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Ramesh D. Gulati

Ramesh D. Gulati
Netherlands Institute of Ecology (NIOO-KNAW) Wageningen, the Netherlands · Aquatic Ecology

M.Sc. Ph.D. (Limnology)

About

165
Publications
26,520
Reads
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6,887
Citations
Citations since 2017
6 Research Items
1744 Citations
2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
Additional affiliations
March 2013 - May 2013
Chinese Academy of Sciences
Position
  • As guest scientist
January 2012 - present
Siberian Federal University, institute of Biophysical Research, Krasnoyarsk
Position
  • Siberian Federal University
Description
  • Involved in cooperative Research since 1999. Received an honorary Doctorate in April from the Siberian Branch of Russian Academy Of Science.
January 2010 - December 2012
Education
August 1958 - June 1964
University of Delhi
Field of study
  • Limnology, Freshwater Ecology

Publications

Publications (165)
Article
s Zooplankton studies in Mexican rivers are few despite the fact that Mexico has >200 rivers. We present data on the seasonal diversity of rotifers during 2013–2014 from the river La Antigua, near Veracruz. We collected samples from 15 stations along a horizontal gradient of ~5 km, from the upper reaches to about 2 km from the sea. The physico‐chem...
Chapter
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We start with the recent developments and reasons why the meromictic lakes should get more attention in limnological literature. Thereafter, we define monimolimnion , mixolimnion and some other terms related to meromixis. The definition of Hutchinson for meromictic lakes holds for more than 60 years while some modification is required. We different...
Chapter
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The term meromixis was introduced more than 80 years ago to denote lakes that do not annually mix completely. Since then our understanding of meromictic lakes has considerably advanced. Physical processes support the difference in water density between deep (monimolimnion ) and surface (mixolimnion ) waters in meromictic lakes; such lakes reveal co...
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Case studies and typical examples for meromictic lakes are used to provide a review of the biology and ecology of these ecosystems. Water column in meromictic lakes is not entirely mixed. These lakes are chemically and/or thermally stratified for several years and have several specific ecological features. The chemocline —the habitat created betwee...
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The introduction of omnivorous tilapia into a variety of aquatic systems worldwide has led to a number of serious ecological problems. One of the main issues is an increase in water turbidity, which affects not only light penetration but also primary production and the distribution of phytoplankton and benthic algae in shallow lakes. These changes...
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Cyanobacteria often have a deleterious effect on zooplankton. We hypothesized that the presence of either M. aeruginosa cells or microcystin extracts from M. aeruginosa would have a significant impact on the population growth rate, survivorship, and fecundity of Moina cf. micrura isolated from L’Albufera, Valencia, Spain. The cladocerans were expos...
Article
Demographic responses and fatty acid profiles of Moina macrocopa were quantified under different temperature regimes (20°C, 25°C and 30°C and diurnally variable 20-30°C) and at fixed ration (10.65μgDWml-1) of Chlorella. Highest constant temperature (30°C) reduced the density of M. macrocopa. The cladocerans under the fluctuating temperature regime...
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The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an unrestored phytoplankton-dominated part. Macrophytes,...
Article
The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an unrestored phytoplankton-dominated part. Macrophytes,...
Article
In this study, we address the question of how the food value of cyanobacterial carbon might be upgraded during the decay process in order to support the growth and reproduction of Daphnia. We undertook an experimental study simulating the natural decay of the cyanobacterium Microcystis over periods of 0, 2, 3, 6, and 9 days, and assessed the effect...
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Competition for resources between coexisting phytoplankton and benthic algae, but with different habitats and roles in functioning of lake ecosystems, profoundly affects dynamics of shallow lakes in the process of eutrophication. An experiment was conducted to test the hypothesis that combined enrichment with nitrogen (N) and phosphorus (P) would b...
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Microcystins (MCs) have a toxic effect on crustacean zooplankton in the laboratory, but there is little or no unequivocal evidence in the literature of their lethal effects on crustacean zooplankton in the field. We used the natural microcystins extracted from Microcystis spp. to test if they could cause any negative effects on crustacean zooplankt...
Data
Although many lake restoration projects have led to decreased nutrient loads and increased water transparency, the establishment or expansion of macrophytes does not immediately follow the improved abiotic conditions and it is often unclear whether vegetation with high macrophyte diversity will return. We provide an overview of the potential bottle...
Article
Understanding of the forces driving the structure of biotic communities has long been an important focus for ecology, with implications for applied and conservation science. To elucidate the factors driving phytoplankton genus richness in the Danish landscape, we analyzed data derived from late-summer samplings in 195 Danish lakes and ponds in a sp...
