upland Calluna heathland[J]. Soil Biology & Biochemistry, 2008,40(40):1519-1532.
[29]
Sinsabaugh R L. Phenol oxidase, peroxidase and organic matter dynamics of soil[J]. Soil Biology & Biochemistry, 2010,42(3):391-404.