Number Of Small Lakes Research Articles

Peculiarities of the Species Composition, Abundance and Biotope Distribution of Mollusks Fam. Sphaeriidae in Rivers with a Many Lakes in the Catchment Area (by the Example of Water Courses of the Onega Lake Basin)

Using the example of the rivers of the Onega Lake basin, the species composition of mollusks of the Sphaeriidae family, their abundance, biomass, and contribution to benthic communities in rivers with many lakes in the catchment areas were analyzed. Patterns of spatial distribution of species across biotopes and gradients of environmental variables were traced. 26 species of mollusks of this family were identified, among them European-Siberian species predominate. Most of the species of mollusks of the family Sphaeriidae found by us have wide ecological ranges and are found in water bodies of various types. It was found that the contribution of Sphaeriidae to the species richness and functioning of aquatic communities in rivers in the conditions of branched lake-river systems (Lake Onega basin) exceeds the values usual for rivers with a small number of lakes in the catchment area. Using the ANOSIM and PERMANOVA methods, it was proved that the species composition of rocky rapids and riffles, sandy rifts and soft bottom soils is different. Using the IndVal test, seven species were shown to have a statistically significant association with one of these biotopes, and four of them, with rocky bottoms of river rapids and riffles. Using the NMDS method, it was shown that the greatest changes in the species composition of representatives of Sphaeriidae are observed when environmental conditions change from small streams with slow current and brown water to large rivers with fast current and clear water.

The natural environment in the vicinity of Lake Sporovskoye in the Late Glacial and Holocene

Due to the relatively small number of lakes in the southern part of Belarus, in the Polesie region, each lake and its bottom sediments are of great scientific interest for palaeoecological reconstructions. Lake Sporovskoye is one of the largest lakes in Belarusian Polesie, previously studied in the field of palaeoecology by a number of researchers. The discovery in 2018 of the Kakoryca-4 archaeological site near Lake Sporovskoye inspired the beginning of this study, during which new palaeoecological data were obtained. The purpose of the article was to build palaeoecological reconstructions based on spore-pollen, macroremains, sedimentological, and radiocarbon analyses of the Sporovo II core. As a result, it was proven that Lake Sporovskoye was formed in the Late Glacial. Water level changes in the lake, as well as a period of increased activity of the Yaselda River, were detected in the Holocene. The author proposed the reconstructions of regional and local vegetation and corrected some previous views on the development of the study area in the Late Glacial and Holocene.

Abrupt increase in thermokarst lakes on the central Tibetan Plateau over the last 50 years

Thermokarst lakes are an important ecosystem component in permafrost terrains; therefore, quantifying changes in these lakes is important for evaluating the water balance and carbon budget on the Qinghai-Tibet Plateau (QTP). In this study, we utilized high spatial resolution aerial and satellite images from 1969, 2010, and 2019 to quantify changes in thermokarst lakes > 0.1 ha across four regions on the central QTP. The results indicated an overall significant increase in the lake number (+158%) and surface area (+123%) for all study regions over the last five decades, despite variations in change in these trends among the different landform types. Changes in individual lake processes indicated that the above lake changes were mainly characterized by a significant increase in the number of small lakes and area enlargements of large lakes, whereas thermokarst lake drainage only occurred in some gentle slope areas. By analyzing the potential factors that drive changes in thermokarst lakes in the study region, we found that persistent climate warming and the increasing of precipitation were the most likely explanations for the observed results. With continued climate warming and permafrost degradation, we expect a persistent increase in the number and surface area of thermokarst lakes; however, the probability of lake drainage may also increase with lake expansion.

Spatio-temporal variability of zooplankton and zoobenthos as the elements of integrated zoocenosis in a marine lake (Crimea, Black Sea): What is a general pattern?