Article
Sediments are of key importance in deter-mining the nutrient levels of water in shallow lakes as they can act as either source or sink for phosphorus (P) depend-ing on environmental conditions, sediment characteris-tics, and external nutrient loading. We examined the role of benthic algae in the P cycling between sediment and overlying water in exp...
Article
Full-text available
Although many lake restoration projects have led to decreased nutrient loads and increased water transparency, the establishment or expansion of macrophytes does not immediately follow the improved abiotic conditions and it is often unclear whether vegetation with high macrophyte diversity will return. We provide an overview of the potential bottle...
Article
Full-text available
The ecosystem of the highly eutrophic Lake Taihu (China) is seriously affected by recurrent cyanobacterial blooms, but little is known about the contribution made by cyanobacteria to the food web. In this study, we investigated the fate of detritus of the cyanobacterium Microcystis in the food web of Lake Taihu through a 19-day mesocosm experiment...
Chapter
IntroductionDisturbance Factors Affecting LakesLake Restoration MeasuresPerspectivesAcknowledgements
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The effect of simultaneously removing algal blooms from water and reducing the resuspension and nutrient release from the sediment was studied using modified local soil/sand flocculation-capping (MLS-capping) in simulated water-sediment systems. Twenty one sediment cores in situ with overlying water containing algal blooms were collected from Meili...
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This study compared the size distributions of the filamentous green alga Ulothrix in Daphnia guts and ambient lake water from February to May 2004 in Meiliang Bay, Lake Taihu, China. The aim was to establish whether daphnids selected the filaments in a certain length range or ingested them indiscriminately regardless of size. We also investigated t...
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A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others (‘reinventing the wheel’). The other challenge is to avoid focusi...
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During two vegetation seasons (2004–2005), we compared feeding spectra of Arctodiaptomus salinus (Calanoida, Copepoda) populations inhabiting two neighboring salt lakes, Shira and Shunet, Khakasia, Russia, using fatty acid (FA) trophic markers. Sestonic FA composition in two lakes moderately differed, whereas levels of diatom FA markers were higher...
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A feature of meromictic lakes is that several physicochemical and biological gradients affect the vertical distribution of different organisms. The vertical stratification of physical, chemical and biological components in saline, fishless meromictic lakes Shira and Shunet (Siberia, Russia) is quite different mainly because both mean depth and maxi...
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In a brackish, temperate, 24-m-deep Lake Shira, the profiles of salinity, temperature, oxygen and sulfide concentrations were measured on a seasonal basis from 2002 to 2009. The lake was shown to be meromictic with autumnal overturn restricted to mixolimnion. The depth of mixolimnion and position of oxic–anoxic interface varied annually. The spring...
Article
The year-to-year variations of vertical distribution and biomass of anoxic phototrophic bacteria were studied during ice periods 2003–2005 and 2007–2008 in meromictic lakes Shira and Shunet (Southern Siberia, Russian Federation). The bacterial layers in chemocline of both lakes were sampled with a thin-layer hydraulic multi-syringe sampler. In wint...
Article
Winter has traditionally been considered as an ecologically insignificant season and, together with technical difficulties, this has led winter limnology to lag behind summer limnology. Recently, rapidly expanding interest in climate warming has increased water research in winter. It has also become clear that neither winter conditions of lakes nor...
Article
We review published data of re-oligotrophication studies in different types of lakes and discuss whether re-oligotrophication by phosphorus reduction measures can affect seston quality in lakes due to an increase in C:P ratios of food for zooplankton. We analyze whether such an increase in elemental ratio may give rise to a stoichiometric constrain...
Article
This paper critically reviews the published works on lake restoration in north-western Europe, with the aim to highlight the causes of failures of lake biomanipulation, and to identify the main bottlenecks that have impeded progress. More importantly, we explore the prospects of applying new ecotechnological measures to lakes with a focus on shallo...
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Submerged macrophytes are known to serve as refuge for zooplankton but also seem to suppress the zooplankton growth. Thus, there is a conflict between the positive and negative role of macrophytes for zooplankton. We tested the influence of physical structure using artificial macrophytes, chemicals released by a macrophyte (Myriophyllum verticillat...
Article
Most Dutch lakes are small and shallow, resulting from peat dredging since the late 18th century. However, deep lakes have appeared recently owing to sand digging. Limnological features of one such lake, Wijde Biik (N. Holland), were studied during 1968–70. The lake with an average depth of 11 4 m (maximum depth 31 m) and area of 2·65 × 10⁶m² is on...
