Renewable marine

Thirty states in the United States border either an ocean or one of the Great Lakes. These states generate and consume 75 percent of the nation s electricity, but the development of renewable marine power resources by these states so far is practically nil. 

Fraenkel, P. (1998). Marine Current Power—An Emerging Energy Resource for the Millenium. Renewable Energy World 1(2) 64-69. 

Consequences of Ozone Depletion. Ozone depletion over Antarctica is causing renewed concern about the consequences of increased levels of UV reaching the earth s biosphere. One area of concern involves the free-floating microscopic plants, known collectively as phytoplankton (the grass of the sea), which through the process of photosynthesis, fix carbon dioxide into living organic matter. Phytoplankton forms the basis of the marine food chain on which zooplankton (animal plankton) and all other components of the ecosystem depend for their sustenance. 

Pederin (104), the powerful cytotoxin of staphylinid beetles of the genus Paederus, has been the object of renewed interest due to the unexpected discovery of a series of closely related compounds in marine sponges that display antitumor activities. The latter, as well as pederin, were prepared by total synthesis and their biological activities were reported [219,220]. A recent review summarizing present knowledge on this family of compounds has been published [221]. 

Marine fish and shellfish constitute a valuable renewable resource that, with proper management, can contribute significantly to the nation s economic growth. The nation s marine resources support both recreational and commercial fishing and are managed to reflect both. 

The increased incidence of food-borne diseases from shellfish contaminated with Vibrio species have brought forward renewed interest in irradiation of shellfish and other seafood. Results are very promising for clams and oysters without killing the molluscs [65]. The radiation decimal reduction dose (Dio) determined for Vibrio cholerae 01 biotype El Tor inoculated into various molluscs was 0.14 kGy [66]. Similar radiation sensitivity of this organism was found in inoculated fish fillets and shrimp tails [67]. The radiation dose to eliminate as high as 10 CFU/g Vibrio spp. in oysters was 1.2 kGy [68]. The radiation Dio value for V. cholerae 01 biotype El Tor in marine snails was 0.11 kGy [69]. 

In work related to the human toxicology of arsenic, Cox (5) noted that within 24 hours after a person eats fish, arsenic can be measured in the urine at levels normally indicative of chronic arsenic poisoning. The subsequent study of Chapman (6) in 1926 established the occurrence of high levels of arsenic in a wide range of marine organisms. Arsenic concentrations in seawater were also reported at this time (7). Over the ensuing years there followed only infrequent reports (e.g., 8) on arsenic in marine samples until the late 1960s. Renewed interest... 

Consequently, there was renewed interest in marine arsenic research, and several groups worked in this area during the 1970s. Not surprisingly, they were from countries such as Japan and Australia and those in Scandinavia, where seafood is either widely consumed or is an important export commodity. The research activity resulted in the identification of arsenobetaine and the range of other arsenic compounds reported in Section IV. 

Discovery of medicinally important metabolites from marine sponges renewed the interest of sponge aquaculture which has been studied early in the twentieth century for commercial supply of sponge metabolites. Sponge mariculture is considered to be the most cost-effective method (Duckworth and Battershill, 2003). Several drawbacks associated with the... 

Also at issue is the preservation of marine biodiversity that relates, in turn, to chemical diversity. As stated previously, discoveries to date reflect a small percentage of the resources available. Measures must be taken to ensure sustainable use of these resources. Alternative renewable sources need to be identified to supply pharmacological evaluation. Due to the critical nature of this aspect of marine natural products drug discovery, several alternative approaches are discussed in detail. 

Naturally occurring oils and fats constitute another important source of renewable raw materials [198]. Whether they are referred to as fats or oils depends on whether they are solid or liquid at room temperature, respectively. They are composed primarily of triglycerides (triesters of glycerol) together with small amounts of free fatty acids, phospholipids, sterols, terpenes, waxes and vitamins. Oils and fats are either of vegetable or animal origin and are produced in the approximate proportions 55% vegetable oils, 40% land-animal fats and 5% marine oils [199]. 

Nitrous oxide (N2O) is a potent greenhouse gas (approximately 200 times more effective than CO2 on a molar basis) that has also been implicated in stratospheric ozone depletion (Kim and Craig, 1990 Yoshida et al., 1989) (see Bange, Chapter 2, this volume). Currendy, N2O accounts for about 5.5% of the enhanced radiative forcing attributed to all gases in the atmosphere (IPCC, 2007). Furthermore, while the atmospheric inventory of N2O is increasing, its sources are not well understood causing a renewed interest in the role of marine ecosystems as a potential source for N2O. 

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