Seasonal Lake Research Articles

Composition, Diversity, and Stability of Microbial Assemblages in Seasonal Lake Ice, Miquelon Lake, Central Alberta

The most familiar icy environments, seasonal lake and stream ice, have received little microbiological study. Bacteria and Eukarya dominated the microbial assemblage within the seasonal ice of Miquelon Lake, a shallow saline lake in Alberta, Canada. The bacterial assemblages were moderately diverse and did not vary with either ice depth or time. The closest relatives of the bacterial sequences from the ice included Actinobacteria, Bacteroidetes, Proteobacteria, Verrucomicrobia, and Cyanobacteria. The eukaryotic assemblages were less conserved and had very low diversity. Green algae relatives dominated the eukaryotic gene sequences; however, a copepod and cercozoan were also identified, possibly indicating the presence of complete microbial loop. The persistence of a chlorophyll a peak at 25–30 cm below the ice surface, despite ice migration and brine flushing, indicated possible biological activity within the ice. This is the first study of the composition, diversity, and stability of seasonal lake ice.

The Conflict-Laden Multi-Functionality of the Kapuas River in Kalimantan, Indonesia

the Kapuas river in west-Kalimantan, indonesia's longest river, is a prime example illustrating the conflict-laden multi-functionality of water in south-east asia. diverse utilisations of the river and adjacent land areas by local residents as well as corporate and state-led environmental transformations affect the river in various ways and bear conflicts at different scales. water as fluid medium connects the various actors and utilisations upstream and downstream. the river is used as a space for living, for personal hygiene and washing clothes, for fishing and aquaculture, as source of water for industrial, agricultural, and domestic purposes, for the discharge of partly toxic domestic and industrial waste water and rubbish, for gold and sand mining, and as a route of transport for people and goods. in the frame of a research project that aims at a spatial theoretical analysis of upstream-downstream and rural-urban interrelations with regard to water as a fluid resource, we undertook an exploratory research trip on the Kapuas river in March 2012 to gain a first overview of the various actors and utilisations positioned along the river, and of related transformations and conflicts. the material presented here provides visual illustrations of selected aspects of human-nature interactions and the conflict-laden multi-functionality of the river. the photographic journey begins in the upstream areas and ends in the coastal city of Pontianak. with its economic and political primacy the city affects human-nature relations upstream, which in turn affect the city via the flow of water.[Sidebar]Citation Lukas, M. C., Julia, radjawali, i., flitner, M., & Pye, o. (2012). the Conflict-Laden Multi-functionality of the Kapuas river in Kalimantan, indonesia. ASEAS - Austrian Journal of South-East Asian Studies, 5(2), 359-368.[Sidebar]1 Life on water - Especially the villages of the Melayu people who advanced to the interior of West Kalimantan from the coastline along the waterways and mainly live from fishing and small-scale trading, are concentrated along the Kapuas river and lake network.2 3 Fishing And Nutrition - The upper Kapuas Basin with the Danau Sentarum region contributes the main portion of freshwater fish caught in West-Kalimantan. The fishers - both women and men - use various fishing gears. The fishing gear shown in Picture 3 allows catching small sized fish in small amounts for everyday consumption.4 Conflicts over nature conservation - Danau Sentarum, a unique ecosystem comprising interconnected seasonal lakes and swamp forests, is valued by the local population for its fish abundance. It also plays a crucial role in regulating the water flows of the Kapuas River. As in other national parks in the upper reaches of the Kapuas and its tributaries, conflicts have arisen between state-led conservation strategies and local residents' resource uses.5 Politicised Water Fl ows - Politicised land-river and upstream-downstream interactions are marked by widely unknown or disputed cause-effect relationships: Local residents blame the operations of a logging company, with which they are in conflict over land, for altered stream flows resulting in river bank erosion that begins to threaten their dwellings.6 HE alth And Sanitation - Throughout the entire catchment area, residents use the river for their daily hygiene, for brushing teeth, and for doing their laundry. The floating wooden huts with their attached platforms along the shoreline serve as toilets and as washing and bathing spots. In some villages, river water had also been used for human consumption until recently but was then replaced by alternative water sources to reduce the incidence of water borne diseases, like cholera and typhoid.7 Mining and Poll ution - Thousands of gold miners, both locals and people from other parts of West-Kalimantan, dig up sediments in many parts of the Kapuas River and its tributaries, thereby polluting the river with mercury and increasing riverine sediment transport. …

