New Benthic Fossils from the Late Ediacaran Strata of Southwestern China

The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,China,is marked by copious macrofossils at the apex of the Ediacaran strata.This fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying Fm.and the Miaohe and Wenghui biotas of the Doushantuo Fm.,elsewhere in China.One novel benthic saccular macroalgal fossil,named here Houjiashania yuxiensis gen.and sp.nov.,from the Jiangchuan Biota is based on fossils that are sausage-shaped,elongate,tubular,ranging from 0.3 to 4 cm in length,and up to 0.8 cm in diameter.One terminus is blunt and rounded to an obtuse angle,the other is bent with a spread-out surface resembling a holdfast,suggesting a three-dimensional thallus.Thin,stipe-shaped outgrowths,likely vestiges of sessile saccular life forms,are prevalent in macroalgal fossils of analogous size and shape,as well as present brown algae Scytosiphonaceae,such as Colpomenia and Dactylosiphon.The new findings augment the diversity of benthic algae,such as those known from the Early Neoproterozoic Longfengshan Biota in North China.The benthic algal macrofossils in the Jiucheng Mb.add to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive macroalgae.The co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.

Inventory and Distribution of Benthic Macroinvertebrates, Indicators of Water Quality in Four Forested Watercourses in Centre Region of Cameroon

The inventory of benthic macroinvertebrate species was carried out in some streams of the Mefou catchment area, from August 2021 to August 2022, in order to determine the biological groups that make up the population and characterise these environments. The dataset acquired during this study made it possible to update the existing database and contribute to the knowledge of the biological groups associated in these environments, and to provide additional information on the existing ones in relation to bioindication. Overall 80 families were identified and, on the basis of frequencies of occurrence greater than 75%, 22 families were retained as potential biological indicators. The remarkable diversity of insects and the low abundance of Diptera reflect the low degradation of environments and the good quality of water. The high diversity indices obtained reflect the maintenance of the favourable ecological conditions that favours the development of a balanced and, integrated biological community capable of adapting to changes.

Impact of Dewatering on the Spatio-Temporal Distribution of Benthic Macroinvertebrate Communities in the Okpara River, Benin

Surface watercourses are areas of very high ecological and heritage value. Macroinvertebrates are bioindicators of the health of aquatic ecosystems. The aim of this study was to assess the effects of dewatering and re-watering cycles on benthic macroinvertebrate (BMI) communities. Two data collections were carried out at two stations (Okpara 1 and Okpara 2) on the Okpara river before and after dewatering. Thus, 8 samples of benthic macroinvertebrates and 12 physico-chemical parameters (T°C, pH, Transparency, Depth, Conductivity, Dissolved Oxygen that were measured in situ, and BOD5, COD, NH4+, NO3-, NO2- and PO43-) were assayed in the laboratory. Canonical Correspondence Analysis (CCA) was used to match physico-chemical data to MIB families. Shannon and Piélou diversity indices were used to determine the effects of dewatering on MIBs. The increase in temperature values of pH, BOD5, COD, NH4+, NO3-, NO2- and PO43-, after re-watering indicates the effect of dewatering on the quality of Okpara aquatic ecosystems. The benthic macrofauna collected consisted of 62.42% insects, 0.65% crustaceans, 6.48% molluscs, 0.72% worms and 0.14% arachnids. Whereas after re-watering, 21.67% insects, 0% crustaceans, 0.22% molluscs, 7.56% worms and 0.29% arachnids were recorded. Insects, crustaceans and molluscs were more abundant before dewatering than after. This was revealed by low abundances and taxonomic richness, as well as low Shannon index values of samples collected after re-watering.

