Diminished storage capacity of ponds caused by sedimentation weakens their nitrogen removal efficiency.

Though their small size, ponds play a disproportionately crucial role in eliminating nitrogen (N) transporting to downstream freshwaters. As significant water infrastructures, ponds are non-sustainable due to loss of storage capacity resulting from sedimentation. However, the effects of pond sedimentation on N removal is widely neglected in landscape N processing.

Effects of riparian pioneer plants on soil aggregate stability: Roles of root traits and rhizosphere microorganisms.

Pioneer plants are vital in stabilizing soil structure while restoring reservoir drawdown areas. However, uncertainties persist regarding the mechanism of pioneer plants to soil stability in these delicate ecosystems. This study aims to unravel the plant-soil feedback mechanisms from the roles of root traits and rhizosphere microorganisms.

Soil Nitrogen and Flooding Intensity Determine the Trade-Off between Leaf and Root Traits of Riparian Plant Species.

The investigation into trade-offs among plant functional traits sheds light on how plants strategically balance growth and survival when facing environmental stress. This study sought to evaluate whether trade-offs observed at both community and individual species levels could indicate adaptive fitness across an intensity of flooding intensity. The study was conducted at 25 sampling sites spanning approximately 600 km along the riparian zone in the Three Gorges Reservoir area, China.

Zonation of bulk and rhizosphere soil bacterial communities and their covariation patterns along the elevation gradient in riparian zones of three Gorges reservoir, China.

Zonation is a typical pattern of soil distribution and species assembly across riparian habitats. Microorganisms are essential members of riparian ecosystems and whether soil microbial communities demonstrate similar zonation patterns and how bulk and rhizosphere soil microorganisms interact along the elevation (submergence stress) gradient remain largely unknown. In this study, bulk and rhizosphere (dominant plant) soil samples were collected and investigated across riparian zones where the submergence stress intensity increased as the elevation decreased.

First insights into diversity and potential metabolic pathways of bacterial and fungal communities in the rhizosphere of L. (Papaveraceae) from the water-level-fluctuation zone of Wudongde Reservoir of the upper Yangtze river, China.

The water-level fluctuation zone (WLFZ) of Wudongde reservoir of the upper Yangtze river is a completely new aquatic-terrestrial transitional zone, and its plant degenerate issue is attracting global concerns. Uncovering the unknown rhizosphere microbiome of dominant plants of this zone is helpful in understanding the plant-microbe interactions and their growth under the largely varying environment. Here, a first exploration of the rhizosphere bacterial and fungal communities of wilted (JB) and unwilted (JA) L.

Plant-plant interactions vary greatly along a flooding gradient in a dam-induced riparian habitat.

Plant-plant interactions under extreme environmental stress are still controversial. The stress gradient hypothesis (SGH) proposes that facilitation prevails under extreme environmental stresses, while an alternative view states that facilitation collapses or even switches back to competition at the extreme end of stress gradients. However, how the relationship between plant-plant interaction and periodic extreme flooding stress varies and its underlying mechanism are still unclear in a dam-regulated riparian ecosystem.

Response of riparian plant community to landscape matrix differs by taxonomic and functional diversity: Implications for the planning of riparian landscapes regulated by dams.

Local plant communities are embedded within the landscape matrix, and thus, diversity of these communities is largely determined by the spatial pattern of surrounding land-use. However, it is not yet clear how taxonomic and functional diversity within riparian plant communities respond differently to the landscape matrix at different scales, and whether and how these landscape-scale responses can be shaped by flooding conditions in the riparian landscape. This study is based upon field surveys of riparian plant communities in a total of 136 quadrats exposed to two different levels of flooding intensity along the reservoir formed by the Three Gorges Dam (TGD).

Light-acquisition traits link aboveground biomass and environment in inner saline-alkaline herbaceous marshes.

A functional response-effect approach could predict how environmental changes affect ecosystem functioning. However, few studies have applied this approach to inner saline-alkaline marsh ecosystems where soil saline-alkaline, flooding/drought and nutrients stresses threat ecological functioning. To disentangle the relationships between environmental conditions and ecosystem functioning, a total of 81 plots were investigated across 22 marsh sites dominated by Phragmites australis and Bolboschoenus planiculmis in Western Songnen Plain wetlands, China.

Shift from soil chemical to physical filters in assembling riparian floristic communities along a flooding stress gradient.

Understanding community assembly is a key issue in recognizing community succession and guiding the restoration of degraded ecosystems. Based on the stress-dominance hypothesis (SDH), along a gradient of increasing environmental stress, the relative importance of environmental filtering is supposed to be dominant but species interaction could be a minor process in assembling communities. However, this hypothesized model of the assembly-rule shift was equivocally supported by various studies.

[Relationship between alien plant invasion and landscape matrix in the water-level fluctuating zone of the Three Gorges Reservoir, China.].

Invasive process of alien species is affected by not only the invaded habitats, but also the surrounding landscape matrix. Understanding the effects of landscape matrix on alien species is of great significance for controlling invasive alien species. We surveyed plant communities along the water-level fluctuating zone (WLFZ) of the Three Gorges Reservoir.

Mercury contamination in the riparian ecosystem during the reservoir discharging regulated by a mega dam.

Mercury (Hg) is extremely poisonous and can be absorbed through touch, inhalation, or consumption. In the living environment, Hg in contaminated sediment can be transferred into grass by the direct absorption through the roots or shoots. The intake of Hg due to Hg emissions may pose a threat to living bodies especially to human beings.

Reservoir NO pollution and chemical weathering: by dual isotopes of δN-NO, δO-NO and geochemical constraints.

