雷州半岛近海夏季浮游植物和浮游细菌生物量的分布及其影响因素

于2010年7月(夏季)调查了雷州半岛近海海域浮游植物和细菌生物量的空间分布特征,并分析了其与海区主要环境因子间的相互关系。结果表明:雷州半岛近海海域夏季浮游植物生物量的变化范围为15.66～1114.92mg.m-3;平均值为192.49mg.m-3;夏季浮游细菌生物量的变化范围为3.36～50.12mgC.m-3,平均值为18.43mgC.m-3;浮游植物生物量水平分布格局在不同区域间没有显著差异,浮游细菌生物量的水平分布呈现西部海区>东部海区>南部海区的格局,差异极显著;浮游植物和浮游细菌生物量在表底层的垂直分布格局没有明显的规律,表、底层生物量或高或低,差异不显著;浮游植物和浮游细菌生物量多体现近岸站位>中间站位>远岸站位,即从陆向向海向呈递减的分布格局;夏季雷州半岛近海海域浮游细菌生物量与水温、pH和硅酸盐呈显著或极显著正相关,与盐度、TOC和磷酸盐呈极显著负相关;浮游植物生物量与pH和DO呈显著或极显著正相关,与盐度和TOC呈显极显著负相关;浮游植物生物量与浮游细菌生物量存在显著的正相关性,二者存在着相互影响的调控关系。     

水东湾海域浮游植物潮汐分布特征及其与环境因子的关系

2014年秋、冬两季,每个季节在大潮期和小潮期对水东湾海域浮游植物群落结构和环境因子进行了调查,共鉴定出4门57属134种。其中硅藻门42属106种,占浮游植物种类数的79.1%;甲藻门13属26种,占浮游植物种类数的19.4%;蓝藻门1属1种,占浮游植物种类数的0.8%;针胞藻纲1属1种,占浮游植物种类数的0.8%。优势种15种,主要为尖布纹藻Gyrosigma aluminatum、圆海链藻Thalassiosira rotula、中肋骨条藻Skeletonema costatum、丹麦细柱藻Leptocylindrus danicus和舟形鞍链藻Campylosira cymbelliformis等。4个航次共有种类数在18—40种,Jaccard种类相似性指数范围在0.200—0.404,多样性指数和均匀度平均值分别为2.60和0.60。秋季大、小潮期多样性指数差异较显著(P0.05),冬季细胞丰度、多样性指数和均匀度大、小潮期均无明显差异。浮游植物细胞丰度变化范围为0.95×10~4个/L—28.0×10~4个/L,平均为6.86×10~4个/L,平均丰度冬季小潮期(9.46×10~4个/L)秋季小潮期(7.56×10~4个/L)冬季大潮期(5.97×10~4个/L)秋季大潮期(4.44×10~4个/L)。主成分分析(PCA)表明:盐度和营养盐可能是影响水东湾海域生态环境的主导因子。对水东湾海域浮游植物群落结构与主要环境因子进行Spearman相关性分析,细胞丰度与盐度在秋季大、小潮期为负相关,在冬季大、小潮期呈显著正相关;与无机氮和磷酸盐在冬季大、小潮期呈极显著负相关,在秋季大、小潮期均无相关性。冬季小潮期水温与多样性指数、均匀度和细胞丰度均呈正相关;从测定结果来看浮游植物细胞丰度、多样性指数和均匀度与叶绿素a含量均无统计学意义上的相关性。     

流沙湾海草床海域浮游植物的时空分布及其影响因素

2008年2月至11月对广东省流沙湾海草床海域的浮游植物进行了周年的季节调查,结果共检出浮游植物151种:冬季57种、春季66种、夏季73种、秋季66种,其中硅藻门44属123种,占浮游植物种类数的81.4%;甲藻门11属26种,占浮游植物种类数的17.2%;绿藻门和蓝藻门各1属1种,各占浮游植物种类数的0.7%。优势种共有26种,主要为夜光藻Noctiluca scintillans、威氏角毛藻Chaetoceros weissflogii、圆海链藻Thalassiosira rotula、菱形海线藻Thalassionema nitzschioides等,都是链状群体或个体较细长或较大的种类,没有个体较短小的优势种群;各季节间共有种类数在22-43种,Jaccard种类相似性指数范围在0.211-0.448,多样性指数和均匀度平均值分别为2.12和0.35,群落结构较脆弱;细胞丰度在0.24×10⁴-5.72×10⁴ 个/L,秋季最高,夏季次之,冬季最低,属季节单峰型变化,与一般亚热带春、秋季出现丰度高峰不一致。相关性分析发现,浮游植物丰度与活性硅酸盐呈极显著的正相关,与盐度呈显著的负相关,与其他因子不存在明显的相关性;叶绿素a浓度与水温呈极显著的负相关,与浮游动物丰度呈显著的负相关。从浮游植物吸收N、P的配比分析,N为四季的营养限制因子,但从N、P的绝对值看,N和P都是全年的营养限制因子,因此其水质营养类型属于亚热带贫营养型。     

