Limnological Survey Research Articles

Zooplankton community structure and ecology of the tropical-highland Lake Hayq, Ethiopia

Lake Hayq, a highland lake in Ethiopia, was stocked with Tilapia fish ( Oreochromis niloticus ) in late 1970s, offering an opportunity to study the effect of fish predation in a natural lake. Since 1930s, some limnological surveys have been done sporadically documenting a change in zooplankton composition including the disappearance of cladocerans, hypothesizing the stocked planktivorous fish could be a cause. Nevertheless, no detailed research was conducted to identify potential effects of fish stocking predominantly due to its remote location. The article presents data about zooplankton composition, abundance and biomass done between October 2007 and January 2009 on short-time intervals including the underlying limnological variables. The zooplankton community was depauperate comprising two copepods, three cladocerans, and six rotifers taxa, as typical for tropical lakes. Total mean standing biomass of all crustacean zooplankton was 237 mg dry mass m −3 , which gave Lake Hayq an intermediate position when compared with other tropical lakes. Of copepods, Thermocyclops ethiopiensis was almost an exclusive species, and its temporal variation was influenced by food supply and water temperature. We refute the hypothesis that Tilapia was the cause for the seasonal disappearance of cladocerans, and attribute it to the adverse effect of episodic mixing. Nevertheless, the planktivorous fish probably plays a key role in structuring the cladocerans in particular the large-sized Daphnia magna . In January 2008, we observed a massive planktivorous fish mortality that triggered high algal biomass, which was later grazed by large-sized D. magna demonstrating the trophic cascade hypothesis in a natural ecosystem.

The Spatial and Temporal Variability of Limnological Properties of Bovilla Reservoir (Albania)

A limnological survey of a man-made reservoir in the central part of Albania was conducted from May 2006 to May 2008. This water body is being constructed 15 years ago for water supply of the Tirana, capital city of Albania. The physical and chemical quality of water in this reservoir was determined and compared against universally accepted water quality standards. Water quality parameters relevant to the study area are discussed considering the ecosystem function and interrelationship among physical and chemical parameters with the biological ones. The water quality of traditional and modern reservoir was not significantly different except for a bed odour that occurs throughout of the summer. Due to the reservoirs life the eutrophication in the nowadays is not a major problem in the reservoir, but due to an intensive sedimentation rate it is predicted that will seriously affect the water body in the near future. Management strategies to improve the water use efficiency with particular reference to eutrophication are proposed. On the other hand it is recommended that an integrated approach following the IRBM criteria will be the best way of management and administration.

Basic Limnological Survey of Twenty-One Northern and Central Mongolian Lakes

Basic Limnological Survey of Twenty-One Northern and Central Mongolian Lakes

The Aral Sea and the Dead Sea: Disparate lakes with similar histories

In spite of significant differences in their sizes, depths, salinity and other properties, the Aral Sea and the Dead Sea share many features, as illustrated by a comparison of the histories of both water bodies. Fifteenth and early sixteenth century maps, based on the ‘Geography’ of Ptolemy, contain both lakes. The first successful limnological surveys of the lakes were made in the same year 1848, when Alexey Butakov explored the Aral Sea and William Lynch mapped the Dead Sea. Paintings and drawings by Taras Shevchenko (Aral Sea) and David Roberts (Dead Sea) document the landscapes around the lakes in the first half of the 19th century. The water balance of both lakes has been strongly negative in the past decades, leading to a decreased water surface area and volume for both lakes, their increased salinity and deterioration of their local infrastructures. Complex and expensive mitigation schemes have been proposed for both lakes, based on the import of large quantities of water from distant sources via canals or pipelines (i.e. Siberian rivers or Caspian Sea to supply water to the Aral Sea, Mediterranean Sea or Red Sea, to be connected with the Dead Sea). Less dramatic solutions to improve the local situations already have resulted in improved water quality in the Aral Sea, and partial restoration of its fisheries. In contrast, the Dead Sea remains much too saline to support higher forms of life. Nevertheless, a biblical prophecy predicts that even this most hypersaline of all lakes will eventually be teeming with fish of many kinds.

