Hongjun Wang

Duke University | DU · Duke University Wetland Center

Peatlands store one-third of global soil carbon 1. Drought/drainage coupled with climate warming present the main threat to these stores 1–4. Hence, understanding drought eeects and inherent feedbacks related to peat decomposition has been a primary global challenge 5,6. However, widely divergent results concerning drought in recent studies 3,7–11...

Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-su...

Recent research suggested that iron oxidation may protect carbon from drought-accelerated decomposition in wetlands by promoting the sorption of lignin derivatives and decreasing phenolic oxidase activities. Here we examined whether this mechanism exists in organic-rich peatlands, which store over 30% of the world's soil carbon, by simulating droug...

Worldwide, regularly recurring wildfires shape many peatland ecosystems to the extent that fire‐adapted species often dominate plant communities, suggesting that wildfire is an integral part of peatland ecology rather than an anomaly. The most destructive blazes are smoldering fires that are usually initiated in periods of drought and can combust e...

Peatlands have persisted as massive carbon sinks over millennia, even during past periods of climate change. The commonly accepted theory of abiotic controls (mainly anoxia and low temperature) over carbon decomposition cannot fully explain how vast low-latitude shrub/tree dominated (wooded) peatlands consistently accrete peat under warm and season...

Peatlands drained for agriculture or forestry are susceptible to the rapid release of greenhouse gases (GHGs) through enhanced microbial decomposition and increased frequency of deep peat fires. We present evidence that rewetting drained subtropical wooded peatlands (STWPs) along the southeastern USA coast, primarily pocosin bogs, could prevent sig...

Currently, global agricultural development is in a critical period, as it contends with a growing population, degraded farmland, and serious environmental issues. Although low-disturbance practices are recommended to improve soil health, it is unclear whether such practices benefit critical deep soil functioning. Here, we compared the soil bacteria...

Grassland soils represent a significant potential pool for sequestering of atmospheric CO2; however, the magnitude of this pool depends to a certain extent on grazing management in grassland. Whether different herbivore species and combination (herbivore assemblage) influence soil organic carbon (SOC) in various grasslands remains unclear. Here we...

Peatlands are responsible for the majority of methane (CH4) emission from wetlands globally. Hydrological changes induced by climatic and anthropogenic disturbance may substantially alter CH4 emission in peatlands. Here we measured CH4 emission monthly for 1.5 years in natural, drained and restored shrub bogs in North Carolina, USA. Methane emissio...

PurposeWildfire, an increasing disturbance in peatlands, could dramatically change carbon stocks and reshape plant/microbial communities, with long-lasting effects on peatland functions. Soil fungi are important in controlling the belowground carbon and nutrient cycling in peatlands; however, the impact of altered fire regimes on these fungi is sti...

An environment transitional zone (ETzone) is usually deemed as a hotspot in biogeochemical cycle, but little is known about its response to climate change. A typical ETzone develops at the subsurface of peatland after experiencing long-term water table fluctuation, characterized by alternative aerobic and anaerobic conditions. By an extensive incub...

Litter decomposition is a fundamental path for nutrient cycling in a natural ecosystem. However, it remains unclear how species diversity, including richness and evenness, affects the decomposition dynamics in the context of grassland degradation. Using a litter bag technique, we investigated the litter-mixing effects of two coexisting dominant spe...

Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-su...

Permafrost thawing may lead to the release of carbon and nitrogen in high-latitude regions of the Northern Hemisphere, mainly in the form of greenhouse gases. Our research aims to reveal the effects of permafrost thawing on CH4 and N2O emissions from peatlands in Xiaoxing’an Mountains, Northeast China. During four growing seasons (2011–2014), in si...

Purpose: Wildfire, an increasing disturbance in peatlands, could dramatically change carbon stocks and reshape plant/microbial communities, with long-lasting effects on peatland functions. Soil fungi are important in controlling the belowground carbon and nutrient cycling in peatlands; however, the impact of altered fire regimes on these fungi is s...

Peatlands have persisted over millennia as massive carbon sinks even during past periods of climate change. The commonly accepted theory of abiotic controls (mainly anoxia and low temperature) over carbon decomposition cannot explain how vast low-latitude wooded peatlands consistently accrete peat under warm and seasonally unsaturated conditions. S...

Intensive conventional farming has degraded soil quality in farmlands and other ecosystems globally. Although low-disturbance practices have been widely adapted to restore soil health and save energy, the underlying mechanisms associated with farm sustainability are still unclear. Here, we compared soil microbiome, physiochemical parameters along 3...

Tidally influenced coastal forested wetlands can be divided into two broad categories, mangroves and freshwater forested wetlands. These forested wetlands perform valuable ecosystem services, and both are endangered by threats of sea level rise and land use. Understanding the mechanisms that control the distribution of tidal forests has been greatl...

Over the past several decades there has been a massive increase in coastal eutrophication, which is often caused by increased runoff input of nitrogen from landscape alterations. Peatlands, covering 3% of land area, have stored about 12–21% of global soil organic nitrogen (12–20 Pg N) around rivers, lakes and coasts over millennia and are now often...

Over millennia peatlands have stored 600–700 gigatonnes of carbon, which is close to the atmopheric carbon pool and exceeds that of global vegetation. The on-going climatic changes, especially drought and warming, are exposing peatlands to decreases in C sequestration or an increase in greenhouse gas fluxes loss or both , a critically situation wor...