Environmental heterogeneity and productivity drive the assemblage of benthic diatom:a case study of the Three Gorges Reservoir

Dam construction has a critical effect on river ecosystems in the world,resulting in a rapid decline in biodiversity and ecosystem health.However,the effect of dam construction on the assemblage pattern of benthic diatoms remains unclear.The benthic diatoms assemblages in the tributary backwater area of the Three Gorges Reservoir(TGR)were investigated under low water level(LWL)and high water level(HWL)conditions.Results show that Discostella stelligera,Nitzschia palea,and Craticula subminuscula were dominant species in LWL,while Achnanthidium minutissimum and Nitzschia dissipata were dominant in HWL.Furthermore,environmental variables,productivity parameters,diversity indices,and community similarity were found significantly different between LWL and HWL periods.The Mantel test indicated that both environmental and spatial factors had significant effects on diatom communities in backwater area,while productivity was also a key driving force in LWL.The variation partitioning analysis(VPA)further demonstrated that environment factors could explain the largest variance of diatom assemblages in HWL(9%)and LWL(11%),followed by spatial factors.The relative importance of productivity to diatom community was significantly enhanced in LWL,but only a slight effect was found in HWL.These results indicate that the diatom assemblages were shaped by both environmental filtering and spatial factors.The relative importance of spatial factors depended on the degree of productivity.Therefore,the homogenization of diatom communities due to environmental disturbance,e.g.eutrophication and dam building,is the underlying mechanism in assembling the benthic diatoms.

Phosphorus speciation,transformation and benthic processes with implications for environmental impacts in the aquaculture area of Rushan Bay

Phosphorus(P)is an essential nutrient for many organisms in the ocean,which plays a central role in the stability of ecosystems and the evolution of the environment.The distribution,occurrence and source-sink process of P in offshore waters are highly influenced by mariculture activities.P transformation in water-sediment system is the key process in P cycling,however,the mechanism is poorly documented in the coastal sea which is influenced by human activities.Based on the comprehensive surveys in the adjacent waters outside Rushan Bay in May,July and August 2014 and February 2015,the form and transformation of P in the suspended particulate matter(SPM)and surface sediment were analyzed.The results showed that contents of total P,authigenic P and organic P of SPM increased with the increase in distance from the shoreline off Rushan Bay,and the detrital-P decreased.The partition coefficient of P between water and SPM was related to the chemical activity of different forms of P,and a higher reactivity of inorganic P associated with SPM was observed.Hypoxia induced by mariculture changes the distribution and morphological composition of P in SPM and sediment in this typical aquaculture area,which can result in a conversion of sink to source of P in the sediment,thereby having a significant impact on the regional nutrient budget and associated with eutrophication.

Benthic Macroinvertebrates of Bull Run Creek: A Pre-Restoration Baseline

In North America, disturbed riparian zones have had a deleterious effect on the life cycles of anadromous fish, especially the commercially and culturally important salmon and steelhead. The result has been a significant reduction in the numbers and average size of these fish. Tributaries of the John Day River are important spawning waters for western populations of these fish, and the National Forest Service and the Confederated Tribes of the Umatilla Indian Reservation are cooperating to restore floodplains and riparian zones in a number of these headwater tributaries. Herein we have conducted a pre-restoration study of macroinvertebrates and basic water quality parameters in one of these important spawning locations in central Oregon, Bull Run Creek. Results of the turbidity, pH, dissolved Oxygen, and temperature determinations indicate that overall water quality is good, and benthic macroinvertebrate sampling yielded a number of sensitive organisms, including members of Chloroperlidae, Peltoperlidae, Ryachophilidae, Odontoceridae, and Brachycentridae. At all sites, chironomid larvae (non-biting midge) dominated the assemblages. The EPT Index suggests that Bull Run Creek ranges from fair to excellent in terms of its ability to support sensitive species. Sorensen’s Similarity Coefficient indicates varying degrees of shared diversity between the sites, and Shannon’s entropy calculations suggest moderate to low species diversity at all sites, including the reference site on nearby Boundary Creek. Overall, this study indicates that Bull Run Creek is in fair condition and that it should benefit significantly from the restoration efforts.