The number of small lakes (<1 km2) on Earth is much greater than the total of all large lakes. Marine small saline lakes play an important environmental, social, and economic role but there is often a lack of studies within these environments. Changes are ongoing in many lakes due to natural and anthropogenic causes, and these changes can be dramatic in marine small saline lakes. The authors conducted a study of the spatio-temporal variability of zooplankton and zoobenthos in a small hypersaline Crimean lake of marine origin. The study was done at three lake sites during 3–5 periods in 2018. Animal composition and abundance were studied in plankton, floating filamentous green algae mats, and soft bottom. The temperature fluctuated between 10 and 28 °C, and salinity varied between 23 and 170 g L−1. 9 macrotaxa of animals were found in plankton, and 9 in the benthos. Harpacticoida dominated in 80% of cases, and Ostracoda in 20% of cases. The total abundance of zooplankton averaged 42.4 × 104 ind. m−3. The total abundance of zoobenthos was on average 9.2 × 105 ind. m−2 in mats, and in the soft bottom community on average 2.4 × 105 ind. m−2. There is a single differentiated integrated zoocenosis in the lake without division into separate zoocenoses of plankton, mat, and bottom. Comparison with data of 2004–2006 showed that despite the high level of variability of the components of the zoocenosis, there were no direct long-term changes within it.

Long-term dataset on aquatic responses to concurrent climate change and recovery from acidification

Concurrent regional and global environmental changes are affecting freshwater ecosystems. Decadal-scale data on lake ecosystems that can describe processes affected by these changes are important as multiple stressors often interact to alter the trajectory of key ecological phenomena in complex ways. Due to the practical challenges associated with long-term data collections, the majority of existing long-term data sets focus on only a small number of lakes or few response variables. Here we present physical, chemical, and biological data from 28 lakes in the Adirondack Mountains of northern New York State. These data span the period from 1994–2012 and harmonize multiple open and as-yet unpublished data sources. The dataset creation is reproducible and transparent; R code and all original files used to create the dataset are provided in an appendix. This dataset will be useful for examining ecological change in lakes undergoing multiple stressors.

8. The Effect of Bythotrephes Longimanus on the Size Structure of Zooplankton Communities in the Muskoka Region, Ontario

Invasive species are considered the greatest threat to aquatic ecosystem biodiversity. Bythotrephes longimanus, an exotic zooplankton species introduced to North America in the 1980s, is threatening the structure of indigenous aquatic ecosystems as it continues to invade inland Ontario lakes. As a predacious zooplankton species, B. longimanus has been shown to decrease zooplankton abundance, species richness and shift zooplankton community size structure in invaded lakes. However, much of the previous research concerning the predatory effects of B. longimanus has been on surveys of a small number of lakes or has been in controlled mesocosm or lab-based experiments. This study examines the effects of B. longimanus on the zooplankton community using size-structure characterizations (grouping individuals from the community based on size) as community measures for 311 lakes in the Muskoka Region, a highly invaded watershed in Southern Ontario. More specifically, the study explores the size-spectra of invaded versus uninvaded lakes, with reference to an array of environmental lake characteristics (water chemistry, lake morphometry,etc.), and the relevance of B. longimanus activity on the regional scale. By using such a large-scale survey we will be able to appreciate regional-scale effects, as well as encompass the multiple and more indirect trophic interactions that B. longimanus is likely having with the entire aquatic community. (Funding: NSERC &amp; CAISN.)

