Effects of benthic algae on release of soluble reactive phosphorus from sediments: a radioisotope tracing study

To evaluate the effect of benthic algae on soluble reactive phosphorus（SRP） release from sediments in shallow lakes, experiments on SRP release with and without benthic algae in sediment cores and an experiment on SRP uptake by benthic algae were conducted using the radioisotope（32P） tracing method. The dissolved oxygen（DO） concentration in sediment cores was also investigated. The results show that benthic algae effectively reduce the release of SRP from sediments to overlying water. The uptake of SRP by benthic algae, which is the direct way in which benthic algae affect the SRP release from sediments, is low in filtered water and increases with the SRP concentration. However, in the experiment, the increased uptake rate lasted for a short time（in one hour）, and after that it returned to a low rate. Benthic algae make the DO concentration and the oxic layer thickness increased, which can indirectly reduce the SRP release from sediments. These findings indicate that benthic algae can reduce the SRP release from sediments in both direct and indirect ways. It seems that the indirect way also plays an important role in reducing the SRP release from sediments.

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.

Study on Optical Properties of Unpigmented Suspended Particles, Yellow Substance and Phytoplankton Algae in Taihu Lake

The optical properties of a waterbody are subjects of research on limnological hydrooptics. The optical properties of, and parameterization methods for, three impurities in Taihu Lake, namely unpigmented suspensions, yellow substance and phytoplankton algae, are analyzed in detail in this paper dealing with the optical types of Taihu Lake waters both in winter and in summer. The results showed that: 1) The optical parameters of suspended particles can be calculated by the application of Mie Theory; 2) The absorption of yellow substance decreases exponentially with increasing wavelength, with the mean value of decreasing rate being about 0.014 nm -1; 3) Taihu Lake waters appeared to be of type PY in winter, with suspended particles and yellow substance being the dominant light absorbers, and type CPY in summer, with suspended particles, yellow substance and phytoplankton algae being the dominant light absorbers; 4) In winter or summer, unpigmented suspension has the main effect on the scattering property of Taihu Lake waters.

Spatio-temporal variability of phytoplankton assemblages and its controlling factors in spring and summer in the Subei Shoal of Yellow Sea, China

The Subei Shoal is a special coastal area with complex physical oceanographic properties in the Yellow Sea.In the present study,the distribution of phytoplankton and its correlation with environmental factors were studied during spring and summer of 2012 in the Subei Shoal of the Yellow Sea.Phytoplankton species composition and abundance data were accomplished by Utermohl method.Diatoms represented the greatest cellular abundance during the study period.In spring,the phytoplankton cell abundance ranged from 1.59×10^3 to 269.78×10^3 cell/L with an average of 41.80×10^3 cell/L,and Skeletonema sp.and Paralia sulcata was the most dominant species.In summer,the average phytoplankton cell abundance was 72.59×10^3 cell/L with the range of 1.78×10^3 to 574.96×10^3 cell/L,and the main dominant species was Pseudo-nitzschia pungens,Skeletonema sp.,Dactyliosolen fragilissima and Chaetoceros curvisetus.The results of a redundancy analysis(RDA)showed that turbidity,temperature,salinity,pH,dissolved oxygen(DO),the ratio of dissolved inorganic nitrogen to silicate and SiO4-Si(DIN/SiO4-Si)were the most important environmental factors controlling phytoplankton assemblages in spring or summer in the Subei Shoal of the Yellow Sea.

Silicon limitation on primary production and its destiny in Jiaozhou Bay, China VI: The ecological variation process of the phytoplankton

The combination effect of light, water temperature and nutrients on phytoplankton growth in Jiaozhou Bay is studied in this paper. The order of importance of the influence on phytoplankton growth is de- termined as nutrients, water temperature, and light. The influence of these factors unveiled the mechanism of the influence, and revealed the variation process of the nutrients limiting phytoplankton primary production, and of the water temperature influencing the phytoplankton reproduction capacity, and hence influencing the structure of phytoplankton assemblage. Temporal and spatial quantification shows different stages of the influence by wa- ter temperature and nutrients on the phytoplankton growth. Moreover, the authors expatiated the ideal state of the phytoplankton growth and the reason of red tide occurrence. People should consider in their activity the input of nutrient Si first, and then the variation of water temperature, advocating sustainable development manner.