Reservoir dams alter the nutrient composition and biogeochemical cycle. Thus, dual isotopes of δO-NO and δN-NO and geochemical signatures were employed to study the NO pollution and chemical weathering in the Three Gorges Reservoir (TGR), China. This study found that the TGR dam alters the δN-NO composition and is enriched in the recharge period.

Dynamic of riverine pCO biogeochemical characteristics, and carbon sources inferred from δC in a subtropical river system.

Rivers significantly contribute to the global carbon budget, but data limitations and uncertainty are hampered by CO quantification in the global rivers. Thus, this study estimated riverine pCO by employing the pH-alkalinity-temperature method, and dissolved inorganic (DIC), dissolved organic (DOC), particulate organic (POC) carbon, and their isotopes (δC) with Chlorophyll-a (Chl a) were measured in river water samples from 26 sampling sites for characterization and source identification in the Yangtze River system. The estimated pCO varies from (120 ppm) to (3400 ppm) with an average (1085 ppm) across the Yangtze River and pCO is almost three times oversaturated than the ambient air (380 ppm).

Heavy metal toxicity, ecological risk assessment, and pollution sources in a hydropower reservoir.

Heavy metal (HM) toxicity, ecological risk, and pollution sources were analyzed using the pollution indexing and statistical methods in the Three Gorges Reservoir (TGR). The average concentration of HM increased in the order of Cr < Ni < As < Cd < Cu < Mn < Pb < Zn < Al < Fe during the recharge period and Cd < Cr < Ni < As < Cu < Pb < Mn < Zn < Al < Fe during the discharge period. Significant spatial variations of Pb, Zn, Cd, As, Mn, Ni, Cr, and Cu were observed at the upstream and downstream sampling sites.

Dam-induced difference of invasive plant species distribution along the riparian habitats.

Riparian ecosystem is structurally unstable due to the frequent disturbances from water fluctuation. Moreover, dams on large rivers tend to trigger fundamental changes of the composition and structure of riparian plant communities, which provides high odds for invasive species to colonize. Yet, how the invasive species distribute along a dam-induced riparian habitat, and how the native species resist to plant invasion are still puzzles.

A higher river sinuosity increased riparian soil structural stability on the downstream of a dammed river.

Hydropower dam constructions and operations have dramatically changed the original hydrological regime of natural rivers. Because of significantly slashed and suspended sediments blocked by damming, discharged "clear" water was found to play a strong undercutting effect on the riverbank and to exacerbate riparian soil erosion on the downstream near dams. Yet, it is still an unsettled issue whether the instability of riparian soil structure would be simply correlated negatively with the distance to a dam.

Plant Morphological, Physiological and Anatomical Adaption to Flooding Stress and the Underlying Molecular Mechanisms.

Globally, flooding is a major threat causing substantial yield decline of cereal crops, and is expected to be even more serious in many parts of the world due to climatic anomaly in the future. Understanding the mechanisms of plants coping with unanticipated flooding will be crucial for developing new flooding-tolerance crop varieties. Here we describe survival strategies of plants adaptation to flooding stress at the morphological, physiological and anatomical scale systemically, such as the formation of adventitious roots (ARs), aerenchyma and radial O loss (ROL) barriers.

Mercury and its form in a dammed reservoir ecosystem during the charging phase.

Throughout continents, reservoirs tend to have elevated methylmercury (MeHg) concentration transformed from mercury (Hg/total Hg). This impact may be pronounced in the reservoir with less velocity of water during the charging period resulted in the deposition of sediments. In sediments on favorable conditions, methylation may be enhanced by the decomposition of flood organic material, which can release Hg and enhance microbial activity.

[Research progress in phytoremediation of heavy-metal contaminated soils with high-biomass economic plants].

Phytoremediation is one of the important methods for restoring heavy-metal contaminated soils. Using high-biomass economic plants to restore heavy-metal contaminated soils can have both ecological and economic benefits, with great application prospects. Based on the analysis of current situation and existing problems of phytoremediation, we propose the advantages of high-biomass economic plants in contaminated soil remediation, and summarize the recent advances and mechanisms involved in absorbing heavy metals in high-biomass economic plants.

Greenhouse gas emissions from riparian zone cropland in a tributary bay of the Three Gorges Reservoir, China.

Background: A huge reservoir was formed by the Three Gorges Dam in China, which also formed a riparian zone along the bank of the reservoir. In the period of low water-level, the riparian zone in tributary bays of the Three Gorges Reservoir (TGR) was always unordered cultivated, owing to its gentle slope and high soil fertility. This land-use practice creates high potential of generating greenhouse gas (GHG) emissions with periodic water level fluctuation.

Reservoir CO evasion flux and controlling factors of carbon species traced by δC at different regulating phases of a hydro-power dam.

As the world largest hydropower reservoir, the Three Gorges Reservoir (TGR) significantly impacted on the carbon cycle since reservoirs are sources of carbon sink. This study was carried out to investigate the effects of damming on the carbon cycle. δC and δC were used to trace the origin of dissolved organic (DOC) and inorganic carbon (DIC).

Anthropogenic Pollution Intervenes the Recovery Processes of Soil Archaeal Community Composition and Diversity From Flooding.

Archaea play vital roles in global biogeochemical cycles, particularly in nitrification and methanogenesis. The recovery of archaeal community following disturbance is essential for maintaining the stability of ecosystem function. To examine whether the archaeal community could recover from water flooding and assess the influence of anthropogenic pollution on the autogenic recovery, soil samples from two riparian zones with contrasting pollution background were investigated.