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Zhang L.,Fujian Normal University | Zeng G.,Fujian Normal University | Zeng G.,Key Laboratory of Humid Sub tropical Eco geographical Process | Tong C.,Fujian Normal University | Tong C.,Key Laboratory of Humid Sub tropical Eco geographical Process
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011

Wetland soils represent globally significant stocks of carbon, and an understanding of carbon cycling in the ecosystems has important implications for global climate change. Soil carbon mineralization is one of the important parts of the carbon cycle in wetland ecosystem. However our knowledge of the ecological processes that control carbon mineralization in wetland soil is limited. This paper reviews the intrinsic mechanisms of biogenic elements and biological factors which affect soil carbon mineralization in wetlands. The active organic carbon pool in the soil was an important sensitive indicator of carbon mineralization. The biogenic elements (N, S and P) were key elements controlling carbon mineralization. The electron acceptors (NO 3 -, SO 4 2-, Fe 3+ and Mn 4+) contribute to anaerobic carbon mineralization, explained by the reducing conditions found in most wetland studies, but the possible use of organic molecules (e. g., humic acids) as alternative electron acceptors was another potentially important pathway. Animal, plants and microorganism were also important driving factors. The fauna of wetland soil has special function in the decomposition, nutrient mineralization and other ecological processes of soil, which can increase soil carbon mineralization. Microbial biomass and its active control of organic detritus decomposition in soil were strongly correlated with carbon mineralization. Plant material can also alter the soil carbon mineralization rate by influencing microorganism activity by aeration near plant roots. It was noted that invasion by exotic species may influence soil carbon pools and soil carbon mineralization but results are inconsistent. Soil carbon mineralization in wetland ecosystems appear to be controlled by biogenic elements, biological factors, and interacting physical factors, e. g. soil temperature, moisture, pH and texture. Finally, we point out the problems that currently exist in studying the relationship between wetland soil carbon mineralization and controlling variables and present some proposals for further study.

Hu F.,Fujian Normal University | Hu F.,Key Laboratory of Humid Sub tropical Eco geographical Process | Hu F.,CAS Institute of Earth Environment | Li Z.,Fujian Normal University | And 15 more authors.
Acta Geographica Sinica | Year: 2013

Grain size characteristics of the coastal aeolian sand and their chronology potential could greatly improve the interpretation of past environmental changes and provide valuable information on the past aeolian activities. However, lacking of direct dating methods, domestic scholars mainly focus on the distribution, grain size characteristics and geomophogensis to the coastal aeolian sand research. In this paper, quartz single aliquot regenerative optically-stimulated luminescence (OSL) dating with high resolution sampling was firstly applied to coastal aeolian sand in China for the Anshan (SHA) section (24°36'32.7″ N, 118°39'20.3″E) near the Anshan archaeological site along the Jinjiang coast, southeast Fujian. Through grain-size analysis, we assume that the SHA section demonstrates typical coastal aeolian sand characteristics, and affected by the blowout and chemical weathering after coastal sand deposited, the grain size parameter and content of different sizes of fraction have a large change, the grain size become coarser, the sorting for worse. The OSL ages of the 11 samples range from 839 ± 132a to 108 ±21a show that SHA section formed in nearly 1000 years, and three periods of coastal aeolian sand activity can be divided, AD1050-1300, AD 1470-1600 and AD 1720-1950 respectively. Especially during the little ice age (LIA), coastal aeolian sand activity is strong, the development of coastal dunes sand is prevailing, and the OSL age shows that the coastal aeolian sand deposition represents a multiphase and episodic feature. We discuss the main controls of coastal aeolian sand development in the research area based on the OSL chronology. Compared with East Asian monsoon change sequence and the history of typhoon landfalls in Fujian, the result shows that the main control is the intensity of East Asian winter monsoon, but not the precipitation, typhoon landfalls and sea level change. The phase of aeolian activity mainly corresponds to the stronger East Asian winter monsoon period, but over the last half-century, the weakened aeolian activity may be due to human activities on a large amount of mining sand beside a weakened winter monsoon.

Wang X.,Fujian Normal University | Wang X.,Key Laboratory of Humid Sub tropical Eco geographical Process | Ren H.,Fujian Normal University | Ren H.,Key Laboratory of Humid Sub tropical Eco geographical Process | And 2 more authors.
Wetland Science | Year: 2014

Salinity is an important environmental factor affecting dynamics of greenhouse gases of estuarine tidal wetlands. CH4 and CO2 production is influenced by abundant SO42- and increased ionic stress with saltwater intrusion. Saltwater intrusion affects the amount of N2O production by nitrification, denitrification and nitrification-denitrification bacteria. Three main mechanisms include to enhance ammonium release from sediment by physical and chemical process; to increase nitrogen release from sediment by physiological process, further affect nitrification, denitrification by direct effects on nitrifying bacteria, denitrifying bacteria activity; to strengthen rate of dissimilatory nitrate reduction to ammonium. Finally, the direction of future research was strengthened.

Huang W.,Key Laboratory of Humid Sub Tropical Eco Geographical Process | Huang W.,Fujian Normal University | Zhu J.,Key Laboratory of Humid Sub Tropical Eco Geographical Process | Zhu J.,Fujian Normal University | And 7 more authors.
Chinese Journal of Ecology | Year: 2010

Stem CO2 efflux rate (FCO2) is a key component of the carbon cycle in forest ecosystem, accounting for 14% - 48% of autotrophic respiration. To study the affecting factors of FCO2 would contribute to the understanding of global carbon cycle and of the responses of forest ecosystem to global climate change. This paper reviewed the effects of biotic and abiotic factors on FCO2, and indicated that these factors not only directly or indirectly affected the FCO2, but also acted interactively. Their contributions to FCO2 varied temporally and spatially. Though a considerable advancement has been achieved in recent years, some issues are still needed to be further studied: 1) partitioning the FCO2 with effective methods, and analyzing the relationships between the FCO2 components and related affecting factors to reveal the FCO2 variation mechanism, 2) incorporating the biotic and abiotic factors into F CO2 dynamic models to improve the accuracy of simulating FCO2, and 3) further approaching the temperature- adaptability of FCO2.

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