Chapter
We review recent works on different life tropical and temperate freshwater bodies, comparing the strategies that cladocerans have evolved to adapt to contrasting environmental conditions in the two geographical regions. These life-history parameters relate to age and size at maturity, survival, fecundity, life-expectancy at birth, lifespan, gross,...
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Seasonal dynamics in elemental composition [carbon (C), nitrogen and phosphorus (P)] of seston and zooplankton were studied over several years in three hypereutrophic Dutch lakes with persistent dominance and high biomass of cyanobacteria. In all three lakes, there was a strong pattern with decreased P-content and increased C:P ratio in seston (<15...
Chapter
Edmondson’s egg ratio (number of amictic eggs per female) is an important life history variable, which has been in wide use to understand and predict patterns of population growth in planktonic rotifers under field conditions. It is also useful as an indicator of the health of rotifers under culture conditions. Generally, an inverse relationship ex...
Article
About this book This volume reflects the latest developments in the research of a global community of rotifer researchers, who came together at Illmitz, Austria in 2003. Contributions are manifold and span fields from phylogeny and evolution of the phylum Rotifera to practical aspects of aquaculture and ecotoxicology. Major issues include phylogeny...
Chapter
Diel vertical migrations of zooplankton were studied in a small, dystrophic Kruczy Staw Lake. Two rotifer species (Synchaeta pectinata Ehrenberg, Trichocerca simonei DeSmet) inhabiting the lake occurred near lake bottom (7–8 m depth) in the daytime. At night they were observed in surface waters (0–2 m). Both amplitude and speed of the rotifer migra...
Article
1. This paper summarizes the salient features of the contributions to the workshop on The Role of Food Quality for Zooplankton. In this paper we attempt critically to evaluate our present knowledge in the light of new studies. 2. For the growth and reproduction of zooplankton, the existing literature considers two main limiting factors in the diet,...
Article
1. The importance of long-chain polyunsaturated fatty acids (PUFAs), in particular eicosapentaenoic acid (EPA), for the growth and development of Daphnia galeata (Sars) was tested using food types differing in PUFA and EPA contents. 2. Life history experiments of D. galeata fed with the cryptophyceans Rhodomonas lacustris (Pascher & Ruttner) and Cr...
Article
Reproduction is an energetically costly biological process. Among the freshwater zooplankton, rotifers and cladocerans reproduce parthenogenetically and the cost of reproduction can be estimated using the life table data from demographic studies. Reduced probability of future survival or future reproduction as a result of current investment in offs...
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The Netherlands are a small, low-lying delta in W. Europe (42000 km2; 50°–54° N; 3°–8° E), mainly consisting of alluvial deposits from the North Sea and from the large rivers Rhine and Meuse. The country was ‘created by man’. The conversion of natural aquatic and terrestrial ecosystems into drained agricultural land was a major cultural operation o...
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This article starts with a brief description of the origin and eutrophication of shallow Dutch lakes, followed by a review of the various lake restoration techniques in use and the results obtained. Most freshwater lakes in the Netherlands are very shallow (<2 m), and owe their origins to large-scale dredging and removal of peat during the early 17...
Article
Data on the seasonal changes in vertical heterogeneity of the physical-chemical and biological parameters of the thermally stratified Shira Lake ecosystem (Khakasia, Siberia) in 1996–2000 have been analyzed. The interaction mechanisms involving: (1) The plankton populations in aerobic and anaerobic zones, involving the cycling of carbon and sulphur...
Article
The paper summarises the results of a three-year research study (European Union Grant: INTAS 97-O519) aimedat investigating the planktonic populations and trophic organization of the Lake Shira ecosystem – a saline lake inKhakasia, Siberia. The lake exhibits a stable summer-autumn stratification of the chemical-biological components.The mechanisms...
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In 1989, a symposium was held under the title `Netherlands-Wetlands', aiming at the presentation of the state of the art of the existing knowledge of structure and functioning of wetlands, characteristic for the Netherlands. The present multi-author volume can be seen as a logical successor of the results of this symposium. The focus is now fully o...
Article
1. This study uses descriptive data to examine the shift in dominance in the rotifer community in summer from Keratella cochlearis to Anuraeopsis fissa in a shallow eutrophic lake. Population density and egg ratio were estimated from May to September for these small loricate rotifers, as well as the soft-bodied Filinia longiseta and Polyarthra spp....
