Phytoplankton and Zooplankton Associations in a Set of Alpine High Altitude Lakes: Geographic Distribution and Ecology

Species composition and interactions, biomass dominance, geographic distribution and driving variables were investigated for two key elements of the pelagic food web of Alpine lakes, the phytoplankton and the zooplankton, based on a single sampling campaign during summer 2000. Altogether, 70 lakes were surveyed, 49 of which located in three different lake districts of the west and eastern Italian Alps and 21 in the central Austrian Alps (within the uppermost Danube catchment). In addition to the analysis of environmental variables affecting distribution and species structure of the two planktonic compartments, a brief review of the main research lines and hypotheses adopted in the past for the study of phytoplankton and zooplankton in high Alpine lakes is given. The lakes, investigated partly within the European project EMERGE (EVK1-CT-1999-00032) and partly within a regional project in the eastern Alps, comprise a wide range of morphological, chemical and trophic conditions. The phytoplankton communities were found to be diverse and mostly dominated by flagellates (chrysophytes, cryptophytes and dinoflagellates), and only to a lesser extent by non-motile green algae, desmids and centric diatoms. The zooplankton communities were mainly dominated by Alpine cladocerans and copepod species, while rotifers were abundant within one group of Italian lakes (sampled in early summer). The multivariate statistical analyses (CCA) showed that catchment features (i.e. percentage of vegetation cover and geochemical composition) and nitrate concentration are essential drivers for the phytoplankton, whereas for zooplankton also trophic status of the lakes and phytoplankton structure are important. The combined variance analysis of the lake clusters outlined by the multivariate analyses on phytoplankton and zooplankton data, respectively, allowed the identification of four principal lake types (three located on siliceous and one on carbonaceous bedrock), each one characterised by a certain combination of habitat features, which in their turn influence trophic state, and phytoplankton and zooplankton species composition and functionality.     

Comparative limnology of nine lakes of Jammu and Kashmir Himalayas

Two lakes in the lower Siwalik Himalayas, five in the Kashmir valley and two situated in the high mountains of the Kashmir Himalayas were investigated for their physico-chemical and biological features. The lakes, differing significantly in their morphology and in thermal behaviour, rank from the subtropical monomictic to the dimictic type. The lakes at high altitudes (> 3000 m) have very low electric conductivity which increases with the decrease in altitude. The most dominant ions in water are calcium and bicarbonate. The macrophytic vegetation of the lakes does not show any definite relationship either with altitude or with physico-chemical milieu. In the lakes with low fertility the phytoplankton is dominated by diatoms and Chlorophyceae but in eutrophic lakes Cyanophyceae predominate. The zooplankton population of the lakes is mainly comprised of rotifera. On the basis of general limnological features and the rates of phytoplankton production most of the lakes may be categorized either as eutrophic or in the process of rapid evolution. Only one lake is oligotrophic.     

Distribution and Abundance of Zooplankton in an Alkaline Freshwater Marsh in Northumberland County,Pennsylvania

The zooplankton community of two ponds in an alkaline marsh in central Pennsylvania were studied. The ponds were found to be distinctly different from one another with regard to species but similar when only zooplankton types are considered. The ponds were quite similar with respect to a number of physico-chemical characteristics but differed significantly with respect to alkalinity, conductivity, habitat type, vegetation, depth, and predation pressure.     

Bioturbation as Driver of Zooplankton Recruitment,Biodiversity and Community Composition in Aquatic Ecosystems

In an experimental study we assessed if benthic bioturbating invertebrates affect the recruitment (hatching) of zooplankton from the sediment, and if this effect persists as differences in the zooplankton community in the water column, that is, if bioturbation quantitatively stimulates benthic–pelagic coupling. We investigated the effects of four different benthic invertebrates (Asellus aquaticus, Chironomus plumosus, Tubifex tubifex in the presence or absence of the predator Sialis lutaria). In total, 45 zooplankton taxa hatched from the sediment and the hatching success of some of these was dependent on the species identity of the bioturbating invertebrate. The predator Sialis reduced the abundance of all three invertebrate species, but tended to positively influence the zooplankton recruitment rates, possibly through increasing the activity of the bioturbating invertebrates. The most striking effect of bioturbation on the hatching and pelagic zooplankton community properties was that, on average, 11% more species hatched in the Asellus treatment than in any other treatment. This was also mirrored in the zooplankton water column community where, on average, 7% more species established a viable population in treatments with Asellus as bioturbator. In a complementary field survey, Asellus was more common in littoral than in profundal sediments. Because Asellus strongly affected recruitment of zooplankton in our experiment, we argue that bioturbation may partly explain why recruitment of resting stages of both phyto- and zooplankton is generally higher in littoral than in profundal areas.     

