MANTEL Project 1

Timescales of Physical Change in the Lake Environment

Harriet Wilson
Dundalk Institute of Technology, Ireland
Project Overview

Water  column  stratification  patterns  in  lakes  fundamentally  affect  how  lakes  function.  Traditional lake monitoring typically occurs at weekly or lower frequency, and patterns of stratification and mixing when viewed through this low frequency filter appear to show gradual seasonal change. We believe that these patterns are strongly influenced by short-lived episodic events that occur over short time intervals, but have much longer lasting effects. These two types  of change, gradual vs. episodic, can lead to very different levels of environmental stability while in the end accounting for similar seasonal patterns of thermal structure.

 

The overall aim of Project 1 was to test the hypothesis that changes in lake thermal structure are strongly affected by short- lived events and to assess indexes of environmental change and stability based on differences in water temperature (density). This PhD will also identify the time scales that must be considered in modelling episodic events in lakes (WP 3). The specific Project 1 objectives were to:

  • Analyse high frequency lake water temperature records to define the distribution of stratification events by both magnitude and duration. Thresholds derived from these distributions will be used to define periods of mixing and stratification.

  • Analyse return period of events of different magnitude, and the duration of relatively calm periods between mixing.

  • Examine seasonal variation in lake thermal structure accounting for episodic changes and how these patterns and the role of episodic events vary between lakes with different climate and morphometry.

Harriet Wilson is the ESR for Project 1. Harriet is primarily based in Dundalk Institute of Technology supervised by Prof.  Eleanor Jennings, and co-supervised by Prof. Hans Peter Grossart, IGB Berlin, Germany and Dr Ian Jones, University of Stirling, UK. The PhD will be co-awarded by Dublin City University and University of Potsdam.

Publications:

Harriet L. Wilson, Ana I. Ayala, Ian D. Jones, Alec Rolston, Don Pierson, Elvira de Eyto, Hans-Peter Grossart, Marie-Elodie Perga, R. Iestyn Woolway, Eleanor Jennings (2020) Variability in epilimnion depth estimations in lakes. Hydrology and Earth System Sciences, 24: 5559–5577. DOI: 10.5194/hess-24-5559-2020