Water and dissolved gas geochemistry of the monomictic Paterno sinkhole (central Italy)

This paper describes the chemical and isotope features of water and dissolved gases from lake Paterno (max. depth 54 m), a sinkhole located in the NE sector of the S. Vittorino plain (Rieti, Central Italy), where evidences of past and present hydrothermal activity exists. In winter (February 2011) lake Paterno waters were almost completely mixed, whereas in summer time (July 2011) thermal and chemical stratifications established. During the stratification period, water and dissolved gas chemistry along the vertical water column were mainly controlled by biological processes, such as methanogenesis, sulfate-reduction, calcite precipitation, denitrification, and NH4 and H2 production. Reducing conditions at the interface between the bottom sediments and the anoxic waters are responsible for the relatively high concentrations of dissolved iron (Fe) and manganese (Mn), likely present in their reduced oxidation state. Minerogenic and biogenic products were recognized at the lake bottom even during the winter sampling. At relatively shallow depth the distribution of CH4 and CO2 was controlled by methanotrophic bacteria and photosynthesis, respectively. The carbon isotope signature of CO2 indicates a significant contribution of deep-originated inorganic CO2 that is related to the hydrothermal system feeding the CO2-rich mineralized springs discharging in the surrounding areas of lake Paterno. The seasonal lake stratification likely controls the vertical and horizontal distribution of fish populations in the different periods of the year.

SEASONAL TRENDS IN TIBETAN LAKE LEVEL CHANGES AS OBSERVED BY ICESAT LASER ALTIMETRY

Abstract. The Tibetan plateau is covered by hundreds of larger and smaller lakes. Until recently there was no method to monitor their water level variations due to lack of in-situ measurements or unfitness of available remote sensing methods. However the ICESat/GLA14 laser altimetry data provide global surface elevations for land during 18 one-month campaigns between 2003 and 2009. This product could be used to accurately monitor water level variations and to estimate annual water level trends of about 150 Tibetan lakes. Based on the ICESat campaign schedule, lake levels derived from the GLA14 data are classified into three groups referenced to the Tibetan seasons: late dry, early wet, and early dry. For each lake sampled by sufficient ICESat campaigns, seasonal water level trends could be estimated and inter-seasonal lake level variations could be determined. The results indicate that most of the southern Tibetan lakes have a downward seasonal trend while most lakes elsewhere in Tibet have a positive seasonal trend. This means that these seasonal trends are similar to the annual trends. Moreover, lake level variations between seasons are much larger in the south than in the north and the west of Tibet. Based on the spatial pattern of the lakes, the Tibetan plateau is divided into four sub-areas corresponding to seasonal lake level trends and inter-seasonal lake level variations. The results confirm climatic trends as discussed in meteorological literature. Therefore, this analysis is expected to improve the understanding of the limnological processes on the Tibetan plateau and their impacts on the surrounding regions.