广西防城港湾周年浮游植物生态特征

2007年3、6、9和12月,对防城港湾海域浮游植物的种类组成、优势种类、群落结构、丰度分布进行了调查,分析了浮游植物丰度、生物指数及其与环境因子的相关性.共鉴定出浮游植物54属138种.其中硅藻门37属112种;甲藻门12属21种;绿藻门和金藻门各2种,蓝藻门1种.全年浮游植物优势种主要为硅藻门的中肋骨条藻.浮游植物种数呈现湾内低于湾外、由春至冬减少的趋势,浮游植物细胞丰度则呈由湾内向湾外递减的趋势.不同季节调查海区浮游植物细胞丰度平面分布格局具有显著差异,夏季(6月)浮游植物丰度最高,达151.39×104 cells·dm-3,冬季(12月)丰度最低,为0.35×104 cells·dm-3.春季防城港湾海域的浮游植物多样性较高,物种较丰富.相关性分析表明,浮游植物群落分布与营养盐、水温、盐度等环境因子存在一定的相关性.西湾内的S1和S2测站,受防城江径流及潮汐等水动力条件的作用,盐度较低,富营养化程度较高,夏季时中肋骨条藻会大量增殖,甚至具有发生赤潮的隐患.     

近15年长江口海域海洋生物变化趋势及健康状况评价

对近15年（2004-2018年）长江口海域海洋生物变化趋势进行分析，评价海洋生物健康状况，并对陆源污染物排放与海洋生物变化进行相关性分析。结果表明，（1）长江口海域海洋生物群落结构组成发生了一定变化，与20世纪90年代末相比，浮游植物种类数有所减少，浮游动物、底栖生物种类数有所增加。浮游植物以硅藻为主，但甲藻占比有所增加，2010年以来硅藻、甲藻群落结构进入新的平衡状态；浮游动物以节肢动物为主，主要类群桡足类占比有所下降；底栖生物种类数明显升高。（2）生物多样性总体水平一般，浮游植物多样性指数总体较低，第一优势种的优势度较高；浮游动物多样性指数和丰富度指数多年呈现下降趋势；底栖生物多样性水平一般，优势种渐趋单一。（3）海洋生物总体处于"不健康"状态，主要影响指标为浮游植物密度偏高，浮游动物密度偏低、生物量偏高，底栖动物密度偏高、生物量偏低。生态系统变化与陆源主要污染物排放、营养结构变化及水体富营养化均具有一定的相关性，其中无机氮（DIN）、石油类入海通量与生物健康指数呈显著负相关关系（P < 0.05），无机磷（DIP）与底栖生物生物量呈显著负相关关系。N/P与浮游植物丰度呈显著负相关，但与浮游植物均匀度和多样性指数呈显著正相关；Si/N与浮游植物多样性指数呈显著负相关。海域严重富营养化面积比例与硅藻甲藻种类数比值呈显著正相关关系。     

吕泗大洋港浮游植物群落与环境因子关系

于2010年4月对江苏省南通市吕泗大洋港近岸海域浮游植物的种类组成、多样性、丰度及其分布进行了调查.结果表明:在20个调查站位共鉴定浮游植物3门30属85种,其中,硅藻门27属81种,占种数的95.29％,蓝藻门2属3种,占种数的3.53％,金藻门1属1种,占种数的1.18％;浮游植物生态类型主要以低盐近岸性类群为主,辅以少量的广温广盐性类群;主要优势种为中肋骨条藻、具边圆筛藻、簇生针杆藻、长菱形藻、偏心圆筛藻、圆海链藻、线形圆筛藻和辐射圆筛藻,优势度分别为0.319、0.308、0.246、0.243、0.186、0.131、0.122和0.120;浮游植物的细胞丰度范围为0.641×104 ～3.136×104 ind.L-1,平均值为1.640×104 ind·L-1;群落特征指数变幅较大(种类数为23～ 42,Margalef丰富度指数为0.603 ～1.339,Shannon指数为2.362 ～3.840,Pielou均匀度指数为0.638～0.958);丰富度指数均值为1.007,Shannon指数均值为3.327,均匀度指数均值为0.859.相关性分析表明:均匀度指数与汞和锌含量呈极显著负相关,与盐度呈极显著正相关,与COD和DIN呈显著和极显著负相关;丰富度指数与砷含量和DO呈显著正相关;Shannon指数仅与锌含量呈极显著负相关.     