Chemical and biological response of two small lakes in the Khumbu Valley, Himalayas (Nepal) to short-term variability and climatic change as detected by long-term monitoring and paleolimnological methods

The most remote regions of the globe are home of the least disturbed ecosystems, yet they are threatened by air pollution and by climatic change. The Himalayas are one of the most isolated and least explored wilderness areas in the world outside the Polar Regions and it is for this reason that the Tibetan Plateau is often referred to as the ‘Third Pole’. Since 1990, an annual limnological survey (including chemistry and biology) has been carried out at two lakes located in the Kumbhu Valley, Nepal, at 5200 and 5400 m a.s.l., respectively. Lake water chemistry surveys reveal a persistent increase in the ionic content of the lake water, a trend which appears to be closely linked to increasing temperature. In this study, we also analysed lake sediment cores for historical changes in algal abundance and community composition to evaluate how long-term variations in primary producer communities corresponded to known regional variations in climate systems during the past 3500 years. Paleolimnological results support the evidence that the strong variability observed in the chemical data drives the variability in lake production and in the composition of algal assemblages. These variabilities can be related to known features of local climate and the values recorded in the recent years compare well with those recorded during warm periods, such as around 2000 BP, and thus support the idea that this area of the Himalayan Range, influenced by the South Asia monsoon, is closely linked to Northern Hemisphere climate dynamics.

Limnological survey of farm fish ponds in Osaka Pref.

Limnological survey of farm fish ponds in Osaka Pref.

An environmental assessment of a small shallow lake (Little Black Lake, MI) threatened by urbanization

A limnological survey was conducted of Little Black Lake, MI, and its tributaries during summer 2007. This small, shallow lake is located in a rapidly developing area of west Michigan. As such, our analytical approach and recommendations can serve as a model for other similar systems threatened by urbanization. Soluble reactive phosphorus and nitrate concentrations in both the inflows to (during baseflow) and Little Black Lake itself were low (≤0.007 and ≤270mg/L, respectively). Nutrient concentrations increased during stormflow conditions, although the magnitude of the increase depended on the nutrient and sampling location. Macrophyte growth was extensive throughout most parts of the lake, with Chara and Potamogeton spp. present in most sites; based on the coefficient of conservatism, plant composition was indicative of good water quality conditions. Chlorophyll a concentration averaged 1.7μg/L in Little Black Lake, with cryptophytes and cyanobacteria being the most dominant members (by biovolume) of the phytoplankton community. The fish community in Little Black Lake was dominated by bluegill (Lepomis macrochirus) and pumpkinseed (L. gibbosus), with no invasive species observed. Overall, abiotic and biotic conditions indicate that Little Black Lake is in good ecological health despite increasing pressures of urbanization in its watershed. To maintain this status, it is recommended that the local municipalities develop a comprehensive watershed management plan and implement best management practices to limit nonpoint source pollutant loading to Little Black Lake.

Assessing the sensitivity of alpine lakes and ponds to nitrogen deposition in the Canadian Rocky Mountains

To demonstrate the sensitivity of aquatic ecosystems to forecasted increases in nitrogen deposition along the eastern ranges of the Canadian Rocky Mountains, we conducted midsummer limnological surveys of 29 remote alpine lakes and ponds via helicopter in 2007. Chemical analysis of water and in vitro nitrogen-enrichment bioassays of phytoplankton collected from each site were performed to estimate nutrient limitation. Use of a common chemical index for nutrient limitation (total dissolved inorganic nitrogen: total phosphorus; DIN:TP) together with supportive experimental evidence revealed nitrogen limitation in only 14% of the cases. Shallow (≤1 m maximum depth) ponds were more likely to be nitrogen-limited than lakes, especially as the former exhibited a significantly lower mean DIN:TP ratio of 7.4 during the late summer. Chemical and bioassay-based inferences of nitrogen limitation agreed in 74.5% of the cases, owing mainly to evidence of phosphorus limitation of the surveyed lake ecosystems (mean DIN:TP = 18) being supported by nonsignificant responses of their phytoplankton to nitrogen amendment. Our findings reveal that increased nitrogen deposition should not result in immediate widespread eutrophication of the Canadian Rockies; however, certain alpine ponds appeared nitrogen-limited, making them sensitive early indicators of the potential effects of anthropogenic nitrogen deposition in remote mountainous regions.

