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MANTEL Project 4

Aquatic microbial community responses to episodic events in Atlantic humic catchments

Alexa Hoke
Host Institute: Dundalk Institute of Technology, Ireland
Project Overview

Peatland (humic) catchments are characteristic of the North-eastern Atlantic fringe of Europe. These aquatic ecosystems are sustained by carbon inputs from terrestrial sources and therefore microbial heterotrophy plays an important role in controlling lake productivity. Many such lakes are also sources of potable water, and are key habitats for salmonid fish. In Europe, much of our current understanding of carbocentric limnology comes from humic systems in Nordic countries where year round monitoring is limited by winter ice. In contrast, little is known about more temperate systems, where warmer winter temperatures and a lack of ice may have surprising implications for biogeochemical processes such as annual greenhouse gas fluxes.


Our ability to assess climate change consequences is still limited by a fundamental lack of knowledge about the diversity and abundance of microbial communities, and the role that episodic events have in controlling community dynamics. Development and testing of specific hypotheses for this ESR will be carried out at LakeLab, while they will also benefit from a focussed fieldwork program based in the Burrishoole catchment (IE) which is situated at the western extreme of Europe. Proximity to the Atlantic means that lakes here track oceanic teleconnections and are subject to frequent storms with wind mixing and heavy precipitation.  The use of this site enables the real-world testing of hypotheses developed using mesocosms, and the scaling up of conclusions to a catchment and ecoregion level.


The overarching objective of this project is to obtain new insights into the role that aquatic microbial communities play in processing autochthonous and allochthonous carbon sources in a western humic catchment. Specific objectives include

  1. To explore changes in the lake microbial community following inflows od carbon; and

  2. How disruption of these communities following climatic episodic events.

The ESR for Project 4 will be primarily based in Dundalk Institute of Technology supervised by Dr Eleanor Jennings, and co-supervised by and spend study time with Prof. Hans Peter Grossart, IGB Berlin, Germany. The ESR will also spend study time with Dr Elvira de Eyto, Marine Institute, Ireland.


Alexa Hoke, Jason Woodhouse, Luca Zoccarato, Valerie McCarthy, Elvira de Eyto, Maria Calderó-Pascual, Ewan Geffroy, Mary Dillane, Hans-Peter Grossart, Eleanor Jennings (2020) Impacts of Extreme Weather Events on Bacterial Community Composition of a Temperate Humic Lake. Water, 12(10): 2757. DOI: 10.3390/w12102757

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