High-frequency remote monitoring of large lakes with MODIS 500 m imagery

Satellite-based remote monitoring programs of regional lake water quality largely have relied on Landsat Thematic Mapper (TM) owing to its long image archive, moderate spatial resolution (30m), and wide sensitivity in the visible portion of the electromagnetic spectrum, despite some notable limitations such as temporal resolution (i.e., 16days), data pre-processing requirements to improve data quality, and aging satellites. Moderate-Resolution Imaging Spectroradiometer (MODIS) sensors on Aqua/Terra platforms compensate for these shortcomings, although at the expense of spatial resolution. We developed and evaluated a remote monitoring protocol for water clarity of large lakes using MODIS 500m data and compared MODIS utility to Landsat-based methods. MODIS images captured during May–September 2001, 2004 and 2010 were analyzed with linear regression to identify the relationship between lake water clarity and satellite-measured surface reflectance. Correlations were strong (R²=0.72–0.94) throughout the study period; however, they were the most consistent in August, reflecting seasonally unstable lake conditions and inter-annual differences in algal productivity during the other months. The utility of MODIS data in remote water quality estimation lies in intra-annual monitoring of lake water clarity in inaccessible, large lakes, whereas Landsat is more appropriate for inter-annual, regional trend analyses of lakes ≥8ha. Model accuracy is improved when ancillary variables are included to reflect seasonal lake dynamics and weather patterns that influence lake clarity. The identification of landscape-scale drivers of regional water quality is a useful way to supplement satellite-based remote monitoring programs relying on spectral data alone.

Battle in the Amazon: Arapaima versus Piranha

AbstractThe scales of theArapaimas, a large freshwater fish (up to 200 kg), are a superb example of a natural material that has evolved to provide protection against predators. TheArapaimaslives primarily in Amazon basin lakes that become infested with piranhas as the dry season advances and is covered with scales having up to 10 cm length. They have a collagen interior with a highly mineralized external layer. The collagen fibers form a cross‐lamellar arrangement which produces a laminate composite. The internal collagenous layer provides the flexibility to the scales, which can undergo significant elastic deformation prior to failure, providing considerable toughness. The mineralized exterior provides the required protection against predation. The flexibility of the biomineral is enabled by two factors: (i) a corrugated configuration in which the tensile strains are minimized; (ii) a graded composition. We propose herein that the structure of the scales, a composite consisting of a mineralized external layer with surface corrugations and an internal flexible collagenous foundation, can serve as inspiration for the design of flexible composites having a hard ceramic surface. The piranha (Serrasalminae) is one of the principal predators in seasonal lakes, in which fish get trapped. Its teeth form triangular arrays creating a guillotine action that is highly effective in slicing through muscle. The bite force is calculated for a piranha with a mass of 1 kg from estimated maximum force values applied by three muscle groups connecting the jaw to the mandible: it is ≈20 N. Mechanical tests on the scales and teeth demonstrate that the cutting and puncturing ability of the piranha teeth cannot penetrate theArapaimasscales.

Quantification of Thiamethoxam in Rhizomes and Leaves of the <i>Hedychium coronarium</i> and Water and Soil by High-Pressure Liquid Chromatography

The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in water, soil and rhizomes and leaves of Hedychium coronarium of the Zingiberaceae family. Mato Grosso do Sul is a predominantly agricultural state in Brazil and has many rivers and permanent and seasonal lakes, in which the Hedychium coronarium, an aquatic plant, is found the swampy environments. The prepared samples were analyzed quantitatively by High Performance Liquid Chromatography with PDA and UV detection for the presence of thiamethoxam. The thiamethoxam was recovered from these samples at rates ranging from 81.16% - 99.93%. The coefficient of variation in the quantitative analysis of the thiamethoxam was under 5%. The linearity of the method was determined by linear regression. The analysis of the samples spiked with known amounts of analyte demonstrated that the response was proportional to the concentrations of the samples with determination coefficients of r2 = 0.9992 (water and soil) and r2 = 0.9990 (leaves and rhizomes) for the linear range of the analytical calibration curves of the samples. The detection limit was 0.36 ug.L-1 and quantification limit was 1.2 ug.L-1 for thiamethoxam. The method was considered sensitive for quantification of the thiamethoxam in water, soil and rhizomes and leaves of Hedychium coronarium.

The brine shrimp artemia: adapted to critical life conditions.