Parasites and Diet of Trout-Perch (Percopsis omiscomaycus) from Northwest Territories, Canada, with Comments on the Range of Crepidostomum percopsisi Nelson, Choudhury and Dick 1997

The trout-perch, Percopsis omiscomaycus (Walbaum), is a widely distributed species in North America. Despite several compound community surveys, the northernmost survey of trout-perch parasites is from southern Manitoba, Canada. A total of 42 parasite species have been reported from trout-perch, with 2 species being strictly host specific. During limnological surveys of Sid and Blitzen lakes, Northwest Territories, Canada, 4 parasite taxa were recovered from trout-perch: Protozoan cysts, Diplostomum sp., Proteocephalus sp., and Crepidostomum percopsisi. The present study area is approximately 1,547 km northwest of Dauphin Lake, which is the northernmost documented range for C. percopsisi. These data provide further support for Halvorsen's “constant fauna” as a general rule for north temperate fish parasite communities. Comparisons with other trout-perch surveys from more southern portions of the biogeographic range suggest that parasite composition, at least in small, nutrient- and species-poor lakes at northern latitudes have decreased richness, despite trout-perch having a diverse diet compared with more southern surveys. The intermediate host of C. percopsisi is unknown. Other Crepidostomum spp. are transmitted through Ephemeroptera, which occur in the diet of the trout-perch from Blitzen and Sid lakes. However, the high prevalence of cladocerans in this study, similar to other published reports, might implicate cladocerans as a potential intermediate host for C. percopsisi.

Seasonal fluctuation of zooplankton in relation to industrial pollution in Irai river water, Dist. Chandrapur, (M.S.), India

With the view to investigate the various changes in hydrobiological features during summer, winter and rainy season and to correlate the same with zooplankton productivity, the limnological survey of Irai river Dist. Chandrapur was undertaken during the year 2003-2004. The parameters such as temperature, conductivity, TDS, pH, CO2 DO have been studied. In the present investigation zooplankton showed low inverse correlation with temperature and pH, while moderate positive correlation with conductivity, turbidity, TDS, CO2. However, dissolved oxygen showed strong inverse correlation with temperature, CO2 and conductivity. In present investigation, among zooplankton Rotifera was the dominant group throughout the study. The highest count of zooplankton was recorded at sampling station D in winter season. The correlation coefficients between each pair of parameter for all possible correlation have been discussed in this paper.

Recent ecological trends in lower trophic levels of the international section of the St. Lawrence River: a comparison of the 1970s to the 2000s

Changes from the 1970s to 2000s in phosphorus and chlorophyll levels, water transparency, zooplankton, and benthic communities in the upper, International Section of the St. Lawrence River were evaluated using trend data from limnological surveys. The influence of Lake Ontario as a source for riverine production was evident in the upper river. Total phosphorus levels from 1976 to 1978 (average ~20 μg/l) sampled during a period of nutrient pollution declined (to 6–7 μg/l) following abatement. As expected, water transparency indicated by summer Secchi depths showed an opposite response increasing from ~3.5 m in the 1970s to >10 m by 2003 but declined to 6–7 m in more recent years. Zooplankton communities have experienced declines in overall densities, and the community has changed but its primary components, Bosmina and Diacyclops remain. Ceriodaphnia lacustris abundance declined substantially from the 1970s to the recent time period while Chydorus sphaericus increased and Eurytemora affinis and Cercopagis pengoi had first appearances. In contrast, benthic invertebrate biomass increased substantially between time periods. Increases in families and occurrence of gastropods were observed, but the primary components–chironomids, amphipods, and oligochaetes–were consistent between the periods with the exception of dreissenid mussels. Dreissena was dominated by D. bugensis, and both D. bugensis and D. polymorpha show evidence of recent declines. Conversely, high abundance of round goby (Apollonia melanostomus) has promoted new trophic pathways. Downstream attenuation in nutrients and chlorophyll, and increased transparency suggest continued strong effects of Lake Ontario on the downstream river environment, but increased energy in the benthos has likely promoted greater in situ production.

