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The classification of Trachelomonas and Strombomonas is based on the morphology of loricae, which may not reflect phylogenetic relationships. There are different views on the relationship between the two genera. It is thus important for researchers to classify the two genera based on more characteristics besides loricae, such as protoplast and molecular data, and to establish a natural classification system. In this study, 29 strains (13 species) of Trachelomonas and 12 strains (eight species) of Strombomonas were collected from various locations in China. The morphological characteristics of Trachelomonas and Strombomonas were observed in the field and culture conditions, and the sequences of nuclear SSU rDNA, nuclear LSU rDNA, plastid-encoded LSU rDNA and plastid-encoded LSU rDNA of strains were obtained. We constructed a phylogenetic tree by combining four gene sequences with maximum likelihood and Bayesian methods. Based on the development of the loricae, it was found that the shape of the loricae and the presence or absence of the collar were relatively stable in culture, while the length of the collar presence or absence of spines and the color of the loricae changed. The phylogenetic tree showed that Trachelomonas and Strombomonas were sister branches, which supported Trachelomonas and Strombomonas as independent genera. Taxa in the genus Strombomonas sorted into two clades and Trachelomonas sorted into five strongly supported clades. Key morphological features could be attributed to each of the clades. [ABSTRACT FROM AUTHOR]

The green alga Prasiola fluviatilis (Sommerfelt) Areschoug ex Lagerstedt occurs in cold lotic environments. The species has a mainly circumarctic distribution, but has also been reported from glacier areas in lower latitude regions in both hemispheres. It was reported from China on a single occasion in the first half of the 20th century, but without description, illustrations or voucher specimens the identity of this record cannot be verified. Here we confirm the presence of P. fluviatilis in the Tianshan Mountains, Xinjiang Province, China based on morphological features, habitat characteristics, and plastid rbcL and tufA gene sequences. The biogeographic distribution of P. fluviatilis and its phylogenetic relationship with other terrestrial and freshwater Prasiola species are discussed. [ABSTRACT FROM AUTHOR]

Three new species of Hannaea Patrick from the Hengduan Mountains in China are formally described herein, based on light and scanning electron microscope observations. Hannaea yalaensis sp. nov. has three continuous inflations along the ventral margin, resulting in an undulate outline compared to the outline of the most commonly reported Hannaea species. The valve of Hannaea hengduanensis sp. nov. is narrower, asymmetrical about the apical axis with capitate apices, dorsal and ventral sides almost parallel. On the ventral side of valve is an unornamented central area. The valve of Hannaea clavata sp. nov. is clavate. Valve margin is straight or slightly curved. The apices of the valve constrict sharply to form the capitate ends. In addition, we also briefly described other Hannaea from this region. Here, we document the morphologies of these new species and discuss the biogeographic distribution of the genus Hannaea in Asia. [ABSTRACT FROM AUTHOR]

Studying interactions of coupled human-natural system components provides better understanding of their influences on ecosystem health and improves effectiveness of managing such systems. To understand how human-nature interactions determine the sustainability of tourist destinations, using Jiuzhaigou Nature Reserve as an example, we analyzed how human-nature interactions influenced the reserve's ecological services extraction, environmental conditions, and corresponding management actions through a historical lens. We first developed a model that represented the components and their interactions under coupled human and natural systems framework. We then summarized such interactions and their resulted environmental conditions in a time sequence. Human activities have changed Jiuzhaigou system from largely human-nature balanced to partially degraded, and then to recovered and intensively managed system during the past six decades. Such changes resulted from human-nature interactions predominantly driven by overuse of natural resources, responded to by natural components in loss of ecosystem functions, and then responded by management actions to restore the functions. The increased nutrient and sediment, modified benthic communities, and decreased travertine (crystal substrate formed by the precipitation of carbonate minerals) indicate that tourism pressure in Jiuzhaigou under the current intensive management strategy has exceeded its carrying capacity. Much more aggressive environmental friendly tourism policies are needed to sustain this valuable tourist destination. Our findings based on coupled human-natural system framework analysis have important implications for sustaining natural resources and ecological services, and the governance of both for the management of nature reserves. [ABSTRACT FROM AUTHOR]

