Production and environmental factors

Primary productivity in the sea is controlled by a number of intricate environmental factors. Temperature in general does not seem to be a major factor in controlling productivity. Rates comparable in magnitude have been obtained in widely differing latitudes. Data collected by Bunt and Lee (1970) from samples from Antarctic Sea ice, however, demonstrate limitation at extreme low temperatures. Photosynthesis in the upper layers of the sea is not necessarily limited by light. It is generally assumed that the photic zone extends to the depth at which the light intensity is reduced to 1% of the value at the surface, which level should not be taken too literally (Bunt, 19751. 

The supply of nutrients to the euphotic upper layer is entirely dependent upon instability of the water column, except where local direct outflows of nutrients from the land occur. Analysis of the world map of marine produc- 

De Vooys (1979) summarised the influences of environmental factors on the primary production in the world ocean as follows At lower latitudes, especially in subtropical regions, open ocean water contains little nitrogen and phosphorus and as a consequence these areas have a low primary production (about 30 g C m yr ). In anticyclones the water column has a great stability, an absence of silt and low amounts of algae and often no water transport, together determining primary production. 

In higher latitudes (40—60°) in winter, insolution is much lower, the water is often more turbid and turbulence carries the algae to depths 5- 10 times deeper than the euphotic zone. As a result primary production is almost completely arrested. When in spring stratification develops, a plankton bloom occurs, exhausting the nutrients in the euphotic zone within a few weeks this is followed by a period with a much lower primary productivity. When in autumn new mixing periods alternate with stable periods, a smaller secondary bloom occurs. In winter there is low primary production due to a much lower level of insolation. 

In turbid and eutrophicated coastal waters and estuaries solar radiation, and not nutrients, often limits production. Estuaries are continually replenished with nutrient enriched (river)water, and as a consequence (when light is not limiting) these waters often have a high primary productivity, which in low latitudes persists throughout the year (Fogg, 1975). 

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Becakos-Kontos, T. (1977) Primary Production and Environmental Factors in an Oligotrophic Biome in the Aegean Sea. Marine Biology, 42, 93-98. 

This area was parallel to the coastline, including the sea areas near the Shandong Peninsula, Jiangsu Province of China and western Korea. Although this area did not cover all the low belts of the six metals, it was the most concentrated low content area. The complicated distributions were the results of the coupling of anthropogenic production and environmental factors. 

Many risks people are subjected to can cause health problems or death. Precautions should be taken based on what is practical, logical, and useful. However, those involved in laws and regulations, as well as the public and, particularly, the news media, should recognize that there is Acceptable Risk. This is the concept that has developed in connection with toxic substances, food additives, air and water pollution, fire and related environmental concerns, and so on. It can be defined as a level of risk at which a seriously adverse result is highly unlikely to occur but it cannot be proven whether or not there is 100% safety. In these cases, it means living with the reasonable assurance of safety and acceptable uncertainty. This concept will always exist. Note the use of automobiles, aircrafts, boats, lawnmowers, food, medicine, water, and the air we breathe. Practically all elements around us encompass some level of uncertainty. Otherwise, life as we know it would not exist. Many products and environmental factors are not perfect and never will be perfect. 

Like its predecessor, the Leblanc process, the Solvay process is on the decline for economic reasons. Increasing costs of production and environmental factors are the key issues in the many closings of synthetic ash plants in the last several years. However, a complete worldwide takeover by natural ash is doubtful because of two factors (1) the limited amount of natural ash compared with the widespread availability of salt and limestone (the essential ingredients of the synthetic ash process) and (2) the locations of natural ash deposits relative to the locations of the ash consumers. Most of the U.S. natural ash is derived from the area of Green River, Wyoming. Significant amounts also are recovered from the alkaline brines of Searles Lake, California. 

Climate and Environmental Factors. The biomass species selected for energy appHcations and the climate must be compatible to faciUtate operation of fuel farms. The three primary climatic parameters that have the most influence on the productivity of an iadigenous or transplanted species are iasolation, rainfall, and temperature. Natural fluctuations ia these factors remove them from human control, but the information compiled over the years ia meteorological records and from agricultural practice suppHes a valuable data bank from which to develop biomass energy appHcations. Ambient carbon dioxide concentration and the availabiHty of nutrients are also important factors ia biomass production. 

Medium requirements and environmental factors involved in citric acid production... 

Designers of most structures specify material stresses and strains well within the pro-portional/elastic limit. Where required (with no or limited experience on a particular type product materialwise and/or process-wise) this practice builds in a margin of safety to accommodate the effects of improper material processing conditions and/or unforeseen loads and environmental factors. This practice also allows the designer to use design equations based on the assumptions of small deformation and purely elastic material behavior. Other properties derived from stress-strain data that are used include modulus of elasticity and tensile strength. 

Today it is estimated that some 90% of the chemicals used have, at some stage in their manufacture, come into contact with a catalyst. The range is truly broad from bulk chemicals such as acetic acid and ammonia to consumer products such as detergents and vitamins. Virtually all major bulk chemical and refining processes employ catalysts. The number of fine, speciality and pharmaceutical processes currently using catalysts is still relatively small by comparison, but a combination of economic and environmental factors is focusing much research on this area. The great... 

Mass indices and environmental factors (equations (5.1) and (5.2)) have been introduced in Section 5.1. For confidentiality reasons, neither chemical names nor exact quantities are specified concerning the industrial case studies. Instead, masses are expressed relatively to input amounts at the laboratory scale. The imit (kg kg ) expresses how many kilograms of substance are needed to produce one kilogram of product. Abbreviations used in captions of the figures are explained in Box 5.2. 

It should be realized that the use of L values from Table 9.1 must be taken as representative for a given material. The values can vary, not just due to the issues associated with the interpretation of experimental data, but also because the materials listed are commercial products and are subject to manufacturing and environmental factors such as purety, moisture, grain orientation, aging, etc. 

Ethylene glycol industry, 24 270 Ethylene glycol monobutyl ether, acrylamide solubility in, l 290t Ethylene glycol production, economic aspects of, 12 652-653 Ethylene glycols (EGs), 10 664-665 12 113, 644-660. See also Glycols derivatives of, 12 656-660 diethers of, 12 658 from ethylene oxide, 10 596 health, safety, and environmental factors related to, 12 653-655 manufacture of, 12 648-652 monoethers of, 12 656-658 properties of, 12 645-648, 649t uses for, 12 645, 655-656... 

A similar method proposed by Hoffmann [26] involves analyzing process alternatives based on two indices. The total armuabzed profit per service unit (TAPPS) and material intensity per service unit (MIPS) are calculated as economic and environmental factors, respectively. TAPPS is used to calculate the maximum profit per unit of product produced. MIPS is used to calculate the number of input and output streams in a process. MIPS was used based on the knowledge that a global reduction in material streams (solvents, reactants,) is necessary to lead toward sustainable development. TAPPS and MIPS are determined for several process alternatives, which are analyzed using a Pareto Chart for their feasibihty within a plant. However, MIPS does not account for the release of toxic solvents and reagents into the environment. Therefore it has been noted that it should be used in conjunction with LCA and other methods to avoid the use of highly toxic solvents and other raw materials [26]. 

The next decade will see both economic and environmental factors affecting process selection and operation. Within the refineries, there is a need to manage effluent streams carefully to reduce the release of pollutants. At the same time, there is a need to remove from products the precursors of pollutants that would otherwise be released during intended use. These requirements combine to place a double burden on the refineries. 

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