Study on Application of Remote Sensing to Limnological Survey in Biwa Lake

Study on Application of Remote Sensing to Limnological Survey in Biwa Lake

Physical and chemical limnology of a 61-lake transect across mainland Nunavut and southeastern Victoria Island, Central Canadian Arctic

We describe the physical and chemical properties of sixty-one tundra lakes, sampled in a latitudinal transect (65―71°N, 105―108°W) across mainland and island regions of Nunavut, central Canadian Arctic, and examine the influence of geology, geography, climate, and vegetation on lake water chemistry. This dataset complements earlier limnological surveys of the Canadian Arctic and provides valuable information for evaluating the vulnerability of tundra lakes to predicted climate change. Principal components analysis revealed a geographical clustering of lakes; pH, DIC, specific conductivity, and trace metal concentrations reflected major lithological differences between the mainland and Victoria Island. Clustering of mainland lakes by ecoregion was also detected. Lakes of the Queen Maud Gulf Lowland and Garry Lake Lowland ecoregions (north) differed from lakes of the Takijuq Lake Upland ecoregion (south) in depth, pH, and specihc conductivity as well as nutrient, DOC, and chlorophyll-a concentrations. Ionic composition of the northern mainland lakes also indicated that the influence of marine aerosols and/or leaching of residual marine salts from post-glacial marine deposits exposed by isostatic rebound. The northern mainland lakes were the most nutrient-rich and biologically productive of the three lake clusters and were characterized by median concentrations of total dissolved nitrogen (518 μg l ―1 ) and chlorophyll-a (1.6 μg l ―1 ) that were higher than previously reported for tundra lakes in the Canadian Arctic. These lakes were chemically similar to lakes of the Tuktoyaktuk Peninsula, in the western Canadian Arctic. Lakes of the southern mainland were dilute, acidic, and nutrient-poor, in accord with earlier limnological surveys in this ecoregion. Concentrations of nutrients, DOC, and chlorophyll-a in Victoria Island lakes fell in the middle of the ranges reported from other islands in the Canadian Arctic. Lithologic and edaphic factors strongly influenced the limnological properties of the tundra lakes surveyed and must be controlled for in order to fully evaluate the influence of future climate and vegetation change.

Limnological Survey of three Tropical Water Reservoirs in Eastern India.

ABSTRACT. Limnological Survey of three Tropical Water Reservoirs in Eastern India. Plankton communities of three water reservoirs of India reflect direct relationship with organic pollution. The assessment of water quality as high or low organically polluted for three water bodies have been achieved with help of algal community, which can be used as indicator of organic pollution. Algal pollution indices according to Palmer (1969) and Watanabe’s (1962) based on genus and species were used in rating water samples for high or low organic pollution. Among 26 genera found in India 20 most frequent and common genera of algae were taken into account for indexing pollution status. Water Quality Index (WQI) on the basis of weighting and rating of the chemical parameter was also used to correlate the Palmer index with Physical-chemical parameters of water reservoirs.Key Words. Palmer Index, organic pollution, water reservoir, algae, plankton, water quality index.RESUMEN. Estudio limnológico de tres embalses de la India Oriental. Las comunidades planctónicas de tres embalses de la India reflejan relaciones directas con la polución orgánica. Se ha evaluado la calidad del agua de estos embalses atendiendo a la comunidad algal que alojan, lo que puede usarse como indicador de polución orgánica. Se ordenaron las muestras de agua, desde alta hasta baja polución orgánica, de acuerdo con los índices de Palmer (1969) y Watanabe (1962) basados en géneros y especies. Entre los 26 géneros encontrados en la India, se seleccionaron los 20 más comunes y frecuentes para los cálculos de los índices citados. También se calculó el índice de la calidad del agua (Water Quality Index, WQI), y se correlacionó con el índice algal de Palmer así como con los parámetros físico-químicos del agua de los embalses.Palabras clave. Índice de Palmer, polución orgánica, embalses, algas, plancton, índice de calidad del agua.

