scholarly journals Effects of long-term non-point eutrophication on the abundance and biomass of macrozoobenthos in small lakes of Estonia

2006 ◽  
Vol 55 (3) ◽  
pp. 187
Author(s):  
T Möls ◽  
H Timm ◽  
T Timm
Keyword(s):  
Small Lakes

scholarly journals Evaluation of historic and operational satellite radar altimetry missions for constructing consistent long-term lake water level records

2021 ◽  
Vol 25 (3) ◽  
pp. 1643-1670
Author(s):  
Song Shu ◽  
Hongxing Liu ◽  
Richard A. Beck ◽  
Frédéric Frappart ◽  
Johanna Korhonen ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Small Lakes ◽  
Radar Altimetry ◽  
Lake Water Level ◽  
Systematic Biases ◽  
Data Missing ◽  
Satellite Radar ◽  
Satellite Radar Altimetry

Abstract. A total of 13 satellite missions have been launched since 1985, with different types of radar altimeters on board. This study intends to make a comprehensive evaluation of historic and currently operational satellite radar altimetry missions for lake water level retrieval over the same set of lakes and to develop a strategy for constructing consistent long-term water level records for inland lakes at global scale. The lake water level estimates produced by different retracking algorithms (retrackers) of the satellite missions were compared with the gauge measurements over 12 lakes in four countries. The performance of each retracker was assessed in terms of the data missing rate, the correlation coefficient r, the bias, and the root mean square error (RMSE) between the altimetry-derived lake water level estimates and the concurrent gauge measurements. The results show that the model-free retrackers (e.g., OCOG/Ice-1/Ice) outperform the model-based retrackers for most of the missions, particularly over small lakes. Among the satellite altimetry missions, Sentinel-3 gave the best results, followed by SARAL. ENVISAT has slightly better lake water level estimates than Jason-1 and Jason-2, but its data missing rate is higher. For small lakes, ERS-1 and ERS-2 missions provided more accurate lake water level estimates than the TOPEX/Poseidon mission. In contrast, for large lakes, TOPEX/Poseidon is a better option due to its lower data missing rate and shorter repeat cycle. GeoSat and GeoSat Follow-On (GFO) both have an extremely high data missing rate of lake water level estimates. Although several contemporary radar altimetry missions provide more accurate lake level estimates than GFO, GeoSat was the sole radar altimetry mission, between 1985 and 1990, that provided the lake water level estimates. With a full consideration of the performance and the operational duration, the best strategy for constructing long-term lake water level records should be a two-step bias correction and normalization procedure. In the first step, use Jason-2 as the initial reference to estimate the systematic biases with TOPEX/Poseidon, Jason-1, and Jason-3 and then normalize them to form a consistent TOPEX/Poseidon–Jason series. Then, use the TOPEX/Poseidon–Jason series as the reference to estimate and remove systematic biases with other radar altimetry missions to construct consistent long-term lake water level series for ungauged lakes.

scholarly journals Estimation of long-term Ph changes in lakes of the Caucasus using a bioindication method based on diatomaceous analysis

2019 ◽  
Vol 46 (1) ◽  
pp. 51-57 ◽  
Author(s):  
L. V. Razumovskii ◽  
V. L. Razumovskii
Keyword(s):  
Sediment Cores ◽  
Western Caucasus ◽  
Small Lakes ◽  
The Caucasus ◽  
Ph Values ◽  
Long Term Changes ◽  
The Western Caucasus ◽  
Central Caucasus ◽  
Hydrological Parameter

To analyze processes that may lead to long-term changes in pH, lake sediments from five small lakes in the Western and Central Caucasus were studied according to diatomaceous complexes from sediment cores. A proprietary principle of hydrological parameter unification was used to reconstruct numerical pH values. In isotopic dating experiments, a series of numerical pH values for 2000–130 years were generated for the lakes. These data indicate an absence of noticeable changes in pH in the lakes of the Western Caucasus and alkalization processes in the lakes of the Central Caucasus.

Long-term effects of climate change on carbon flows through benthic secondary production in small lakes

2018 ◽  
Vol 63 (6) ◽  
pp. 530-538 ◽  
Author(s):  
Simon Belle ◽  
Simona Musazzi ◽  
Ilmar Tõnno ◽  
Anneli Poska ◽  
Bérangère Leys ◽  
...  
Keyword(s):  
Climate Change ◽  
Secondary Production ◽  
Long Term Effects ◽  
Small Lakes ◽  
Benthic Secondary Production

Variable preservation of tephra from the 1991 eruption of Volcán Hudson in small lakes: implications for reconstructing past eruption parameters

2021 ◽  
Author(s):  
Richard Streeter ◽  
Nick Cutler ◽  
Ian Lawson
Keyword(s):  
Environmental Gradients ◽  
Small Lakes ◽  
Multiple Cores ◽  
Tephra Deposits ◽  
Tephra Layers ◽  
Tephra Thickness ◽  
Lake Catchment ◽  
Long Term Preservation ◽  
Degree Of Similarity