BIOLOGICAL SIGNIFICANCE OF EFFECTS OF PHYTOPHAGOUS FISHES ON PHYTOPLANKTON

The effects of phytophagous fishes on phytoplankton primary productivity in a freshwater pond , the importance of recycling of algae in fish feces .and the species specific interaction with phytoplanktons were studied . Phaeopigment amounts in pond water and in feces of fish were compared . The reduction of chlorophylla into phaeopigments in the process of passing through the phytophagous fish intestines was analyzed , and used for a direct comparison of the production rates of phytoplanktons before and after intestinal passage .

METHODOLOGY FOR STUDIES OF CARBONDYNAMICS BETWEEN PHYTOPLANKTONPRIMARY PRODUCTION AND HETEROTROPHICBACTERIAL SECONDARY PRODUCTION

The SCENTO-System was used to study the carbon dynamics between phytoplankton primary production and heterptrophic bacterial secondary production. Most of the methods used nowadays in situ for limnological synecology studies were applied. Primary production measurement showed an increasing tendency with increasing content of chlorophylla .It provided a true photosynthetic rate lying within the range of eutrophic lakes. Net EOC released from the algae ranged from 8.5 to 27.5μg C l-1 (6h)-1. Accompanying the algal products the number of bacteria increased from 1.475×109 to 8.074×109 cells l-1. The bacterial mean cell volume was small, between 0.0315 and 0.0548um3. Bacterial carbon production from direct growth estimates was compared with independent calculations of bacterial growth from EOC uptake and 3H-thymidine incorporation. Direct estimates were 2.97-10.0μg Cl-1 (24 h)-1 with the exception of a zero-growth on the third day. EOC uptake was 123.5-191.0μg Cl-1 (6h)-1.That calculated from

Seasonal change of ice algal and phytoplankton assemblages in the Nella Fjord near Zhongshan Station, East Antarctica

The ice algal and phytoplankton assemblages were studied from Nella Fjord near Zhongshan Station, East Antarctica from April 12 to December 30, 1992. Algal blooms occurred about 3 cm thick on the bottom of sea ice in late April and mid November to early December respectively, and a phytoplankton bloom appeared in the underlying surface water in mid December following the spring ice algal bloom. The biomass in ice bottom was 1 to 3 orders of magnitude higher than that of surface water. Amphiprora kjellmanii, Berkeleya sp., Navicula glaciei, Nitzschia barkelyi, N. cylindrus /N. curta, N. lecointei and Nitzschia sp. were common in the sea ice temporarily or throughout the study period. The biomass in a certain ice segment was decreased gradually and the dominant species were usually succeeded as the season went on. Nitzschia sublineata and Dactyliosolen antarctica were two seasonal dominant species only observed in underlying water column. The assemblages between bottom of ice and underlying surface water were different except when spring ice algae bloomed. The evidence shows that the ice algal blooms occurred mainly by in situ growth of ice algae, and the phytoplankton bloom was mostly caused by the release of ice algae.

Abundance,biomass and composition of spring ice algal and phytoplankton communities of the Laptev Sea(Arctic)

