scholarly journals Relationship between bream (Abramis brama) activity and water turbidity in a shallow lake under different season conditions

2019 ◽  
Vol 78 (2) ◽  
Author(s):  
Joan H. Hansen ◽  
Jakob Brodersen ◽  
Henrik Baktoft ◽  
Christian Skov
Keyword(s):  
Shallow Lakes ◽  
Activity Patterns ◽  
Winter Season ◽  
Antenna System ◽  
Ecosystem Dynamics ◽  
Natural Conditions ◽  
Benthivorous Fish ◽  
Water Turbidity ◽  
Lake Ecosystems ◽  
Turbid State

The foraging activity of large-bodied benthivorous fish has been suggested to be of key importance for maintaining shallow lakes in a turbid state. Since especially the spring ecosystem dynamics determines the successive state of shallow lakes, such impact could depend on seasonality in benthivore activity patterns. However, we do not yet know to what extent the activity of large-bodied benthivorous fish affects lake turbidity across the year. In order to investigate seasonal dynamics in bream activity and its impact on water turbidity under natural conditions, bream daily activity was studied in a small (39 ha) shallow Danish lake using passive biotelemetry technology, i.e. a modified Passive Integrated Transponder (PIT)-tag antenna system. We tracked the activity of 448 benthivorous bream over a period of four years (2012 to 2016) and during the same period wind conditions, water turbidity and temperature was measured. Results showed a clear relationship between bream activity and water turbidity at water temperature below 15°C indicating that winter season activity of benthivorous bream may play an important role for maintaining lake ecosystems in a turbid state. Also wind speed and wind direction affected water turbidity, suggesting that wind induced resuspension can be important even in small shallow lakes. This is to our knowledge the first full-scale study under natural conditions to describe how bream activity influence lake turbidity on a day-to-day basis. Our findings also add a seasonal component to previous findings by showing that benthivorous feeding bream have the potential to increase water turbidity also in the winter season and thereby, ultimately, impact ecosystem functioning within shallow lakes.

scholarly journals Seasonal activity pattern of Swamp deer (Rucervus duvaucelii duvaucelii) in Dudhwa National Park, Uttar Pradesh, India

2014 ◽  
Vol 6 (1) ◽  
pp. 246-253 ◽  
Author(s):  
Kaleem Ahmed ◽  
Jamal A. Khan
Keyword(s):  
Activity Pattern ◽  
National Park ◽  
Time Budget ◽  
Activity Patterns ◽  
Winter Season ◽  
Uttar Pradesh ◽  
Seasonal Activity ◽  
Adult Males ◽  
Continuous Feeding ◽  
Swamp Deer

The data on activity pattern and time budget of Swamp deer (Rucervus duvauceli duvauceli) were collected through instantaneous scan sampling from Dudhwa National Park, Uttar Pradesh, India Diurnal activity pattern of Swamp deer showed marked reduction in resting in winter as compared to summer. In winter resting in adult males showed polymodal pattern with peaks occurring at different hours of the day and continued throughout the day without any break. Feeding of adult females in winter and summer seasons showed a polymodal pattern with peaks occurring at different hours of the day without break. In yearling males feeding and resting was observed to occur throughout the day during winter season with peaks occurring between 11:00 to 12:00 hours. Yearling females showed continuous feeding throughout the day with peaks in different times in both the seasons. The seasonal distribution of activity patterns of the fawns showed that feeding was slightly more in summer as compared to winter. In time budget, of the expenditure on different activities, resting accounted for 63.77% and feeding 24.70%. In both the seasons resting was the major portion of their activity. Analysis showed that in all age and sex categories of Swamp deer in the Dudhwa NP, resting dominated on all other activities. The observation on endangered Swamp deer indicates synchronization in activity only in the feeding in the morning and evening hours and resting throughout the day.

scholarly journals Comparison of Community and Function of Dissimilatory Nitrate Reduction to Ammonium (DNRA) Bacteria in Chinese Shallow Lakes with Different Eutrophication Degrees

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 174 ◽  
Author(s):  
Xiaowen Li ◽  
Chunlei Song ◽  
Zijun Zhou ◽  
Jian Xiao ◽  
Siyang Wang ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Shallow Lakes ◽  
Nitrate Reduction ◽  
Bacterial Community Structure ◽  
Physical Parameters ◽  
Lake Chaohu ◽  
Lake Ecosystems ◽  
Dissimilatory Nitrate Reduction ◽  
Significant Difference

