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The marine sciences have undergone a sequence of historical changes related to new methodologies, approaches and challenges. Most recently, deteriorating natural ecosystems and threatened component species have prompted a renewed change in the focus of scientific research on the marine environment. This study analyzes the scientific literature on cetaceans during the period 2005–2008 to demonstrate that a key focus of modern research is on conservation-related topics, and then compares it to the period 1970–1973 to demonstrate that this new focus represents a shift from basic biological and ecological issues. On average, approximately 46% of papers published on whales, dolphins and porpoises in 2005–2008 were categorized as conservation oriented versus focused on biology or ecology. This contrasts to approximately 10% in 1970–1973. This shift parallels other marine research subjects, such as benthic communities, coral reefs and sea turtles and reflects a general paradigm shift in marine research towards anthropogenic impacts. This is important guidance for institutions and organizations that wish to base their agendas and decisions on state-of-the-art scientific priorities. 相似文献
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Abstract. Using an in situ observational approach, the food preferences among hard corals were examined for the two obligate coral‐feeding butterflyfishes Chaetodon austriacus and C. trifascialis in the Northern Red Sea, Gulf of Aqaba, Egypt. Chaetodon austriacus is a generalist coral feeder that feeds mainly on three genera of abundant hard corals (Acropora, Porites and Pocillopora). In contrast, C. trifascialis is a specialist coral feeder on Acropora spp. and Pocillopora verrucosa. In general, C. austriacus had a lower feeding rate than C. trifascialis (both species in the Northern Red Sea reefs had high feeding rates compared with other reefs). Ivlev's electivity index was calculated for the two species. This index shows that C. austriacus prefers Montipora and Pocillopora, and avoids Lobophyllia and Favites. On the other hand, C. trifascialis prefers Acropora valida and avoids Porites solida. Thus, the feeding preference and avoidance of these chaetodontids depend on both biting rate and food availability in the environment rather than on biting rate alone. 相似文献
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Abstract. The wide range of macroscopic mucus aggregates in the Adriatic Sea is documented. These structures arc considered to be initially produced by diatoms. A differentiation into five states or stages: macroflocs, stringers, clouds, creamy surface layers, and gelatinous surface layers is proposed. This classification is based not only on size and shape, but also takes relative position in the water, stability, behavior, and effect on benthos into consideration. An interrelationship between these aggregates - as different manifestations or phases of the same phenomenon - is postulated.
Macroflocs and stringers arc more common. Larger aggregates (clouds, creamy layers, gelatinous layers) arc less frequent. The general term "marine snow" is inadequate to describe the entire range of aggregate sizes and shapes, while the Italian designation "mare sporco" (dirty sea) is misleading. Two massive occurrences of dense clouds coupled with surface accumulations were recorded in the Adriatic in 1988 and 1989. The effect of the various stages on the shallow coastal ecosystem of the Northern Adriatic Sea is discussed. 相似文献
Macroflocs and stringers arc more common. Larger aggregates (clouds, creamy layers, gelatinous layers) arc less frequent. The general term "marine snow" is inadequate to describe the entire range of aggregate sizes and shapes, while the Italian designation "mare sporco" (dirty sea) is misleading. Two massive occurrences of dense clouds coupled with surface accumulations were recorded in the Adriatic in 1988 and 1989. The effect of the various stages on the shallow coastal ecosystem of the Northern Adriatic Sea is discussed. 相似文献
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