Abundance, biomass and composition of the ice algal and phytoplankton communities were investigated in the southeastern Laptev Sea in spring 1999. Diatoms dominated the algal communities and pennate diatoms dominated the diatom population. 12 dominant algal species occurred within sea ice and underlying water column, including Fragilariopsis oceanica, F. cylindrus, Nitzschla frigida, N. promare, Achnanthes taeniata, Nitzschia neofrigida, Navicula pelagica , N. vanhoef fenii, N. septentrionalls, Melosiraarctica , Clindrotheca closterium and Pyramimonas sp. The algal abundance of bottom 10cm sea ice varied between 14.6 and 1562.2 × 10^4 cells 1^-1 with an average of 639.0 × 10^4 cells 1^-1 , and the algal biomass ranged from 7.89 to 2093.5μg C 1^-1 with an average of 886.9μg C1^-1 , which were generally one order of magnitude higher than those of sub-bottom ice and two orders of magnitude higher than those of underlying surface water. The integrated algal abundance and biomass of lowermost 20 cm ice column were averagely 7.7 and 12.2 times as those of upper 20 m water column, respectively, suggesting that the ice algae might play an important role in maintaining the coastal marine ecosystem before the thawing of sea ice. Ice algae influenced the phytoplankton community of the underlying water column. However, the ＂seeding＂ of ice algae for phytoplankton bloom was negligible because of the low phytoplankton biomass within the underlying water column.

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.

Growth characteristics of algae during early stages of phytoplankton bloom in Lake Taihu,China

Three treatments, sediment plus lake water （S＋W）, sterilized sediment plus lake water （SS＋W）, and sediment plus filtered lake water （S＋FW）, were recruited to investigate the growth characteristics of algae during pre-bloom and the importance of algal inocula in the water column and sediment. The results showed that in the water column, biomass of all algae increased in all treatments when recruitment was initiated, whereas this tendency differed among treatments with further increment of temperature. The process of algal growth consisted of two stages： Stage I, the onset of recruitment and Stage II, the subsequent growth of algae. Compared with S＋W, in Stage I, SS＋W significantly increased the biomass of cyanophytes by 178.70%, and decreased the biomass of non-cyanophytes by 43.40%; In Stage II, SS＋W notably stimulated the growth of all algae, thus incurring the occurrence of phytoplankton bloom. Further analyses revealed that both metabolic activity and photochemical activity of algae were enhanced in SS＋W, which resulted from the releasing of nutrients from sediment. These results suggest that algal growth in Stage II and algal inocula in the water column can be important factors for the formation of phytoplankton bloom. In addition, possible mechanisms promoting algal recruitment and subsequent growth of algae were explored.

Potential influence of overwintering benthic algae on water quality

Overwintering benthic algae not only directly impact drinking water safety, but also affect the algae recruitment in warm spring seasons. Thus, understanding the characteristics of overwintering benthic algae can provide scientific references for formulating preventative strategies of reasonable water resource. However, they have received less attention. In this study, the spatiotemporal variation of benthic algae and their harmful secondary metabolites were studied from autumn to summer in Qingcaosha Reservoir. Benthic algae(picophytobenthos accounting for 55.42%) had a high biomass during overwintering, and the groups of overwintering benthic algae included pico-Cyanobacteria, pico-Cryptomonas, pico-Chlorophyta, pico-Diatoms, Cyanobacteria, Chlorophyta, Cryptomonas and Diatoms, which were consistent with the planktonic algae species in warm seasons. In oligotrophic or mesotrophic water bodies, micronutrients of iron and manganese were key nutrient factors influencing the biomass of benthic algae. Furthermore, picophytobenthos were important potential contributors of harmful secondary metabolites. The content of microcystins, anatoxin-a, geosmin and 2-methylisoborneol in sediment were 15.75 μg/kg ·FW, 48.16 μg/kg ·FW, 3.91 ng/kg ·FW, and 11.76 ng/kg ·FW during winter, which had potential to be released into water bodies to impact water quality. These findings indicate that water quality monitoring programs need to consider sediment in winter as a potential source of toxins and preventative measures to prevent excessive proliferation of algae should be implemented in winter.

Trace Metals in Sediments, Macroalgae and Benthic Species from the Western Part of Algerian Coast

The concentrations of Cd, Pb, Cu and Zn were measured in sediments and specimens of four marine organisms： green algae （Enteromorpha linza）, red algae （Corallina officinalis）, mollusc limpet （Patella ferruginea） and sea urchin （Paracentrotus lividus）. The samples were collected at four coastal stations located in two areas in the North-Western Algerian coast： Ghazaouet and Beni-saf. These areas are influenced by anthropogenic activities （harbour and industrial and urban wastes）. Metal concentrations measured in sediments and biota indicated that the area of Ghazaouet was the most polluted. We found high variability of metal bioaccumulation among the four species analysed. The highest concentrations were recorded in the algae whereas metal concentrations in sea urchin and limpet were more correlated with sediments metal concentrations.

