A high spatial dataset was produced using a new continuous flow nutrient analyser on a recent RV Investigator voyage. The primary voyage objective was to characterize the sources and biogeochemical cycling of iron and associated nutrients and their impact on productivity along the eastern coast of Tasmania. Inorganic nutrients form the basis of the marine food web, providing a vital source of nutrient for algae and cyanobacteria, however the ability to quantify nutrient availability at a fine scale is not well observed or understood. Typical nutrient analysis is spatially and temporally limited due to discrete sample collection, with water column samples collected from a CTD rosette aboard a vessel. The recent voyage used a continuous flow analyser to measure surface water phosphate and nitrate + nitrite (NO_x) concentrations continuously. The instrument was connected to the underway seawater inlet 7 meters below the surface and operated for periods up to 24 hours. This allowed the collection of 7000 nutrient measurements over a 28 day voyage, with each data point representing a 90 second measurement window. Accuracy was gauged using a certified reference material, accuracy was within 1% error of the certified value. Reproducibility of measurements was also very good, with a typical relative standard deviation of XX%. Discrete grab samples were also taken and analysed aboard the ship to confirm results produced by the instrument analysing the water underway.

Further implementation of the instrument on small coastal vessels allows the collection of high resolution (100m gridding) datasets. The resolution of these datasets is paramount in producing quality biogeochemical models that influence placement of marine infrastructure such as aquaculture pens.