Zooplankton Distribution in Tropical Reservoirs,South China

The zooplankton of 18 reservoirs of South China was investigated in 2000. 61 Rotifera species, 23 Cladoceras and 14 Copepodas were identified. The most frequent Rotifera genera were Keratella, Brachionus, Trichocerca, Diurella, Ascomorpha, Polyarthra, Ploesoma, Asplanchna, Pompholyx and Conochilus. Bosmina longirostris, Bosminopsis deitersi, Diaphanosoma birgei, D. brachyurum and Moina micrura were typical of Cladocera in the reservoirs. Phyllodiaptomus tunguidus, Neodiaptomus schmackeri and Mesocyclops leuckarti were the most frequent Copepoda and M. leuckarti dominated Copepoda in most reservoirs. High zooplankton species richness with low abundance was characteristic of the throughflowing reservoir, whereas low species richness with low abundance was found in the reservoir with the longest retention time. Relative high abundance and medium species diversity were the distinction of intermediate retention time reservoirs.     

Vertical Distribution of Zooplankton in a Strongly Stratified Hypertrophic Lake

The vertical and temporal distribution of metazooplankton in the small hypertrophic, strongly stratified, temperate Lake Verevi (Estonia) was studied during 1998–2001. The zooplankton of Lake Verevi is characteristic of hypertrophic lakes, with a small number of dominant species, rotifers being the main ones, and juveniles prevailing among copepods. In 1999–2001, the average abundance of metazooplankton in the lake was 1570 × 10³ ind m⁻³; in the epilimnion 2320 × 10³ ind m⁻³, in the metalimnion 2178 × 10³ ind m⁻³, and in the hypolimnion 237 × 10³ ind m⁻³. The average biomass of metazooplankton was 1.75 g m⁻³; in the epi-, meta- and hypolimnion, accordingly, 2.16, 2.85 and 0.26 g m⁻³. The highest abundances – 19,136 × 10³ ind m⁻³ and 12,008 × 10³ ind m⁻³ – were registered in the lower half of the metalimnion in 24 May and 5 June 2001, respectively. Rotifer Keratella cochlearis f. typica (Gosse, 1851) was the dominating species in abundance. In biomass, Asplanchna priodonta Gosse, 1850, among the rotifers, and Eudiaptomus graciloides (Lilljeborg, 1888), among the copepods, dominated. According to the data from 2000–2001, the abundance and biomass of both copepods and rotifers were highest in spring. Zooplankton was scarce in the hypolimnion, and no peaks were observed there. During the summers of 1998 and 1999, when thermal stratification was particularly strong, zooplankton was the most abundant in the upper half of the metalimnion, and a distinct peak of biomass occurred in the second fourth of the metalimnion. Probably, the main factors affecting the vertical distribution of zooplankton in L. Verevi are fish, Chaoborus larvae, and chemocline, while food, like phytoplankton, composition and abundance may affect more the seasonal development of zooplankton.     

Distribution of filter-feeding caddisflies (Trichoptera) and plankton drift in a Swedish lake-outlet stream

The objectives of this investigation were to relate the longitudinal distribution of filter-feeding caddisflies to quality and quantity of seston, and to document factors facilitating coexistence among filter-feeding species, in a 4th-order lake-outlet stream in central Sweden. A sharp decline in abundance and biomass of filtering caddisflies was evident within 1 km from the lake outlet following negative power functions. In contrast to particulate organic carbon, significant reductions of both phytoplankton and zooplankton biomass, especially some large species, were recorded between the lake-outlet and 1.9 km downstream. Differences in longitudinal and temporal distribution provide evidence of resource partitioning between filtering species included.     

