Effects of inlake application of glyphoste and 2, 4‐D to control shoreline water hyacinth on diversity and abundance of associated macrofauna

The purpose of inlake herbicide trials was to assess on the aquatic environment and resources, of in-lake of weeder 64 (2,4-0 amine) and Rodio (Glyphosate) water hyacinth the effects application to control water hyacinth. The experiments reported here specifically studied the effects of the herbicides on the diversity and abundance of aquatic macrofauna associated with the water weed. Results from this and similar experiments which assessed herbicide efficacy on water hyacinth; dissipation in water, impact on water quality, algal biomass and on diversity and abundance of zooplankton and macrofauna were all to be evaluated as input into the environmental impact assessment exercise required to facilitate decisions on the use of herbicides to control water hyacinth in Uganda.

Diversity and abundance of ammonia-oxidizing bacteria in eutrophic and oligotrophic basins of a shallow Chinese lake (Lake Donghu)

Classical cultivation and molecular methods based on the ammonia monooxygenase gene (amoA) were used to study the abundance and diversity of beta-proteobacterial ammonia-oxidizing bacteria (AOB) in lake sediments. The eutrophic and oligotrophic basins of a Chinese shallow lake (Lake Donghu), in terms of ammonium (NH4+) concentrations, were sampled. The AOB number was significantly lower in the oligotrophic basin, but significantly higher in the eutrophic basin. In addition, using restriction fragment length polymorphism targeting the amoA, ten restriction patterns including six unique ones were found in the eutrophic basin, while five patterns were observed in the oligotrophic basin with only one unique restriction group. Phylogenetic analysis for AOB revealed that Nitrosomonas oligotropha- and Nitrosomonas ureae-related AOB and Nitrosospira-affiliated AOB were ubiquitous; the former dominated in the eutrophic basin (87.2%), while the latter dominated in the oligotrophic basin (65.5%). Furthermore, Nitrosomonas communis-related AOB was only detected in the eutrophic basin, at a small proportion (3.2%). These results indicate significant selection and adaptation of sediment AOB in lakes with differing trophic status. (C) 2009 Elsevier Masson SAS. All rights reserved.

Clonal diversity and genealogical relationships of gibel carp in four hatcheries

To conserve and utilize the genetic pool of gynogenetic gibel carp (Carassius auratus gibelio), the Fangzheng and Qihe stock hatcheries have been established in China. However, little information is available on the amount of genetic variation within and between these populations. In this study, clonal diversity in 101 fish from these two stock hatcheries and 35 fish from two other hatcheries in Wuhan and Pengze respectively was analysed for variation in serum transferrin. Thirteen clones were found in Fangzheng and Qihe, of which 12 were novel. Six clones were specific to Fangzheng and three specific to Qihe, whereas four were shared among the Fangzheng and Qihe fish. To obtain more knowledge on genetic diversity and genealogical relationships within gibel carp, the complete mitochondrial DNA (mtDNA) control region (similar to 920 bp) was sequenced in 64 individuals representing all 14 clones identified in the four hatcheries. Differences in the mtDNA sequences varied remarkably among hatcheries, with the Fangzheng and Qihe lines demonstrating high diversity and Wuhan and Pengze showing no variation. The Fangzheng and Qihe lines might represent two distinct matrilineal sources. One of the Qihe samples carried the haplotype shared by a most widely cultivated Fangzheng clone, indicating that a Fangzheng clone escaped from cultivated ponds and moved into the Qihe hatchery. Four Fangzheng samples clustered within the lineage formed mainly by Qihe samples, most likely reflecting historical gene flow from Qihe to Fangzheng. It is suggested that clones in Wuhan originated from Fangzheng, consistent with their introduction history, supporting the hypothesis that gibel carp in Pengze were domesticated from individuals in the Fangzheng hatchery.

Microsatellite diversity and population genetic structure of redfin culter (Culter erythropterus) in fragmented lakes of the Yangtze River

Redfin culter (Culter erythropterus) is a small lethic freshwater fish and widely distributed in the adjacent lakes of the Yangtze River of China. Five microsatellite loci were applied to investigate the genetic variation and population structure of redfin culter from seven lakes in the middle-and-lower reaches of the Yangtze River. The gene diversity was high among the populations (H > 0.9), the average number of alleles among seven populations was low with a range from 2.00 to 3.87. The mean observed (H-O) and expected (H-E) heterozygosity ranged from 0.111 to 0.419 and from 0.162 to 0.750, respectively. Significant deviations from Hardy-Weinberg Equilibrium expectation were found in 50% of the total locus-population combination tests in which heterozygote deficits were apparent. The analysis of molecular variance (AMOVA) indicated that the percentage of variance among and within these populations were 6.18 and 93.82, respectively. The Fst values (0.062, P < 0.001) among studied populations indicated that there were significant genetic differentiations among redfin culture populations from the scattered lakes with different connections to the Yangtze River. These results are useful for the evaluation and conservation of small freshwater fishes. The factors that may be involved in low intra-population polymorphism and the pattern of the population genetic structure of redfin culter from the Yangtze River were discussed.

