Lake Bank Research Articles

Variation in vegetation and seed banks of freshwater lakes with contrasting intensity of aquaculture along the Yangtze River, China

We examined species composition and richness in the seed banks and established vegetation in lakes along the Yangtze River with two contrasting aquaculture types: pen-culture lakes, characterized by pen-culture of commercial fish and crab, and lake-culture lake with more intensive stocking of the entire lake. The mean live biomass and species richness of submerged vegetation was significantly reduced or absent in lake-culture lakes (0–159 g m −2 and 0–0.3 species per sample, respectively), compared to those with pen-culture lakes (1552–2971 g m −2 and 1.5–3.2 species per sample, respectively) in all three study years. Also mean seedling density and species richness of seed banks were significantly lower in these lake-culture lakes (133 m −2 vs. 265 m −2 and 0.6 species vs. 0.9 species per sample, respectively). These results suggest that intensive aquaculture in these lakes has had serious negative effects on submerged vegetation and the associated seed banks. Vegetation history was partly reflected by distribution patterns of seed banks across sediment depth strata. A principal component analysis produced a very clear separation of lakes from pen-culture and lake-culture on the basis of their species composition. Moreover, the principal component analysis also indicated that the variation in the soil seed bank corresponded poorly with vegetation data. This probably reflects species-specific strategies for seed production.

Respiratory effects in people exposed to arsenic via the drinking water and tobacco smoking in southern part of Pakistan

In this study, a survey has been conducted during 2005–2007 on surface and groundwater arsenic (As) contamination and its impact on the health of local population, of villages located on the banks of Manchar lake, southern part of Sindh, Pakistan. We have also assessed the relationship between arsenic exposure through respiratory disorders in male subjects with drinking water and smoking cigarettes made from tobacco grown in agricultural land irrigated with As contaminated lake water. The biological samples (blood and scalp hair) were collected from As exposed subjects (100% smokers) and age matched healthy male subjects (40.2% smoker and 59.8% non smokers) belong to unexposed areas for comparison purposes. The As concentration in drinking water (surface and underground water), agricultural soil, cigarette tobacco and biological samples were determined by electrothermal atomic absorption spectrometry. The range of As concentrations in lake water was 35.2–158 µg/L (average 97.5 µg/L), which is 3–15 folds higher than permissible limit of World Health Organization (WHO, 2004). While the As level in local cigarette tobacco was found to be 3–6 folds higher than branded cigarettes (0.37–0.79 µg/g). Arsenic exposed subjects (with and without RD) had significantly elevated levels of As in their biological samples as compared to referent male subject of unexposed area. These respiratory effects were more pronounced in individuals who had also As induced skin lesions. The linear regressions showed good correlations between As concentrations in water versus hair and blood samples of exposed subjects with and without respiratory problems.

PLoS Neglected Tropical Diseases Issue Image | Vol. 3(5) May 2009

Tsetse flies are the vectors of human sleeping sickness and nagana in domesticated animals. Glossina fuscipes spp., which currently are responsible for more than 90% of all sleeping sickness cases, are associated with the vegetation along the banks of rivers and lakes and commonly include the reptiles found there in their diet (see Omolo et al., doi:10.1371/journal.pntd.0000435). Image Credit: Johan Esterhuizen, Liverpool School of Tropical Medicine

Bank filtration as managed surface-groundwater interaction

Riverbank Filtration (RBF) is a managed surface-groundwater interaction process where surface water is induced to flow to pumping wells installed on the banks of rivers and lakes. We present the surface-groundwater interaction issues at various geomorphologic settings, from the headwaters of a river to its confluence with the oceans/lakes. In each reach, the factors for the sustainable operation of RBF systems are discussed. Siting of wells with respect to the river/lake, scouring and clogging of the river beds and the resulting impacts on pollutant removal, managing the wells during floods, and RBF at other settings have been addressed.

