MANILA, Philippines - More than 200 families were brought to a village hall Monday night after flash floods hit their homes in the Brookside area in Quezon City.Radio dzBB's Tuesday Niu reported that village official Armando Endaya had village workers cook soup and porridge for the evacuees at the temporary shelter.However, some residents declined to be rescued, saying they would rather stay and keep watch over their homes.There was no electric power in the area, prompting the residents who stayed behind to use candles.Earlier, some children were reported missing after flash floods reaching chest and neck levels hit the area. -
Source: GMANews.TV
Monday, May 12, 2008
Marine biology
Marine biology is the scientific study of living organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy.Marine life is a vast resource, providing food, medicine, and raw materials, in addition to helping to support recreation and tourism all over the world. At a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the oxygen cycle, and are involved in the regulation of the earth's climate.Shorelines are in part shaped and protected by marine life, and some marine organisms even help create new land.
Marine biology covers a great deal, from the microscopic, including zooplankton and phytoplankton, which can be as small as 0.02 micrometers and are both hugely important as the primary producers of the sea, to the huge cetaceans (whales) which reach up to a reported 48 meters (125 feet) in length.
The habitats studied by marine biology include everything from the tiny layers of surface water in which organisms and abiotic items may be trapped in surface tension between the ocean and atmosphere, to the depths of the abyssal trenches, sometimes 10,000 meters or more beneath the surface of the ocean. It studies habitats such as coral reefs, kelp forests, tidepools, muddy, sandy, and rocky bottoms, and the open ocean (pelagic) zone, where solid objects are rare and the surface of the water is the only visible boundary.
A large amount of all life on Earth exists in the oceans. Exactly how large the proportion is still unknown. While the oceans comprise about 71% of the Earth's surface, due to their depth they encompass about 300 times the habitable volume of the terrestrial habitats on Earth.
Many species are economically important to humans, including the food fishes. It is also becoming understood that the well-being of marine organisms and other organisms are linked in very fundamental ways. Human understanding is growing of the relationship between life in the sea and important cycles such as that of matter (such as the carbon cycle) and of air (such as Earth's respiration, and movement of energy through ecosystems). Large areas beneath the ocean surface still remain effectively unexplored
Ocean
An ocean (from Greek Ωκεανός, Okeanos (Oceanus)) is a major body of saline water, and a principal component of the hydrosphere. Approximately 971% of the Earth's surface (an area of some 361 million square kilometers) is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas. More than half of this area is over 3,000 meters (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt.
Though generally recognized as several 'separate' oceans, these waters comprise one global, interconnected body of salt water often referred to as the World Ocean or global ocean.This concept of a global ocean as a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean (which is sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans), and the Arctic Ocean (which is sometimes considered a sea of the Atlantic). The Pacific and Atlantic may be further subdivided by the equator into northerly and southerly portions. Smaller regions of the oceans are called seas, gulfs, bays and other names. There are also some smaller bodies of saltwater that are on land and not interconnected with the World Ocean, such as the Aral Sea, and the Great Salt Lake – though they may be referred to as 'seas', they are actually salt lakes.
Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle where there are no continents. From this perspective, there are three oceans today: the World Ocean and the Caspian and Black Seas, the latter two having been formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is very nearly a discrete ocean, being connected to the World Ocean through the Strait of Gibraltar, and indeed several times over the last few million years movement of the African continent has closed the strait off entirely. The Black Sea is connected to the Mediterranean through the Bosporus, but this is in effect a natural canal cut through continental rock some 7,000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar
Though generally recognized as several 'separate' oceans, these waters comprise one global, interconnected body of salt water often referred to as the World Ocean or global ocean.This concept of a global ocean as a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean (which is sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans), and the Arctic Ocean (which is sometimes considered a sea of the Atlantic). The Pacific and Atlantic may be further subdivided by the equator into northerly and southerly portions. Smaller regions of the oceans are called seas, gulfs, bays and other names. There are also some smaller bodies of saltwater that are on land and not interconnected with the World Ocean, such as the Aral Sea, and the Great Salt Lake – though they may be referred to as 'seas', they are actually salt lakes.
Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle where there are no continents. From this perspective, there are three oceans today: the World Ocean and the Caspian and Black Seas, the latter two having been formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is very nearly a discrete ocean, being connected to the World Ocean through the Strait of Gibraltar, and indeed several times over the last few million years movement of the African continent has closed the strait off entirely. The Black Sea is connected to the Mediterranean through the Bosporus, but this is in effect a natural canal cut through continental rock some 7,000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar
Biological classification
Biological classification or scientific classification in biology, is a method by which biologists group and categorize species of organisms. Biological classification is a form of scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis. Modern biological classification has its root in the work of Carolus Linnaeus, who grouped species according to shared physical characteristics. These groupings since have been revised to improve consistency with the Darwinian principle of common descent. Molecular systematics, which uses DNA sequences as data, has driven many recent revisions and is likely to continue to do so. Biological classification belongs to the science of biological systematics
Brackish water
Brackish water (less commonly brack water) is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty." Certain human activities can produce brackish water, in particular certain civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the blue energy process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment (see article on shrimp farms).
Technically, brackish water contains between 0.5 to 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (ppt or ‰). Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time.