Dissimilatory nitrate reduction to ammonium (DNRA) plays an important role in controlling nitrogen (N) loading in lake ecosystems. However, studies on the linkage between DNRA bacterial community structure and lake eutrophication remain unclear. We examined the community and abundance of DNRA bacteria at six basins of four shallow lakes with different degrees of eutrophication in China. Measurements of the different forms of N and phosphorus (P) in the water column and interstitial water as well as total organic carbon (TOC) and sulfide in the sediments in summer (July 2016) were performed. The nutritional status of Lake Chaohu was more serious than that of the lakes in Wuhan, including Lake Qingling, Lake Houguan, and Lake Zhiyin by comparing geochemical and physical parameters. We found a higher abundance of the nrfA gene, which is a function gene of DNRA bacteria in sediments with higher contents of TOC and sulfide. Moreover, nitrate was a significant factor influencing the DNRA bacterial community structure. A significant difference of the DNRA bacterial community structure between Lake Chaohu and the lakes in Wuhan was discovered. Furthermore, DNRA bacterial abundance and community positively correlated with NH4+ and Chl a concentrations in Lake Chaohu, in which a percent abundance of dominant populations varied along eutrophication gradients. Overall, the abundance and community structure of the DNRA bacteria might be important regulators of eutrophication and cyanobacteria bloom in Lake Chaohu.

scholarly journals Reproductive and Environmental Drivers of Time and Activity Budgets of Striped Skunks

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
V Y Zhang ◽  
C T Williams ◽  
T C Theimer ◽  
C Loren Buck
Keyword(s):  
Activity Patterns ◽  
Winter Season ◽  
Late Summer ◽  
Weather Conditions ◽  
Environmental Drivers ◽  
Activity Levels ◽  
Lactation Period ◽  
Investment In Reproduction ◽  
Mating Interval ◽  
Striped Skunks

Synopsis The regulation of daily and circannual activity patterns is an important mechanism by which animals may balance energetic requirements associated with both abiotic and biotic variables. Using collar-mounted accelerometers, we assess the relative importance of reproductive stage and environmental conditions on the overall dynamic body acceleration (ODBA) of free-living striped skunks (Mephitis mephitis). We found that activity timing relative to photoperiod varied across seasonal stages for both sexes. Surprisingly, male skunks did not commence activity earlier than females during the mating interval. Moreover, while female skunks began activity before dusk and terminated activity after dawn during mid- through late summer (lactation period), the duration of activity bouts in females during this period was not different from other seasons. Both male and female skunks exhibited high variability and fragmentation in daily activity rhythms except during the lactation period, when females appear to switch to prolonged bouts of nocturnal activity. Overall, ODBA varied by season and sex, with changes in ODBA indicative of seasonal reproductive requirements such as conspecific competition for mates in males and lactation in females. Weather conditions had little effect on skunk activity levels except during the winter season, when snow cover and temperature negatively influenced daily ODBA. Taken together, the activity patterns of striped skunks appear to be primarily driven by seasonal investment in reproduction and secondarily by thermoregulatory constraints during the non-winter months. Our results highlight the importance of considering how environmental and reproductive drivers may interact to affect activity across both the daily and seasonal cycle.

Intrinsic processes causing periodic changes in stability in a shallow biomanipulated lake

2011 ◽  
Vol 62 (2) ◽  
pp. 197 ◽  
Author(s):  
István Tátrai ◽  
Ágnes I. György ◽  
Kálmán Mátyás ◽  
János Korponai ◽  
Piroska Pomogyi ◽  
...  
Keyword(s):  
Food Web ◽  
Shallow Lakes ◽  
Nutrient Loading ◽  
Fish Biomass ◽  
Alternative States ◽  
Fish Manipulation ◽  
Water State ◽  
Benthic Fishes ◽  
Turbid State