Earth System Models (ESMs) predict increased frequency of extreme wet and dry periods in the subtropics and tropics over the next century, resulting in uncertain carbon (C) budgets and greenhouse gases (GHG) fluxes. Globally, approximately 1/3 of peat stores are found in subtropical and tropical peatlands (STPs) formed from high-lignin woody biomas...

Peatlands store one third of global soil carbon. Drought/drainage coupled with climate warming presents a vital threat to those stores. Understanding drought effects and inherent feedbacks related to peat decomposition has been a major global challenge. Here, linking field and microcosm experiments, we show a previously unrecognized mechanism that...

Peatlands store one third of global soil carbon. Drought/drainage coupled with climate warming presents a vital threat to those stores. Understanding drought effects and inherent feedbacks related to peat decomposition has been a major global challenge. Here, linking field and microcosm experiments, we show a previously unrecognized mechanism that...

Shrub/Tree and sedge/grass peatlands cover millions of hectares throughout the South Atlantic coast (SAC) that range from the Great Dismal Swamp in VA, through North Carolina, into the lower Atlantic coastal plain, the Okefenokee Swamp in Georgia, to the Cladium dominated Florida Everglades. These peatlands store about 1/5 of soil carbon in peatlan...

Over the past several decades there has been a massive increase in coastal eutrophication, especially along the north Atlantic coasts of North American and Europe, leading to widespread “dead zones” with cascading environmental consequences. Such eutrophication is often caused by increased nitrogen input. Peatlands, covering 3% of land area, store...

Background/Question/Methods Peatlands, covering 3% of land area, not only store one-third of all terrestrial soil carbon but also contain vast amounts of organic nitrogen, amounting to approximately 12-21% global soil N (12-20 Pg N). Generally, peatlands are important sinks of nitrogen with low mineralization rates because of waterlogged conditio...

Background/Question/Methods Natural peatlands are threatened by projected increases in prolonged droughts and increased temperatures according to recent IPCC models. Millions of hectares of former peatlands have also been drained and converted to agriculture and forestry in the U.S. However, while drought and drainage promotes the decomposition o...

Many peatlands are experiencing increased frequency and severity of drought due to climate change. It is commonly predicted and observed that drought can unlock historical stored carbon in boreal peat and release more CO2. However, some studies also show that drought does not affect CO2 emission in some peatlands where the initial water level is be...

Biogenic volatile organic compounds (BVOCs) profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field exper...

Biogenic volatile organic compounds (BVOCs) profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field exper...

Algae which bloom in open water and accumulate in the littoral zones may affect the biogeochemical cycle of phosphorus in eutrophic lakes. To determine such effects, a part of the lakeshore with little allochthonous nutrient input in Taihu Lake, China was selected for this field study. Distinct differences in sedimentary P forms were found among th...

Littoral zone has important influence on the eco-environment of lakes, in which most of the physical phenomena and ecological process changes take place because plants are in close contact with the environmental conditions of a lake, through the root-system of plant which has the function of purifying the nutrition. At the same time, eutrophication...

Spatio-temporal distribution of nitrogen was examined along the gradient from open water to lakeshore in Lake Taihu, China. Two types of undulating littoral zones were selected: natural reed belt and bare lakeshore. The reed belt affected nitrogen transformation and was sink for internal-lake nitrogen, whereas the bare lakeshore showed little effec...

Riparian wetlands are important components of the lake ecosystem, and they play essential roles in maintaining system health. Remediation of degraded lakeshore wetlands is an essential component of lake restoration. A study was conducted to investigate the restoration of lakeshore wetlands, which were converted to rice fields and then abandoned for...

Nitrous oxide (N2O) fluxes were measured in hyper-eutrophic Meiliang Bay of Lake Taihu by the static chamber method for two years. The lake was an important source of atmospheric N2O. Large temporal variations were recorded for N2O fluxes, ranging from −278 to 2101 μg N2O m−2 h−1 in the littoral zone and from −177 to 164 μg N2O m−2 h−1 in the pelag...

Alongshore drinking water supplies in eutrophic lakes are impaired seriously by algal blooms. Large amounts of terrestrial pollutants are intercepted in the littoral zone. In this field study, macrophyte-covered littoral zones in Taihu Lake in China were effective traps for algae coming from open water and decreased negative effects on water suppli...

Methane (CH4) fluxes were measured in hypereutrophic Meiliang Bay of Taihu Lake with static chambers for 1 year. The results showed that the macrophyte-covered infralittoral zones were the ``hotspots'' of CH4 emission in water systems. There were large temporal variations for CH4 fluxes, ranging from -1.7 to 131 mg CH4 m-2 h-1, in the macrophyte-co...

N2O emissions were measured monthly for 1 year using the static chamber method along the littoral and pelagic zones of Meiliang Bay in hyper-eutrophic Taihu Lake. The results indicated that littoral zones were the “hotspots” of N2O emissions (−278∼2101μgN2Om−2h−1). While the littoral zone accounted for only 5.4% of the area of Meiliang Bay, the N2O...

Methane, as an important radiative trace gas, account for about 15 % of the greenhouse effect. Wetland is one of the important natural CH 4sources, which occupies 40% the global methane flux to the atmosphere. Littoral zone between aquatic and terrestrial environments can be recognized as biogeochemical active wetlands that support high CH4 release...