Technically, brackish water contains between 0.5 to 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (ppt or ‰). Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time.
Estuaries
Brackish is a mixture of sea water and fresh water. An estuary is a body of water with fresh and salt water.The most important brackish water habitats are estuaries, where a river meets the sea. The River Thames flowing through London is one of the most familiar of river estuaries. The town of Teddington a few miles west of London marks the limit of the tidal part of the Thames, although it is still a freshwater river about as far east as Battersea insofar as the average salinity is very low and the fish fauna consists predominantly of freshwater species such as roach, dace, carp, perch, and pike. The Thames Estuary becomes truly brackish between Battersea and Gravesend, and the diversity of freshwater fish species present is smaller, primarily roach and dace, euryhaline marine species such as flounder, European seabass, mullet, and smelt become much more common. Further east, the salinity increases and the freshwater fish species are completely replaced by euryhaline marine ones, until the river reaches Gravesend, at which point conditions become fully marine and the fish fauna resembles that of the adjacent North Sea and includes both euryhaline and stenohaline marine species. A similar pattern of replacement can be observed with the aquatic plants and invertebrates living in the river .
This type of ecological succession from a freshwater to marine ecosystem is typical of river estuaries. River estuaries form important staging points during the migration of anadromous and catadromus fish species, such as salmon and eels, giving them time to form social groups and to adjust to the changes in salinity. Salmon are anadromous, meaning they live in the sea but ascend rivers to spawn; eels are catadromous, living in rivers and streams, but returning to the sea to breed. Besides the species that migrate through estuaries, there are many other fish that use them as "nursery grounds" for spawning or as places young fish can feed and grow before moving elsewhere. Herring and plaice are two commercially important species that use the Thames Estuary for this purpose. Estuaries are also used as fishing grounds and as places for fish farming or ranching. Atlantic salmon farms are often located in estuaries, for example, though this has caused controversy because in doing so, fish farmers expose migrating wild fish to large numbers of external parasites such as sea lice that escape from the pens the farmed fish are kept in
This type of ecological succession from a freshwater to marine ecosystem is typical of river estuaries. River estuaries form important staging points during the migration of anadromous and catadromus fish species, such as salmon and eels, giving them time to form social groups and to adjust to the changes in salinity. Salmon are anadromous, meaning they live in the sea but ascend rivers to spawn; eels are catadromous, living in rivers and streams, but returning to the sea to breed. Besides the species that migrate through estuaries, there are many other fish that use them as "nursery grounds" for spawning or as places young fish can feed and grow before moving elsewhere. Herring and plaice are two commercially important species that use the Thames Estuary for this purpose. Estuaries are also used as fishing grounds and as places for fish farming or ranching. Atlantic salmon farms are often located in estuaries, for example, though this has caused controversy because in doing so, fish farmers expose migrating wild fish to large numbers of external parasites such as sea lice that escape from the pens the farmed fish are kept in
Mangroves
Another important brackish water habitat is the mangrove swamp or mangal. Many, though not all, mangrove swamps fringe estuaries and lagoons where the salinity changes with each tide. Among the most specialised residents of mangrove forests are mudskippers, fish that forage for food on land, and archer fish, perch-like fish that "spit" at insects and other small animals living in the trees, knocking them into the water where they can be eaten. Like estuaries, mangrove swamps are extremely important breeding grounds for many fish, with species such as snappers, halfbeaks, and tarpon spawning or maturing among them. Besides fish, numerous other animals use mangroves, including such specialists as the American crocodile, proboscis monkey, diamondback terrapin, and the Crab-eating frog, Fejervarya cancrivora formerly Rana cancrivora. Although often plagued with mosquitoes and other insects that make them unpleasant places to visit, mangrove swamps are very important buffer zones between land and sea, and are a natural defense against hurricane and tsunami damage in particular
Brackish seas and lakes
Some seas and lakes are brackish. The Baltic Sea is a brackish sea adjoining the North Sea. Originally the confluence of two major river systems prior to the Pleistocene, since that it has been flooded by the North Sea but still receives so much freshwater from the adjacent lands that the water is brackish. Because the salt water coming in from the sea is more dense than freshwater, the water in the Baltic is stratified, with salt water at the bottom and freshwater at the top. Limited mixing occurs because of the lack of tides and storms, with the result that the fish fauna at the surface is freshwater in composition while that lower down is more marine. Cod are an example of a species only found in deep water in the Baltic, while pike are confined to the less saline surface waters .
The Caspian Sea is the world's largest lake and contains brackish water with a salinity about one-third that of normal seawater. The Caspian is famous for its peculiar animal fauna, including one of the few non-marine seals (the Caspian seal) and the great sturgeons, a major source of caviar.
In the Black sea the surface water is brackish with an average salinity of about 18 parts per thousand compared to 30 to 40 for the oceans. The deep, anoxic water of Black sea originates from warm, salty water of the Mediterranean
The Caspian Sea is the world's largest lake and contains brackish water with a salinity about one-third that of normal seawater. The Caspian is famous for its peculiar animal fauna, including one of the few non-marine seals (the Caspian seal) and the great sturgeons, a major source of caviar.