Egg banks in hypersaline lakes of the South-East Europe

The cyst banks of 6 coastal hypersaline lakes of South-East Europe have been investigated. The study concerned the bottom sediments of Khersonesskoe and Koyashskoe lakes in the Crimea (Ukraine), Nartë saltworks (Albania), Vecchia Salina at Torre Colimena (Apulia, Italy), Pantano Grande and Pantano Roveto at Vendicari (Sicily, Italy). A total of 19 cyst types were recognised. The cyst banks of lakes were found to be well separated in the representation derived from a statistical multivariate data analysis. For all the lakes examined a comparison was possible between the resting community in sediments (cyst bank) and the active one in the water. The cyst banks contained more species than those recorded over a multi-year sampling effort in the water column. The study of cyst hatching, performed on 5 cyst types under lab conditions, demonstrated that cysts do not hatch under the same conditions. Furthermore, each cyst type shows a wide range of preferential hatching conditions, which allow us to confirm the ecological generalism of salt lake species.

Transient Leakance and Infiltration Characteristics during Lake Bank Filtration

Infiltration capacity of bank filtration systems depends on water extraction and hydraulic resistance of the bed sediments. Lakebed hydraulics may be especially affected by clogging, which is dependent on settlement of fine particles, redox potential, and other factors. In the field, most of these processes are difficult to quantify, and thus, when calculating response to pumping the water flux across the sediment surface is assumed to be linearly dependent on the hydraulic gradient. However, this assumption was not adequate to describe conditions at a bank filtration site located at Lake Tegel, Berlin, Germany. Hence, we first assumed the leakage coefficient (or leakance) is spatially distributed and also temporally variant. Furthermore, observations show that the leakance is considerably higher in shallow than in deeper areas; hence, leakance was assumed to be dependent on the existence and thickness of an unsaturated zone below the lake. The proposed explanation of spatial and temporal variability in leakance involves a hypothesis for redox dependent and reversible biogeochemical clogging, supported by geochemical observations in surface water and ground water. Four leakance approaches are implemented in the ground water flow code MODFLOW2000 and calibrated by inverse modeling using the parameter estimation software PEST. These concepts are evaluated by examining the fit to the hydraulic heads, to infiltration measurements, transport modeling results, and considering the degrees of freedom due to the number of calibration parameters. The leakage concept based on the assumption of the influence of an unsaturated zone on clogging processes best explains the field data.

Makroszczątki roślinne w torfie w analizie paleośrodowiskowych uwarunkowań osadnictwa na przykładzie stanowiska Łane Małe w dolinie Kłodnicy

Results of archaeological studies from the territory of Poland show that prehistorical settlements were often founded on the banks of lakes and mires. Botanical composition of organic deposits allows reconstructing historical plant communities and palaeohydrological conditions of the settlement, the subject of research was a peatland situated in the neighborhood of the archaeological site at Łany Małe. The latter is located on hillslopes of the Kłodnica valley (Upper Silesia, southern Poland). Peat formation at the Łany Małe site took place in the Pre-Boreal Period as an effect of the valley floor paludification. In the Mesolithic and Neolithic Periods as well as the Early Bronze Age, swampy alder forests occupied the entire area of the peatland. At that time, the fen surface was relatively easily accessible for humans, especially for people of the Funnel Beaker Culture in the Middle Neolithic Period. It was then when, probably, the ground water level dropped down and peat decay processes took over those of peat production. In the Hallstatt Period, during the presence of the Lusatian Culture settlement, there was subsequent increase in biotope moisture. Forest communities became more open and trees were gradually displaced by grasslike plants, especially of sedge (Carex) genus. In the Fate Roman Period (the Przeworsk Culture settlement) and in the early Middle Ages, the peatland was subject to inundation due to frequent flooding, the peat accumulation was then halted by the delivery of fine-grained products of soil erosion.

Leishmaniose tegumentar americana em municípios da região noroeste do estado do Paraná: utilização de sensoriamento remoto para análise do tipo de vegetação e os locais de ocorrência da doença

American cutaneous leishmaniasis, an endemic disease in the northwestern region of Paraná, Brazil, is transmitted by phlebotomines to man and animals like dogs, armadillos, opossums and wild rodents. This disease has been occurring in places where forests have been felled and on the banks of rivers and lakes with arboreal vegetation, where man comes into contact with infected insects. This disease is a public health problem because of the occurrence of epidemic outbreaks throughout Paraná. Because of the importance of finding out about endemic areas, this study used epidemiological file data on patients attended between 1999 and 2004. These data were correlated with areas of forest felling that were identified by means of satellite remote sensing techniques and products. The results showed that the occurrences of cases in the municipalities of this region coincided with the presumed likely areas for patient infection.