Ambient sediment quality conditions in Minnesota lakes, USA: Effects of watershed parameters and aquatic health implications

Surficial sediments were collected from 50 randomly selected Minnesota lakes, plus four a priori reference lakes, in 2007. The lakes encompassed broad geographic coverage of the state and included a variety of major land uses in the surrounding watersheds. Sediment samples were analyzed for a suite of metals, metalloids, persistent organic pollutants, total organic carbon, and particle size fractions. In addition, a small fish survey was conducted to assess PBDEs in both whole fish and fish tissues. Sediment quality in this set of lakes ranged from good (43%) to moderate (57%) based on an integrative measure of multiple contaminants. On an individual basis, some contaminants (e.g., arsenic, lead, DDD, and DDE) exceeded benchmark values in a small number of lakes that would be detrimental to benthic invertebrates. The sediments in two developed lakes tended to be more contaminated than sediments in lakes from other major watershed land uses. These differences were often statistically significant (p<0.05), particularly for lakes with developed versus cultivated land uses for arsenic, lead, zinc, and numerous PAH compounds. Multivariate statistical approaches were used on a subgroup of contaminants to show the two urban lakes, as well as a few northeastern Minnesota lakes, differed from the rest of the data set. Background threshold values were calculated for data with <80% nondetects. Source apportionment modeling of PAHs revealed that vehicle emissions and coal-related combustion were the most common sources. A general environmental forensic analysis of the PCDD/F data showed that ubiquitous combustion sources appeared to be important. BDE-209, a decaBDE, was detected in 84% of lake sediment samples, whereas fish at the top of the food chain (i.e., predator trophic group) had significantly higher (p<0.05) mean lipid-normalized concentrations of BDEs-47, 100, and 153 than lower trophic fish. These results will be used for future status and trends work.

Water quality assessment in a shallow lake used for tourism

Abstract The routine evaluation of water quality is limited to lakes with the largest area. In Poland, only lakes with an area exceeding 50 hectares are monitored by the State Environmental Monitoring System. For many local communities, however, small lakes are more important. This applies mainly to areas with a small number of lakes, where even the smallest lakes are used for various purposes. This paper presents the results of phytoplankton analysis in a small and shallow lake used for recreation. The study was conducted at three sites located in different parts of the lake. A total of 122 algae taxa were identified in the phytoplankton, mainly diatoms and green algae. The most constant taxa in the lake were: Stephanodiscus hantzschii, Desmodesmus communis, Pediastrum tetras and Crucigenia tetrapedia. The average phytoplankton biomass was 37 mg l−1. The maximum biomass, almost 140 mg dm−3, was recorded in late July at the site located near the beach. At that time, there was a massive cyanobacterial bloom composed of Microcystis wesenbergii and Aphanizomenon issatschenkoi. Based on these studies, the lake should be classified as hypertrophic with bad ecological status. This lake should not be used for recreational purposes in the current state.

Imputing recreational angling effort from time-lapse cameras using an hierarchical Bayesian model

Digital time-lapse cameras (cameras) are increasingly used for monitoring recreational angling effort on water bodies such as lakes and rivers. Cameras are an attractive alternative to traditional methods for monitoring angling effort such as aerial counts and on-water creel surveys because of their relatively low running costs. However, cameras take photographs intermittently and it is not possible for the camera field of view to cover the entire water body in most applications. It is therefore necessary to bias correct (uprate) the camera observations of angling effort to obtain estimates of total angling effort including those out of the camera field of view. We developed a hierarchical Bayesian model to predict total angling effort from camera observations of angling effort. The model was fitted to creel effort survey data and then used to impute (‘fill-in’) total angling effort data for a larger dataset of camera observations where there were no creel survey data. The model accounted for three issues encountered when uprating camera observations of angling effort to total angling effort: (1) camera observations of zero angler effort when anglers were outside the field-of-view; (2) incomplete creel survey data; and (3) occasional data gaps caused by equipment malfunction. We applied the model to camera data from a number of small lakes in British Columbia, Canada using it to predict total angling effort that accounts for observation error. We explore the various model assumptions and discuss the limitations of the approach.