<p>Volcanic ash (tephra) deposits are used to reconstruct past eruption parameters. The ways in which tephra deposits are modified between deposition and their long-term preservation in the stratigraphic archive are poorly understood. In particular, we don’t know if tephra layers preserved in lake sediments from small lakes accurately reflect the initial tephra fallout. We address this by re-surveying tephra deposits from the 1991 eruption of Volcán Hudson, Chile. We measured tephra thickness, mass-loading and grain-size distribution of tephra from multiple cores in six small (<0.2 km<sup>2</sup>) lakes at locations 76-110 km from the volcano and in areas of contrasting land cover and climate. We also measured tephra preservation in terrestrial sites within each lake catchment. These data were compared with measurements taken shortly (days to weeks) after the eruption to determine how the tephra deposits have changed in the 29 years since the eruption. Preservation is variable within and between lakes, and also varies with the vegetation cover at terrestrial sites adjacent to the lakes. Tephra thicknesses are broadly comparable to the original fallout, but the degree of similarity varied notably and is sensitive to preservation environment. These findings have implications for reconstructing eruption parameters from tephra deposits in small lakes, and where the fallout area crosses large environmental gradients and contrasting vegetation regimes.</p>

Long-term assessment of the effect of introduced predatory fish on minnow diversity in a regional protected area

2012 ◽  
Vol 69 (11) ◽  
pp. 1798-1805 ◽  
Author(s):  
James K. Aiken ◽  
C. Scott Findlay ◽  
François Chapleau
Keyword(s):  
Species Richness ◽  
Protected Area ◽  
Negative Impact ◽  
Predatory Fish ◽  
Small Lakes ◽  
Total Species Richness ◽  
Total Species ◽  
Overlapping Sets ◽  
Fish Species Diversity

Introduced piscivorous fishes had a dramatic impact on small-bodied fish species diversity of small temperate lakes in Gatineau Park, Quebec, Canada, on the basis of three surveys carried out over a 38-year period from 1970 to 2007. For three overlapping sets of lakes based on different combinations of survey years (lakes surveyed in 1970–1971, 1991–1992, and 2006–2007 (N = 14); lakes surveyed in 1970–1971 and 2006–2007 (N = 21); and lakes surveyed in 1991–1992 and 2006–2007 (N = 16)), those with introduced piscivores showed substantial and consistent temporal declines in average minnow species richness but much weaker, if any, declines in total species richness. By contrast, lakes without introduced piscivores showed no such decline. Whereas lakes without piscivores showed a strong species–elevation relationship early in the record, the strength of this relationship was much lower in lakes with introduced piscivores. Moreover, the strength of the species–elevation relationship declined precipitously over time in lakes with introduced piscivores, but remained stable in lakes where introduced piscivores were absent. The negative impact of piscivore introductions on small-bodied fish biodiversity in small lakes underscores the importance of action to mitigate the risk of future introductions or invasions.

scholarly journals Evaluation of Historic and Operational Satellite Radar Altimetry Missions for Constructing Consistent Long-term Lake Water Level Records

2020 ◽  
Author(s):  
Song Shu ◽  
Hongxing Liu ◽  
Richard A. Beck ◽  
Frédéric Frappart ◽  
Johanna Korhonen ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Small Lakes ◽  
Radar Altimetry ◽  
Lake Water Level ◽  
Systematic Biases ◽  
Data Missing ◽  
Satellite Radar ◽  
Satellite Radar Altimetry

Abstract. Thirteen satellite missions have been launched since 1985, with different types of radar altimeters onboard. This study intends to make a comprehensive evaluation of historic and currently operational satellite radar altimetry missions for lake water level retrieval over the same set of lakes and to develop a strategy for constructing consistent long-term water level records for inland lakes at global scale. The lake water level estimates produced by different retracking algorithms (retrackers) of the satellite missions were compared with the gauge measurements over twelve lakes in four countries. The performance of each retracker was assessed in terms of the data missing rate, the correlation coefficient r, the bias, and the Root Mean Square Error (RMSE) between the altimetry-derived lake water level estimates and the concurrent gauge measurements. The results show that the model-free retrackers (e.g. OCOG/Ice-1/Ice) outperform the model-based retrackers for all missions, particularly over small lakes. Among the satellite altimetry missions, Sentinel-3 gave the best results, followed by SARAL. ENVISat has slightly better lake water level estimates than Jason-1 and -2, but its data missing rate is higher. For small lakes, ERS-1 and ERS-2 missions provided more accurate lake water level estimates than Topex/Poseidon mission. In contrast, for large lakes Topex/Poseidon is a better option due to its lower data missing rate and shorter repeat cycle. GeoSat and GeoSat Follow-On (GFO) both have extremely high data missing rate. Although several contemporary radar altimetry missions provide more accurate lake level estimates than GFO, GeoSat was the sole radar altimetry mission between 1985 and 1990 that provided the lake water level estimates. With a full consideration of the performance and the operational duration, the best strategy for constructing long-term lake water level records should be a two-step bias correction and normalization procedure. In the first step, use Jason-2 as the initial reference to estimate the systematic biases with Topex/Poseidon, Jason-1 and Jason-3 and then normalize them to form a consistent Topex/Poseidon-Jason series. Then, use Topex/Poseidon-Jason series as the reference to estimate and remove systematic biases with other radar altimetry missions to construct consistent long-term lake water level series for ungauged lakes.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

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