The brine shrimp Artemia is a micro-crustacean, well adapted to the harsh conditions that severely hypersaline environments impose on survival and reproduction. Adaptation to these conditions has taken place at different functional levels or domains, from the individual (molecular-cellular-physiological) to the population level. Such conditions are experienced by very few equivalent macro-planktonic organisms; thus, Artemia can be considered a model animal extremophile offering a unique suite of adaptations that are the focus of this review. The most obvious is a highly efficient osmoregulation system to withstand up to 10 times the salt concentration of ordinary seawater. Under extremely critical environmental conditions, for example when seasonal lakes dry-out, Artemia takes refuge by producing a highly resistant encysted gastrula embryo (cyst) capable of severe dehydration enabling an escape from population extinction. Cysts can be viewed as gene banks that store a genetic memory of historical population conditions. Their occurrence is due to the evolved ability of females to “perceive” forthcoming unstable environmental conditions expressed by their ability to switch reproductive mode, producing either cysts (oviparity) when environmental conditions become deleterious or free-swimming nauplii (ovoviviparity) that are able to maintain the population under suitable conditions. At the population level the trend is for conspecific populations to be fragmented into locally adapted populations, whereas species are restricted to salty lakes in particular regions (regional endemism). The Artemia model depicts adaptation as a complex response to critical life conditions, integrating and refining past and present experiences at all levels of organization. Although we consider an invertebrate restricted to a unique environment, the processes to be discussed are of general biological interest. Finally, we highlight the benefits of understanding the stress response of Artemia for the well-being of human populations.

Assessment of wetland dynamics in Sirohi district of Rajasthan, India using remote sensing and GIS techniques

Wetlands are very dynamic ecosystems in the world. The present study provides scenario of wetlands of Sirohi district of Rajasthan, India. Landsat TM data of October, 1992, IRS-P6 LISS-III data of October 2005 and IRS-P6 AWiFS data of January, February, March, April and May months (2005) have been used in the study. Visual interpretation technique was adopted to map the areal extent of wetlands on 1:50,000 scale. Wetlands were classified following the Ramsar classification. The total extent of wetlands for the Sirohi district as a whole is estimated to 11,961 ha with representation 189 wetlands during 1992 which later decreased 11,307 ha in 2005 with a loss of 654.2 ha during 13 years. Of the total wetland area of the district, rivers accounted for 61.9% area, followed by reservoirs (15.1%), seasonal lakes (15%), perennial lakes (5.6%), and ponds (2.5%). Further it is also observed that drastic reduction in the water spread area from February to May months. For conservation of wetlands it is necessary to assess the changes which take place in the water bodies from time to time. Key words: GIS; Rajasthan; Remote sensing; Sirohi district; Wetlands DOI: http://dx.doi.org/10.3126/jowe.v5i0.4996 J Wet Eco 2011 (5): 66-72

Modeling and Validating Long‐Term Dynamics of Diel Dissolved Oxygen with Particular Reference to pH in a Temperate Shallow Lake (Turkey)

AbstractLong‐term monitoring of changes in dissolved oxygen (DO) and pH is of great importance to quantifying aquatic ecosystem metabolism, particularly for lakes under the changing global environment. During 173 days, diel DO cycles were measured in situ along with the main driving variables of pH, wind speed (WS), and net solar radiation (Rn) in a temperate shallow lake. Best‐fit multiple non‐linear regression (MNLR) models of diel DO time series were built and validated on a monthly basis, with R2 values ranging from 42.4% in September to 95.4% in November for validation. The strong relationship between diel DO and pH (r = 0.6) appeared to be related to the patterns of ecosystem productivity and respiration, and sensitivity of decomposing bacteria to changes in pH. pH‐driven lake metabolism appears to have significant implications for diel and seasonal lake metabolism in a changing global environment.