Thermokarst lake changes between 1969 and 2010 in the Beilu River Basin, Qinghai–Tibet Plateau, China

This work presents changes of thermokarst lakes from Beilu River Basin on the Qinghai–Tibet Plateau over the past four decades (1969–2010) using aerial and satellite image interpretation. The results indicated that thermokarst lake activity had generally increased rapidly between 1969 and 2010. The number of thermokarst lakes had increased by approximately 534, and their coverage expanded by about 410ha. The two main changes observed were an increase in the number of small lakes and the expansion of larger lakes. These changes are likely the result of persistent climate warming and a gradually increasing imbalance between precipitation and evapotranspiration (P–ET). However, some non-climatic factors, such as the lake-bottom substrate and local engineering activities, have also influenced the lake changes. If air temperature and P–ET continue to rise, the number of thermokarst lakes and the area they cover may continue to increase in the future.

Spatial-temporal characteristics of lake area variations in Hoh Xil region from 1970 to 2011

As one of the areas with numerous lakes on the Tibetan Plateau, the Hoh Xil region plays an extremely important role in the fragile plateau eco-environment. Based on topographic maps in the 1970s and Landsat TM/ETM+ remote sensing images in the 1990s and the period from 2000 to 2011, the data of 83 lakes with an area above 10 km2 each were obtained by digitization method and artificial visual interpretation technology, and the causes for lake variations were also analyzed. Some conclusions can be drawn as follows. (1) From the 1970s to 2011, the lakes in the Hoh Xil region firstly shrank and then expanded. In particular, the area of lakes generally decreased during the 1970s–1990s. Then the lakes expanded from the 1990s to 2000 and the area was slightly higher than that in the 1970s. The area of lakes dramatically increased after 2000. (2) From 2000 to 2011, the lakes with different area ranks in the Hoh Xil region showed an overall expansion trend. Meanwhile, some regional differences were also discovered. Most of the lakes expanded and were widely distributed in the northern, central and western parts of the region. Some lakes were merged together or overflowed due to their rapid expansion. A small number of lakes with the trend of area decrease or strong fluctuation were scattered in the central and southern parts of the study area. And their variations were related to their own supply conditions or hydraulic connection with the downstream lakes or rivers. (3) The increase in precipitation was the dominant factor resulting in the expansion of lakes in the Hoh Xil region. The secondary factor was the increase in meltwater from glaciers and frozen soil due to climate warming.

How many lakes are there, and how big are they?

Because of the important role lakes play in regional and local biogeochemical cycling, including carbon storage and emissions, scientists need to know how many lakes of various sizes exist. However, determining the size distribution of lakes is more difficult than it may seem—the smallest lakes are often not recorded on maps. Some researchers have suggested that the number of small lakes is underestimated and have used size distributions to suggest that small lakes dominate the global lake surface area.

Newman Lake restoration: A case study. Part II. Microfloc alum injection

Microfloc alum injection, in contrast to whole-lake alum treatments, is a relatively new technique for alum delivery that has been implemented in a relatively small number of lakes and reservoirs. Microfloc alum injection is primarily designed to precipitate phosphorus in the water column using low doses applied on a continuous or intermittent basis. The technique employs diffusers to create ultra-small aluminum hydroxide particles with lower settling velocities and longer residence times, compared to whole lake treatments, to strip dissolved phosphorus from the water column. Because relatively few microfloc systems have been deployed, a brief review of their characteristics and performance is provided. In Newman Lake, Washington, a microfloc alum injection system has been in use since spring 1997. We tested microfloc residence times using in situ enclosures; residence time was determined to be at least 10 days, supporting the underlying concept. In the lake itself, turnover events prior to alum injection consistently produced higher algae growth with accompanying lower Secchi transparency. Since alum injection, post-turnover Secchi depths have all improved. In 18 years with 32 monitored turnover events, this relatively robust dataset consistently indicates the short-term ability of microfloc to improve transparency through algae reduction. Volume-weighted total phosphorus concentrations also have generally declined following alum injection. Adverse biological impacts were not observed in either enclosures or the lake. In the enclosure studies, total zooplankton and cladoceran densities and biomass in treatments were not significantly different from controls. Further applications and study of this promising technology are warranted.