Spatio-temporal variation of subtidal macrobenthic fauna and the ecological assessment of Longkou Artificial Island construction in Bohai Sea, China

To evaluate the status and changes of macrobenthic communities related to the construction of the Longkou Artificial Island(LAI)in the Bohai Sea,China,four annual surveys were conducted from 2010 to 2013.Significant changes on environmental variations and macrobenthic communities were observed in 2013 after the LAI construction a couple of years later.The changing environment was primarily presented by lower values of pH,dissolved oxygen(DO),organic material(OM)percentage,and higher salinity,suspended particulate matter(SPM)concentration and oil concentration.The main dominant species shifted from Polychaeta taxa in 2010 to Mollusca taxa in 2013 due to the changes of environmental variables.An apparent miniaturization tendency in body size of macrobenthic species was presented from 2010 to 2013.The biodiversity indices increased yearly from 2010 to 2013.However,inter-site homogenization was observed in both the community structure and health status.Multivariate AZTI Marine Biotic Index(M-AMBI)analysis showed that the health status of stations changed depending on its original status and distance to the LAI.However,no significant differences were found in the spatial distribution of either environmental variables or abundance,biomass and biodiversity of macrobenthic communities.All the results will provide a basis for the long-term ecological assessment of reclamation.

Benthic microbial biogeography along the continental shelf shaped by substrates from the Changjiang River plume

Coastal zones are active reactors of continental material including that transported by rivers via a series of microbiota-mediated reactions. Nevertheless, current knowledge of the ecology and functioning of the microbiota in coastal areas affected by large riverine inputs remains insufficient on a global scale. Here, an investigation on sediment microbial composition, including taxonomy and metabolic network, as well as their relationship with major benthic reaction substrates, namely carbon, nitrogen, sulphur and phosphorus, was conducted in the continental shelf affected by the spread of the Changjiang River plume. Surface sediment samples(48 samples)were collected during March 2018, obtaining a mean Operational Taxonomic Units(OTUs) number of 3 341.Proteobacteria, Acidobacteria and Actinobacteria were abundant phyla in the studied sediments. Bray-Curtis distance analysis classified the 48 samples into 4 clusters(MG1 to MG4) at the phylum-level. MG1 and MG2 are found near the river mouth, receiving substantial land-derived particles from the Changjiang River runoff.Particle-attached microbes may be settled in these regions and influenced the observed sediment microbial diversity and biomass, e.g., increased Crenarchaeota relative abundance. The relative enrichment of these two groups in heterotrophic microbes further suggests a reliance of benthic microbiota on substrates with terrestrial origin, particularly specialized on processing sulphur-rich substrates. Regions MG3 and MG4 are located in the outer margin of the area affected by the Changjiang River plume, mainly fed by settling pelagic particles from phytoplankton. Compared to MG1 and MG2, a significant increase in the abundance of Thaumarcheota(phylumlevel) and Nitrosopumilus(genus-level) was found in MG3, suggesting nitrogen-related transformations as the key reactions to sustain microbial metabolism in this region. Coupled with the identified variations in the taxonomic composition, significant differences in the keystone taxa between MG1/MG2 and MG3/MG4 were identified via OTU co-occurrence analyses. A higher abundance of Actinobacteria, Thaumarchaeota and Acidobacteria in MG3 and MG4 reinforced the identified spatial variability in benthic metabolism and highlighted the significance of substrate inputs on the sediment microbial structure and biogeography.

Biomass,species composition and diversity of benthic diatoms in mangroves of the Houyu Bay,China

The biomass, species composition and diversity of benthic diatom assemblages in mud-flat soils in Kandelia candel (L.) Druce communities with and without vegetation were studied seasonally at the Houyu Bay in Fuding City, Fujian Province, China. A total of 103 taxa were identified (including varieties). Eighty-four taxa were found in the mud-flat with vegetation and 74 taxa in the mud-flat without vegetation, while the biomass was large in January and April and decreased from July to October. The most abundant species in the mud-flat with vegetation are Nitzschia cocconeiformis, Gyrosigma scalproides and N. fasciculata, compared with G. scalproides and N. obtusa var. scalpelliformis in the mud-flat without vegetation. High H' values at 2 sites during all seasons suggest that diatom assemblages in the sediments of the Houyu Bay represent an original environment. Multi-dimensional scaling of diatom assemblages from mud-flats with and without vegetation shows that a slight seasonal change and only a single association occur in the mangroves.