广西近岸海域浮游植物群落的生态特征

根据2009年9月(丰水期)和2010年1月(枯水期)广西近岸海域的调查资料,分析了该海域浮游植物的种类组成、优势种、丰度及其分布和多样性等群落生态特征。结果表明:调查海域共鉴定浮游植物4门40属134种,其中硅藻是主要优势类群,占总种数的87.3%;丰水期和枯水期共有种类达84种,种类相似性指数为81.4%,无明显的季节性差异;丰水期优势种较多,其中最主要的优势种为旋链角毛藻(Chaetoceros curvisetus)和柔弱伪菱形藻(Pseudo-nitzschia delicatissima);枯水期优势种组成相对简单,以球形棕囊藻(Phaeoecystis globosa)占绝对优势,优势度指数为96.1%;浮游植物的丰度呈显著的区域和季节差异;丰水期表现为近岸海域自东向西递减,沿岸普遍高于离岸海域的特征;浮游植物群落的Shannon指数和Pielou均匀度指数平均值分别为2.79和0.58,多样性水平较高;多样性指数和均匀度指数季节变化不明显,但具有显著的空间分布规律,呈中部高而两侧低的单峰态;相关性分析表明,浮游植物丰度与环境因子存在一定的相关性;丰水期,浮游植物丰度与水温呈负相关(P0.05);枯水期,浮游植物丰度与无机氮呈显著正相关(P0.01),而与生化需氧量(P0.01)、盐度(P0.05)呈负相关。     

2009年冬季东海浮游植物群集

2009年12月23日—2010年1月5日在东海海域(24°00’—32°00’N,120°00’—128°00’E)68个站位进行了水文、化学和生物的综合调查,应用Utermhl方法对调查海域的浮游植物群集进行了研究。经284个浮游植物采水样品的分析,共发现浮游植物4门67属171种(含13个未定种)。浮游植物群集主要由硅藻和甲藻组成,还有少量的蓝藻和金藻,物种以沿岸广温型为主,优势种为:具槽帕拉藻(Paralia sulcata)、菱形海线藻(Thalassionema nitzschioides)、柔弱伪菱形藻(Pseudo-nitzschia delicatissima)、安哥拉海链藻(Thalassiosira angulata=并基海链藻Thalassiosira decipens)和细弱海链藻(Thalassiosira subtilis)等。调查浮游植物细胞丰度介于0.356×103—142.578×103个/L,平均值为14.137×103个/L;硅藻占浮游植物细胞丰度的比例最大,介于0.356×103—142.578×103个/L,平均值为13.023×103个/L;其次为甲藻,细胞丰度介于0.356×103—11.378×103个/L,平均值为1.177×103个/L。调查海域表层浮游植物细胞丰度的平面分布由硅藻刻画,高值区出现在调查区北部即长江口东北部海域,甲藻在调查区南部和东南部丰度较高。细胞丰度在水体中的垂直分布趋势为先上升后下降,最大值出现在10m层。从断面分布上看,细胞丰度在调查区近岸和远岸较高、中部较低。Pearson相关性分析表明,调查区浮游植物细胞丰度与磷酸盐和硅酸盐浓度呈显著正相关,与温度呈显著负相关,与硝酸盐相关性不明显。     

湛江湾角毛藻群落的时空分布及其影响因素

2009年2-11月以水采、网采和显微鉴定的方法分别对湛江湾的浮游植物进行了周年的季节调查,分析了湛江湾角毛藻(Chaetoceros)群落的时空分布和影响因素.结果表明:湛江湾角毛藻共有32种,其中有17种为赤潮种,优势种有旋链角毛藻(C.curvisetus)、假弯角毛藻(C.pseudocurvisetus)和牟氏角毛藻(C.muelleri)3种;种类丰富度和细胞丰度在季节分布上表现为春夏季高于秋冬季,而在空间分布上总体表现为湾口高,向内湾逐渐降低.相关分析表明:角毛藻细胞丰度与水温、盐度、pH、叶绿素a浓度及浮游植物细胞丰度呈极显著的正相关,与DIN、SiO32-呈极显著的负相关,与PO43-相关性不显著:角毛藻细胞丰度的季节变化主要取决于水温,由季节更替而产生的种间竞争和浮游动物的摄食压力也是重要的影响因素,而空间变化则受到光照、盐度、pH和高丰度养殖贝类滤食压力的影响.     