The correlation of arsenic levels in drinking water with the biological samples of skin disorders

Arsenic (As) poisoning has become a worldwide public health concern. The skin is quite sensitive to As and skin lesions are the most common and earliest nonmalignant effects associated to chronic As exposure. In 2005–2007, a survey was carried out on surface and groundwater arsenic contamination and relationships between As exposure via the drinking water and related adverse health effects (melanosis and keratosis) on villagers resides on the banks of Manchar lake, southern part of Sindh, Pakistan. We screened the population from arsenic-affected villages, 61 to 73% population were identified patients suffering from chronic arsenic toxicity. The effects of As toxicity via drinking water were estimated by biological samples (scalp hair and blood) of adults (males and females), have or have not skin problem ( n = 187). The referent samples of both genders were also collected from the areas having low level of As (< 10 μg/L) in drinking water ( n = 121). Arsenic concentration in drinking water and biological samples were analyzed using electrothermal atomic absorption spectrometry. The range of arsenic concentrations in lake surface water was 35.2–158 μg/L, which is 3–15 folds higher than World Health Organization [WHO, 2004. Guidelines for drinking-water quality third ed., WHO Geneva Switzerland.]. It was observed that As concentration in the scalp hair and blood samples were above the range of permissible values 0.034–0.319 μg As/g for hair and < 0.5–4.2 μg/L for blood. The linear regressions showed good correlations between arsenic concentrations in water versus hair and blood samples of exposed skin diseased subjects ( R 2 = 0.852 and 0.718) as compared to non-diseased subjects ( R 2 = 0.573 and 0.351), respectively.

Summer soil CH 4 emission and uptake in taiga forest near Yakutsk, Eastern Siberia

Summer CH 4 emission and uptake was measured in three contrasting environments (eutrophic lake bank, hummocky mesotrophic fen, forest floor) in taiga forest near the Spasskaya Pad field station (north of Yakutsk, Eastern Siberia). Wet eutrophic lake bank sites showed locally high emission rates (up to 49 mg CH 4 m −2 h −1, average 11.9 mg m −2 h −1). By contrast, fen emissions were an order of magnitude lower despite high water tables. Emission did not exceed 4.2 mg m −2 h −1 (average 1.3 mg m −2 h −1). The emission was highly dependent on water table, slight differences in water table could turn a soil from a source into a sink of CH 4. The dry forest sites show uptake of CH 4 (average 0.4 mg m −2 h −1), even at sites where the water table was situated a few centimeters below the soil surface. A clear relation with water temperature or soil temperature appears to be absent. Also in the wet year of 2006, with higher water table in the forest during the measurement period, CH 4 uptake remained stable. Spatial variation of the uptake fluxes within the site is minimal, but on a larger scale spatial differences are caused by soil texture differences. Our data indicate that the Siberian taiga forest floor is a small sink for CH 4 in the boreal summer.

Lake bank filtration at Nainital, India: water-quality evaluation

There are different water-supply schemes in Uttarakhand, India to tap the water from streams, rivers and lakes. At Nainital, seven tube-wells (depths 22.6–36.7 m), located at a distance of <100 m from the lake, are being used to abstract (1) lake water after passage through the soil and (2) subsurface water/groundwater flowing towards the lake. Water samples from the lake and tube-wells were analyzed in monsoon and non-monsoon periods from 1997 to 2006. Total dissolved solids, EC, alkalinity and hardness were found to be marginally greater in tube-well waters. The difference in hydrochemistry of tube-well water was mainly due to variation in flow regimes during monsoon and non-monsoon periods. Results clearly indicate that lake water as such is not potable as it contains unacceptable levels of organic matter in terms of COD (~44 mg/L), coliforms (~15.6 × 104 MPN/100 mL) and nutrients. Coliform bacteria and COD have not been detected in any of the tube-well water samples over the years. Lake water, treated by sand filters did not conform to drinking water standards. These investigations have led to the closure of the treatment facility and installation of two tube-wells in addition to the existing five tube-wells.