An Interesting Plant Community of Hypo-saline Seasonal Lakes in the Muir-Unicup Catchment, Western Australia

An Interesting Plant Community of Hypo-saline Seasonal Lakes in the Muir-Unicup Catchment, Western Australia

Are seasonal lakes as productive as permanent lakes? A case study from Ireland

This paper compares, for the first time, nutrient levels and chlorophyll a measured in a set of seasonal lakes with those reported for permanent lakes in the literature. Twenty-two turloughs (karstic seasonal lakes) in western Ireland were sampled monthly from the onset of flooding (October) until they dried out (6 to 9 months). The turloughs showed similar levels of nutrients and chlorophyll a to those reported for Irish and international lakes. Chlorophyll a peaked between November and February in the majority of turloughs, sometimes with values higher than those measured in mesotrophic lakes in summer. A significant log-linear regression was found between total phosphorus and chlorophyll a, which suggests P limitation of algal biomass in the majority of the turloughs. The regression characteristics were not significantly different than those described in similar studies of permanent lakes. Patterns in seasonal variation of nutrients are also presented, their underlying causes being discussed in relation to their transport within catchments. Our results show that despite being predominantly winter phenomena, turloughs can be as productive as permanent lakes.

Polystoma okomuensisn. sp. (Monogenea: Polystomatidae) from Boulenger's striped frog,Phlyctimantis boulengeri(Perret, 1986) in Nigeria

Polystoma okomuensis is described as a new species of the Polystomatidae parasitic in the urinary bladder of Boulenger's striped frog Phlyctimantis boulengeri in the Okomu National Park, Edo State, Nigeria. Although other African polystomes have been reported from Nigeria, this is the first to be described from the country and the first from Phlyctimantis. It is distinguished from other African Polystoma species by a combination of characters, including the body size, size and shape of the hamuli, size and shape of marginal hooklets and intestinal location. Phlyctimantis boulengeri was found to be infected in two of four seasonal lakes where specimens were caught with prevalences and mean intensities ranging from 14.3 to 22% and 1.0 to 1.5, respectively. Of the total number of 45 frogs examined, the prevalence was 15.6% and mean intensity 1.4.

Challenges of water resource management and food production in a changing climate in Kenya

The Tropics depend upon rain as the main source of water supply for agriculture. Concerns of food security and water scarcity in the wake of climate change are global and real particularly in the sub-Saharan Africa. As communities struggle to adapt to the challenges of food insecurity caused by climate change, they are also sensitive to the diminishing and management problems of water resources. Kenya with an estimated population of 36 million people of whom 10 million are faced with starvation is highly vulnerable to climate change effects. There is evidence from Food and Agricultural Organisation (FAO) that 850 million people in the world are affected by food insecurity, of whom 820 million live in the developing countries. To come up with climate change associated challenges on food security and water resource management in Kenya, the study carried out climate and food related researches on agriculture in Arid and semi-arid parts of Kenya (ASAL), irrigation and fishing activities in the ASAL districts, evaluated climate and socio-economic data from Drought Monitoring Centre Nairobi (DMCN). It also evaluated and collected data from selected industrial towns in the country. It was established that Kenya faces severe food insecurity problem caused by climate change and mismanagement of water resources. Many seasonal rivers dry up due to poor management of irrigation processes, a lot of fish die due to release of industrial effluent to rivers, there is drying up of seasonal rivers, lakes and boreholes due to prolonged droughts, there is persistent crop failure and animal death and increased environmental migration from the ASAL due to increasing aridity. Proper management of water resources therefore, calls for the implementation of such measures as Environmental Impact Assessment (EIA) for industrial operations, Assessment of sustained yields for rivers before abstraction is allowed, re-afforestation and forest protection for sustained river yields and increased rainfall for increased food production. Key words:

Modelling spatial‐temporal change of Poyang Lake using multitemporal Landsat imagery

Poyang Lake is a seasonal lake, exchanging water with the lower branch of the Yangtze River. During the spring and summer flooding season it inundates a large area while in the winter it shrinks considerably, creating a large tract of marshland for wild migratory birds. A better knowledge of the water coverage duration and the beginning and ending dates for the vast range of marshlands surrounding the lake is important for the measurement, modelling and management of marshland ecosystems. In addition, the abundance of a special type of snail (Oncomelania hupensis), the intermediate host of parasite schistosome (Schistosoma japonicum) in this region, is also heavily dependent on the water coverage information. However, there is no accurate digital elevation model (DEM) for the lake bottom and the inundated marshland, nor is there sufficient water level information over this area. In this study, we assess the feasibility of the use of multitemporal Landsat images for mapping the spatial‐temporal change of Poyang Lake water body and the temporal process of water inundation of marshlands. Eight cloud‐free Landsat Thematic Mapper images taken during a period of one year were used in this study. We used the normalized difference water index (NDWI) and the modified normalized difference water index (MNDWI) methods to map water bodies. We then examined the annual spatial‐temporal change of the Poyang Lake water body. Finally we attempted to obtain the duration of water inundation of marshlands based on the temporal sequence of water extent determined from the Landsat images. The results showed that although the images can be used to capture the snapshots of water coverage in this area, they are insufficient to provide accurate estimation of the spatial‐temporal process of water inundation over the marshlands through linear interpolation.