Shallow lakes experience alternative states in their biotic organisation over time. In this study, we analysed a long-term dataset on the recovery from eutrophication of a shallow hypertrophic lake (Lake Major, Hungary) following fish manipulation. Disturbances in the food web triggered a shift, markedly affecting both abiotic and biotic variables. Clear and turbid states of Lake Major over the period 1999–2009 were defined by concentrations of chlorophyll-a. Lake Major in a clear-water state had higher transparency and submerged macrophyte cover, lower turbidity and fish biomass, and total phosphorus was relatively low compared to that shown during the turbid-water state. It follows from our study that a regime shift from a turbid state to a clear state can be expected in response to fish manipulation. Reduction in fish biomass increases light conditions, decreases internal nutrient loading and promotes macrophyte dispersion. Food-web effects appear to be considerable in these shallow lakes containing benthic fishes. The roles of phosphorus and submerged macrophytes are essential in maintenance of alternative states of vegetation in shallow lakes of various climatic zones.

Temperature Rising (Two Celsius) Effect on Planktonic Biomass in Subtropical Marshes, Iraq

2021 ◽  
Vol 5 (1) ◽  
pp. 44-52
Author(s):  
Mohammed Al-Haidarey
Keyword(s):  
Climate Change ◽  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Winter Season ◽  
Heating System ◽  
Early Spring ◽  
Natural Sediment ◽  
Lake Ecosystems

Planktonic species may respond to climate change through their niche across three axes which include self, space and time. This study was designed to investigate the effect of increasing winter temperature on the plankton biomass, the mesocosm was constructed as a collection of 16 enclosures with a water-outlet system and natural sediment, two aquatic plant species and heating system. This research was conducted over 12 weeks (beginning on Dec. 2018) when the temperature of eight enclosures was 2±0.2 °C higher than the ambient temperature. Weekly abiotic parameters (salinity, pH, PO4, NO3, DIC) and biotic (chlorophyll-a, zooplankton and phytoplankton biomass) were reported. The obtained results showed that there were no major improvements in salinity, pH, PO4, NO3 and dissolved inorganic carbon (DIC). Whereas, chlorophyll-a, zooplankton and phytoplankton biomass have dramatically improved. Therefore, this research has indicated that water temperature change during the winter season due to climate change could affect planktonic biomass and early spring in subtropical marshes, but this study was performed in the mesocosm experiment and it needs to be studied in large-scale natural lake ecosystems.

scholarly journals Multiple states in river and lake ecosystems

2002 ◽  
Vol 357 (1421) ◽  
pp. 635-645 ◽  
Author(s):  
C. Lisa Dent ◽  
Graeme S. Cumming ◽  
Stephen R. Carpenter
Keyword(s):  
Linear Models ◽  
Nonlinear Models ◽  
Explanatory Power ◽  
Current Theory ◽  
Ecosystem Dynamics ◽  
Physical Factors ◽  
Nonlinear Behaviour ◽  
Positive Feedbacks ◽  
Lake Ecosystems ◽  
Physical Forcing

Nonlinear models of ecosystem dynamics that incorporate positive feedbacks and multiple, internally reinforced states have considerable explanatory power. However, linear models may be adequate, particularly if ecosystem behaviour is primarily controlled by external processes. In lake ecosystems, internal (mainly biotic) processes are thought to have major impacts on system behaviour, whereas in rivers, external (mainly physical) factors have traditionally been emphasized. We consider the hypothesis that models that exhibit multiple states are useful for understanding the behaviour of lake ecosystems, but not as useful for understanding stream ecosystems. Some of the best–known examples of multiple states come from lake ecosystems. We review some of these examples, and we also describe examples of multiple states in rivers. We conclude that the hypothesis is an oversimplification; the importance of physical forcing in rivers does not eliminate the possibility of internal feedbacks that create multiple states, although in rivers these feedbacks are likely to include physical as well as biotic processes. Nonlinear behaviour in aquatic ecosystems may be more common than current theory indicates.

scholarly journals VIIRS-Derived Water Turbidity in the Great Lakes

2019 ◽  
Vol 11 (12) ◽  
pp. 1448 ◽  
Author(s):  
Son ◽  
Wang
Keyword(s):  
Great Lakes ◽  
Lake Erie ◽  
Lake Michigan ◽  
Seasonal Pattern ◽  
Ocean Color ◽  
Winter Season ◽  
Water Quality Monitoring ◽  
Temporal Variations ◽  
Water Turbidity ◽  
Satellite Ocean Color

