Figure 1: Lough Namachree, Co. Monaghan, Ireland
Agriculture in Ireland has adhered to strict regulations to improve the quality of surface waters since 2006, such as restrictions on application of fertiliser and slurry, both in timing and concentration. Have these regulations been successful in their objective?
To know if a water body has improved, particularly to reference conditions, the quality of the water body, prior to anthropogenic influences, needs to be ascertained. In recent years, palaeolimnology has been used to identify changes in land use and in diatom-inferred water quality. A core was taken from a small inter-drumlin lake in Co. Monaghan for analysis (Figure 1 and 2) to look for changes in diatom species and number which can provide an insight into significant changes in water quality due to the industrial revolution, the introduction of fertiliser and its subsequent restricted use, and fluctuations in market prices.
Figure 2: Retrieving the core using the Renburg corer
This study led by Barry O’Dwyer (Trinity College Dublin), identified that the possible causes of eutrophication in the catchment were due to soil erosion and an increase in fertiliser application. These are connected to an increase in farming intensity in the region. However, a decrease in the diatom-inferred total phosphorus concentrations detected in the core suggests that the transfer of sediment from the catchment has reduced thus indicating that agricultural restrictions are limiting nutrient transfer.
O’Dwyer, B., Crockford, L. Jordan, P. Hislop, L. and Taylor, D. (2013) A palaeolimnological investigation into nutrient impact and recovery in an agricultural catchment, Journal of Environmental Management,