Fundamental determinations of the physical properties of seawater have previously been made for Atlantic surface waters, referred to as ‘‘Standard Seawater’’. In this paper a Reference Composition consisting of the major components of Atlantic surface seawater is determined using these earlier analytical measurements.
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Standard seawater (SSW) has been employed by oceanographers as a reference material in the determination of salinity for over a century. In all that time, this is the first study to determine the uncertainty of the SSW manufacturing process.
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Salinity is one of the most measured parameters in oceanography. The importance of high quality salinity data has long been recognised in open ocean studies and more recently in coastal and estuarine processes. Many of the data are collected using in-situ instrumentation but the measurement of salinity in the laboratory also remains an important and widely used technique. This article describes the methodology used in the high precision, accurate measurement of Practical Salinity in the laboratory.
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There is an ever-growing demand for high-quality marine scientific data to contribute to global programmes. The need for harmonisation of those data is of paramount importance. An essential component of that harmonisation is the adoption of internationally agreed calibration standards and techniques for the instrumentation. This article explains the advantages and pitfalls in the calibrations of modern oceanographic instruments.

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The amount of data available from marine systems and programmes is growing. New information is gathered every day on environmental conditions, pollution and physical properties to name just a few. The demand for new real-time (NRT) data is increasing rapidly as a result of the need to see and to be able to act, on changes in conditions, within a short time frame. This need may be driven by legislation (to comply with regulations), safety, competitive advantage or for research.
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Increasing demands for high accuracy sound speed data has prompted the development of a next generation sound velocimeter, which overcomes some of the inherent problems associated with the sing-around technique in use since the early 1950's. The authors show short path length sing-around techniques cannot achieve accuracies better than 0.25 m/s due in part to phase errors introduced from multiple reflections and by thickness/radial mode ringing of the transducer element(s). Overall, accuracies reported thus far on the new velocimeter are better than 0.06 m/s r.m.s. with respect to Del Grosso and Mader's pure water equation. Comparisons between sound speed equations incorporating pressure and salinity terms show significant deviations in excess of the accuracy capabilities of the new technology. This accuracy level places considerable constraints on calibration technique and highlights the requirement for a universally accepted sound speed standard.
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The lower Neuse River estuary is a wind driven, highly productive system suffering from significant perturbation. Algal "blooms", suppressed dissolved oxygen, anoxia and consequent fish kills have plagued this reach of the Neuse for many years. North Carolina State University (NCSU) Center for Applied Aquatic Ecology (CAAE) researchers Dr. Robert Reed and David Toms, under the supervision of Dr. Howard Glasgow, have developed a real time remote monitoring (RTRM) program in the lower Neuse River estuary, that includes a network of autonomous and realtime data acquisition stations with surface to bottom sensor profiling. This program is collecting the data necessary to characterize physicochemical and biological response of the Neuse River in the presence of natural and anthropogenic phenomena.

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As terrestrial sources of oil diminish, the oil industry has moved its exploration further and further offshore in their quest for new fields. Whilst much has been learned over decades about sub-sea production from near-shore sites such as Gulf of Mexico, North Sea, Black Sea and Australia, new problems are being encountered as exploration moves further offshore. If the forecast holds true that known oil reserves will run out within 40 years, then exploitation of deep-sea methane hydrates may take the industry into waters over 4 kilometres deep. All this has resulted in a greater demand for oceanographers to help in overcoming a range of problems.
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As large-scale international projects (e.g., the World Ocean Circulation Experiment, Global Ocean Observing System, Joint Global Ocean Flux Study, Climate Variability and Predictability Study) occupy increasingly important roles in the production of oceanographic data, greater demands are made on the instrumentation used. However, the quality of those data depends on the calibration accuracy of the instruments and so increasing demands are also made on the standards and reference materials. This is particularly true of salinity data for which the need to define their accuracy is essential for an understanding of oceanic profiles.

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Mass balance equations have shown that the input of the major biologically active nutrients (nitrogen, phosphorous and silicon) to the ocean plays an important role in regulating global oceanic production.  Once in the marine system, nutrients are made available to biological organisms for primary production either through nutrient-rich water being drawn up from below, or by local regeneration resulting from cell breakdown. In surface waters of the open ocean, uptake of nutrients by organisms usually results in one or more of those nutrients becoming limiting to their growth (i.e. when the nutrient is used up, production ceases). However, coastal and estuarine waters are increasingly subject to anthropogenic input stress, whereby frequent input of nutrients as run-off from agricultural land results in artificially prolonged algal growth. In either case, the need for high-quality measurement of nutrients is driven by economic factors associated with climate change, depleted fisheries, eutrophication and aquatic ecosystems being out of balance.
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The growing interest in the development of accurate waste load and assimilative capacity models, as well as in models for determination of transport and fate of instantaneous pollutant discharges, has increased the need for the accurate characterization of water movement. In the United States programs such as National Pollutant Discharge Elimination System (NPDES) and Total Maximum Daily Loads have been a significant impetus behind this interest. Water tracing using dye fluorometry is the most common method by which data are collected for these purposes.
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