STUDIES ON CULTURE CONDITIONS OF BENTHIC DIATOMS FOR FEEDING ABALONE Ⅲ. EFFECTS OF IRON AND SILICON NUTRIENTS AND OF ORTHOGONAL COMBINATIONS OF NITROGEN,PHOSPHORUS,IRON AND SILICON ON GROWTH RATE

Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The results of monofactor tests of ironand silicon shawed that Fe-EDTA was bettef than ferric citrate in the culture of these diatoms;that the favourable concentration of Fe-EDTA was about 0.5 mg/L of Fe and that of silicate was 2.5 mg/L of Si or more.The orthogonal test showed that the optimal concentration ratios(mg/L)of nitrogen, phosphorus, iron and silicon were: 5. 0: 0. 25: 0.5: 2. 0 for Cocconeis scutellum var. parva; 2.5: 1.0: 1.0: 2.0 for Amphora coffeaeformis; and 5.0: 0. 15: 0.5: 2.0 for N. mollis.

Biomass of meiobenthic in the Bohai Sea, China

A grid of 22 stations, giving a broad geographic coverage of the Bohai Sea and the Bohai Strait was selected. Undisturbed sediments were collected from sampling stations during cruises in June 1997, in September/October 1998 and again in April/May 1999. Based on the results of Juario (1975), the average biomass, 0.404 g/(m2a) of meiofauna (including nematode, harpacticoida, bivalve larvae, polycheata and kinorhyncha) in the Bohai Sea is given and accounts for 4.5 percent of the macrofauna in the Bohai Sea. The horizontal distribution of the biomass of meiofauna showed that it was higher at the stations of middle east part of the Bohai Sea and the strait in 1998 and 1999 cruises and it decreased at the stations near to the strait mouth and increased at Station B1 in 1999 cruise. The annual average production in the Bohai Sea is 3.636 g/m2 calculated in term of the formula P = 9B. Compared with the biomass of other sea areas in the world, the biomass of the Bohai Sea is similar but slightly lower. The individual average dry weight of nematodes given by different authors is analyzed.

Assessing the benthic habitat quality in the Huanghe(Yellow River) Estuary and its adjacent areas using AMBI and M-AMBI

The protection of the biological diversity and the maintenance of the regional ecological integrity for the Huanghe （Yellow River） Estuary and its adjacent areas are practically significant and valuable. However, frequent human activities and natural climate changes have caused vigorous disturbances on the ecosystem in these sea areas. An objective assessment on the benthic habitat quality （BHQ） of the Huanghe Estuary and its adjacent areas is conducted, using AZTI＇s Marine Biotic Index （AMBI） and multivariate AMBI （M-AMBI） based on the data of macrobenthos in May and August 2011. The results show that both the indices do not correlate significantly, and their assessment results are greatly different. All of the samples assessed using the AMBI were ＂high＂ or ＂good＂, because the ecological group I （EGI） and the ecological group II （EGII） were dominant macrobenthic ecological groups in the research area. Owing to a low species＇ richness and a high individual abundance in some samples, the BHQ levels using the M-AMBI were worse than those of the AMBI. Significant correlations are observed between the M-AMBI, water depth, bottom water salinity and dissolved inorganic nitrogen, thus the M-AMBI could sensitively respond to environmental changes and distinguish influences from uninfluenced stations, but the AMBI could not. The consistent results between the AMBI and the M-AMBI mainly appeared in the uninfluenced （undisturbed or slightly disturbed） sta- tions. Therefore, the M-AMBI is more effective than the AMBI in assessing the benthic habitat quality in the Huanghe Estuary and its adjacent areas. Using the M-AMBI to assess the BHQ of the Huanghe Estuary and its adjacent areas, the results show that 3% of the stations are undisturbed and the BHQs are ＂high＂, and 61% of the stations are slightly disturbed and those of the BHQ are ＂good＂, and the rest are meanly disturbed and those of the BHQ are ＂moderate＂.

