Resolving the links between nutrient and carbon budgets in the Burrishoole
catchment

As with many oligotrophic catchments nutrient cycling has not been a primary focus within the
Burrishoole monitoring programme to date. This work package will address this major gap by
quantifying macro-nutrient concentrations through monitoring of major nutrient fractions such
as total phosphorus (TP, unfiltered), dissolved reactive phosphorus (SRP), total dissolved
phosphorus (TDP), total nitrogen (TN, unfiltered), dissolved inorganic nitrogen (DIN),
dissolved silicate-Si and DOC. It will utililise the laboratory facilities at the CFES in DkIT and
will deploy three new dissolved nitrogen sensors at the two main inflows and in Lough Feeagh.
Phosphate sensor systems are not yet commercially available at a low enough limit of

Marine Research Programme 2014-2020 Application Form (Project-Based Awards)
detection for oligotrophic systems. However, this work package will also work with DCU
partners to deploy and test a new phosphate sensor that has been developed by their group.
In addition, other HFM data will be used using both the existing technologies deployed in the
Burrishoole catchment in addition to new emerging technologies as outlined in WP3 and WP4.
This WP will also support the activities of WP3 by carrying out profile sampling to support
Remote Sensing activities. Activities in this work package will be overseen by Dr Valerie
McCarthy (DkIT). In addition to informing on the nutrient loading and cycling, this work
package aims to establish the relative importance of seasonal allochthonus versus
autochthonous contributions to ecosystem production using stable isotope analysis (C and N),
building on preliminary work that has been recently undertaken by Dr Elvira de Eyto (MI), and
by Dr Liz Ryder (Ryder et al. 2014). Humic systems such as Burrishoole tend to be
characterised by high allochthonous (terrestrial) C sources, leading to low light conditions and
the promotion of high bacterial production at the expense of phytoplankton production, this
has potential implications for food quality for higher trophic levels. In order to provide a
reliable evaluation of potential effects on food web structure and ecosystem productivity the
partitioning of carbon and other nutrients between different trophic compartments will be
measured on a monthly basis and related to light and the availability of dissolved nutrients.
Finally these data will be used to determine basel and secondary production.