Nano-functional materials with 3D porous architectures have gained increasing importance due to their potential applications deriving from outstanding physical and chemical reaction properties. It is still a long-standing challenge to assemble organic energetic molecules and their composites into functional macroscale architectures with porous networks for practical applications. Herein, we introduce a general approach for constructing 3D architectures (sizes in dozens of millimeters) with a porous network of energetic molecules through the two-step self-assembly of energetic nanoparticles, which involves electrostatic interactions and micro-crystallization on interfaces of nanoparticles driven by an ice-template process. 3D porous architectures of several typical energetic molecules were successfully prepared to further illustrate the effectiveness of this approach. The significantly enhanced chemical reactivity induced by thermal and shock stimuli contributed to 3D architectures with hierarchical pore network. This study demonstrates the potential of the controlled preparation of organic energetic materials with 3D porous architecture, which meets a wide range of applications on optimization of physical and chemical properties. [ABSTRACT FROM AUTHOR]

Periphytic diatoms play important functional roles in aquatic ecosystems. Their community compositions are widely used in water quality monitoring due to their wide distribution, short reproductive cycles, and sensitivity to environmental changes. In this study, 116 samples of periphytic diatom samples were collected from lakes in the lower reaches of the Yangtze River. The weighted average without tolerance down-weighting regression method was used to develop total phosphorus (r2 = 0.661), total nitrogen (r2 = 0.699), and chemical oxygen demand (r2 = 0.423) models, and the optimal and tolerance values of 78 periphytic species were calculated. Then, a new index, the comprehensive diatom index (CDI), was established on the basis of the optima and tolerances of these 78 species concerning the three environmental variables (TP, TN, and COD) to assess the water trophic status of the lakes in this region. According to the CDI, the trophic statuses of 8, 17, 23, 30, 22, and 14 sample sites were oligotrophic, mesotrophic, light eutrophication, moderate eutrophication, heavy eutrophication, and ultra-eutrophication, respectively. The CDI was more strongly correlated with the conductivity, pH, TP, TN, COD, and TDS than other diatom indices. These results demonstrate that the CDI is a useful metric for assessing the water trophic status of the lakes in the lower reaches of the Yangtze River. [ABSTRACT FROM AUTHOR]

Benthic diatoms are an indispensable link of the water ecological system in terms of energy flow and material cycling, and they directly or indirectly reflect the status of the water environment. We sampled benthic diatoms and environmental factors from April to May of 2013 from 53 sites along the Ying River to study their application in local water trophic status assessment, with a focus on the dominant benthic diatom species, their composition and distribution pattern, and the relationship between benthic diatoms and environmental factors. A total of 370 species and varieties were identified, belonging to 56 genera and six orders. The dominant species were as follows: Nitzschia inconspicua Grunow, Achnanthidium minutissimum (Kützing) Czarnecki, Navicula aitchelbee L. L. Bahls, Nitzschia palea (Kützing) Smith, Cyclotella meneghiniana Kützing, Navicula submuralis Hustedt and Mayamaea atomus (Kützing) Lange-Bertalot. The Ying River was divided into five orders using the Strahler method and three regions according to total nitrogen, total phosphorus and ammonia nitrogen. In region Y-1, which had the lowest nutrient level, the dominant species was Achnanthidium minutissimum. In region Y-2, which had the highest nutrient level, Navicula aitchelbee, Nitzschia palea, and Cyclotella meneghiniana were dominant, while in region Y-3, which had moderate nutrient levels, Nitzschia inconspicua was dominant. Pearson’s correlation analysis and canonical correspondence analysis (CCA) revealed a significant correlation between the environmental factors with dominant species and diatom indices (especially the SPI). Our study indicates that dominant species and diatom indices can, to some extent, indicate the environment, especially nutrient distribution. [ABSTRACT FROM AUTHOR]