Satellite ocean color products from the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) since 2012 and in situ water turbidity measurements from the U.S. Environmental Protection Agency’s Great Lakes Environmental Database System are used to develop a water turbidity algorithm for satellite ocean color applications in the Great Lakes for water quality monitoring and assessments. Results show that the proposed regional algorithm can provide reasonably accurate estimations of water turbidity from satellite observations in the Great Lakes. Therefore, VIIRS-derived water turbidity data are used to investigate spatial and temporal variations in water turbidity for the entirety of the Great Lakes. Water turbidity values are overall the highest in Lake Erie, moderate in Lake Ontario, and relatively low in lakes Superior, Michigan, and Huron. Significantly high values in water turbidity appear in the nearshore regions, particularly in Thunder Bay (Lake Superior), Green Bay (Lake Michigan), and Saginaw Bay (Lake Huron). Seasonal patterns of water turbidity are generally similar in lakes Superior, Michigan, Huron, and Ontario, showing relatively high values in the spring and autumn months and lows in the winter season, while the seasonal pattern in Lake Erie is apparently different from the other lakes, with the highest value in the winter season and the lowest in the summer season. A strong interannual variability in water turbidity is shown in the time series of the VIIRS-derived water turbidity data for most of the lakes.

The Ecological Significance of Activity Patterns in the Woodlouse Porcellio Scaber Latr. (Isopoda)

1962 ◽  
Vol 14 (3) ◽  
pp. 283-409 ◽  
Author(s):  
P.J. Den Boer
Keyword(s):  
Water Uptake ◽  
Activity Patterns ◽  
Great Majority ◽  
Compact Objects ◽  
The Body ◽  
Ecological Significance ◽  
Air Humidity ◽  
Natural Conditions ◽  
Porcellio Scaber ◽  
Mean Trend

AbstractFrom the literature it is known that woodlice are badly equipped for life on land, but because they can generally be found in dense populations they must be able to maintain life in land habitats. In 1952 it was found that in the dune area "Meijendel" near Den Haag woodlice show remarkable nocturnal activities, and it was supposed that these activities had something to do with their adjustment to the habitat. In 1953 an investigation into the ecological significance of activity patterns in the woodlouse Porcellio scaber Latr. was started in two aspen woods in "Meijendel". It was found that the amount of different forms of activity and the quantitative relations between these forms are correlated with air humidity. The duration of the individual periods of activity depends on air humidity and is for the great majority of active specimens about one hour. The activity patterns of P. scaber have a distinct effect on the distribution of the animals over a wood (day-habitat) and contribute to an effective dispersal of the species. The suitability of a day-habitat for P. scaber depends on its moistness, since it must essentially be considered a shelter against the relative dryness of the day-period. Generally the best shelters are offered by the loose bark of dead or dying trees and by compact objects lying flat on the ground. The observations made under natural conditions may be generally understood by the working hypothesis: "The activities of P. scaber are a means of losing by transpiration the excess of water which has accumulated in the bodies of the animals during a stay inside a very moist shelter". An experiment with artificial tree-shelters under natural conditions has yielded new data which confirm the hypothesis. With experiments in the laboratory it could be shown that specimens of P. scaber take up water from saturated or nearly-saturated air and that this results in an increasing preference for lower air humidities (for becoming active) and vice versa. Water-uptake occurs through the cuticle and the amount of water-uptake increases with temperature up to about 15-20° C. It is apparent that in saturated or nearly-saturated air, "normal" excretion cannot compensate for water-uptake, so that water is accumulated in the body. The activity patterns of P. scaber must be considered an active regulation of the water-balance, by which the animals move at intervals from a habitat with a very high air humidity (shelter) to a habitat with a lower air humidity (locality for adequate transpiration) and vice versa. It could be shown that at high humidities the animals have a greater tendency to move upwards. They then reach places where the evaporative power of the air is greater and transpiration of water is thus increased. The results from experiments in the laboratory on the effect of humidity or temperature on the amount of activity agree with corresponding findings under natural conditions. A number of unexpected results of these experiments demonstrate that the form and amount in which the activity patterns arise depend on the structure of the shelters and of the habitat in which the activities occur. Habitat-selection in P. scaber depends on the mean trend of temperature and humidity of the air during a number of years and on the presence and accessibility of suitable shelters and of localities where adequate transpiration is possible.

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