Relationship between species diversity and ecotope diversity

The relationship between species diversity and ecotope diversity has long been debated. But these debates seem meaningless because most of them were based on different definitions. In this paper, diversity has two components: richness based on the total number and evenness based on the relative abundance. Species diversity is distinguished into individual-counting diversity and biomass-based diversity. Ecotope diversity is divided into individual ecotope-counting diversity and ecotope-area based diversity. Under this definition, we make a comprehensive investigation into Dongzhi tableland of Loess Plateau by cooperating with local technicians. We find that individual-counting diversity is significantly correlated with biomass-based diversity in grassland ecosystems; individual ecotope-counting diversity and ecotope-area based diversity have a significant correlation. Therefore, it is unnecessary to divide species diversity into individual-counting diversity and biomass-based diversity in grassland ecosystems and to distinguish ecotope diversity into individual ecotope-counting and ecotope-area based diversity for the issues that have no special requirement for accuracy. But the analyses of the investigation data demonstrate that species diversity has no significant correlation with ecotope diversity.

Diversity and spatial distribution of amoA-encoding archaea in the deep-sea sediments of the tropical West Pacific Continental Margin

The ecological characteristics of the deep-sea amoA-encoding archaea (AEA) are largely unsolved. Our aim was to study the diversity, structure and distribution of the AEA community in the sediments of the tropical West Pacific Continental Margin, to develop a general view of the AEA biogeography in the deep-sea extreme environment. Archaeal amoA clone libraries were constructed. Diverse and novel amoA sequences were identified, with the Bohol Sea, Bashi Strait and Sibuyan Sea harbouring the highest and the Bicol Shelf the lowest AEA diversity. Phylogenetic and statistical analyses illustrate a heterogeneous distribution of the AEA community, probably caused by the differential distribution of the terrestrial or estuarine AEA in the various sampling sites. The deep-sea sedimentary environments potentially harbour diverse and novel AEA in the tropical West Pacific Continental Margin. The stations in the Philippine inland seas (including station 3043) may represent AEA assemblages with various terrestrial influences and the stations connected directly to the open Philippine Sea may represent marine environment-dominant AEA assemblages. Our study indicates the potential importance of geological and climatic events in the transport of terrestrial micro-organisms to the deep-sea sedimentary environments, almost totally neglected previously.

Diversity and spatial distribution of sediment ammonia-oxidizing crenarchaeota in response to estuarine and environmental gradients in the Changjiang Estuary and East China Sea

Ammonia-oxidizing archaea (AOA) have recently been found to be potentially important in nitrogen cycling in a variety of environments, such as terrestrial soils, wastewater treatment reactors, marine waters and sediments, and especially in estuaries, where high input of anthropogenic nitrogen is often experienced. The sedimentary AOA diversity, community structure and spatial distribution in the Changjiang Estuary and the adjacent East China Sea were studied. Multivariate statistical analysis indicated that the archaeal amoA genotype communities could be clustered according to sampling transects, and the station located in an estuarine mixing zone harboured a distinct AOA community. The distribution of AOA communities correlated significantly with the gradients of surface-water salinity and sediment sorting coefficient. The spatial distribution of putative soil-related AOA in certain sampling stations indicated a strong impact of the Changjiang freshwater discharge on the marine benthic microbial ecosystem. Besides freshwater, nutrients, organic matter and suspended particles, the Changjiang Diluted Water might also contribute to the transport of terrestrial archaea into the seawater and sediments along its flow path.

Diversity and Distribution of Sediment NirS-Encoding Bacterial Assemblages in Response to Environmental Gradients in the Eutrophied Jiaozhou Bay, China

A gene-clone-library-based molecular approach was used to study the nirS-encoding bacteria-environment relationship in the sediments of the eutrophic Jiaozhou Bay. Diverse nirS sequences were recovered and most of them were related to the marine cluster I group, ubiquitous in estuarine, coastal, and marine environments. Some NirS sequences were unique to the Jiaozhou Bay, such as the marine subcluster VIIg sequences. Most of the Jiaozhou Bay NirS sequences had their closest matches originally detected in estuarine and marine sediments, especially from the Chesapeake Bay, indicating similarity of the denitrifying bacterial communities in similar coastal environments in spite of geographical distance. Multivariate statistical analyses indicated that the spatial distribution of the nirS-encoding bacterial assemblages is highly correlated with environmental factors, such as sediment silt content, NH4+ concentration, and OrgC/OrgN. The nirS-encoding bacterial assemblages in the most hypernutrified stations could be easily distinguished from that of the least eutrophic station. For the first time, the sedimentological condition was found to influence the structure and distribution of the sediment denitrifying bacterial community.