Landsat ETM+ Images in the Estimation of Seasonal Lake Water Quality in Boreal River Basins

We investigated the use of Landsat ETM+ images in the monitoring of turbidity, colored dissolved organic matter (CDOM), and Secchi disk transparency (Z(SD)) in lakes of two river basins located in southern Finland. The ETM+ images were acquired in May, June, and September 2002 and were corrected for atmospheric disturbance using the simplified method of atmospheric correction (SMAC) model. The in situ measurements consisted of water sampling in the largest lake of the region, routine monitoring results for the whole study area, and Z(SD) observations made by volunteers. The ranges of the water quality variables in the dataset were as follows: turbidity, 0.6-25 FNU; absorption coefficient of CDOM at 400 nm, 1.0-12.2 m(-1); Z(SD), 0.5-5.5 m; and chlorophyll a concentration, 2.4-80 microg L(-1). The estimation accuracies of the image-specific empirical algorithms expressed as relative errors were 23.0% for turbidity, 17.4% for CDOM, and 21.1% for Z(SD). If concurrent in situ measurements had not been used for algorithm training, the average error would have been about 37%. The atmospheric correction improved the estimation accuracy only slightly compared with the use of top-of-atmospheric reflectances. The accuracy of the water quality estimates without concurrent in situ measurements could have been improved if in-image atmospheric parameters had been available. The underwater reflectance simulations of the ETM+ channel wavelengths using water quality typical for Finnish lakes (data from 1113 lakes) indicated that region-specific algorithms may be needed in other parts of the country, particularly in the case of Z(SD). Despite the limitations in the spectral and radiometric resolutions, ETM+ imagery can be an effective aid, particularly in the monitoring and management of small lakes (<1 km(2)), which are often not included in routine monitoring programs.

The influence of habitat heterogeneity on freshwater bacterial community composition and dynamics

Multiple forces structure natural microbial communities, but the relative roles and interactions of these drivers are poorly understood. Gradients of physical and chemical parameters can be especially influential. In traditional ecological theory, variability in environmental conditions across space and time represents habitat heterogeneity, which may shape communities. Here we used aquatic microbial communities as a model to investigate the relationship between habitat heterogeneity and community composition and dynamics. We defined spatial habitat heterogeneity as vertical temperature and dissolved oxygen (DO) gradients in the water column, and temporal habitat heterogeneity as variation throughout the open-water season in these environmental parameters. Seasonal lake mixing events contribute to temporal habitat heterogeneity by destroying and re-creating these gradients. Because of this, we selected three lakes along a range of annual mixing frequency (polymictic, dimictic, meromictic) for our study. We found that bacterial community composition (BCC) was distinct between the epilimnion and hypolimnion within stratified lakes, and also more variable within the epilimnia through time. We found stark differences in patterns of epilimnion and hypolimnion dynamics over time and across lakes, suggesting that specific drivers have distinct relative importance for each community.