湛江港湾浮游桡足类群落结构的季节变化和影响因素

2009年2月、5月、8月和11月分别对湛江港湾浮游动物进行了季度月调查,并对该海域浮游桡足类群落结构的季节变化及影响因素进行了分析.结果共鉴定出桡足类72种,其中冬季36种,占浮游动物种类数的29.5％;春季33种,占浮游动物种类数的39.3％;夏季24种,占浮游动物种类数的29.6％;秋季19种,占浮游动物种类数的40.4％.主要优势种为中华哲水蚤Calanus sinicus、强额拟哲水蚤Paracalanus crassirostris、短角长腹剑水蚤Oithona brevicornis、亚强真哲水蚤Eucalanus subcrassus、刺尾纺锤水蚤Acartia spinicauda和桡足类幼体.季节变化模式为:夏季丰度最高,达960.0个/m3,春季次之为421.0个/m3,冬季为303.4个/m3,秋季最低仅为252.8个/m3.平面分布冬春季丰度内湾高,往湾口逐渐降低,夏季内湾低往湾口逐渐增大,而秋季分布较均匀.调查海区桡足类丰度与水温、叶绿素a和浮游植物细胞丰度呈极显著的正相关,与DIN和PO3-4呈显著的负相关,与盐度、pH值和活性硅酸盐相关性不明显.     

在种与属两个级别评价太子河硅藻群落与环境因子的关系

2009年8—9月,对辽宁省太子河流域67个点位进行采样调查,以硅藻群落为研究对象,比较硅藻属级水平与种级水平相对多度、物种丰富度以及生物多样性指数间的相关性,并比较硅藻属级与种级属性与环境因子的相关性。实验结果表明,太子河流域硅藻属级水平的相对多度、丰富度和多样性指数与硅藻种级水平都极显著相关。Pearson相关性分析表明,硅藻属级水平的丰富度与环境显著相关的因子与种级水平丰富度与环境显著相关的因子相一致。Mantel-Test相关性分析表明,硅藻属级水平的相对多度与环境因子的相关性弱于种级水平与环境因子相关性。典范对应分析结果显示,影响硅藻属级和种级群落结构分布的主要环境因子均为悬浮物。基于硅藻生物评价指数的流域健康评价结果表明,应用硅藻属级和种级属性对太子河流域进行健康评价,其评价结果相一致。     

Benthic macroinvertebrate assemblages of coastal and continental streams and large rivers of southwestern British Columbia, Canada

In southwestern British Columbia (BC, Canada) and within a relatively small geographic area, lotic environments range from streams in coastal rainforests, to streams in arid continental grasslands, to very large rivers. Little is known about the invertebrate communities in large rivers in general, or in the streams of continental BC. The purpose of this study was to determine whether the benthic invertebrate community structure changes spatially between small coastal and small interior streams; between small streams versus large rivers; and whether changes in the benthic community are related to the environmental conditions. Kicknet samples and environmental data were collected from three coastal streams, three continental streams and two large rivers (discharge of 781 and 3620 m³/s, respectively). The large river sites had low invertebrate abundance, species richness and diversity, relative to the small streams. The coastal streams had the highest species richness and the continental streams had the highest invertebrate abundance. A number of taxa were specific to each class of stream. Invertebrate abundance decreased with river size, and increased with elevation, pH, conductivity, alkalinity, NO₂NO₃-N, total Kejldahl nitrogen and percent carbon in suspended solids.     

The species composition of Antarctic phytoplankton interpreted in terms of Tilman's competition theory

Summary An attempt was made, to test for the impact of resource competition on Antarctic marine phytoplankton. According to theory, species composition near competitive equilibrium should be determined by the ratios of limiting resources. Enrichment bioassays identified silicon and nitrogen as limiting nutrients for some of the most important phytoplankton species during early austral summer in the region near the Antarctic Peninsula. Together with the generally acknowledged limiting resource light, this gave three meaningful ratios of essential resources (Si:N, Si:light, N:light) and one ratio of substitutable resources (NO₃:NH₄). Phytoplankton species assemblages were found to be well separated by the ratios of the essential resources and by mixing depth. Nine out of 12 individual species were found to be separated along at least one of the gradients of resource ratios. Where comparison with competition experiments was available, predicted and realized distributions of species were compatible.     

