Diffuse inputs of nutrients to Dublin Bay.

The River Liffey is the main source of diffuse nutrients to Dublin Bay and accounts for some 85% of all riverine inputs. The total load from the various rivers has been calculated at some 6601 kg N d(1) and 748 kg P d(1), of which around 82% and 52% are in the form of DIN and phosphate respectively. Sewage discharge adds almost the same again to the load, with minor contributions from the sediments (which may simply be remineralising the particulates) and from nitrogen fixation. However, these inputs are very much less than those exchanged twice-daily by tidal action. These contributions are due to change very shortly with the advent of the new STW in Dublin, but the major change may be more in the speciation of the nutrients, and in particular the dissolved/particulate balance.