长湖草/藻型湖区浮游植物群落特征及与环境因子的关系

研究长湖草型湖区和藻型湖区浮游植物群落结构特征及其与环境因子的关系,为长湖草型湖泊生态系统的培植、水环境保护和生态修复提供理论支撑。根据长湖形态特征共设5个采样点,于2020年4、7、10月和2021年1月进行采样调查,测定水化学指标并鉴定浮游植物样品,通过对湖泊内草型湖区(水生植物为主)和藻型湖区(水生植物分布较少或无水生植物覆盖)浮游植物群落结构进行对比分析。结果表明,草型湖区和藻型湖区分别鉴定出浮游植物80种和91种,以绿藻门种类数最多,分别为38种和50种。两类湖区均以小球藻属(Chlorella)和小环藻属(Cyclotella)为主要优势属。草型湖区和藻型湖区浮游植物丰度分别为0.59×10^(7)~2.34×10^(7)个/L和0.73×10^(7)~3.06×10^(7)个/L,生物量分别为8.98~18.98 mg/L和10.08~28.25 mg/L。藻型湖区多样性指数略高于草型湖区,两湖区水质整体为轻污染到中污染。冗余分析(RDA)结果显示,草型湖区浮游植物优势种主要受水温、DO、TN、TP和水位影响,藻型湖区主要受DO、TN、氮磷比和水位影响。

黄河流域河南段浮游藻类功能群分布特征及影响因子

为研究黄河流域藻类功能群分布及关键环境驱动因子,于2021年6—7月在黄河河南段设置16个采样位点,对黄河流域河南段浮游藻类群落组成、藻类功能群分布特征、不同空间环境因子特征及藻类-环境因子相关性进行分析,(1)共鉴定浮游藻类7门65属154种,在物种数上,绿藻门类(68种)>硅藻门类(60种)>蓝藻门类(11种),以小环藻(Cyclotella sp.)、颗粒沟链藻极窄变种(Aulacoseira granulata var.angustissima)、束丝藻(Aphanizomenon sp.)、假鱼腥藻(Pseudanabaena sp.)为流域内主要优势种(优势度≥0.02);(2)黄河流域河南段浮游藻类共划分为23个功能群,分别是功能群B、C、D、E、F、G、H1、J、LM、Lo、M、MP、N、P、S1、T、W1、W2、X1、X2、X3、X_(ph)和Y,所调查流域功能群空间分布差异较大,其中干流功能群种类最少,支流种类最多;从优势度来看,以适应富营养化、混动水体的功能群C、D、MP、P和J占优势;(3)RDA分析结果表明,优势功能群C与TN呈负相关;功能群MP与TP、NH_(4)^(+)-N、WT、pH和CODMn呈负相关;功能群P与NH_(4)^(+)-N、WT和CODMn呈正相关;功能群D与TN呈正相关,功能群J与NTU呈正相关,与DO呈强负相关,其中CODMn是驱动藻类功能群分布的关键因子;(4)结合地表水环境评价、基于功能群的Q指数与Qr指数评价、生物多样性指数评价,此次调查流域水体呈重度氮污染,水库呈轻度磷污染,洛河流域相对其他支流水质偏差。

