The potential of high-frequency profiling to assess vertical and seasonal patterns of phytoplankton dynamics in lakes: an extension of the Plankton Ecology Group (PEG) model

The seasonal and trend decomposition of a univariate time-series based on Loess (STL) has several advantages over traditional methods. It deals with any periodicity length, enables seasonality change over time, allows missing values, and is robust to outliers. However, it does not handle trading day variation by default. This study offers how to deal with this drawback. By applying multiple STL decompositions of 15-minute trading volume observations, three seasonal patterns were discovered: hourly, daily, and monthly. The research objective was not only to discover if multi-seasonality exists in trading volume by employing high-frequency data but also to determine which seasonal component is most time-varying, and which seasonal components are the strongest or weakest when comparing the variation in the magnitude between them. The results indicate that hourly seasonality is the strongest, while daily seasonality changes the most. A better understanding of trading volume multiple patterns can be very helpful in improving the performance of trading algorithms.

Download Full-text

Modelling sub-daily phytoplankton dynamics and analysing primary production controls in the lower Thames catchment, UK

10.5194/egusphere-egu2020-8010 ◽

2020 ◽

Author(s):

Devanshi Pathak ◽

Michael Hutchins ◽

François Edwards

Keyword(s):

Water Quality ◽

Primary Production ◽

Water Temperature ◽

High Frequency ◽

Phytoplankton Growth ◽

Quality Data ◽

Phytoplankton Dynamics ◽

Water Quality Data ◽

River Thames ◽

The Impact

<p>River phytoplankton provide food for primary consumers, and are a major source of oxygen in many rivers. However, high phytoplankton concentrations can hamper river water quality and ecosystem functioning, making it crucial to predict and prevent harmful phytoplankton growth in rivers. In this study, we modify an existing mechanistic water quality model to simulate sub-daily changes in water quality, and present its application in the River Thames catchment. So far, the modelling studies in the River Thames have focused on daily to weekly time-steps, and have shown limited predictive ability in modelling phytoplankton concentrations. With the availability of high-frequency water quality data, modelling tools can be improved to better understand process interactions for phytoplankton growth in dynamic rivers. The modified model in this study uses high-frequency water quality data along a 62 km stretch in the lower Thames to simulate river flows, water temperature, nutrients, and phytoplankton concentrations at sub-daily time-steps for 2013-14. Model performance is judged by percentage error in mean and Nash-Sutcliffe Efficiency (NSE) statistics. The model satisfactorily simulates the observed diurnal variability and transport of phytoplankton concentrations within the river stretch, with NSE values greater than 0.7 at all calibration sites. Phytoplankton blooms develop within an optimum range of flows (16-81 m<sup>3</sup>/s) and temperature (11-18&#176; C), and are largely influenced by phytoplankton growth and death rate parameters. We find that phytoplankton growth in the lower Thames is mainly limited by physical controls such as residence time, light, and water temperature, and show some nutrient limitation arising from phosphorus depletion in summer. The model is tested under different future scenarios to evaluate the impact of changes in climate and management conditions on primary production and its controls. Our findings provide support for the argument that the sub-daily modelling of phytoplankton is a step forward in better prediction and management of phytoplankton dynamics in river systems.</p>

Download Full-text

High-frequency monitoring of phytoplankton dynamics within the European water framework directive: application to metalimnetic cyanobacteria

Biogeochemistry ◽

10.1007/s10533-010-9446-1 ◽

2010 ◽

Vol 106 (2) ◽

pp. 229-242 ◽

Cited By ~ 11

Author(s):

B. Le Vu ◽

Brigitte Vinçon-Leite ◽

B. J. Lemaire ◽

N. Bensoussan ◽

M. Calzas ◽

...

Keyword(s):

Water Framework Directive ◽

High Frequency ◽

European Water Framework Directive ◽

Phytoplankton Dynamics ◽

European Water ◽

Frequency Monitoring

Download Full-text

High-frequency measurements of gas ebullition in a Brazilian subtropical reservoir—identification of relevant triggers and seasonal patterns

Environmental Monitoring and Assessment ◽

10.1007/s10661-019-7498-9 ◽

2019 ◽

Vol 191 (6) ◽

Cited By ~ 3

Author(s):

Lediane Marcon ◽

Tobias Bleninger ◽

Michael Männich ◽

Stephan Hilgert

Keyword(s):

High Frequency ◽

Seasonal Patterns ◽

Frequency Measurements ◽

Reservoir Identification ◽

Gas Ebullition

Download Full-text

HELMINTHS OF MICROTINAE IN WESTERN MONTANA

Canadian Journal of Zoology ◽

10.1139/z67-038 ◽

1967 ◽

Vol 45 (3) ◽

pp. 269-274 ◽

Cited By ~ 7

Author(s):

John M. Kinsella

Keyword(s):

High Frequency ◽

New Records ◽

First Record ◽

Microtus Pennsylvanicus ◽

Western Montana ◽

Seasonal Patterns ◽

Mixed Infections ◽

Microtus Montanus ◽

Phenacomys Intermedius ◽

Aspiculuris Tetraptera

Seventeen species of helminths were found in 134 voles of 5 species (Phenacomys intermedius, Clethrionomys gapperi, Microtus longicaudus, Microtus montanus, Microtus pennsylvanicus) collected in 1964 and 1965 in western Montana. Ten new records for North America and 26 new records for Montana were recorded. Seasonal patterns of infection were noted in Quinqueserialis quinqueserialis and Paranoplocephala infrequens. The taxonomy of the nematode Heligmosomum dubius (Baylis, 1926) Tenora, 1958 was discussed. The first record of Aspiculuris tetraptera in. microitne rodents and the second record of Pelodera sp. in the orbits of North American rodents were reported. A high frequency of mixed infections of the digestive tract was found, usually accompanied by a pronounced stratification of the helminths within the tract.

Download Full-text