The status of Arctic charr Salvelinus alpinus in Britain and Ireland

Abstract – The Arctic charr occurs in lakes across Britain and Ireland and was previously described here as 15 separate species. Most authorities now agree that all these stocks belong to a single polymorphic species complex Salvelinus alpinus (L.). This fish is given little protection in British and Irish law and there has been a steady loss of natural populations in recent years in all the countries concerned. A few new stocks have been created either intentionally or accidentally. In Scotland, only a small proportion of the 258 recorded natural populations has been studied and at least 12 of these are now extinct. There are at least four introduced populations originating from native Scottish stocks, but the fate of stocks introduced from Canada for aquaculture is uncertain. In England, there are eight extant populations in Cumbria and four others extinct. The status of introduced stocks in England is uncertain but there is probably one population surviving in Yorkshire. In Wales, eight lakes with resident Arctic charr populations have been recorded, three of these populations are natural, one is extinct and four have been introduced. In Ireland, of the 74 known populations, approximately 30% are extinct. There is no evidence to indicate that introduced stocks (some of them from Iceland) in a small number of lakes have survived there. A range of factors is involved in the extinction of populations and these include pollution, eutrophication, acidification, afforestation, engineering, exploitation, aquaculture, introductions and climate change. Much research remains to be done and unique stocks of this valuable species will continue to be lost unless positive action is taken through local conservation management backed by appropriate national legislation.

Predicting Recovery from Acidic Deposition: Applying a Modified TAF (Tracking and Analysis Framework) Model to Maine (USA) High Elevation Lakes

We adapted a reduced-form model, built to predict the aquatic effects of alternative nitrogen and sulfur emissions scenarios on Adirondack lakes, New York, for use on high elevation lakes of Maine (HELM), USA. The Tracking and Analysis Framework (TAF) model was originally designed to evaluate the biotic, economic, and health effects of acid deposition. The TAF model developed in our study was used to assess the biotic effects of different levels of sulfate deposition resulting from alternative emissions scenarios. The aquatic portion of the model is based on a lumped-parameter watershed chemistry model, MAGIC (Model of Acidification of Groundwater in Catchments). The original TAF model was built by calibrating MAGIC to 33 lakes in the Adirondack Mountains. We calibrated MAGIC to 78 HELM lakes, and built reduced-form models from these MAGIC predictions. We evaluated TAF predictions of acid neutralizing capacity (ANC), a fish acid stress index (ASI), and the probability of fish presence in 2030 for four different SO2 emissions-reduction scenarios. The most dramatic emissions reduction scenario produced only modest increases in mean ANC (16.8 µeq/L ± 7.9 µeq/L) and slight increases in mean predicted probability of presence of acid- sensitive fish (0.07 ± 0.09) across all lakes. However, a small number of lakes were predicted to have more substantial increases in ANC and improvements in other conditions for acid-sensitive fish. Our results reflect the reality that many of the high elevation lakes of Maine historically had low ANC and that some were even acidic in pre-industrial times. Thus, 'recovery' for most of the high elevation lakes of Maine will be modest under any scenario of reduced acidic deposition.

Habitat Characteristics ofEurytemora lacustris(Poppe, 1887) (Copepoda, Calanoida): The Role of Lake Depth, Temperature,Oxygen Concentration and Light Intensity