Review ofDue south, by John Kelly

This small volume is basically the diary of John Kelly, who visited the British Antarctic Survey station on Signy Island in the South Orkney Islands. It includes about 60 monochrome plates (mainly half-page ones), a few sketches and a map of the island. The text is essentially a diary of the author’s time, from beginning in the Falkland Islands, sailing aboard RRS Ernest Shackleton , staying on the island from 25 January to 8 March 2003 to the return journey. As well as the illustrations, the text is accompanied by brief poetical extracts by the author and others. It is substantially a personal account of the visit, and may be best understood by those who have seen exhibitions of his artistic works. Impressions of Signy Island are confined to modern ones gained during the artist’s visit; thus, there is no reference to the Norwegian aspects of its history (neither the derivation of the name from Signy, daughter of the whaling captain Petter Sorlle, nor the graves of five whalers on Factory Bluff, is mentioned). Similarly, reference to the continuing scientific research conducted at the station is minimal although he accompanied a limnological survey.

Studies on Latin American water mites of the genus Torrenticola Piersig, 1896 (Torrenticolidae, Hydrachnidia, Acari)

In this paper the Latin American species of the water mite genus Torrenticola are presented and discussed comprehensively for the first time. All 21 previously known species from Central and South America are portrayed in detail, descriptions are given for 36 new species from Costa Rica: Torrenticola adunca, T. alargada, T. alexandra, T. alticola, T. altifontana, T. amalgamada, T. ambigua, T. australis, T. baderi, T. chicacoxalis, T. chirripoensis, T. collina, T. conopalpis, T. corta, T. cortobrazo, T. costaricense, T. cumbrensis, T. delgada, T. dispersa, T. elhachensis, T. esferica, T. esquinada, T. fastigata, T. flexirostris, T. fontinale, T. guanacastensis, T. harpagophora, T. levicoxalis, T. menudopalpis, T. monticola, T. pervagata, T. rapidensis, T. ratoncitoi, T. rubella, T. tilaranensis and T. torpebrazo. The Latin American species of Torrenticola are subdivided in a clear, robust system of ten species groups – five of these are regarded as phylogenetic entities, five as rather artificial groups. An identification key to these species groups is given, as well as keys, measurement tables, figures and detailed descriptions of all species within these groups. The males of T. gennada Cook, 1980 and T. keesdavidsi Cramer, 1992, as well as the female of T. amala Cook, 1980 are described for the first time. Descriptions and figures of the genital skeleton of nine formerly described species are given for the first time. All information available on the habitat preferences (habitat type, stream velocity, altitudinal distribution, choriotope types, temperature and conductivity) and the geographical distribution of the species is presented. Zoogeographical characteristics, endemicity and habitat preferences of the 42 species of Torrenticola found in Costa Rica are analysed. The main object of this study is to facilitate further systematic and ecological work on this important genus and to make it accessible for general limnological surveys.

Physical and chemical limnological characteristics of lakes and ponds across environmental gradients on Melville Island, Nunavut/N. W. T., High Arctic Canada

Physical and chemical limnological variables were measured from 40 ponds and 6 lakes across Melville Island, Nunavut/N.W.T., Canadian high Arctic, an environmentally sensitive region where very limited limnological data were available. Mean values of most variables were mid-range when compared to other high Arctic limnological surveys, yet the ranges of most measured variables were amongst the largest yet encountered in Canadian high Arctic regional surveys. The first two axes of a Principal Components Analysis explained 55.2 % of the variation in the environmental data. Variables most strongly associated with axis one were pH, dissolved organic carbon, total dissolved nitrogen, specific conductivity and related variables, while axis two represented gradients of other nutrients and trace metals. High elevation sites near permanent ice caps recorded the lowest specific conductivity and Ca 2+ values yet reported in high Arctic systems. High phosphorus values (>20 μg/L) in some of the Melville Island sites are likely indicative of re-suspended sediments, rather than eutrophic conditions. Total nitrogen to total phosphorus ratios suggest that ∼50 % of the sites are P limited, while 33 % are N limited, supporting previous research which suggests N limitation is more commonly encountered in Arctic than in temperate freshwater ecosystems. Finally, when freshwater sites on Melville Island were grouped according to predefined bioclimatic zones, only the most lushly vegetated zone appeared to affect limnological conditions. with these sites having higher mean total dissolved nitrogen, pH, and specific conductivity.