Effects of Greater flamingo Phoenicopterus ruber on macrophytes, chironomids and turbidity in natural marshes in Donana, SW Spain

Top predators and nutrient inputs are important factors determining the structure of freshwater aquatic systems. Greater flamingos (Phoenicopterus ruber) have been shown to destroy submerged macrophytes and may promote a switch from clear water to turbid water in the temporary marshes of Donana National Park. We excluded flamingos from twenty 4x4 m plots distributed between two lucios (shallow seasonal lakes) within the marshes from February to July 2004. In July, we measured total suspended solids (TSS), macrophyte biomass and abundance and size of chironomid larvae in the twenty exclosures and twenty adjacent control plots. TSS was lower and macrophyte biomass was higher in exclosures, but not significantly so. Flamingos were found to cause a significant reduction in chironomid abundance and an increase in the proportion of larger larvae. The effect of exclusion was greater where the density of flamingos was highest. Comparison with the results of previous studies suggests that the impact of flamingos is context dependent and largely determined by bird density and/or factors related to macrophyte productivity. Water levels were especially high in 2004 owing to heavy rains, and flamingos may have stronger effects in years of lower rainfall.

East African flyway and key site network of the Lesser Flamingo (Phoenicopterus minor) documented through satellite tracking

In October 2002, four adult Lesser Flamingos were tagged at Lake Bogoria, Kenya: two with solar-powered platform transmitter terminals (PTTs) and two with battery-powered PTTs, one of which stopped transmitting after 38d. In July 2003, an additional four birds were tagged with solar-powered PTTs. During the first two years (November 2003–October 2004), flight patterns of the tagged birds were independent. Interlake flight distances ranged from 16–441km (mean: 111.5km, n = 243), 68.3% being less than 100km and 96% less than 300km. There was no significant difference among the birds in the median length of their interlake flights. The number of days spent at each stopover ranged from 0 (less than 1d) to 153d (mean: 14.4d, n = 250). There was a significant difference among the birds in the number of days spent at each stopover. This difference was due to one very active bird that made 133 interlake flights during the period, visiting 12 different sites, spending a mean 5.2d at each site and travelling 12 600km. There was no significant difference among the other six birds. The seven birds' flights were confined to a 940km north-south range within the Great Rift Valley between Lake Logipi in northern Kenya and Bahi Swamp in central Tanzania. Their key site network consisted of eight alkaline lakes (Logipi, Bogoria, Elmenteita, Nakuru, Natron, Empakai Crater Lake, Manyara and Eyasi), and Lake Bahi, a seasonal lake in central Tanzania. The conservation status of these nine sites varies from well-protected to completely unprotected. None of the birds appears to have bred during either the 2002–2003 or the 2003–2004 breeding seasons (October–January), although other Lesser Flamingos bred at Lake Natron during both seasons, Lake Natron being the only East African site where the Lesser Flamingo has bred successfully during the past 45 years.

MyLake—A multi-year lake simulation model code suitable for uncertainty and sensitivity analysis simulations

Uncertainty and sensitivity analysis provide powerful means to enhance the performance of the models, to increase the transparency and credibility of the model results, and to allow the decision-maker to judge whether the model results are sufficiently accurate and precise to support decision-making or not. Uncertainty and sensitivity analysis of numerical models usually require hundreds, thousands, or even more, repeated model runs (e.g., in Monte Carlo simulation) as well as access to change the model parameters and variables on each model run. Consequently, many model codes, although widely used and well-formulated, are not well-suited for uncertainty and sensitivity analysis due to too long model execution time or due to lack of suitable interface to change model parameters and variables in an automated way. In this paper, we describe in details a lake model code, which aims to combine good simulation capabilities with efficient model execution time and easy application of numerical uncertainty and sensitivity analysis techniques. This model code is called MyLake (Multi-year Lake simulation model) and it is a one-dimensional process-based model code for simulation of daily vertical distribution of lake water temperature and thus density stratification, evolution of seasonal lake ice and snow cover, sediment–water interactions, and phosphorus-phytoplankton dynamics. After giving a detailed technical description of the different processes and algorithms included in the current version 1.2 of the MyLake model code, we present some results from a model application example including an Extended Fourier Amplitude Sensitivity Test (Extended FAST) sensitivity analysis and a simple Monte Carlo simulation based uncertainty analysis. Finally we discuss the performance of the MyLake code, especially in connection with numerical uncertainty and sensitivity analysis techniques.