Identifying early signs of anthropogenic disturbances in protected areas is critical for determining overuse, safeguarding natural beauty, protecting biodiversity, and sustaining resource use and economy. Assessing disturbances to aquatic systems of such areas is challenging due to the low-dose, diffused, and cumulative nature of disturbances; high risk at iconic sites; and difficulty of linking human activities with degradation. Using Jiuzhaigou Nature Reserve as an example study to overcome such challenges, we developed an approach that integrated human activities known to impact aquatic systems to calculate a holistic disturbance index for assessing the extent of human uses at scales of entire reserve and individual sub-watersheds. We linked human disturbance index with benthic algae and macroinvertebrate indicators of individual waterbodies to identify early signs of degradation. We conducted in situ nutrient experiments and intensive sampling of biota at iconic sites with early signs of degradation to provide direct linkage between tourist activities and eutrophication, and to pinpoint mechanisms of how human disturbances have resulted in such degradations. We found that the human disturbance index significantly correlated with benthic algae and macroinvertebrate indicators, and Jiuzhaigou is largely in healthy condition. For the two identified iconic sites with early signs of degradation, intensive tourist activities at observation and rest areas of Five-Color Lake seemed to link to extra amount of nitrogen input into the lake and resulted in overgrowth of phytoplankton and filamentous algae during summer peak tourist months. Extra amount of phosphorus input from tourism activities at Pearl Shoal seemed the cause of changes in substrate colors and of shifts in attached moss and algal communities. Our example study demonstrates that early signs of degradation can be visually observed and should be further assessed by measuring water quality and sensitive biological indicators at high risk areas of a waterbody during summer and peak tourist seasons. Sensitive biological indicators (e.g., intolerant diatom and macroinvertebrates) are better indicators than nutrient concentrations because of rapid assimilation of nutrients by algae and macrophytes. Our assessment approach and findings of studying Jiuzhaigou have broad applications to other protected areas for determining overuse, and hence for making science-based policy and taking adequate management actions to prevent overuses. [ABSTRACT FROM AUTHOR]

Zooplankton play an important role in the pelagic food web as a mediator of nutrient and energy fluxes. Understanding factors determining zooplankton abundance, composition, and dispersal provides information needed for improving plankton dynamic predictions and enhancing effective water resource management and biodiversity conservation. We studied zooplankton dispersal and identified factors influence zooplankton composition and abundance under a unique in situ environment with four connected water types from the natural river to a man-made main canal, then interior canal-web, and finally lake that have different flow regimes. We found that, after seven years creation of the water system and zooplankton community development, the main canal, interior canal-web, and lake had 53%–64% zooplankton taxa similar to their water origin river but that each water type was represented and dominated by different zooplankton taxa. Our optimal model identified three key local factors that affected the difference in zooplankton abundance and composition among the four water types: Chlorophyll a concentration, turbidity, and salinity. We concluded that both zooplankton dispersal through watercourse and species sorting by local factors were important for structuring communities in our study system. Since most studies on dispersal and influence of local factors on zooplankton assemblages in new environment have been done largely in temporal ponds, our findings provide unique insights on how zooplankton communities are jointly regulated by their species dispersal origins and local environmental factors in newly created canals and lakes. [ABSTRACT FROM AUTHOR]