In the Black sea the surface water is brackish with an average salinity of about 18 parts per thousand compared to 30 to 40 for the oceans. The deep, anoxic water of Black sea originates from warm, salty water of the Mediterranean
Oceanic trench
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor.
Trenches define one of the most important natural boundaries on the Earth’s solid surface, that between two lithospheric plates. There are three types of lithospheric plate boundaries: divergent (where lithosphere and oceanic crust is created at mid-ocean ridges), convergent (where one lithospheric plate sinks beneath another and returns to the mantle), and transform (where two lithospheric plates slide past each other). Trenches are the spectacular and distinctive morphological features of plate boundaries. Plates move together along convergent plate boundaries at convergence rates that vary from a few millimeters to ten or more centimeters per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and trenches about 200 km from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The deepest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench at a depth of 10,911 m (35,798 ft) below sea level. Oceanic lithosphere disappears into trenches at a global rate of about a tenth of a square meter per second
Trenches define one of the most important natural boundaries on the Earth’s solid surface, that between two lithospheric plates. There are three types of lithospheric plate boundaries: divergent (where lithosphere and oceanic crust is created at mid-ocean ridges), convergent (where one lithospheric plate sinks beneath another and returns to the mantle), and transform (where two lithospheric plates slide past each other). Trenches are the spectacular and distinctive morphological features of plate boundaries. Plates move together along convergent plate boundaries at convergence rates that vary from a few millimeters to ten or more centimeters per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and trenches about 200 km from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The deepest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench at a depth of 10,911 m (35,798 ft) below sea level. Oceanic lithosphere disappears into trenches at a global rate of about a tenth of a square meter per second
Tide pool
Tide pools (also tidal pools, rock pools or rock and roll pools) are rocky pools by oceans that are filled with seawater. Tide pools can either be small and shallow or deep. The small ones are usually found far back on the shore and the large ones are found nearer to the ocean. Tide pools are formed as a high tide comes in over a rocky shore. Water fills depressions in the ground, which turn into isolated pools as the tide retreats. This process, repeated twice a day, replenishes the seawater in what otherwise might be a stagnant pool.
The area that is covered by high tide and exposed by low tide is called the intertidal zone, or foreshore. This area is often further divided into different zones based on the life forms that live there
The area that is covered by high tide and exposed by low tide is called the intertidal zone, or foreshore. This area is often further divided into different zones based on the life forms that live there
Kelp forest
Occurring worldwide throughout temperate and polar coastal oceans, kelp forests are recognized as one of the most productive and dynamic ecosystems on Earth. (In 2007, kelp forests were also discovered in tropical waters near Ecuador.)Physically formed by brown macroalgae of the order Laminariales, kelp forests provide a unique three-dimensional habitat for marine organisms and are a source for understanding many ecological processes. Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns and provide many ecosystem services to humankind. However, the influence of humans has often contributed to kelp forest degradation. Of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the over-grazing of kelp and other algae.This can rapidly result in transitions to barren landscapes where relatively few species persist.The implementation of marine protected areas (MPAs) is one management strategy useful for addressing such issues since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors
Aquatic ecosystem
An aquatic ecosystem is an ecosystem located in a body of water. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems.
Aquatic ecosystems can be divided into two general types: marine ecosystems and freshwater ecosystems.
Neritic (the relatively shallow part of the ocean that lies over the continental shelf); profundal (bottom or deep water); benthic (bottom substrates); intertidal (the area between high and low tides); estuaries
Aquatic ecosystems can be divided into two general types: marine ecosystems and freshwater ecosystems.
Neritic (the relatively shallow part of the ocean that lies over the continental shelf); profundal (bottom or deep water); benthic (bottom substrates); intertidal (the area between high and low tides); estuaries
Marine ecosystem
Marine ecosystems are part of the earth's aquatic ecosystem. They include oceans, estuaries, salt marshes, lagoons, some tropical ecosystems, such as mangrove forests and coral reefs, rocky, subtidal ecosystems, and shores. The main difference between this and other aquatic ecosystems is its salt content larger than that of fresh water.
Marine conservation
Marine conservation, also known as marine resources conservation, is the protection and preservation of ecosystems in oceans and seas. Marine conservation focuses on limiting human-caused damage to marine ecosystems, and on restoring damaged marine ecosystems. Marine conservation also focuses on preserving vulnerable marine species.
Marine conservation is the study of conserving physical and biological marine resources and ecosystem functions. This is a relatively new discipline. Marine conservationists rely on a combination of scientific principles derived from marine biology, oceanography, and fisheries science, as well as on human factors such as demand for marine resources and marine law, economics and policy in order to determine how to best protect and conserve marine species and ecosystems. Marine conservation can be seen as a subdiscipline of conservation biology.
Marine conservation is the study of conserving physical and biological marine resources and ecosystem functions. This is a relatively new discipline. Marine conservationists rely on a combination of scientific principles derived from marine biology, oceanography, and fisheries science, as well as on human factors such as demand for marine resources and marine law, economics and policy in order to determine how to best protect and conserve marine species and ecosystems. Marine conservation can be seen as a subdiscipline of conservation biology.
Subfields
The marine ecosystem is large, and thus there are many subfields of marine biology. Most involve studying specializations of particular species (i.e., phycology, invertebrate zoology, ichthyology).
