Effect of carbon addition on trophic interactions

I have tested how a three week continuous addition of dissolved organic carbon (sugar cane) at low concentration (1 mg/L) may affect the food web and nutrient (N, P) cycling in a small first order stream in the Scottish highlands. This work is in collaboratrion with Nikolai Friberg (NIVA, Norway), Barry Thornton (The James Hutton Institute), Joanna Kemp (SEPA, Scotland) and Baptiste Marteau (University of Aberdeen, Scotland). I have been able to trace the added carbon through the food web and estimate macroinvertebrate carbon retention using a before and after control impact experimental design.


Trophic transfer efficiency

I have tested the effect of temperature on the trophic transfer efficiency of energy and carbon from light availability to gross primary production, invertebrate secondary production and trout top predator production, using the model ecosystem of Hengill, Iceland. The analysis was based on hard won data by collaborators and is now published as part of a study investigating trout production along the natural thermal gradient encountered in Hengill (4-25°C) - see O'Gorman et al 2016.


Effects of temperature and trophic cascade on ecosystem photosynthesis

I am testing the relative effect of temperature (5-50°C) and trophic cascade (presence-absence of fish) on gross primary productivity in four Icelandic geothermal areas in collaboration with Gisli Gislason (University of Iceland), Jon Olafsson (Fisheries Research Institute, Iceland), Russ Manson (Stockton University, USA), Nikolai Friberg (NIVA, Norway), Eoin O'Gorman (Imperial College London, England), Jim Hood (Montana University) and Thomas Freitag (The James Hutton Institute).