Genetic diversity and historical population structure of Schizopygopsis pylzovi (Teleostei : Cyprinidae) in the Qinghai-Tibetan Plateau

1. Complete sequences of 1140 base pair of the cytochrome b gene from 133 specimens were obtained from nine localities including the inflow drainage system, isolated lakes and outflow drainage system in Qinghai-Tibetan Plateau to assess genetic diversity and to infer population histories of the freshwater fish Schizopygopsis pylzovi.2. Nucleotide diversities (pi) were moderate (0.0024-0.0045) in populations from the outflow drainage system and Tuosuo Lake, but low (0.0018-0.0021) in populations from Qiadam Basin. It is probable that the low intra-population variability is related with the paleoenvironmental fluctuation in Qiadam Basin, suggesting that the populations from Qiadam Basin have experienced severe bottleneck events in history.3. Phylogenetic tree topologies indicate that the individuals from different populations did not form reciprocal monophyly, but the populations from the adjacent drainages cluster geographically. Most population pairwise F-ST tests were significant, with non-significant pairwise tests between Tuosu Lake and Tuosuo Lake in the north-west of the Qinghai-Tibetan Plateau. Analysis of molecular variance (AMOVA) indicates that the significant genetic variation was explained at the levels of catchments within and among, not among specific boundaries or inflow and outflow drainage systems.4. The nested clade phylogeographical analysis indicates that historical processes are very important in the observed geographical structuring of S. pylzovi, and the contemporary population structure and differentiation of S. pylzovi may be consistent with the historical tectonic events occurred in the course of uplifts of the Qinghai-Tibetan Plateau. Fluctuations of the ecogeographical environment and major hydrographic formation might have promoted contiguous range expansion of freshwater fish populations, whereas the geological barriers among drainages have resulted in the fragmentation of population and restricted the gene flow among populations.5. The significantly large negative F-s-value (-24.91, P < 0.01) of Fu's F-s-test and the unimodal mismatch distribution indicate that the species S. pylzovi underwent a sudden population expansion after the historical tectonic event of the Gonghe Movement.6. The results of this study indicate that each population from the Qinghai-Tibetan Plateau should be managed and conserved separately and that efforts should be directed towards preserving the genetic integrity of each group.

Effects of altitude on plant-species diversity and productivity in an alpine meadow, Qinghai-Tibetan plateau

During the growing seasons of 2002 and 2003, biomass productivity and diversity were examined along an altitudinal transect on the south-western slope of Beishan Mountain, Maqin County (33 degrees 43'-35 degrees 16'N, 98 degrees 48'-100 degrees 55'E), Qinghai-Tibetan Plateau. Six altitudes were selected, between 3840 and 4435 m. Soil organic matter, soil available N and P and environmental factors significantly affected plant-species diversity and productivity of the alpine meadows. Aboveground biomass declined significantly with increasing altitude (P < 0.05) and it was positively and linearly related to late summer soil-surface temperature. Belowground biomass (0 - 10-cm depth) was significantly greater at the lowest and highest altitudes than at intermediate locations, associated with water and nutrient availabilities. At each site, the maximum belowground biomass values occurred at the beginning and the end of the growing seasons (P < 0.05). Soil organic matter content, and available N and P were negatively and closely related to plant diversity (species richness, Shannon-Wiener diversity index, and Pielou evenness index).

The effect of land management on plant community composition, species diversity, and productivity of alpine Kobersia steppe meadow

Grassland degradation is widespread and severe on the Tibet Plateau. To explore management approaches for sustainable development of degraded and restored ecosystems, we studied the effect of land degradation on species composition, species diversity, and vegetation productivity, and examined the relative influence of various rehabilitation practices (two seeding treatments and a non-seeded natural recovery treatment) on community structure and vegetation productivity in early secondary succession. The results showed: (1) All sedge and grass species of the natural steppe meadow had disappeared from the severely degraded land. The above-ground and root biomass of severely degraded land were only 38 and 14.7%, respectively, of those of the control. So, the original ecosystem has been dramatically altered by land degradation on alpine steppe meadow. (2) Seeding measures may promote above-ground biomass, particularly grass biomass, and ground cover. Except for the grasses seeded, however, other grass and sedge species did not occur after seeding treatments in the sixth year of seeding. Establishment of grasses during natural recovery treatment progressed slowly compared with during seeding treatments. Many annual forbs invaded and established during the 6 years of natural recovery. In addition, there was greater diversity after natural recovery treatment than after seeding treatments. (3) The above-ground biomass after seeding treatment and natural recovery treatment were 114 and 55%, respectively, of that of the control. No significant differences in root biomass occurred among the natural recovery and seeded treatments. Root biomass after rehabilitation treatment was 23-31% that of the control.

Diversity and Inclusion at UMD Libraries Survey Results

The survey was made available online to library faculty, staff, and student workers. Participation in the survey was completely voluntary, and each individual question was entirely optional. In accordance with UMD policy, responses were treated as confidential. Fewer than five responses in a particular category were considered identifiable by the U.S. Department of Education and were not included in this report. Those who participated in the survey represent a significant portion of the Libraries’ community.