Molecular diversity and biogeography of benthic ciliates in the Bohai Sea and Yellow Sea

This study explored the molecular diversity and biogeography of benthic ciliates in Chinese marginal seas, the Bohai Sea(BHS), North Yellow Sea(NYS) and South Yellow Sea(SYS). From a previous 18S rRNA gene pyrosequencing dataset of the benthic microeukaryotes, we retrieved the sequences affiliated with phylum Ciliophora and analyzed alpha and beta diversities of ciliate communities. We found that BHS had the highest ciliate operational taxonomic unit(OTU) richness than NYS and SYS, whereas the richness was not significantly different between summer and winter. Among all the measured environmental variables, water depth showed consistently the strongest correlations with alpha diversities. Overall, the class Spirotrichea(mostly Choreotrichia and unassigned lineages within the class) dominated the communities in terms of both relative proportion of sequences(77.0%) and OTU richness(66.5%). OTU-level ciliate community structure was significant different among the three basins, but not between the seasons. Structurally, significant differences in relative proportion among the basins were detected for the class Litostomatea, but not for other classes. Partial Mantel tests demonstrated that water depth difference was more important than geographic and environment distances in shaping the community structure of benthic ciliates in the studied area. About 60% OTUs were not assigned at a class or order level and at least 45% OTUs shared a sequence similarity no more than 97% with the described species, indicating a great potential for ciliate species discovery in the offshore sediments. Compared with previous morphology-based surveys, the spatial pattern of ciliate diversity(decreasing from NYS to SYS) is also identified in the present study. Nevertheless, structurally, the dominant class appeared to be Spirotrichea in the sequencing dataset, which differs from previous morphology-based results(dominance of classes Prostomatea and Karyorelictea in biomass). The potential causes for the discrepancies between molecular and morphological findings are also discussed.

Spatial and seasonal pattern of macrozoobenthic assemblages and the congruence in water quality bioassessment using different taxa in artificial Mingzhu Lake in Shanghai

The spatial and seasonal pattern of macrozoobenthic structure and its relationship with environmental factors were studied from July 2006 to April 2008 in Mingzhu Lake,Chongming Island,Shanghai at the Changjiang River mouth.The congruences in water quality bioassessment based on diversity and biotic indices and using different taxonomic categories were also explored to find the best assessment method of water quality for the lake.All major structural characteristics of macrozoobenthic community,including species composition,abundance,biomass and four biomass-based diversity indices(Shannon's diversity,Simpson's diversity,Pielou's evenness and Simpson's evenness index) fluctuated significantly in season but in space.The above four abundance-based diversity indices plus abundance-based Margalef's richness index did not display significant spatial variations;and significant seasonal differences were found in three indices only.Water temperature was the key environmental factor responsible for macrozoobenthic spatio-temporal distribution patterns.Water quality assessed by Shannon's index(H_a') and biological pollution index(BPI) rather than the other four biotic indices were consistent with those by trophic state index(TSI).Results from chironomids and oligochaetes did not always agree to those from the whole community when H_a' or Hilsenhoff biotic index was applied to bioassessment.Therefore,combining multiple indices and avoiding a single taxonomic category to assess water quality are strongly recommended and in Mingzhu Lake using a mixture of H_a' and BPI will ensure the most effective investigation of water quality.Our results also show that the main structural characteristics of macrozoobenthic communities in the small lake may display consistent spatial patterns.

