Marine Ecology, a sub-discipline of Ecology, is an integrative science focused on research on and assessment of the biotic and abiotic components and processes of Earth's marine and oceanic environments. The National Oceanic and Atmospheric Administration estimates that oceans comprise an astonishing 70 percent of the Earth's surface.
This environmental medium is supplemented by estuaries and coastal areas, and such other brackish bodies of water as the Great Lakes. Marine environments and their ecology are, therefore, critical for life, human habitation, and food and other natural resources. Also, basic and applied marine ecological research address human activity that affects ocean ecosystem composition, structure and function.
Wrasses (the family Labridae) are the most abundant and conspicuous fishes on tropical reefs around the world. Wrasses also comprise an important element of the coldwater fish...
Alcids in marine ecosystemsLast Updated on 2015-04-11 18:42:04
Alcidae is the name for a family of marine birds that includes murres, razorbills, dovekies, puffins, guillemots, auklets, and murrelets. They are commonly referred to as alcids or auks. These birds of the open ocean spend most of their lives at sea, coming to shore only to breed. Most alcids are colonial breeders, nesting in dense colonies on mainland cliffs or offshore islands, where they are inaccessible to terrestrial predators. They are long-lived and socially monogamous, often returning to the same nesting site to mate with the same partner, year after year. Females lay a single egg (or two eggs in a few species), and both parents contribute to egg incubation, chick brooding, and feeding the nestling(s) until they are ready to leave the nest for the sea.
Three distinct chick-rearing strategies exist among the alcids. Chicks of most species remain at the nest site and... More »
Marine biodiversity and food securityLast Updated on 2015-02-28 19:05:44
Harvesting of wild fish and shellfish from the oceans provides food to the earth’s population, particularly in the developing world, and is a major contributor to the world economy. In the USA alone, fishing supports an industry worth nearly $50 billion annually. Although fishing commenced very early in human history, it was during the 20th century that its reach and impact spread around the globe and into deep waters, first with the advent of motorized vessels near the turn of the century, and later as a result of widespread availability of cheap oil, refrigeration, and increasingly effective technology. These developments made fishing an intensive global industry, particularly after Word War II. Modern fisheries, including both landings and by-catch, currently consume 24-35% of global marine primary production in the continental shelf and major upwelling areas,... More »
Daugava RiverLast Updated on 2015-01-12 07:37:16The Daugava River drains portions of the countries of Latvia, Belarus and Russia, prior to discharging to the Gulf of Riga. Also known as the West Dvina River, this watercourse is the fourth largest river discharging to the Baltic Sea catchment.
This 1005 kilometer long river has suffered environmental damage from agricultural runoff and from hydroelectric dam construction, with major impacts dealt in the Soviet era of collective farming. In ancient history the Daugava estuary was a locus of prehistoric settlement, and later marked one of the eastern limits of the voyages of the Vikings.
The lower Daugava valley (nearest the Gulf of Riga) was formed in relatively recent times, as glacial meltwater formed incision on the relatively level terrain near the Baltic Sea coast; these events occurred in the early Holocene, approximately 11,000 years before present. The relatively soft upper... More »
Marine biodiversityLast Updated on 2014-12-15 19:53:24Biodiversity is now commonly defined as the variety of life in genes, species and habitats. According to the definition of the Convention on Biological Diversity, biodiversity is the variability among living organisms from all sources, including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.
The three domains of life, bacteria, archaea and eukarya are present in the marine environment. In addition there are viruses. About 230,000 species of marine plants and animals have been scientifically described and a few thousand bacteria and archaea. This known biodiversity only represents a small fraction of the number of species existing, except for the macrophytes and seagrasses which are living in coastal environments and, in general, for the pelagic... More »
OverfishingLast Updated on 2014-12-07 17:22:32Overfishing is the human act of extracting aquatic (that is, marine and freshwater) fauna from natural water bodies at a rate greater than the reproductive and recruitment functions can replace that extraction. While there is some evidence that localized overfishing may have occurred in prehistoric eras, the bulk of overfishing has taken place in the last 150 years as the human population has expanded greatly and fishing technologies have enabled harvesting of many species at rates not imagined in earlier times. For over a century man's role in the depletion of certain regional fisheries has been noted. A functional definition of overfishing is sometimes given as the reduction in catch per unit effort by fishermen. Typically the concept of overfishing is linked to an individual aquatic species, and this issue is most often discussed within a specific marine or lacustrine province... More »
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