基于高通量测序技术的深圳湾真核浮游植物群落结构研究

以18S rDNA V4区为目标基因,采用Illumina Miseq高通量测序技术,对深圳湾2019年冬季—2021年春季4个季节海水中浮游植物群落结构进行研究,并整理该海域有害藻华生物的历史纪录数据,以探讨深圳湾有毒有害浮游植物的群落组成及演替规律。高通量测序结果显示,深圳湾海域真核浮游植物含硅藻、甲藻、绿藻、褐藻、定鞭藻、隐藻和红藻7个类群,共82科269种。其中以微微型浮游植物为主要类群,春季和秋季以微拟球藻(Nannochloris sp.)为优势种,夏季以球等鞭金藻(Isochrysis galbana)为优势种,冬季以极小海链藻(Thalassiosira minima)为优势种。冬季浮游植物多样性指数为全年最高。此次调查共检测出有毒有害浮游植物32种,其中甲藻15种、硅藻13种、褐藻3种、定鞭藻1种。与历史资料相比,深圳湾海域的有毒有害浮游植物呈微型化和多样性逐渐增加的趋势,呈现由甲藻或硅藻为主的有毒有害单类群群落演替到以甲藻和硅藻为主的有毒有害双类群群落的趋势。

黄河流域典型山区河流水生生物群落调查评价——以大峪河为例

通过对大峪河5个点位的水生生物展开调查,鉴定出浮游植物38种,浮游动物8种,底栖动物13种,这3类水生生物密度分别为4.29×10^(5)~2.76×10^(6)cells/L,0.8~231.4 ind/L和18~200 ind/m^(2),生物量分别在0.2~1.97,0.004~0.82 mg/L和0.023~1.095 g/m^(2)之间。多样性评价显示大峪河浮游植物多样性和丰富度较高,水体处于清洁状态,浮游动物和底栖动物多样性一般,其时空变化规律显示农业面源污染汇入、人类活动干扰及物理生境为主要影响因素。

基于模拟数据分析长江调水对棘洪滩水库的影响

目前南水北调东线调水工程水源复杂多变,显著影响了受水水体的水质与浮游藻类。为量化与评估这一影响,本研究在调水周期内采集不同季节的供水(长江水)、受水(棘洪滩水库水)水样,同时开展室内藻类生长潜力试验,比较分析了不同比例的供、受水体混合处理后的理化因子、浮游藻类细胞密度与群落结构的变化情况。结果显示,春、秋季长江水的引入一定程度上削弱了棘洪滩水库的营养负荷;pH在季节间均表现为下降的趋势;秋季长江水的引入导致棘洪滩水体浮游藻类密度峰值显著增加(P<0.05),而在春季,仅当长江调水比例高于40%时,藻类密度峰值才随调水量的增加而显著增大(P<0.05)。群落结构方面,春、秋季长江与棘洪滩水体浮的游藻类均以蓝藻为主要优势,不同的是,春季以色球藻属(Chroococcus)的种类占主要优势,秋季则以假鱼腥藻属(Pseudanabaena)、尖头藻属(Raphidiopsis)与细鞘丝藻属(Leptolyngbya)的种类为优势。随长江水引入比例的增加,春季调水进一步增加了色球藻属的优势度;秋季调水则削弱了尖头藻属优势度同时增加了假鱼腥藻属的优势度。综合表明,不同季节长江调水对棘洪滩水库的浮游藻类生长影响存在差异,浮游藻类群落结构显著受到供水水体与季节的综合影响。

嘉陵江南充出境江段枯水期浮游生物群落结构及水质评价

为了解嘉陵江南充出境段枯水期水质状况及浮游生物群落结构现状,于2022年冬季在嘉陵江南充出境江段调查了9项常规理化指标,并计算了多样性指数,结果表明:枯水期嘉陵江南充出境江段水质符合单指标评价Ⅱ类标准;浮游植物共126种(变种),隶属于7门19目33科66属,水体属于硅藻-绿藻-蓝藻型,浮游植物的总平均密度为(42.55±13.81)×10^(4)ind.·L^(-1),总平均生物量为(0.55156±0.16307)mg·L^(-1);浮游动物共37种,以轮虫为主(占48.56%),总平均密度为(47.80±14.78)ind.·L^(-1),总平均生物量为(0.16261±0.06635)mg·L^(-1);着生藻类共74种(变种),隶属于5门14目20科32属,总平均密度为(15.31±4.81)×10^(4)ind.·cm^(-2),总平均生物量为(0.28470±0.09390)mg·cm^(-2);群落结构和多样性指数研究表明,该江段属于寡污型且处于中营养状态。