Origin and Distribution of Clay Minerals in Calcareous, Gypsiferous, Saline Soils and Sediments of Bakhtegan Lake Bank, Southern Iran

Pedogenesis and clay mineralogy of soils and rock samples were studied in a transect of calcareous, gypsiferous, saline soils and sediments of Bakhtegan lake bank in southern Iran. The main objectives of study were to determine the occurrence of clay minerals and factors controlling their distribution pattern and relative abundance in soils and parent materials. The soil parent material is highly calcareous in all regions. However, gypsiferous and saline soils mainly occur near the Bakhtegan Lake with much evaporitic sediments (gypsum and halite) and where there is a saline and alkaline ground water table. XRD, TEM, SEM and EDX analyses indicated that chlorite, illite, palygorskite, smectite and interstratified minerals are the dominant clay minerals in both soil and rock samples. The presence of illite, chlorite abundance could be attributed to the parent rock samples and inherited origin. Interstratified minerals of chlorite-smectite or illite-smectite are observed in clay fraction of soils situated in plains and down slope due to further weathering and transportation from upslope to down slope. Studies indicated the presence of neoformed, transformed and inherited forms of palygorskite in all soils. Studies have showed that arid soils in southern Iran were affected by post-Tethyan sediments and some minerals have evolved from the weathering of these sediments.

Seasonal and spatial distribution of redox zones during lake bank filtration in Berlin, Germany

Redox processes during bank filtration were evaluated in Berlin, where bank filtered water is abstracted for drinking water production. The investigations included the mapping of the infiltration zone, a column study and hydrochemical analyses of the groundwater sampled between lake and production well. The organic carbon content increased and the permeability of the lake sediments decreased with distance from the shoreline. The most important changes with regard to the redox state of the infiltrate occurred within the first metre of flow. Infiltration was mostly anoxic, as oxygen was rapidly consumed within the organic rich sediments. The infiltration zone revealed a vertical redox stratification with hydrochemical conditions becoming more reducing with depth rather than with distance from the lake. The redox zones were found to be very narrow below the lake and wider towards the production wells, suggesting that other than differing flow paths, reaeration after infiltration may also occur and possible mechanisms are presented. Redox conditions were influenced by strong annual temperature variations of the surface water affecting the microbial activity. Aerobic infiltration only took place close to the shore in winter.

Hymenoptera aculeata of raised bogs in Belarus

The long-term studies (1986–2003) of raised bogs of Belarus revealed 167 species of aculeates belonging to 7 families: Sapygidae (1), Chrysididae (11), Pompilidae (19), Eumenidae (19), Vespidae (9), Sphecidae (76), and Apidae (32). The dominant species (not counting ants) are Vespula rufa (16.6%), Bombus jonellus (11.3%), B. lucorum (7.5%), Anoplius nigerrimus (5.1%), B. pascuorum (3.9%), Passaloecus turionum (3.8%), Argogorytes mystaceus (3.2%), Dipogon bifasciatus (3.1%), Pemphredon lugens (3.0%), and Trypoxylon attenuatum (2.6%). Approximately two-thirds of the species found in raised bogs nest in the upper layer. The spatial distribution of aculeates depends primarily on the distance from the bog margins and the presence of contrasting areas, such as lake banks or glades. The highest activity of various aculeate families (except for Vespidae) was observed in June. The total abundance of aculeates was found to be correlated with solar activity, the strongest correlation being observed in Vespidae. The abundance of different wasp families varied noticeably from year to year, depending on climatic parameters.