Field observations, laboratory experiments and a literature survey were conducted to evaluate the habitat characteristics of Eurytemoralacustris (Poppe 1887), a freshwater calanoid copepod species. Combined effects of temperature and oxygen concentration in the deep water of thermally stratifying lakes seem to be the ultimate factors governing the occurrence of the species throughout its home-territory. E. lacustris is largely restricted to relatively deep lakes (>30 m) providing a hypolimnetic refuge characterised by low temperatures (<∼10 °C) and oxygenated water during summer. Therefore, although the species is spread over much of Europe it was only found in a small number of lakes. Long-term records in different lakes revealed E. lacustris to be perennial with relatively high biomasses occurring from May to September. During thermal stratification on average 87% of the nauplii and 72% of the copepodite biomass was found in hypolimnetic waters colder than 10 °C. Diurnal vertical migration was observed for the copepodid stages, but the migration amplitude clearly decreased from May to September. The migration amplitude was significantly related to light intensity. According to its special habitat requirements, E. lacustris might be considered a glacial relict sensitive to temperature increase and oxygen depletion. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Constructed wetlands: high-quality habitats for Odonata in cultivated landscapes

Abstract In Norway and throughout the rest of Europe, a continuous decline in the number of small lakes and ponds has taken place. As a consequence, many pond-dwelling organisms have become rare or extinct. Constructed wetlands (CWs) have since the 1990s been used as a remedial action against agricultural runoff. This study has investigated the potential these wetlands have as habitat for freshwater organisms, exemplified by Odonata. Four different CWs in southern Norway were investigated, and larval Odonata species composition was related to a wide range of environmental variables. The material was ordinated using Detrended Correspondence analysis (DCA) and Canonical Correspondence analysis (CCA). All the CWs had high nutrient values and high diversities of aquatic plants. Of the 11 Odonata species found, the richest CW contained 10 species. During the study, one of the CWs was exposed to diazinon (an insecticide). Sun exposure and nutrient content were the most important variables determining species co...

Basin evolution within the Kitakami Massif, northeast Japan: relationship between sedimentation, tectonics and volcanism in an incipient Neogene continental back-arc basin

Abstract The Ichinohe basin in the western margin of the Kitakami Massif, northeast Japan, consists of the Early to Middle Miocene Yotsuyaku and Keiseitoge formations and represents the incipient stage of Neogene back-arc sedimentation that extends toward the north and northwest. Megaclast breccias derived from Mesozoic basement rocks of the Kitakami Massif were transported from southern areas as debris flows. The debris-flow deposits of the Yotsuyaku Formation grade northwards along the basin axis into clast-supported, braided-stream deposits, where floodplains developed. In the center of the basin voluminous volcanic eruptives of the Keiseitoge Formation were derived from eastern and southeastern volcanic ranges and formed transversal distributaries. The deposition of both clastic and pyroclastic sediments suggests that volcanism and tectonic uplift took place simultaneously during basin evolution. Parallel-laminated, fine-grained sediments intercalated with lignite beds suggest lacustrine deposition, and large cross-beds of volcanic breccias indicate Gilbert-type progradation into the lakes. A number of small lakes in the center of the basin was probably formed as the result of damming tributary mouths by the main drainage from eastern and southeastern volcanoes or the reciprocal blocking by lahars and non-volcanic debris flows derived from the southern uplift. Damming episodes produced by thick lava flows were not recognized in this study. The evolution of the N–S trending, longitudinal Ichinohe Basin indicates that E–W extensional tectonism related to the opening of the Sea of Japan affected not only the Green Tuff Region, to the west of the studied basin, but also even the Mesozoic basement during the Miocene. Although the mingling of volcanic and basement-derived deposits indicates the complexities of sedimentary facies and provenances, our view of the stratigraphic architecture has relevance to the interpretation of the evolution of other extensional basin systems.

Federal Report on Acid Rain Draws Criticism

Congress established a 10-year interagency research program in 1980 to examine the causes and effects of acid rain and recommend actions to limit or reduce its harmful effects. On September 17, the National Acid Precipitation Assessment Program (NAPAP) is scheduled to release its interim assessment. The impression that emerges from the summary is that there is not much to worry about. Acid rain has negligible or no effects on crops and forests, though tropospheric ozone may be a serious problem. Only a small number of lakes have been acidified, and no further significant acidification is likely in the northeast. No abrupt increase in damage to crops, forests, and lakes is likely at current emissions.