Limnology is the scientific field of knowledge that investigates terrestrial freshwater and saline aquatic systems. This includes the study of streams, lakes, ponds, rivers, springs, wetlands and even human-made reservoirs. Limnologists often utilize academic perspectives from a variety of disciplines, including biology, chemistry, geology, ecology, environmental science, hydrology and physics for their investigations.
Benthos is one of three major ecological groups into which marine organisms are divided, the other two being the nekton and the plankton. The benthos are organisms and...
Seas of the worldLast Updated on 2013-10-08 22:27:11A sea is commonly defined to be an extended body of saline water associated with one of the worlds five oceans (Atlantic, Indian, Pacific, Arctic, and Southern oceans). Some seas can appear to be distant from the ocean to which they are associated, like the Black Sea which is connected to the Atlantic Ocean, two thousand miles away, via the Mediterranean Sea and several very narrow straits.
Other bodies of inland waetr carry the name sea but are not directly associated with one of the world's oceans, such as the Caspian Sea and the Aral Sea. In most cases, seas are areas of an oceans that are close to and bounded to a greater or lesser degree by land.The degree to which seas are enclosed by land affects the degree to which they share water flows with the larger oceans or seas which they conect to. There are two types of sea defined by their degree of enclosure and connection to... More »
Black SeaLast Updated on 2013-09-21 16:00:44The Black Sea is a Mediterranean sea, centered at approximately 35o E and 44o N; it is considered the world’s largest inland water basin, although technically it is connected to the world's oceans via the Bosporus and the Dardanelles.
It has a surface area of about 461,000 km2 and a volume of 537,000 km3 with a mean depth of around 1200 to 1300 metres (m), although depths greater than 2000 m are common in the central basin.
The western part of the Black Sea is a wide shelf that gradually narrows to the south and breaks at around 100-150 m. In the rest of the basin the shelf doesn’t exceed 10 to 15 kilometres in width. It is connected to the Sea of Marmara via the narrow (760 m wide) and shallow (27.5 m maximum depth) Bosporus Straits, and further connects to the Mediterranean Sea via the long and narrow Dardanelles. It is also connected to the Sea of Azov to... More »
Secchi diskLast Updated on 2013-07-11 20:20:07
The Secchi disk is a device used to measure water transparency in all kinds of open waters (ponds, lakes, reservoirs, bays, oceans). The Secchi disk is an 8-inch (20 centimeter) white disk or with alternating black and white equal quadrants. It is lowered into the water of a lake or other water body until it can be no longer seen by the observer. This depth of disappearance, called the Secchi depth, Secchi disk reading, Secchi disk visibility or Secchi disk transparency (SDT), is a conventional measure of the transparency of the water. For the measurement of turbidity, the disk is lowered into the open water by unwinding the waterproof tape or calibrated line to which the disk is attached and until the observer loses sight of the disk. The disk is then raised until it reappears. The depth, measured from the water surface to the level where the disk vanishes and... More »
AlgaeLast Updated on 2013-07-11 19:54:38
Algae comprise a diverse group of typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are generally termed seaweeds. Algae convert solar energy to biomass using photosynthesis, like plants, although they lack the many distinct organs found in mostterrestrial vegetation.
Algae lack most of the structures that are associated with terrestrial flora, such as phyllids (leaves) and rhizoids in non-vascular plants; furthermore, they are without leaves, roots, and certain other organs that are found in vascular plants. Many are autotrophic although some groups contain species that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular taxa rely solely on external energy sources and have limited or no photosynthetic... More »
Panama CanalLast Updated on 2013-05-23 00:00:00
The Panama Canal is a 51 mile (85 km) long man-made waterway for ships connecting the Pacific Ocean with the Caribbean Sea and Atlantic Ocean that cuts across the Isthmus of Panamá from Colon on the north-side, through the man-made Gatun Lake, to Panama City on the south-side.
Closure of the Panama Canal would greatly increase transit times and costs adding over 8000 miles of travel. Vessels moving between the eastern Pacific and western Atlantic would require rerouting around the Straits of Magellan, Cape Horn and Drake Passage below the tip of South America.
The canal, a major artery of international shipping, uses a series of massive locks, manmade lakes, and water supplied by the copious tropical rainfall of the region to lift and lower transiting ships a height of 85 feet over the continental divide.
Over 14,000 vessels transit the Canal... More »
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