Review of Due south, by John Kelly

This small volume is basically the diary of John Kelly, who visited the British Antarctic Survey station on Signy Island in the South Orkney Islands. It includes about 60 monochrome plates (mainly half-page ones), a few sketches and a map of the island. The text is essentially a diary of the author’s time, from beginning in the Falkland Islands, sailing aboard RRS Ernest Shackleton , staying on the island from 25 January to 8 March 2003 to the return journey. As well as the illustrations, the text is accompanied by brief poetical extracts by the author and others. It is substantially a personal account of the visit, and may be best understood by those who have seen exhibitions of his artistic works. Impressions of Signy Island are confined to modern ones gained during the artist’s visit; thus, there is no reference to the Norwegian aspects of its history (neither the derivation of the name from Signy, daughter of the whaling captain Petter Sørlle, nor the graves of five whalers on Factory Bluff, is mentioned). Similarly, reference to the continuing scientific research conducted at the station is minimal although he accompanied a limnological survey.

Biological recovery of the Bohemian Forest lakes from acidification

AbstractA limnological survey of eight small, atmospherically acidified, forested glacial lakes in the Bohemian Forest (Šumava, Böhmerwald) was performed in September 2003. Water chemistry of the tributaries and surface layer of each lake was determined, as well as species composition and biomass of the plankton along the water column, and littoral macrozoobenthos to assess the present status of the lakes. The progress in chemical reversal and biological recovery from acid stress was evaluated by comparing the current status of the lakes with results of a survey four years ago (1999) and former acidification data since the early 1990s. Both the current chemical lake status and the pelagic food web structure reflected the acidity of the tributaries and their aluminium (Al) and phosphorus (P) concentrations. One mesotrophic (Plešné jezero) and three oligotrophic lakes (Černé jezero, Čertovo jezero, and Rachelsee) are still chronically acidified, while four other oligotrophic lakes (Kleiner Arbersee, Prášilské jezero, Grosser Arbersee, and Laka) have recovered their carbonate buffering system. Total plankton biomass was very low and largely dominated by filamentous bacteria in the acidified oligotrophic lakes, while the mesotrophic lake had a higher biomass and was dominated by phytoplankton, which apparently profited from the higher P input. In contrast, both phytoplankton and crustacean zooplankton accounted for the majority of plankton biomass in the recovering lakes. This study has shown further progress in the reversal of lake water chemistry as well as further evidence of biological recovery compared to the 1999 survey. While no changes occurred in species composition of phytoplankton, a new ciliate species was found in one lake. In several lakes, this survey documented a return of zooplankton (e.g., Cladocera: Ceriodaphnia quadrangula and Rotifera: three Keratella species) and macrozoobenthos species (e.g., Ephemeroptera and Plecoptera). The beginning of biological recovery has been delayed for ∼20 years after chemical reversal of the lakes.

Limnological characteristics of the freshwater ecosystems of Byers Peninsula, Livingston Island, in maritime Antarctica

A limnological survey of 15 lakes and 6 streams was carried out on Byers Peninsula (Living- ston Island, South Shetland Islands, Antarctica) during austral summer 2001-2002. Most of the surface waters had low conductivities (20-105 Sc m i1 ) and nutrients (total phosphorus 0.01-0.24 M), but some coastal lakes were enriched by nutrient inputs from seal colo- nies and marine inputs. Plankton communities in the lakes contained picocyanobacteria (10 2 -10 4 cells ml i1 ), diatoms, chrysophytes and chlorophytes, and a large fraction of the total biomass was bacterioplankton. Zooplankton communities were dominated by Boeck- ella poppei and Branchinecta gainii; the benthic cladoc- eran Macrothrix ciliata was also recorded, for the Wrst time in Antarctica. The chironomids Belgica antarctica and Parochlus steinenii, and the oligochaete Lumbricil- lus sp., occurred in stream and lake benthos. The phyto- benthos included cyanobacterial mats, epilithic diatoms and the aquatic moss Drepanocladus longifolius. These observations underscore the limnological richness of this seasonally ice-free region in maritime Antarctica and its value as a long-term reference site for monitor- ing environmental change.