Zooplankton-trophic state relationships in some north and central Florida lakes

In a survey of eight lake systems located in north-central Florida, total zooplankton abundance showed a strong positive correlation (r²=0.87, a=0.01) with trophic state. Zooplankton abundance averaged 1.0 × 10⁵ organisms · m^–2 in oligotrophic systems and up to 8.2 × 10⁵ organisms · m^–2 in the eutrophic systems. Seasonal variations in total abundance were greatest in the eutrophic lakes where rotifers dominated and periodically produced sharp population peaks (approaching 2.0 × 10⁶· m^–2). In contrast, the more oligotrophic systems had relatively stable levels of total abundance and were dominated by copepods. Diversities of the major taxa in the lakes were variable with one to three species of copepods, zero to four species of cladocera, and two to seven species of rotifers dominant at any one time. Planktonic cladoceran communities were often composed of only one or two species. Low cladocera diversity in these subtropical systems was suggestive of increased predation pressure on this group of crustaceans. A comparison of the total crustacean abundance in the Florida systems to those of some of the Great Lakes indicated that lower standing crops of crustacean zooplankton in the Florida lakes may be a response to both predation and temperature.Contribution Number 043, Marine Science Programs Laboratory, Dauphin Island, Alabama, U.S.A.Contribution Number 043, Marine Science Programs Laboratory, Dauphin Island, Alabama, U.S.A.     

Primary productivity and trophic status of a Kashmir Himalayan Lake

The paper deals with general limnology, phytoplankton production and trophic status of a Himalayan lake of Kashmir. The primary production as measured by in situ ¹⁴C istope technique ranged from 36 to 906 mgC.m^–2 d^–1 with characteristic seasonal variation. The photosynthetic efficiency was from 0.02 to 0.48% during the same period. The yearly (1975–1976) production was estimated at 134 gC.m^–2 m^–2, which shows that the lake has not yet reached a high level of eutrophication. The waterbody has been classified as mesotrophic.Formed part of thesis for which Ph. D. was awarded to MAK by Kashmir University, India     

莽山自然保护区陆生贝类的种类组成及区系分析

首次报道了莽山自然保护区陆生贝类39种,隶属于2亚纲、10科、19属;介绍了莽山的自然概况;对莽山自然保护区陆生贝类的种类组成、区系特点、生态分布与栖息环境之间的关系进行了分析。     

Species Composition, Abundance, and Distribution of Seabirds along the Northeastern Coast of Sakhalin

Seabirds were counted in September 1998 from the research vessel Professor Khromovand a motorboat in Pil'tun and Lunskii bays and in the contiguous areas of the eastern Sakhalin shelf. Data on the species composition, abundance, and distribution of seabirds are presented. A fairly high species diversity and significantly high density of seabirds were recorded in Pil'tun and Lunskii bays, which are the main areas where they concentrate during the summer months.     

广西猫儿山地区鸟类组成及垂直分布格局

猫儿山是华南地区的最高峰,为了了解其鸟类随着海拔高度变化的规律,利用网捕法和样线法对猫儿山地区的鸟类组成及分布格局进行了研究。结果表明,猫儿山地区共有鸟类268种,隶属于16目51科,其中留鸟130种,夏候鸟51种,冬候鸟15种,旅鸟72种。依据不同海拔的典型植被类型把猫儿山地区分成7类生境,其中低海拔的农田生境鸟类多样性最丰富,有156种。随着海拔的升高,猫儿山鸟类种数逐渐减少,G-F指数也表现相似的规律。猫儿山鸟类在区系组成上主要以东洋界鸟类为主,在181种繁殖鸟中,东洋界鸟类有149种,古北界鸟类有15种,其余为广布种。随着海拔的升高,东洋界的鸟类所占的比例逐渐降低,而古北界的鸟类所占的比例逐渐升高。猫儿山鸟类组成的垂直分布格局的形成是多种因素共同作用的结果。     

The Significance of Zooplankton in the Cycling of Phosphorus in Lakes of Different Trophic Categories

The species composition, number, biomass and phosphorus excretion rate (PER) of zooplankton (Crustacea and Rotatoria) in 8 mesotrophic and eutrophic lakes were studied. PER were calculated using specific expenditures on metabolism estimated from the oxygen uptake, phosphorus content in zooplankton and field observations of number and biomass of planktonic Rotatoria and Crustacea. The zooplankton biomass and PER increased from mesotrophic to eutrophic lakes. The values of PER were compared with primary production and spring phosphorus concentration. The relative significance of zooplankton in phosphorus cycling declined with increasing trophic category of lakes.     

