Marine environment measurement, methods

Eberlein and Kattner [194] described an automated method for the determination of orthophosphate and total dissolved phosphorus in the marine environment. Separate aliquots of filtered seawater samples were used for the determination orthophosphate and total dissolved phosphorus in the concentration range 0.01-5 xg/l phosphorus. The digestion mixture for total dissolved phosphorus consisted of sodium hydroxide (1.5 g), potassium peroxidisulfate (5 g) and boric acid (3 g) dissolved in doubly distilled water (100 ml). Seawater samples (50 ml) were mixed with the digestion reagent, heated under pressure at 115-120 °C for 2 h, cooled, and stored before determination in the autoanalyser system. For total phosphorus, extra ascorbic acid was added to the aerosol water of the autoanalyser manifold before the reagents used for the molybdenum blue reaction were added. For measurement of orthophosphate, a phosphate working reagent composed of sulfuric acid, ammonium molyb-... 

While a great many compounds that have been or might be found in the marine environments have been accused of chelation, this section deals only with the nonspecific measurements of chelation, with what has been called chelation capacity . In general, this capacity is measured by spiking the solution with a transition metal, preferably one that is easily measured, and then determining either how much is complexed or how much is left over. While the principle of all of the methods is the same, the details are different, and often quite ingenious. 

In this paper we review three types of field studies where the method is used to determine very different aspects of sulfur chemistry in the marine environment. These studies include i) the measurement of the intracellular thiol composition of marine phytoplankton in response to light ii) the reduced sulfur composition of anaerobic sediments and iii) the metabolism of potentially toxic hydrogen sulfide by sediment dwelling bivalve molluscs housing endosymbiotic sulfur oxidizing bacteria. 

R7. Regoli, F., and Winston, G. W., Applications of a new method for measuring the total oxyradical scavenging capacity in marine invertebrates. Marine Environ. Res. 46, 439-442 (1998). 

The activities of the Working Parties cover corrosion topics associated with inhibition, education, reinforcement in concrete, microbial effects, hot gases and combustion productions, environment sensitive fracture, marine environments, refineries, surface science, physico-chemical methods of measurement, the nuclear industry, the automotive industry, computer based information systems, coatings, tribo-corrosion and the oil and gas industry. Working Parties and Task Forces on other topics are established as required. 

As an alternative to partial assimilatory NOs reduction by phytoplankton, oxidation of NH4+ by Bacteria and Archaea (the first step in the 2-step process of nitrification) can produce N02 as an intermediate product. Nitrifying bacteria were first isolated from the marine environment by Watson (1965) and are now known to be ubiquitous in the global ocean. Wada and Hattori (1971) used a sensitive chemical assay to measure changes in N02 in incubated samples, to conclude that NH4+ was the major source of N02 in the PNM in the central North Pacific Ocean. Miyazaki et al. (1973, 1975), using a N tracer method, found that, in Sagami Bay and in the western North Pacific, NH4+ and NOs were both important sources ofN02. ... 

Arnosti C. (1996) A new method for measuring polysaccharide hydrolysis rates in marine environments. Org. Geochem. 25, 105-115. 

Alterations in trace metal concentrations in the marine environment due to man s activities are difficult to establish, since natural levels are often poorly known, or when known show variations. At present, measurement of concentration gradients (both vertical and horizontal) from known pollution sources is the primary method to assess trace metal contamination of the marine environment. High trace metal inputs into estuarine or coastal areas from industrial effluents as well as from river run-off have been measured. Without knowledge of the make-up of these source materials, distinguishing between a natural and an anthropogenic origin for increased metal concentrations is an insoluble problem. 

Since we may logically expect to find any organic compound known to exist in marine life released into the water by various mechanisms (Gagosian and Lee, Chapter 5), our efforts should be directed to the analysis of those compounds whose functions are well defined. Carbohydrates for example are being produced in the marine environment in significant amounts yet the analysis of constituent saccharides has attracted little attention in the past and measurements of total carbohydrate, by often unspecific methods, have been favoured. 

Dynamic loading problems in the offshore environment depend on either estimated or measured values of shear modulus. In practice, in situ determination of shear wave velocity on land has been used as the best approximation to the actual values for laboratory tests on samples (Richart, 1975). The techniques for using these seismic methods and data acquisition techniques to determine shear wave velocity for land-based applications have been well developed. The problem in the marine environment has been to develop methods to determine in situ shear wave velocity measurements both at the seabed surface and at known depths in the sediment column, which can be determined in a cost-effective manner. 

This test method establishes the procedures, equipment, materials, and conditions to measure the degree and rate of biodegradation of plastic materials under aerobic mesophilic marine water conditions. This test method is designed to produce repeatable and reproducible test results under controlled test conditions that simulate the marine environment. 

A standard for measurement of true biodegradation was published afterwards ASTM D6691-09 - Standard test method for determining aerobic biodegradation of plastic materials in the marine environment by a defined microbial consortium or natural seawater inoculum. 

Another ASTM method, ASTM D6691-01 [71] is determining the aerobic biodegradation of plastic materials in the marine environment by a defined microbial consortium. The latest development at ASTM is the inclusion of a marine variant in a new revision of the Sturm test, ASTM D5209 [10]. Yet, this project is still in development. As it looks now, it would be the first norm that determines the biodegradation of plastics under marine conditions by measuring directly the mineralisation and not a secondary parameter. 

Cl in conjunction with a direct exposure probe is known as desorption chemical ionization (DCI). [30,89,90] In DCI, the analyte is applied from solution or suspension to the outside of a thin resistively heated wire loop or coil. Then, the analyte is directly exposed to the reagent gas plasma while being rapidly heated at rates of several hundred °C s and to temperatures up to about 1500 °C (Chap. 5.3.2 and Fig. 5.16). The actual shape of the wire, the method how exactly the sample is applied to it, and the heating rate are of importance for the analytical result. [91,92] The rapid heating of the sample plays an important role in promoting molecular species rather than pyrolysis products. [93] A laser can be used to effect extremely fast evaporation from the probe prior to CL [94] In case of nonavailability of a dedicated DCI probe, a field emitter on a field desorption probe (Chap. 8) might serve as a replacement. [30,95] Different from desorption electron ionization (DEI), DCI plays an important role. [92] DCI can be employed to detect arsenic compounds present in the marine and terrestrial environment [96], to determine the sequence distribution of P-hydroxyalkanoate units in bacterial copolyesters [97], to identify additives in polymer extracts [98] and more. [99] Provided appropriate experimental setup, high resolution and accurate mass measurements can also be achieved in DCI mode. [100]... 

Table 15.5 lists concentrations of the major photooxidants in surface waters, diurnally averaged over 24 hours. Note that, even if kox(i) values are measured or estimated accurately (within a factor two or three), oxidant concentrations in the environment vary widely, and averaged values have a variance of five- to tenfold for any given location. In extreme locations, such as pristine marine waters, or heavily polluted surface waters, oxidant concentrations may be 100 times smaller or larger than the values Table 15.5 lists. Table 15.6 lists rate constants (kox) for various photooxidants in their reaction with major classes of organic compounds. To estimate the rate of an indirect photoreaction for chemical C (Equation (18)), either a measured or estimated value of kox is required, specific for each oxidant and for each class of organic compounds. Methods for estimating kox from molecular structure with structure-activity relationships (SARs) have been developed for many photooxidants and are discussed below. 

U.S. Environment Protection Agency (2002) Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition, EPA-821-R-02-012. 

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