1. Abstract
This project had the primary aim of monitoring phytoplankton community dynamics in a
eutrophic inter-drumlin lake and its variance through a 6-month sampling period from
18/1/12 through to 18/7/12. Phytoplankton assemblages, and their changes, are very useful
in monitoring water quality in a wide range of habitats; aquatic, estuarine, marine and
wetland. These ecotones make up the vast majority of the earths surface (~70%, USGS,
1984) and are also critically important to terrestrial life that depend on these surface waters
as a water, food & recreational resource. The lake being studied is located in Co. Monaghan,
Republic of Ireland and has managed to maintain its almost eutrophic status despite efforts
by An Taisce’s (the National Trust for Ireland) ACP (Agricultural Catchments Program) to
rehabilitate the lake. This study monitors changes in phytoplankton assemblages (through
succession), extrapolates the changing growth conditions and examines the literature to
relate observed phytoplankton assemblage succession with lake health and trophic status
through the above-mentioned sampling period.
Phytoplankton assemblages were found to follow clear-cut and definite successional stages
in line with changing water quality parameters and were offered a considerable amount of
support by published authors to be indicative of a healthy lake bordering on the
mesotrophic/eutrophic border. Their sensitivities and efficacy as biological indicators of
ecological status for compliance with the Water Framework Directive (WFD; 2000/60/EC)
were explored and evaluated.