Other subfields study the physical effects of continual immersion in sea water and the ocean in general, adaptation to a salty environment, and the effects of changing various oceanic properties on marine life. A subfield of marine biology studies the relationships between oceans and ocean life, and global warming and environmental issues (such as carbon dioxide displacement).
Recent marine biotechnology has focused largely on marine biomolecules, especially proteins, that may have uses in medicine or engineering. Marine environments are the home to many exotic biological materials that may inspire biomimetic materials.
Other subfields study the physical effects of continual immersion in sea water and the ocean in general, adaptation to a salty environment, and the effects of changing various oceanic properties on marine life. A subfield of marine biology studies the relationships between oceans and ocean life, and global warming and environmental issues (such as carbon dioxide displacement).
Recent marine biotechnology has focused largely on marine biomolecules, especially proteins, that may have uses in medicine or engineering. Marine environments are the home to many exotic biological materials that may inspire biomimetic materials.
Related fields
Marine biology is a branch of oceanography and is closely linked to biology. It also encompasses many ideas from ecology. Fisheries science and marine conservation can be considered partial offshoots of marine biology
Oceanography (from the greek words Ωκεανός meaning Ocean and γράφω meaning to write), also called oceanology or marine science, is the branch of Earth Sciences that studies the Earth's oceans and seas. It covers a wide range of topics, including marine organisms and ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within it: biology, chemistry, geology, meteorology, and physics
Oceanography (from the greek words Ωκεανός meaning Ocean and γράφω meaning to write), also called oceanology or marine science, is the branch of Earth Sciences that studies the Earth's oceans and seas. It covers a wide range of topics, including marine organisms and ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within it: biology, chemistry, geology, meteorology, and physics
Microscopic life
Microscopic life undersea is incredibly diverse and still poorly understood. For example, the role of viruses in marine ecosystems is barely being explored even in the beginning of the 21st century.
The role of phytoplankton is better understood due to their critical position as the most numerous primary producers on Earth. Phytoplankton are categorized into cyanobacteria (also called blue-green algae/bacteria), various types of algae (red, green, brown, and yellow-green), diatoms, dinoflagellates, euglenoids, coccolithophorids, cryptomonads, chrysophytes, chlorophytes, prasinophytes, and silicoflagellates.
Zooplankton tend to be somewhat larger, and not all are microscopic. Many Protozoa are zooplankton, including dinoflagellates, zooflagellates, foraminiferans, and radiolarians. Some of these (such as dinoflaggelates) are also phytoplankton; the plant/animal distinction often breaks down in very small organisms. Other zooplankton include cnidarians, ctenophores, chaetognaths, molluscs, arthropods, urochordates, and annelids such as polychaetes. Many larger animals begin their life as zooplankton before they become large enough to take their familiar forms. Two examples are fish larvae and sea stars (also called starfish
The role of phytoplankton is better understood due to their critical position as the most numerous primary producers on Earth. Phytoplankton are categorized into cyanobacteria (also called blue-green algae/bacteria), various types of algae (red, green, brown, and yellow-green), diatoms, dinoflagellates, euglenoids, coccolithophorids, cryptomonads, chrysophytes, chlorophytes, prasinophytes, and silicoflagellates.
Zooplankton tend to be somewhat larger, and not all are microscopic. Many Protozoa are zooplankton, including dinoflagellates, zooflagellates, foraminiferans, and radiolarians. Some of these (such as dinoflaggelates) are also phytoplankton; the plant/animal distinction often breaks down in very small organisms. Other zooplankton include cnidarians, ctenophores, chaetognaths, molluscs, arthropods, urochordates, and annelids such as polychaetes. Many larger animals begin their life as zooplankton before they become large enough to take their familiar forms. Two examples are fish larvae and sea stars (also called starfish
Plants and algae
Plant life is relatively rare undersea. Most of the niche occupied by sub plants on land is actually occupied by macroscopic algae in the ocean, such as Sargassum and kelp which are commonly known as seaweeds. The non algae plants that do survive in the sea are often found in shallow waters, such as the seagrasses (examples of which are eelgrass, Zostera, and turtle grass, Thalassia). These plants have adapted to the high salinity of the ocean environment. The intertidal zone is also a good place to find plant life in the sea, where mangroves or cordgrass or beach grass might grow. Sea kelp is very important to small sea creatures because the creatures can hide from predators
Marine vertebrate
Marine vertebrates are vertebrates which live in a marine environment. These primarily include fish, seabirds, marine reptiles, and marine mammals. These animals have an internal skeleton and make up about 4% of the sea's animal population. Marine vertebrates include fish, reptiles,and mammals like sea otters, california halibut, and many more species of sea living creatures. Most of the ocean's vertebrates are fish and crusteans.
Marine invertebrates
As on land, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes Cnidaria such as jellyfish and sea anemones; Ctenophora; sea worms including the phyla Platyhelminthes, Nemertea, Annelida, Sipuncula, Echiura, Chaetognatha, and the Phoronida; Mollusca including shellfish, squid, octopus; Crustacea; Porifera; Bryozoa; Echinodermata including starfish; and Urochordata - sea squirts or tunicates.The term "marine invertebrates" is used to describe animals found in a marine environment which are invertebrates: lacking a notochord. In order to protect themselves, they may have evolved a shell or a hard exoskeleton, but this is not always the case.