Composition and abundance of phytoplankton in tributaries of the lower Colorado river,Grand Canyon region

Phytoplankton distribution and abundance in eleven tributaries of the Colorado River within the Grand Canyon were investigated from April, 1975 to June, 1976. During this period a total of 56 genera and 156 species of phytoplankton was identified. Phytoplankton species of the individual tributaries were quite distinct, with only four diatom species, Diatoma vulgare, Navicula tripunctata, Nitzschia linearis and Synedra ulna, common to all the tributaries. Bright Angel Creek, Shinumo Creek and Elves Chasm were the tributaries with the most diverse algal flora, whereas Vaseys Paradise, Tapeats Creek, Deer Creek and Havasu Creek showed the lowest species richness. Elves Chasm and Diamond Creek had the highest phytoplankton numbers. Phytoplankton abundance and species richness appeared to be influenced by high turbidity, current velocity, fluctuating water levels and age of the water. Some of the dominant algal species, Biddulphia laevis, Cocconeis pediculus, Cymbella ventricosa, Epithemia sorex, Gomphonema parvulum and Synedra ulna, showed significant correlations with specific physico-chemical characteristics of the tributaries.Grand Canyon National Park Colorado River Research Series Contribution No. 66. This research was supported by the National Park Service, U. S. Department of the Interior.     

Structural variations of phytoplankton in the coastal seas of Yucatan,Mexico

A study was done of the relationship between hydrographic variables and the composition, abundance, community structure and biomass spectrums of coastal phytoplankton at scales greater than 100 km on the Yucatan Peninsula (SE Gulf of Mexico). This was done during the season of greatest environmental instability in the region, the northwind season (late fall to winter). Samples were collected at stations in the west (Campeche), north (Yucatan), and east (Quintana Roo) zones of the Peninsula. Measurements were taken of temperature, salinity, dissolved oxygen, dissolved inorganic nutrients (ammonia, nitrite, nitrate and phosphate) and chlorophyll a, and samples were taken for phytoplankton analysis. The hydrographic results showed the Campeche zone as having the lowest salinity (<35 psu) values, as well as the highest inorganic nutrient and chlorophyll a values, all of which are related to continental water contributions. The Yucatan zone had the lowest temperatures and the lowest inorganic nutrient values, indicating influence from the Yucatan Current and the Gulf of Mexico. A total of 159 phytoplankton species were identified, dominated by diatoms (>80%) and dinoflagellates. Phytoplankton exhibited greater concentration, richness, equitability and diversity in Campeche, while the lowest community structure values were had in the Quintana Roo zone. The ordination analysis demonstrated that the dominant genera were the diatoms Chaetoceros, Pseudonitzschia and Thalassionema. The biomass spectrums exhibited the lowest slope in environments of higher heterogeneity, with Campeche being the most disturbed and heterogeneous zone and Quintana Roo that with the least heterogeneity.     

Water quality and phytoplankton community structure in mangrove streams under different logging regimes in Cameroon

Mangrove logging is rampant, and its effects on phytoplankton dynamics have not been investigated. Phytoplankton are valuable in biomonitoring pollution in mangrove ecosystems. This study assessed the relationship between physico‐chemical characteristics of the water and observed phytoplankton community structure, in relation to anthropogenic activities. Water samples were collected from seven sites within the mangrove ecosystem that differed in wood harvesting age and proximity to human settlements. Characterization of samples followed standard methods. pH of all water samples indicated acidity. Phytoplankton species richness and soluble P were positively correlated (r = 0.822, P ≤ 0.023), but no correlations existed with logging age (r = ?0.273, P = 0553). The site with highest soluble phosphorus concentration (Site 4) had highest phytoplankton abundance, diversity and richness. A total of 127 species were identified in 58 families. Euglenaceae was the most abundant family (13 species) and Anacystis sp. the most frequent species (100%). The most common genera were Microcystis and Anacystis, bioindicators of pollution. The site at which harvesting was most recently performed had more eutrophic species, while site harvested earliest (Site 5) had the least. These results are discussed with respect to how anthropogenic activities influence water quality, phytoplankton community structure, mangrove conservation and management.     