Article
The Loosdrecht Lakes comprise three shallow, hypereutrophic lakes in The Netherlands. Research conducted over the past two decades suggests that absence of large-bodied Daphnia from these lakes can be explained by size-specific effects of both poor food quality and predatory mortality. The phytoplankton is dominated by filamentous cyanobacteria, wh...
Article
We studied population dynamics, phosphorus balance, and individual growth to evaluate limitation of Daphnia cucullata by dietary phosphorus (P) in three interconnected, hypereutrophic Dutch lakes. Consistent with the P-limitation hypothesis, declines in egg production and population density coincided with seasonal increases in the seston C:P ratio...
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Oscillatoria spp. are generally very abundant in many shallow, eutrophic lakes in the Netherlands. However, this is less true for Daphnia galeata. The main aim of this study was to investigate whether the edibility of live Oscillatoria limnetica by Daphnia galeata, and of the detritus derived from this filamentous cyanobacterium, was, among others,...
Article
The Loosdrecht lakes comprise three shallow, interconnected hypereutrophic lakes in The Netherlands. A lake restoration project conducted during the 1980s resulted in reduced phosphorus loading. However, no changes in phytoplankton abundance or species composition were noted, although seston carbon:phosphorus (C:P) ratios increased. Filamentous cya...
Article
We used laboratory growth and feeding experiments to study the balance of carbon (C) and phosphorus (P) in Daphnia magna. Daphnia were fed high-concentration mixtures of P-sufficient and p-deficient green algae (Scenedesmus acutus; molar C:P 80 and 900, respectively) or mixtures of P-deficient Scenedesmus and a P-rich cyanobacterium (Synechococcus...
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Bioavailable N and P release rates by juveniles and adults of three Daphnia taxa (D. hyalina, D. galeata and its interspecific hybrids D. hyalina galeata) were measured to assess the effect of weight and interspecific differences on these rates in Daphnia. Immobilized Scenedesmus obliquus cells were used to estimate the release rates. The specific...
Article
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1. The fatty acid (FA) composition of Daphnia galeata and their algal food was analysed and showed many similarities, however, some significant differences were also found in the relative abundance of the FA C16 : 4ω3 and docosahexaenoic acid (DHA). Their relative abundances were much lower in daphnids than in their algal diet. 2. When daphnids wer...
Article
The importance of changes in elemental and fatty acid composition of the algal food for Daphnia galeata was investigated. The green alga Chlamydomonas reinhardtii was grown under nitrogen or phosphorus limitation to modify its elemental and biochemical composition. Both N- and P-Limited algae exhibited similar fatty acid compositions but differed f...
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This dedication marks the retirement of Prof. Dr J. Ringelberg from the University of Amsterdam. In this article his contributions to the aquatic ecology in the Netherlands are reviewed. After his Ph.D. study on The positively phototactic reaction of Daphnia magna Straus, a contribution to the understanding of diurnal vertical migration (1964), Joo...
Article
1. Phytoplankton dynamics, food chain changes and resilience in Lake Zwemlust, a shallow lake in The Netherlands, are described for the period 1986–94. 2. After biomanipulation in 1987, the lake moved through two alternative states, while the external nutrient loadings were maintained. A clear-water phase, mostly dominated by macrophytes, persisted...
Article
Six years after application of biomanipulation in 1987, Lake Zwemlust (The Netherlands) returned during the summer from a clear water state dominated by aquatic vegetation to a turbid state characterized by high algal biomass. Herbivory and growth of epiphytes on macrophytes were the main factors triggering the switch. Selective herbivory by coots...
Article
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Data on phosphate excretion rates of zooplankton are based on measurements using the pelagic crustacean zooplankton of Lake Vechten and laboratory-cultured Daphnia galeata. In case of Daphnia sp we measured the effects of feeding on P-rich algae and P-poor algae (Scenedesmus) as food on the P-excretion rates at 20C. The excretion rates of the natur...
Article
1. Fluorescently labelled algae (FLA) were used to measure clearance rates of the rotifer Keratella cochlearis. The freshwater algae Chlorella vulgaris and Stichococcus bacillaris were labelled with a fluorescent dye, 5-(4,6-dichlorotriazin-2-yl) aminofluorescein (DTAF), following a modified staining procedure. 2. Keratella cochlearis ingested both...
Article
Bacterivory of pelagic rotifers and cladocerans in eutrophic Lake Loosdrecht (The Netherlands) was determined by microscopic observation of in situ tracer particle uptake. Ingestion rates of rotifer species using 0.51 μm microspheres or fluorescently labelled bacteria as tracers differed, with one exception. The ingestion rates depended on both the...