As on land and in the air, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes:
Bryozoa, also known as moss animals or sea mats;
Cnidaria, such as jellyfish, sea anemones and corals;
Crustaceans, such a such as lobsters, crabs, shrimp, crayfish and barnacles;
Ctenophora: sea worms including flatworms, ribbon worms, annelids, Sipuncula, Echiura, Chaetognatha, and the phoronids;
Echinoderms, including starfish, brittle stars, sea urchins, sand dollars, sea cucumbers, and crinoids;
Mollusca, including shellfish, squid, octopus;
Sponges;
Tunicates, also known as sea squirts.
As on land and in the air, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes:
Bryozoa, also known as moss animals or sea mats;
Cnidaria, such as jellyfish, sea anemones and corals;
Crustaceans, such a such as lobsters, crabs, shrimp, crayfish and barnacles;
Ctenophora: sea worms including flatworms, ribbon worms, annelids, Sipuncula, Echiura, Chaetognatha, and the phoronids;
Echinoderms, including starfish, brittle stars, sea urchins, sand dollars, sea cucumbers, and crinoids;
Mollusca, including shellfish, squid, octopus;
Sponges;
Tunicates, also known as sea squirts.
Fish
Fish have evolved very different biological functions from other large organisms. Fish anatomy includes a two-chambered heart, operculum, secretory cells that produce mucous, swim bladder, scales, fins, lips and eyes. Fish breathe by extracting oxygen from water through their gills. Fins propel and stabilize the fish in the water.Well known fish include: sardines, anchovy, ling cod, clownfish (also known as anemonefish), and bottom fish which include halibut or ling cod. Predators include sharks and barracuda
Fish are aquatic vertebrates that are typically ectothermic (previously cold-blooded), covered with scales, and equipped with two sets of paired fins and several unpaired fins. Fish are abundant in the sea and in fresh water, with species being known from mountain streams (e.g., char and gudgeon) as well as in the deepest depths of the ocean (e.g., gulpers and anglerfish). They are of tremendous importance as food for people around the world, either collected from the wild (see fishing) or farmed in much the same way as cattle or chickens (see aquaculture). Fish are also exploited for recreation, through angling and fishkeeping, and are commonly exhibited in public aquaria. Fish have an important role in many cultures through the ages, ranging as widely as deities and religious symbols to subjects of books and popular movies
Marine reptile
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semi-aquatic life in a marine environment.
The earliest marine reptiles arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs, placodonts, and mosasaurs.
After the first mass extinction at the end of the Cretaceous period, marine reptiles were less numerous, consisting largely of sea turtles, sea snakes, Marine Iguanas and some species of crocodylians.
Some marine reptiles, such as ichthyosaurs and mosasaurs, rarely venture onto land and give birth in the water. Others, such as sea turtles and saltwater crocodiles, still return to shore to lay their eggs
The earliest marine reptiles arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs, placodonts, and mosasaurs.
After the first mass extinction at the end of the Cretaceous period, marine reptiles were less numerous, consisting largely of sea turtles, sea snakes, Marine Iguanas and some species of crocodylians.
Some marine reptiles, such as ichthyosaurs and mosasaurs, rarely venture onto land and give birth in the water. Others, such as sea turtles and saltwater crocodiles, still return to shore to lay their eggs
Reptiles
Reptiles which inhabit or frequent the sea include sea turtles, Marine Iguana, sea snakes, and Saltwater Crocodiles. All extant marine reptiles are oviparous and need to return to land to lay their eggs. Thus most species, excepting sea turtles, live on or near land rather than in the ocean. Some extinct marine reptiles, such as ichthyosaurs, evolved to be viviparous and had no requirement to return to land
Seabirds
Seabirds are species of birds adapted to living in the marine environment, examples including albatross, penguins, gannets, and auks. Although they spend most of their lives in the ocean, species such as gulls can often be found thousands of miles inland.
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.
In general, seabirds live longer, breed later and have fewer young than other birds do, but they invest a great deal of time in their young. Most species nest in colonies, which can vary in size from a few dozen birds to millions. Many species are famous for undertaking long annual migrations, crossing the equator or circumnavigating the Earth in some cases. They feed both at the ocean's surface and below it, and even feed on each other. Seabirds can be highly pelagic, coastal, or in some cases spend a part of the year away from the sea entirely.
Seabirds and humans have a long history together: they have provided food to hunters, guided fishermen to fishing stocks and led sailors to land. Many species are currently threatened by human activities, and conservation efforts are under way
In general, seabirds live longer, breed later and have fewer young than other birds do, but they invest a great deal of time in their young. Most species nest in colonies, which can vary in size from a few dozen birds to millions. Many species are famous for undertaking long annual migrations, crossing the equator or circumnavigating the Earth in some cases. They feed both at the ocean's surface and below it, and even feed on each other. Seabirds can be highly pelagic, coastal, or in some cases spend a part of the year away from the sea entirely.