Determinação da formulação e caracterização do néctar de camu-camu (Myrciaria dubia McVaugh)

O camu-camu é um fruto silvestre, encontrado nas margens de rios e lagos da Amazônia, com grande potencial econômico pelas suas características agronômicas, tecnológicas e nutricionais. Entretanto, seu consumo ainda é restrito, devido à alta acidez, amargor e adstringência da casca, necessitando, dessa forma, de tecnologias adequadas para o seu uso. O presente estudo teve por objetivo determinar a formulação ideal do néctar de camu-camu e avaliar as suas caraterísticas físicas e físico-químicas. Para a obtenção do néctar, foram elaboradas nove formulações com diferentes concentrações de polpa e açúcar, as quais foram submetidas ao teste de preferência de 30 provadores não treinados. Dentre as formulações testadas, a de maior preferência foi a preparada com 17,5% de açúcar e 17% de polpa, a qual apresentou valor de L Hunter de 32,00, aHunter de 3,22 e bHunter de -0,38, ácido ascórbico de 382,07 mg/100 mL, antocianinas de 2,51 mg/100 g e aceitabilidade global de 89,1%. Os resultados demonstram a viabilidade tecnológica e nutricional do néctar de camu-camu por ser um produto atraente de cor, sabor, aroma, aceitabilidade e como fonte de Vitamina C.

A new species ofSalicornia (Chenopodiaceae)from European Russia

Beer (Pankova), S. S. & Demina, O. N.: A new species of Salicornia (Chenopodiaceae) from European Russia. — Willdenowia 35: 253–257. — ISSN 0511-9618; © 2005 BGBM Berlin-Dahlem. doi:10.3372/wi.35.35204 (available via http//dx.doi.org/)Salicornia heterantha is described as a new species from the Rostov province in SE European Russia. It differs from other species of Salicornia by (1) the central flower of the dichasia being fused to the main axis of the spike, and (2) the comparatively long anthers in combination with short inflorescences. Only two localized populations are known, from saline clays on the banks of a salt lake. S. heterantha shows a peculiar heterocarpy: fruits of lateral flowers are dispersed freely while the fruit of the central flower remains fixed to the spike.

Critical hydrologic conditions for overflow burst of moraine lake

Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glacial landslide falling into moraine lake. On the premise that moraine lake is full, instantaneous burst in part of the lake bank happens, as flow velocity at burst mouth caused by overflow head is higher than threshold flow velocity of glacial till. Under some supposes, d(90) and d(10) of the glacial till in the hank were used as the threshold sizes of coarse and fine grains respectively. Thus, the formula of calculating threshold flow velocity of uniform sand was simplified, and threshold flow velocity of glacial till was calculated with the formula. Then, with synthesis formula calculating flow velocity of instantaneous part burst, flow velocity at overflow burst mouth was calculated, and calculation formula of critical height (H(0)) of overflow head was derived. Overflow head was caused by volume and surge of glacial landslide falling into moraine lake, calculation formulas of ascendant height (H(1)) of lake water surface and surge height (H(2)) on burst mouth caused by glacial landslide falling into moraine lake were derived. To sum up, critical hydrologic conditions of moraine lake burst with overflow form are: the burst is inevitable as H(1) > H(0); the burst is possible as H(1) H(0); the burst is impossible as (H(1)+H(2)) < H(0). In the factors influencing the burst critical conditions, it is advantageous for the burst that scale of the lake is 10(5)m(2) range; terminal glacial till is more fine and is even more uniform; the width of overflow mouth is even smaller than the length of the bank; the landslide has large scale and steep slip surface; and glacial end is close to the lake. With burst of Guangxiecuo Lake in Midui Valley of the Polongzangbu River in Xizang as an example, the burst critical conditions were tested.

Palaeoenvironments of Lake Assom near Tibati (south Adamawa, Cameroon). What happened in Tibati around 1700 years BP?

Two vibrodrill and six core drill cores were recovered in Lake Assom near Tibati, south of Adamawa. From eight radiocarbon ages on samples from the two vibrodrill cores and on the basis of sedimentological analysis, a reconstitution of the environmental history of this site for the late Holocene has been done. These results suggest the Lake Assom has remained swampy or even dry since 2800 years BP. Spectacular deposition of compact muddy intraclasts strongly suggests that this situation was suddenly interrupted close to ≈1700 years BP when the lake was inundated by water. This deposition can be compared to that of coarse materials observed at the base of the erosion profile “Basse Terrasse”. In spite of this present filling trend, the lacustrine state of the site seems to still pertain. Observations done on the lake banks and the occidental swampy plain, compiled with those from the well in the centre of the small adjacent depression of Ngwana, enable us to better understand the recent functioning of the lake. The Mandjara river certainly played a major role in the sedimentation of sandy gley, and later in the high energy reworking of older coarse intraclasts at ≈1700 years BP. Lake Assom seems to have originated from the dissolution of a more extensive iron crust covering the hole region of Mbella Assom. The presence today of two adjacent depressions is due to local morphology following changes in the lake during the dry period. On the other hand, palynologic studies show no indication of the proximity of any humid forest to this wooded savannah over the past 4500 years BP.

