Liwei Zhang

Peking University | PKU · College of Urban and Environmental Sciences

Despite their small spatial extent, fluvial ecosystems play a significant role in processing and transporting carbon in aquatic networks, which results in substantial emission of methane (CH4) into the atmosphere. For this reason, considerable effort has been put into identifying patterns and drivers of CH4 concentrations in streams and rivers and...

Despite their small spatial extent, fluvial ecosystems play a significant role in processing and transporting carbon in aquatic networks, which results in substantial emission of methane (CH4) to the atmosphere. For this reason, considerable effort has been put into identifying patterns and drivers of CH4 concentrations in streams and rivers and es...

Streams and rivers emit substantial amounts of nitrous oxide (N2O) and are therefore an essential component of global nitrogen (N) cycle. Permafrost soils store a large reservoir of dormant N that, upon thawing, can enter fluvial networks and partly degrade to N2O, yet the role of waterborne release of N2O in permafrost regions is unclear. Here we...

Riverine nitrogen loss makes a large contribution to the global nitrogen budget. However, little research has focused on nitrogen loss from large turbid rivers with high suspended sediment (SPS) concentrations. In this work, nitrogen loss amounts and related drivers were studied across fluvial networks of the Yellow River, the largest turbid river...

The source identification of organic matter (OM) is important for understanding its fate and effect in the aquatic environment. However, little relevant research has been reported from alpine rivers. In this study, elemental, stable isotopic, and molecular proxies were integrated to determine the relative contributions of various sources to suspend...

Inland waters are large sources of methane to the atmosphere. However, considerable uncertainty exists in estimating the emissions of this potent greenhouse gas from global streams and rivers due, in part, to a lack of direct measurements in the high-altitude cryosphere and poor accounting for ebullition. Here we present methane concentrations and...

Ammonia-oxidizing bacteria (AOB) and archaea (AOA) as well as complete ammonia oxidizers (comammox) aerobically catalyze ammonia oxidation which plays essential roles in riverine nitrogen cycle. However, performances of these ammonia oxidizers in high-elevation river sediments have rarely been documented. This study investigated the abundance, comm...

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) as well as comammox contribute to ammonia oxidation, which plays significant roles in riverine nitrogen cycle and N 2 O production. Source regions of numerous rivers in the world lie in high-elevation zones, but the abundance, community, and activity of ammonia oxidizers in rivers in high-elevation...

Nitrate source identification in river systems is important for water quality management. Recently, the oxygen isotopic anomaly of nitrate in atmospheric deposition (Δ¹⁷Oatm) is used to identify unprocessed atmospheric nitrate in river systems to reduce the uncertainty caused by the wide range of δ¹⁸O. In high-elevation regions, such as the Qinghai...

Anammox is a newly discovered nitrogen transformation process. However, its role in nitrogen removal in fresh water is far from understood. Here, we hypothesized that anammox could occur on suspended sediment in oxic river water. To test this hypothesis, simulation experiments with a nitrogen stable (15N) isotopic tracer technique were conducted to...

Rivers are important sites of both nitrogen removal and emission of nitrous oxide (N2O), a powerful greenhouse gas. Previous measurements have focused on nitrogen-rich temperate rivers, with cold, low-nitrogen river systems at high-altitude receiving less attention. Here, nitrogen removal rates were estimated by directly measuring dissolved N2 and...

Nitrogen is a requisite and highly demanded element for living organisms on the earth. However, increasing human activities have greatly altered the global nitrogen cycle, especially for rivers and streams, resulting in eutrophication, formation of hypoxic zones, and increased production of N2O, a powerful greenhouse gas. This review focuses on thr...

Rivers play a vital role in geochemical processes of the critical zone. As the Third Pole, the geochemical processes of the Qinghai-Tibetan Plateau are vital to global element cycles. The Yellow River source region is located in the northeastern Qinghai-Tibetan Plateau, yet there has been little research concerning water chemistry in this region. I...

Anaerobic ammonium oxidation (anammox) is believed to be an important sink for fixed inorganic nitrogen in terrestrial and aquatic ecosystems, and many studies have reported that macroscale oxic–anoxic interfaces, such as riparian zones, were hotspots of anammox reaction. However, no research has linked microscale interfaces with the anammox proces...

Although the Brunauer–Emmett–Teller (BET) measurement based on gas adsorption is the widely recognized method of characterizing the specific surface area (SSA) and pore structures, this method is limite to the analysis of dried particles, and thus has little relevance to the determination of the behavior and performance of those particles in liquid...

Suspended sediment (SPS) is ubiquitous in rivers, and SPS with different particle sizes and compositions may affect coupled nitrification-denitrification (CND) occurring on SPS significantly. However, there is no related research report. In this work, 15N isotope tracer technique was adopted to explore the CND in systems containing SPS (8 g L−1 and...