Seabirds and humans have a long history together: they have provided food to hunters, guided fishermen to fishing stocks and led sailors to land. Many species are currently threatened by human activities, and conservation efforts are under way
Groups
There are some 120 extant species of marine mammals, generally subdivided into the five groups bold-faced below.Order Sirenia: Sirenians
family Trichechidae: manatees (3 species)
family Dugongidae: dugong (1 species)
Order Cetacea: Cetaceans
Suborder Mysticeti: Baleen whales (14 or 15 species)
Suborder Odontoceti: Toothed whales (around 73 species)
Order Carnivora,
superfamily Pinnipedia
family Phocidae: true seals (around 20 species)
family Otariidae: eared seals (around 16 species)
family Odobenidae: walrus (1 species)
family Mustelidae
sea otter (Enhydra lutris)
marine otter (Lontra felina)
family Ursidae
polar bear (Ursus maritimus)
The sirenians and cetaceans are thought to be descendent from an ungulate ancestor, while the pinnipeds, otters and polar bear are descended from a caniform ancestor. The morphological similarities between these diverse groups are a result of convergent and parallel evolution.
Adaptations
Since mammals originally evolved on land, their spines are optimized for running, allowing for up-and-down but only little sideways motion. Therefore, marine mammals typically swim by moving their spine up and down. By contrast, fish normally swim by moving their spine sideways. For this reason, fish mostly have vertical caudal (tail) fins, while marine mammals have horizontal caudal fins.
Some of the primary differences between marine mammals and other marine life are:
Marine mammals breathe air, while most other marine animals extract oxygen from water.
Marine mammals have hair. Cetaceans have little or no hair, usually a very few bristles retained around the head or mouth. All members of the Carnivora have a coat of fur or hair, but it is far thicker and more important for thermoregulation in sea otters and polar bears than in seals or sea lions. Thick layers of fur contribute to drag while swimming, and slow down a swimming mammal, giving it a disadvantage in speed.
Marine mammals have thick layers of blubber used to insulate their bodies and prevent heat loss. Sea otters and polar bears are exceptions, relying more on fur and behavior to stave off hypothermia.
Marine mammals give birth. Most marine mammals give birth to one calf or pup at a time.
Marine mammals feed off milk as young. Maternal care is extremely important to the survival of offspring that need to develop a thick insulating layer of blubber. The milk from the mammary glands of marine mammals often exceeds 40-50% fat content to support the development of blubber in the young.
Marine mammals maintain a high internal body temperature. Unlike most other marine life, marine mammals carefully maintain a core temperature much higher than their environment. Blubber, thick coats of fur, bubbles of air between skin and water, countercurrent exchange, and behaviors such as hauling out, are all adaptations that aid marine mammals in retention of body heat.
The polar bear spends a large portion of its time in a marine environment, albeit a frozen one. When it does swim in the open sea it is extremely proficient and has been shown to cover 74 km in a day. For these reasons, some scientists regard it as a marine mamm
Some of the primary differences between marine mammals and other marine life are:
Marine mammals breathe air, while most other marine animals extract oxygen from water.
Marine mammals have hair. Cetaceans have little or no hair, usually a very few bristles retained around the head or mouth. All members of the Carnivora have a coat of fur or hair, but it is far thicker and more important for thermoregulation in sea otters and polar bears than in seals or sea lions. Thick layers of fur contribute to drag while swimming, and slow down a swimming mammal, giving it a disadvantage in speed.
Marine mammals have thick layers of blubber used to insulate their bodies and prevent heat loss. Sea otters and polar bears are exceptions, relying more on fur and behavior to stave off hypothermia.
Marine mammals give birth. Most marine mammals give birth to one calf or pup at a time.
Marine mammals feed off milk as young. Maternal care is extremely important to the survival of offspring that need to develop a thick insulating layer of blubber. The milk from the mammary glands of marine mammals often exceeds 40-50% fat content to support the development of blubber in the young.
Marine mammals maintain a high internal body temperature. Unlike most other marine life, marine mammals carefully maintain a core temperature much higher than their environment. Blubber, thick coats of fur, bubbles of air between skin and water, countercurrent exchange, and behaviors such as hauling out, are all adaptations that aid marine mammals in retention of body heat.
The polar bear spends a large portion of its time in a marine environment, albeit a frozen one. When it does swim in the open sea it is extremely proficient and has been shown to cover 74 km in a day. For these reasons, some scientists regard it as a marine mamm
Marine mammals
There are five main types of marine mammals.
Cetaceans include toothed whales (Suborder Odontoceti), such as the Sperm Whale, dolphins, and porpoises such as the Dall's porpoise. Cetaceans also include baleen whales (Suborder Mysticeti), such as the Gray Whale, Humpback Whale, and Blue Whale.
Sirenians include manatees, the Dugong, and the extinct Steller's Sea Cow.
Seals (Family Phocidae), sea lions (Family Otariidae - which also include the fur seals), and the Walrus (Family Odobenidae) are all considered pinnipeds.
The Sea Otter is a member of the Family Mustelidae, which includes weasels and badgers.
Finally, the Polar Bear (Family Ursidae) is sometimes considered a marine mammal because of its dependence on the sea
Cetaceans include toothed whales (Suborder Odontoceti), such as the Sperm Whale, dolphins, and porpoises such as the Dall's porpoise. Cetaceans also include baleen whales (Suborder Mysticeti), such as the Gray Whale, Humpback Whale, and Blue Whale.