Lead and lead toxicity in domestic and free living birds

At present, domestic and wild fauna are being exposed to aspects and factors which are foreign to the habitat in which they live. One that stands out is the enormous amount and variety of chemical compounds which, in many cases, are highly complex and which are constantly being released into the atmosphere, mainly from agricultural and industrial activity. All these substances affect some species more than others, whether they be plants or animals, from the most insignificant micro-organism to the most evolved species, among them birds. Finally, another cause of mortality in many birds is plumbism, namely death caused by the ingestion of lead. Lead has been one of the main causes of poisoning in man since ancient times due to its use in many activities although it is only recently that this toxicity has been recognized. Moreover, the use of lead pellets for shooting has resulted in the release into the environment of millions of these over many years, with serious repercussions for many bird species populations, which have ingested them either directly or indirectly. Added to this use of lead in cynegetic activities is the fate of the lead weights (sinkers or ballast) used by rod fishers, which sink to the bottom or accumulate on the banks of rivers, lakes, lagoons or reservoirs. The problem arises when these pellets or weights are ingested by birds, mainly Anatidae, which mistake them for the small stones or grit they use to triturate food in their gizzards. Small particles of lead enter the digestive tract, start dissolving in the form of lead salts, are incorporated into the bloodstream and the rest of the body, accumulate in organs like the liver or kidneys, and cause physiological or behavioural changes. When certain concentrations of lead are reached, the birds then die. If lead-poisoned birds are consumed by carrions or predators, the latter also ingest the lead so that they may also be affected or die from plumbism since, being a heavy metal, its degradation and/or elimination is very difficult. There is, therefore, no doubt that millions of birds die annually worldwide from lead poisoning (in the U.S.A., around 3 000 000), this problem being most acute in marshland. The solutions could include the introduction of legislation regulating or banning shooting, in the use of non-toxic ammunition in marshes and protected areas, the substitution of lead pellets for other non-toxic ones, such as steel, bismuth, tungsten or other suitable metals, and to go on studying other possible alternatives to end such a dramatic situation for birds all over the world.

Biologia floral e fenologia reprodutiva do camu-camu (Myrciaria dubia (H.B.K.) McVaugh, Myrtaceae) no Estado Pará, Brasil

The camu-camu (Myrciaria dubia (H. B.K.) McVaugh, Myrtaceae) is a native fruit tree found on seasonaly flooded banks of Amazonian rivers and lakes, which is being domesticated for cultivation on non-flooded areas. Its high ascorbic acid content, approximately 2,800 mg.100g-1 of pulp has increased the demand for local market and exportation. The floral biology and reproductive phenology of camu-camu were investigated in 1997 and 1998. The studies were carried out in orchards at Embrapa Amazonia Oriental, located in Belem and in areas of natural occurrence in Santarem and Oriximina, Para State, northern Brazil. Direct observations on the visitors behavior were done, as well as capturing of specimens for identification. M. dubia showed inflorescences with white, polyandrous, hermaphroditic flowers. Anthesis occurred between 5:00 to 7:00 a.m. The pollen grains are dry, easily carried by wind or gravity, being the main flower resource. The osmophores are located at the calyx, corolla, anthers and stigma. The flowering phenology was steady-state type, and showed a peak in March. Fruitification was higher in July. Partial leaf fall was observed in all the studied plants, mainly in November. The main flower visitors were Nannotrigona punctata and Trigona pallens (Meliponinae), as well as small beetles (Chrysomelidae). The stingless bees were considered the legitimate pollinators.