东黄海秋季浮游动物优势种聚集强度与鲐鲹渔场的关系

一、前言日本鲐鱼(Pneumatophorus japonicus)和蓝圆鲹(Decaterus maruadsi)是东黄海主要中上层鱼类资源。秋季鲐鲹鱼在黄海南部和东海北部(北纬32°00′—33°30′,东经124°00′—128°30′)以及东海中南部(北纬26°30′—29°00′,东经123°00′—126°00′)形成两个索饵渔场,前者简称为北部渔场,后者简称为南部渔场。为了开发和利用东黄海鲐鲹鱼索饵渔场资源,需要对两渔场鲐鲹鱼资源分布的特点进行研究。根据以往国内外的一些报道,鲐鲹鱼是一类以浮游动物为主食的鱼类,其分布特点往往同浮游动物的分布有密切关系。因此,本     

Species composition and phytoplankton biomass in a tropical African lake (Lake Awassa,Ethiopia)

The species composition and phytoplankton biomass of Lake Awassa, Ethiopia were studied from September 1985 to July 1986 in relation to some limnological features of the lake. During the study period, three phases of thermal stratification were recognized: a period of unstable stratification and near-complete mixing was followed by a stable stratification period and another period of complete mixing. Complete mixing was associated with cooling of air temperature with an influx of cool rain and high rainfall. The underwater light penetration showed a similar pattern over the whole period with the highest in the red, and the lowest in the blue spectral region. Euphotic depth varied between 1.6 and 3.0 meters with the highest measurements corresponding to the stable stratification period. PO₄-P concentrations ranged between 23 and 45 µg l^–1 and NO₃-N concentrations varied between 7 and 14 µg l^–1 during the study period. Both nutrients showed increasing values associated with mixing periods and/or the rainy season.A total of 100 phytoplankton species were identified with 48% of the taxa represented by green algae, 30% by blue-green algae, 11% by diatoms, and the rest by chrysophytes, dinoflagellates, cryptomonads and euglenoids. The dominant phytoplankton species were Lyngbya nyassae, Botryococcus braunii and Microcystis species. Seasonal biomass variation was pronounced in the first two species but not in Mycrocystis. Phytoplankton biomass increased following the mixing period in December, and thermal destratification during May to July which was also a period with high rainfall and relatively high nutrient concentration. While the seasonal variation of the total phytoplankton community in Lake Awassa was relatively low (coefficient of variation < 20%), it was higher in some of the individual component species.     

A Short-Term Study of Vertical and Horizontal Distribution of Zooplankton During Thermal Stratification in Lake Kinneret,Israel

This study documents for the first time both vertical and horizontal distribution patterns of the zooplankton community in Lake Kinneret during the period of thermal stratification. The zooplankton distribution patterns were explored in relation to abiotic (temperature, oxygen) and biotic (picocyanobacteria, ciliates, flagellates, phytoplankton, fish) environmental gradients. Sampling was carried out on 6–7 July 1992 at five stations and six depths from nearshore to offshore. Zooplankton abundance and biomass varied from 5 to 267 ind. l^–1(mean: 95 ind. l^–1), and from 0.1 to 65 d.w. mg m^–3(mean: 24 d.w. mg m^–3). Zooplankton taxonomic groups (Rotifera, Cladocera, Cyclopoida, Calanoida) and size classes (micro-, meso- and macrozooplankton) showed peaks of maximal density and biomass in the epilimnetic and metalimnetic strata (5 and 14 m). Depth, accounting for 31–39% of total spatial variation, reflected the vertical distribution of zooplankton in relation to temperature and oxygen declines, and the higher concentration of food resources (protists and phytoplankton) in the epilimnion and metalimnion. Onshore–offshore distance, accounting for 17–22% of the total spatial variance, reflected different distribution patterns shown among zooplankton groups and size classes. The macrozooplankton (Copepoda, Cladocera) was more abundant offshore, whereas microzooplankton (Rotifera and nauplii) predominated nearshore. These horizontal distribution patterns were related to small increases in temperature and phytoplankton biomass, and higher concentrations of fish in the littoral zone. Although limited to a short temporal scale, our study indicated that zooplankton spatial distribution in Lake Kinneret during the period of thermal stratification was related to physicochemical, food and predation factors, manifested differently along the vertical and nearshore–offshore gradients.     