Sirenians include manatees, the Dugong, and the extinct Steller's Sea Cow.
Seals (Family Phocidae), sea lions (Family Otariidae - which also include the fur seals), and the Walrus (Family Odobenidae) are all considered pinnipeds.
The Sea Otter is a member of the Family Mustelidae, which includes weasels and badgers.
Finally, the Polar Bear (Family Ursidae) is sometimes considered a marine mammal because of its dependence on the sea
Coral reef
Coral reefs are aragonite structures produced by living organisms, found in shallow, tropical marine waters with little to no nutrients in the water. High nutrient levels such as those found in runoff from agricultural areas can harm the reef by encouraging the growth of algae.In most reefs, the predominant organisms are stony corals, colonial cnidarians that secrete an exoskeleton of calcium carbonate. The accumulation of skeletal material, broken and piled up by wave action and bioeroders, produces a massive calcareous formation that supports the living corals and a great variety of other animal and plant life. Although corals are found both in temperate and tropical waters, reefs are formed only in a zone extending at most from 30°N to 30°S of the equator.
Oceanic habitats
Reefs comprise some of the densest and most diverse habitats in the world. The best-known types of reefs are tropical coral reefs which exist in most tropical waters; however, reefs can also exist in cold water. Reefs are built up by corals and other calcium-depositing animals, usually on top of a rocky outcrop on the ocean floor. Reefs can also grow on other surfaces, which has made it possible to create artificial reefs. Coral reefs also support a huge community of life, including the corals themselves, their symbiotic zooxanthellae, tropical fish and many other organisms.
Much attention in marine biology is focused on coral reefs and the El Niño weather phenomenon. In 1998, coral reefs experienced a "once in a thousand years" bleaching event, in which vast expanses of reefs across the Earth died because sea surface temperatures rose well above normal. Some reefs are recovering, but scientists say that 58% of the world's coral reefs are now endangered and predict that global warming could exacerbate this
Much attention in marine biology is focused on coral reefs and the El Niño weather phenomenon. In 1998, coral reefs experienced a "once in a thousand years" bleaching event, in which vast expanses of reefs across the Earth died because sea surface temperatures rose well above normal. Some reefs are recovering, but scientists say that 58% of the world's coral reefs are now endangered and predict that global warming could exacerbate this
Deep sea and trenches
The deepest recorded oceanic trenches measure to date is the Mariana Trench, near the Philippines, in the Pacific Ocean at 10924 m (35838 ft). At such depths, water pressure is extreme and there is no sunlight, but some life still exists. Small flounder (family Soleidae) fish and shrimp were seen by the American crew of the bathyscaphe Trieste when it dove to the bottom in 1960.
Other notable oceanic trenches include Monterey Canyon, in the eastern Pacific, the Tonga Trench in the southwest at 10,882 m (35,702 ft), the Philippine Trench, the Puerto Rico Trench at 8605 m (28232 ft), the Romanche Trench at 7760 m (24450 ft), Fram Basin in the Arctic Ocean at 4665 m (15305 ft), the Java Trench at 7450 m (24442 ft), and the South Sandwich Trench at 7235 m (23737 ft).
In general, the deep sea is considered to start at the aphotic zone, the point where sunlight loses its power of transference through the water. Many life forms that live at these depths have the ability to create their own light.
Much life centers on seamounts that rise from the deeps, where fish and other sea life congregate to spawn and feed. Hydrothermal vents along the mid-ocean ridge spreading centers act as oases, as do their opposites, cold seeps. Such places support unique biomes and many new microbes and other lifeforms have been discovered at these locations
Other notable oceanic trenches include Monterey Canyon, in the eastern Pacific, the Tonga Trench in the southwest at 10,882 m (35,702 ft), the Philippine Trench, the Puerto Rico Trench at 8605 m (28232 ft), the Romanche Trench at 7760 m (24450 ft), Fram Basin in the Arctic Ocean at 4665 m (15305 ft), the Java Trench at 7450 m (24442 ft), and the South Sandwich Trench at 7235 m (23737 ft).
In general, the deep sea is considered to start at the aphotic zone, the point where sunlight loses its power of transference through the water. Many life forms that live at these depths have the ability to create their own light.
Much life centers on seamounts that rise from the deeps, where fish and other sea life congregate to spawn and feed. Hydrothermal vents along the mid-ocean ridge spreading centers act as oases, as do their opposites, cold seeps. Such places support unique biomes and many new microbes and other lifeforms have been discovered at these locations
Open ocean
The great expanse of open ocean habitat is huge, and many species can be found passing through it and living in it. The term "open ocean" usually is meant to refer to the vast stretches of water between points of land, or between undersea mounts. Contrary to popular notions the open ocean is often not the place where marine animals spend the majority of their lives. Most species simply pass through the open ocean on their ways to other places. Larger species are the main ongoing inhabitants.
Intertidal and shore
Tide pools with sea stars and sea anemone in Santa Cruz,CaliforniaIntertidal zones, those areas close to shore, are constantly being exposed and covered by the ocean's tides. A huge array of life lives within this zone.