An ecological survey of the abundance and diversity of benthic macrofauna in Indonesian multispecific seagrass beds

Seagrasses are one of the most productive ecosystems in coastal areas and support a wide variety of associated fauna. The tropical Indo-Pacific region is considered to have the highest diversity of seagrass plant species and the largest distribution areas of seagrass, yet the seagrass macrofauna in this region are poorly understood. To help fill this gap in our knowledge, an ecological survey was conducted to describe the abundance and diversity of benthic macrofauna from tropical seagrass beds and to determine between-station variations within a transect and between-site variations in macrofaunal abundance, taxa richness and community structure. Benthic macrofaunal samples associated with seagrass beds were collected with a core sampler on the east coast of North Sulawesi in May 2014 and on the west coast in October 2015. A total of 149 species from 14 higher taxa was collected. The most species-rich groups were polychaetes（56 species, 26% of total individual numbers）, decapods（20 species, 9% of total numbers） and amphipods（18 species, 35% of total numbers）. Between-station variations within a transect displayed different patterns between the east coast and the west coast. On the east coast, there were marked variations in abundance between stations within a transect for the macrofauna and amphipod assemblages. Both taxa richness and abundance varied with station for the macrofauna and polychaete assemblages on the west coast, resulting from the heterogeneity of the substrate along a transect. One-way ANOSIM together with MDS ordination indicated that macrofaunal community structure in seagrasses differed significantly between the east coast and the west coast, corresponding with the division of seagrasses into two broad categories of habitats, i.e.,mangrove-seagrass-reef continuum and seagrass-reef continuum. Compared with other studies in tropical areas,the abundance and diversity of benthic macrofauna in the present study were moderate. The reason for the two markedly distinct macrofaunal communities might be attributed to multiple factors, including sediment pattern,seagrass structure and temporal changes.

Benthic Habitat Quality Assessment Based on Biological Indices in Xiaoqing River Estuary and Its Adjacent Sea of Laizhou Bay,China

Based on the macrofauna data(2008-2011) in Xiaoqing River estuary and its adjacent sea, Laizhou Bay of Bohai Sea, China, the AZTI Marine Biotic Index(AMBI) and Multivariate AMBI(M-AMBI) were used for benthic habitat quality(BHQ) assessment. Results showed that BHQ presented an obvious trend of improvement along the direction of stream channel and river mouth, and in the coastal areas. AMBI and M-AMBI were significantly related to environmental pressure gradient data. Therefore, the two indices can well indicate BHQ in the studied area. However, there were significant differences between results of the two indices. In the cases of low taxa number and high abundance of single species, AMBI might overestimate BHQ. We thus adjusted its thresholds to solve this problem. And M-AMBI might overestimate BHQ when benthic assemblage was dominated by the opportunistic species. Then we could raise the weight of AMBI in the calculation of M-AMBI to handle the problem.

Cenomanian-Coniacian Sea-level Change and Dissolved Oxygen Fluctuations in Tethys-Himalaya: Evidences from Benthic Foraminifera of Gamba, Tibet

Benthic foraminifera, preserved in the Late Cretaceous organic carbon-rich sediments of Gamba, southern Tibet, provide high-resolution proxies for sea-level changes and dissolved oxygen fluctuations of southeastern Tethys. The fossils were statistically analyzed and divided into three faunas of ＂Cenomanian fauna＂, ＂Turonian fauna＂, and ＂Coniacian fauna＂. A middle neritic-upper bathal environment （50-250m） was estimated considering the ratios of planktonic and epifaunal benthic foraminifera （P/（P＋E））, the morphological analysis according to the studies of recent foraminifera and the abundant distributions of depth-related species such as Alabamina creta, Laevidentalina sp., Praebulimina spp., Pleurostomella cf. naranjoensis, Pyrulina sp., Quinqueloculina spp., Haplophragmoides spp., etc. The result shows an almost parallel trend with the global transgressive and regressive cycles, but the former fluctuates more frequently at upper Cenomanian, which probably indicates tectonic instability of the continental margin. According to the benthic foraminiferal richness （BFN）, Shannon-Weiner diversity （H（s））, as well as benthic foraminiferal oxygen index （BFOI）, five periods of oxygen depleted conditions （dysoxic-anoxic） have been recognized. They correspond to the OAE2, the lower Turonian, the upper Turonian, the Turonian- Caniacian boundary event and the probably OAE3. In addition, the oxygen fluctuations in Gamba might be controlled directly by sea-level changes, while the paleoproductivity and oxygen conditions interacted with each other under oxygen deficiency environments.