The Species and Size Composition of Tropical Freshwater Zooplankton with Special Reference to the Oriental Region (South East Asia)

A contrast between temperate and tropical Cladocera, Copepoda and Rotifera zooplankton fauna shows a markedly different size composition and species diversity. There are fewer species, and these are generally smaller in the tropics than in either the North or South Temperate Zones. Larger species of the genera Daphnia and Simocephalus are relatively rare in the tropics, while members of Eurycerus and Saycia are absent. Members of the families Holopedidae, Leptodoridae and Polyphemidae increase in abundance toward the temperate regions. Two small cyclopoid copepods are common in tropical zooplankton, while many of the common larger species of other regions are absent or very rare. The chief rotifer components are Keratella tropica and species of Brachionus.     

澳门红树林植物组成及种群分布格局的研究

调查工作于１９９２年４月～１９９４年９月在路环及凼仔红树林区内进行．路环红树林面积约７．１１５ｈｍ２,凼仔红树林面积约５７．２０５ｈｍ２．在两地区的海滩中,红树林植物计有４科４种,分属于红树科（Ｒｈｉｚｏｐｈｏｒａｃｅａｅ）、紫金牛科（Ｍｙｒｏｉｎａｃｅａｅ）、马鞭草科（Ｖｅｒｂｅｎａｃｅａｅ）和爵床科（Ａｃａｎｔｈａｃｅａｅ）．海岸半红树植物计有１５科２７种．利用样带法研究澳门红树林种群的分布格局,除秋茄为随机分布外,桐花树、白骨壤及老鼠勒均趋于集群的分布格局．结合数据分析８个研究区域种群生态位序列,只有凼仔红树林研究区最具有显著的生态位序列．     

Zooplankton Composition and Ecology in Western Boreal Shallow-water Wetlands

Zooplankton are a functionally important but poorly studied component of western boreal forest (WBF) wetland ecosystems. To characterize patterns in zooplankton abundance and composition an exploratory study of 24 shallow-water wetlands in northern Alberta, Canada was carried out over the summers of 2001 and 2002. Results suggest zooplankton communities in WBF wetlands tend to exist as: (1) small-cladoceran dominated communities, (2) larger sized cladoceran (e.g. Daphnia) dominated communities, or (3) communities composed primarily of rotifers and/or other crustacean zooplankton. The presence/absence of brook stickleback (Culea inconstans) was the factor most strongly linked to zooplankton structure with small cladocerans tending to dominate in wetlands with stickleback. In fishless wetlands, communities dominated by medium-large sized cladocerans tended to correspond with low-chlorophyll/high-submerged aquatic vegetation (SAV) conditions. Conversely, communities composed of rotifers and other crustaceans were associated with high-chlorophyll/low-SAV states. Macro-invertebrate predator abundance was not strongly linked to patterns in zooplankton composition suggesting macro-invertebrate predation is not a significant factor influencing zooplankton structure in fishless wetlands. Results suggest activities that spread stickleback (e.g. ditching) or inhibit development of macrophyte-dominated/clear-water conditions (e.g. nutrient loading) may seriously alter the zooplankton community structure, and thereby the functional ecology, of these valuable wetland ecosystems.     

古尔班通古特沙漠生物结皮藻类的组成和生态分布研究

通过对新疆古尔班通古特沙漠中9个样地73份生物结皮土样藻类的培养和鉴定,分析了古尔班通古特沙漠中生物结皮藻类的种类组成和生态分布特点。结果表明．该沙漠中有藻类植物49属121种．隶属于蓝藻门、绿藻门、硅藻门和裸藻门。其中监藻83种,绿藻20种,硅藻11种。裸藻7种。蓝藻占总种数的68．60％,其中又以丝状种类为优势．占66．27％;绿藻则以单细胞种类为主。在古尔班通古特沙漠不同地带中,其藻类物种多样性和群落组成均有所不同,中部藻类物种最为丰富,北部和南部次之。而东部和西部则明显减少。在沙垄不同部位的分布中,少数种类对地貌部位的选择性不明显,但有些种类在不同地貌部位分布有差异。藻类在结皮不同层次的分布不同,在结皮层中藻类的种类和数量都较丰富．且以丝状种类较多,而在结皮下层藻类的种类和数量明显减少。