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An intercomparison study has been carried out on the analysis of inorganic nutrients at sea following the operation of two nutrient analysers simultaneously on the GO-SHIP A02 trans-Atlantic survey in May 2017. Both instruments were Skalar San ++ Continuous Flow Analyzers, one from the Marine Institute, Ireland and the other from Dalhousie University, Canada, each operated by their own laboratory analysts following GO-SHIP guidelines while adopting their existing laboratory methods. There was high comparability between the two data sets and vertical profiles of nutrients also compared well with those collected in 1997 along the same A02 transect by the World Ocean Circulation Experiment. The largest differences between data sets were observed in the low-nutrient surface waters and results highlight the value of using three reference materials (low, middle and high concentration) to cover the full range of expected nutrients and identify bias and non-linearity in the calibrations. The intercomparison also raised some interesting questions on the comparison of nutrients analysed by different systems and a number of recommendations have been suggested that we feel will enhance the existing GO-SHIP guidelines to improve the comparability of global nutrient data sets. A key recommendation is for the specification of clearly defined data quality objectives for oceanic nutrient measurements and a flagging method for reported data that do not meet these criteria.The A02 nutrient data set is currently available at the National Oceanographic Data Centre of Ireland: https://doi.

During the months of May, June, July and August 2019 the Red Band Difference algorithm was tested over Irish waters to assess its suitability for the Irish harmful algal bloom alert system. Over the 4 weeks of June an extensive localised surface phytoplankton bloom formed in the Celtic Sea, south of Ireland. Satellite imagery from the Sentinel-3a’s Ocean and Land Colour Instrument, processed using the Red Band Difference algorithm detected the bloom in surface shelf waters and helped monitor its movement. Daily satellite images indicated that the bloom appeared at the sea surface on the 2nd June 2019 and peaked in size and surface abundance in offshore shelf waters within 4 weeks, remnants remained at the surface into July. A particle tracking approach was used to replicate oceanic circulation patterns in the vicinity of the observed algal bloom and estimate its trajectory. The initial horizontal distribution of particles in the tracking model were based on a satellite imagery polygon of the bloom when it first appeared in surface waters. Good agreement was observed between satellite imagery of the bloom and the particle tracking model. In situ sampling efforts from a research cruise and the national inshore phytoplankton monitoring programme confirmed that Karenia mikimotoi was the causative organism of the bloom. This pilot study shows great potential to use the Red Band Difference algorithm in the existing Irish harmful algal bloom alert system. In addition, satellite ocean colour data combined with particle tracking model estimates can be a useful tool to monitor high biomass harmful algal bloom forming species, such as Karenia mikimotoi, in surface coastal waters around Ireland and elsewhere.

Mr. REDMAN said, that a few facts had come to his knowledge since the Paper had been prepared. H e had referred to the modern buoyage of the Prince's Channel as being deeper than the Quecn's Channel to the south of it, to illustrate the changes in the Thames' estuary. From the most recent surveys of the sand-banks and channels, it appeared that other changes had lately occurred in the first-named channel. The west entrance, the Girdler Channel, had, two years back, been superseded by a channel more to the N.E. between the West Girdler and Shingles, called the Shingles Channel, up to the arrival of the Princess Alexandra, who passed through it, subsequently it was called the Alexandra Channel. Owing to the breaking away of the crest of the West Girder sand, the western outlet of the Prince's Channel, the Girdler Channel, was rapidly shoaling, and the Alexandra Channel had also lost depth, but at the east end of the Prince's Channel, bctween the Girdler and Long Sands, Bullock's Channel had broken through the sand separabing its deep-water head from the 'Black Deep,' and at that point it was now 20 feet.deeper than shown in the last-published charts. This channel, not yet buoyed, was 3 miles long, and 1 mile wide, and 40 feet to 50 feet deep, throughout. Should the west approaches to the Prince's Channel continue to shoal, the lights would in all probability be removed, and the Bullock Channel, leading into the ' Black Deeps ' of the South Channel, would be lighted and used instead. This channel would be wider and freer for navigation, but would be 16 mile longer. The Middle, and Overland Channels to the westward wcre also 226 THE EAST COAST. low water, with a channel on the north side 20 feet deep, and a channel 15 feet on the south side. At IIarwich the ' Beach End ' buoy, moored in 18 feet of water, laid in 1.842, was shifted each year, and last moored in February, 1863. He did not know the amount of movement each year, but it would in all probability closely coincide with the late Admiral Washington's estimate, of 12 yards per annum. By comparing the Admiralty surveys of 1842 with others of the present time, he found the S.W. progression in the last twenty years, was 200 yards, equal to 10 ynrds per annum. Respecting the engineering and commercial value of the question, he had prepared from Mr. Ingham's *shipping returns for the years 1856-1859 and 1862 (Appendix) the registered tonnage of the thirteen ports from Maldon to Boston, within the limits of coast described. It would be seen that the aggregate registered tonnage-nearly a stationary quantit,y for the last seven yearswas nearly 130,000 tons ; and the amount of exports and imports, coasting, colonial, and foreign, from the various ports along the coast reviewed, was nearly 14 million of tons ; the colonial (a small amount) nearly stationary ; the foreign slightly falling 0% and the coasting considerably so, for that, on the whole, there was a falling off due to the extension of railways and the diversion of the carrying trade to London. Still the amount ...