Park managers in nature reserves need scientifically defensible and operationally feasible ecological indicators to better manage protected areas for both nature conservation and tourism. Such needs are much more urgent in karst aquatic ecosystems where spectacular natural scenic wonders attract millions of visitors to natural areas with streams and lakes that are particularly vulnerable to nutrient pollution. To identify a set of biotic indicators of phosphorus (P) pollution in a karst stream, we conducted an in situ P enrichment experiment in a nearly pristine karst stream located at a UNESCO world heritage site in China. Our results show that both benthic algal assemblages and macroinvertebrates were sensitive to P enrichment. Changes in diatoms (e.g., Achnanthidium minutissimum, Delicata delicatula ) and macroinvertebrates (e.g., collectors) were indicative of P enrichment. The color change of travertine bryophyte beds from creamy white to green was largely due to increase in filamentous green algae such as Zygnema sp., which may provide a visual cue for P enrichment and pollution. Our findings, in conjunction with further studies that directly link these indicators with human disturbance (e.g., tourist activities) throughout the park, could improve the operation of park managers in minimizing tourist-induced nutrient pollution and in operationalizing these indicators in the current environmental monitoring and assessment program. [ABSTRACT FROM AUTHOR]

• Cyanobacteria impacted plankton bio-diversity and resource use efficiency. • No clear relation between cyanobacteria and phytoplankton absolute abundances. • Cyanobacteria had opposite relation with phytoplankton and zooplankton bio-diversities. • Cyanobacteria increased total algae and cladocerans RUEs. • Cyanobacteria decreased phytoplankton and rotifers RUEs. Cyanobacterial blooms are global threats to freshwater ecosystem functioning, human health, and ecoservices. We assessed impacts of cyanobacterial bloom intensity on plankton ecosystem functioning using eukaryotic phytoplankton and zooplankton indicators and associated key physicochemical data collected from four seasons of two years at 24 evenly distributed sites in Lake Taihu that has year-around cyanobacterial blooms. Our analyses involved comparison of four site-groups with different bloom intensities and analyzing all sampling sites together using comparison, hierarchical partitioning analysis, generalized additive mixed model, and structural equation model. We found that cyanobacterial abundance positively associated with TP and temperature (negatively with TN:TP), while phytoplankton positively associated with TN. There was an inverse relation trend between relative abundances of phytoplankton and cyanobacteria, but there was no clear trend between absolute abundances of phytoplankton and cyanobacteria. Rotifers were most dominant when cyanobacteria were unabundant, while cladocerans presented higher abundance when cyanobacteria were in high abundance. Phytoplankton functional richness and species richness negatively and zooplankton functional richness and species richness positively associated with cyanobacterial bloom intensity. Cyanobacterial bloom intensity negatively associated with resource use efficiencies (RUEs) of phytoplankton and rotifers, and positively associated with RUE of cladocerans. Our analytical approach of integrating comparison of site-groups and analyzing all sites together uncovered how cyanobacterial bloom intensity shifted and altered physicochemical and biological conditions and plankton ecosystem functioning, and identified the mechanism and strength of the interactive linkages among physicochemical and biological indicators. Although our results may be different from oligotrophic lakes or reservoirs, our findings provide new insights in understanding the impacts of cyanobacterial bloom intensity on the dynamics of plankton communities and ecosystem functioning for polymictic eutrophic lakes, which may have broad application in enhancing the knowledge of this subject and provides the science base for managing polymictic eutrophic lake water quality and ecosystem functioning. [ABSTRACT FROM AUTHOR]

We describe two new Achnanthidium species, A.anhuense sp. nov. and A.qingxiense sp. nov. , from Qingxi River, Anhui Province, China, based on light and scanning electron microscopy. Both species belong to the " A.pyrenaicum complex" of the Achnanthidium genus, based on their possession of transapically-elongated areolae and deflected external distal raphe fissures. A.anhuense sp. nov. has a slightly irregular linear-lanceolate valve with rounded or weakly protracted apices and a transapically rectangular or bow tie central area on the raphe valve. A.qingxiense sp. nov. has a linear-lanceolate valve with rounded apices and the axial area distinct expanded apices on the rapheless valve. Both species differ sufficiently from other similar species, based on valve outline, shape of the axial and central areas and striae density. These new species were all collected from stone substratum., (Pan Yu, Qingmin You, Wanting Pang, Quanxi Wang.)