Shore habitats span from the upper intertidal zones to the area where land vegetation takes prominence. It can be underwater anywhere from daily to very infrequently. Many species here are scavengers, living off of sea life that is washed up on the shore. Many land animals also make much use of the shore and intertidal habitats. A subgroup of organisms in this habitat bores and grinds exposed rock through the process of bioerosion.
How oceanic factors affect distribution of various organisms
An active research topic in marine biology is to discover and map the life cycles of various species and where they spend their time. Marine biologists study how the ocean currents, tides and many other oceanic factors affect ocean lifeforms, including their growth, distribution and well-being. This has only recently become technically feasible with advances in GPS and newer underwater visual devices.
Most ocean life breeds in specific places, nests or not in others, spends time as juveniles in still others, and in maturity in yet others. Scientists know little about where many species spent different parts of their life cycles. For example, it is still largely unknown where sea turtles travel. Tracking devices do not work for some life forms, and the ocean is not friendly to technology.
Most ocean life breeds in specific places, nests or not in others, spends time as juveniles in still others, and in maturity in yet others. Scientists know little about where many species spent different parts of their life cycles. For example, it is still largely unknown where sea turtles travel. Tracking devices do not work for some life forms, and the ocean is not friendly to technology.
Famous marine biologists
Ali Abdelghany (born 1944), Egyptian marine biologist
Jakob Johan Adolf Appellöf (1857-1921), Swedish marine zoologist.
Samuel Stillman Berry (1887-1984), U.S. marine zoologist.
Henry Bryant Bigelow (1879–1967), U.S. marine biologist.
Rachel Carson (1907-1964), American Marine Biologist and Author.
Carl Chun (1852-1914), German marine biologist
Jacques-Yves Cousteau (1910-1997), French marine biologist and explorer
Charles Darwin (1809-1882), wrote Structure and Distribution of Coral Reefs (1842) while aboard the HMS Beagle
Anton Dohrn (1840-1909), German marine biologist
Sylvia Earle (born 1935), American oceanographer
Hans Hass (born 1919), Austrian marine biologist and diving pioneer
Gotthilf Hempel (born 1929), German marine biologist
Ilham Artüz (1924-1993), Turkish Marine Biologist and Oceanographer
Johan Hjort (1869-1948), Norwegian marine zoologist and one of the founders of ICES
Bruno Hofer (1861-1916), German fisheries scientist
Emperor Showa of Japan (1901-1989), jellyfish taxonomist
Uwe Kils (born 1951), German marine biologist
August David Krohn (1803–1891), Russian/German zoologist
William Elford Leach (1790-1836), English zoologist and marine biologist
Nicholai Miklukho-Maklai (1846-1888), Russian marine biologist and anthropologist
Sir John Murray (1841-1914), Scots-Canadian marine biologist
Ed Ricketts (1897-1948), American marine biologist noted for a pioneering study of intertidal ecology
Harald Rosenthal (born 1937), German hydrobiologist known for his work in fish farming and ecology
Michael Sars (1809–1869), Norwegian theologian and biologist
Georg Sars (1837-1927), Norwegian marine biologist
Gunnar Thorson (1906-1971), Danish marine biologist
Ruth Turner (1915-2000), marine biologist
Charles Wyville Thompson (1832-1882), Scottish marine biologist
Jakob Johan Adolf Appellöf (1857-1921), Swedish marine zoologist.
Samuel Stillman Berry (1887-1984), U.S. marine zoologist.
Henry Bryant Bigelow (1879–1967), U.S. marine biologist.
Rachel Carson (1907-1964), American Marine Biologist and Author.
Carl Chun (1852-1914), German marine biologist
Jacques-Yves Cousteau (1910-1997), French marine biologist and explorer
Charles Darwin (1809-1882), wrote Structure and Distribution of Coral Reefs (1842) while aboard the HMS Beagle
Anton Dohrn (1840-1909), German marine biologist
Sylvia Earle (born 1935), American oceanographer
Hans Hass (born 1919), Austrian marine biologist and diving pioneer
Gotthilf Hempel (born 1929), German marine biologist
Ilham Artüz (1924-1993), Turkish Marine Biologist and Oceanographer
Johan Hjort (1869-1948), Norwegian marine zoologist and one of the founders of ICES
Bruno Hofer (1861-1916), German fisheries scientist
Emperor Showa of Japan (1901-1989), jellyfish taxonomist
Uwe Kils (born 1951), German marine biologist
August David Krohn (1803–1891), Russian/German zoologist
William Elford Leach (1790-1836), English zoologist and marine biologist
Nicholai Miklukho-Maklai (1846-1888), Russian marine biologist and anthropologist
Sir John Murray (1841-1914), Scots-Canadian marine biologist
Ed Ricketts (1897-1948), American marine biologist noted for a pioneering study of intertidal ecology
Harald Rosenthal (born 1937), German hydrobiologist known for his work in fish farming and ecology
Michael Sars (1809–1869), Norwegian theologian and biologist
Georg Sars (1837-1927), Norwegian marine biologist
Gunnar Thorson (1906-1971), Danish marine biologist
Ruth Turner (1915-2000), marine biologist
Charles Wyville Thompson (1832-1882), Scottish marine biologist
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