Complementary DNA sequencing (cDNA): an eff ective approach for assessing the diversity and distribution of marine benthic ciliates along hydrographic gradients

The Yellow Sea Cold Water Mass(YSCWM)is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobenthos diff ers inside and outside of the YSCWM.However,such a pattern has never been observed in the microbenthic ciliate communities.Therefore,we hypothesized that benthic ciliates followed a similar distribution pattern as meio-and macrobenthos,but this pattern has not been uncovered by morphological methods.We evaluated the diversity and distribution of benthic ciliates at fi ve stations along hydrographic gradients across the YSCWM and adjacent shallow water by using morphology and DNA and complementary DNA(cDNA)high-throughput sequencing of the V4 region of 18S rRNA gene.Results showed that the diversity of benthic ciliates detected by DNA(303 OTUs),and the cDNA(611 OTUs)sequencing was much higher than that detected by the morphological method(79 species).Morphological method detected roughly diff erent ciliate communities inside and outside of the YSCWM,but without statistical signifi cance.No clear pattern was obtained by DNA sequencing.In contrast,cDNA sequencing revealed a distinct distribution pattern of benthic ciliate communities like meioand macrobenthos,which coincided well with the results of the environmental parameter analysis.More than half of the total sequences detected by DNA sequencing belonged to planktonic ciliates,most(if not all)of which were recovered from historic DNA originating through the sedimentation of pelagic forms because none of them were observed morphologically.The irrelevant historic DNA greatly infl uenced the recovery of rare species and thus limited the understanding of the benthic ciliate diversity and distribution.Our research indicates that the methods used have signifi cant eff ects on the investigation of benthic ciliate communities and highlights that cDNA sequencing has great advantages in estimating the diversity and distribution of benthic ciliates,as well as the potential for benthic environmental assessments.

Studies on island intertidal benthic ecology in Fujian

A total of 862 benthic species were identified in the island intertidal zone in Fujian, of which 734 species are animals and 128 species algae. Determination of Jaccard's similarity index of species was made on the intertidal communities around 11 major islands. Based on hierarchical clustering (WPGMA) and polar ordination, the benthic communities may be classified into three types; the estu-arine type, the bay and harbour type and open sea type. The distribution of the benthic community is related to the location of the island and its habitats of which, salinity and hydrodynamics are the major factors controlling the distribution of the communities.

Response of benthic algae to environmental conditions in an urban lake recovered from eutrophication, China

Benthic algae communities dominate the primary production in littoral zone of shallow lake.To tmderstand the long-term effect of alteration in the composition of benthic algae community assemblage in such as a lake in China,we analyzed the benthic algae developments and indicators in the Donghu Lake in Wuhan,central China in 2004 and 2014.We compared the benthic algae biomass,compositions,and species richness of aquatic macrophytes and the changes of primary physicochemical parameters.The results show that in the 10-year period,chl a and conductivity declined significantly but nutrient level of the whole lake remained largely stable.The benthic algae biomass doubled and the relative proportion of green algae increased,whereas the benthic diatom ratio decreased.The benthic diatom assemblages and taxa differed in a number of ways,showing more epiphytic diatom species,and the relative abundance and species richness changed markedly.The number of aquatic macrophyte species increased from 3 in 2004 to 15 in 2014,presenting a remarkable recovery from previous eutrophication conditions.The changes of water level,chl a,and conductivity played a crucial role in governing aquatic macrophytes re-colonization in the littoral zones in the period.The ecological characteristics of littoral benthic diatoms reflect habitat coupling as indicated by redundancy analysis.Therefore,the close link between benthic algae and macrophyte recovery demonstrates that the benthic algae metrics are much more useful than nutrient levels to quantify the process of restoration in the lake.