东海低氧区及邻近水域浮游植物的季节变化

根据2011年5月、8月、11月在东海低氧区及邻近水域(25°00'—33°30'N,120°00'—127°30'E)进行的多学科综合调查,对东海低氧区及邻近水域浮游植物群落结构特征及季节变化进行了相关研究。经Utermhl方法初步分析共鉴定出浮游植物4门74属248种(含变种、变型,不含未定种),主要由硅藻和甲藻组成,此外还有少量的金藻和蓝藻。春季优势种主要为具齿原甲藻(Prorocentrum dentatum)、柔弱伪菱形藻(Pseudo-nitzschia delicatissim)、骨条藻(Skeletonema sp.)和具槽帕拉藻(Paralia sulcata);夏季主要是中肋骨条藻(Skeletonema costatum)和海链藻(Thalassiosira sp.);秋季主要是具槽帕拉藻、圆筛藻(Coscinodiscus sp.)和柔弱伪菱形藻。调查区浮游植物平均细胞丰度在夏季最高,达到85.002×103个/L,春季次之,秋季最低。在水平方向上,春、夏两季,表层浮游植物细胞丰度在近岸出现高值,由近岸到外海细胞丰度逐渐降低;而在秋季则相反,在调查海域的东北部出现高值,随离岸距离的增加细胞丰度逐渐增加。在垂直方向上,春、夏两季,浮游植物细胞丰度在表层出现最大值,随着深度的增加细胞丰度逐渐降低;而在秋季细胞丰度分布比较均匀,随水深变化不明显。调查区表层浮游植物ShannonWiener多样性指数和Pielou均匀度指数的平面分布基本一致,并且与细胞丰度的分布大致呈镶嵌分布。调查浮游植物群落的演替规律是:从春季的甲藻(具齿原甲藻、微小原甲藻(Prorocentrum minimum)等)为主,硅藻(柔弱伪菱形藻、骨条藻等)为辅;演替至夏季的硅藻(中肋骨条藻、海链藻等)为主,甲藻(主要是梭状角藻(Ceratium fusus)和叉状角藻(Ceratium furca))为辅,到秋季进一步演替为硅藻(具槽帕拉藻、圆筛藻、柔弱伪菱形藻等)为主,铁氏束毛藻(Trichodesmium thiebaultii)为辅。浮游植物物种组成、优势种、细胞丰度及多样性指数均表现出明显的时空变化。低氧区与非低氧区浮游植物群集存在明显差异。     

湘西石漠化区3种造林模式土壤真菌群落结构差异

湘西石漠化地区是我国生态系统脆弱而又敏感的区域,土壤微生物在维持石漠化区森林生态系统结构和功能稳定中发挥重要作用。选取石漠化地区立地条件相同的32年生的马尾松纯林、光皮桦纯林及马尾松-光皮桦混交林为研究对象,以立地条件相似的未造林荒地演变成的灌草群落作为对照,比较分析石漠化地区不同造林模式对土壤真菌群落结构和多样性的影响及其主要驱动因素。采用Illumina HiSeq第二代高通量测序技术,分析了3种森林土壤真菌群落组成及多样性。结果表明,不同造林模式下土壤真菌优势类群不同,光皮桦、马尾松-光皮桦混交林以及石漠化灌草地土壤真菌优势门均为子囊菌门(Ascomycota),且在石漠化灌草地相对丰度最大,为64.0%;马尾松则以担子菌门(Basidiomycota)为优势类群,其相对丰度占57.9%。混交林土壤真菌物种总数和Shannon指数显著高于马尾松和光皮桦林地,整体上真菌群落多样性表现为：未造林灌草地>混交林>马尾松林>光皮桦林。与未造林灌草地相比,马尾松-光皮桦混交林和光皮桦纯林显著提升了土壤有机碳(SOC)和全氮(TN)含量。Mantel test检验结果显示,...     

广州海域浮游植物群落结构特征

2003年5月至2004年5月对广州海域进行的浮游植物周年调查表明,广州海域浮游植物种类丰富,共有89属209种。其中硅藻为优势类群,共41属122种,占总种数的58.4%。中肋骨条藻为全年优势种。浮游植物种数和数量的平面分布表现为由河口处向外海递减的格局,受径流影响较大的河口处种数和数量均较多。调查期间浮游植物数量年平均值为4.11×10⁵cells·L^-1,周年变化为双峰型。