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| Ocean habitats |
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| aquatic ecosystem |
| continental shelf |
| neritic zone |
| littoral zone |
| intertidal |
| pelagic zone |
| demersal zone |
| benthic zone |
| benthic life |
| coral reefs |
| estuaries |
| seamounts |
| fishing banks |
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A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island. A biome is a climatically and geographically defined area of ecologically similar climatic conditions such as communities of Plants Animals and An aquatic ecosystem is an Ecosystem located in water bodies. The continental shelf is the extended perimeter of each Continent and associated Coastal plain, which is covered during interglacial periods such The neritic zone, also called the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the Continental shelf, with a relatively Littoral refers to the coast of an ocean or sea or to the banks of a river lake or estuary Intertidal ecology is the study of intertidal Ecosystems where organisms live between the low and high Tide lines Any water in the sea that is not close to the bottom is in the pelagic zone. The demersal zone is the part of the Sea or Ocean (or deep Lake) comprising the Water column that is near to (and is significantly affected The benthic zone is the ecological region at the lowest level of a Body of water such as an Ocean or a Lake, including the sediment surface and some sub-surface Benthos are the organisms which live on in or near the Seabed, also known as the Benthic zone. Coral reefs are Aragonite structures produced by living organisms found in marine waters with little to no nutrients in the water An estuary is a semi-enclosed Coastal body of Water with one or more Rivers or Streams flowing into it and with a free connection to the open A mountain is a Landform that extends above the surrounding Terrain in a limited area with a peak An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. "Ocean Floor" redirects here For the 2001 song by Audio Adrenaline, see Lift (Audio Adrenaline album. Mean sea level (MSL is the average (mean height of the Sea, with reference to a suitable reference surface An island (ˈaɪlənd or isle (/ˈaɪl/ is any piece of land that is completely surrounded by water in two dimensions above high tide and isolated from other significant These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of 1,000 - 4,000 meters depth. They are defined by oceanographers as independent features that rise to at least 1,000 meters above the seafloor. Oceanography (from the greek words Ωκεανός meaning Ocean and γράφω meaning to write also called oceanology or The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. The deep sea, or deep layer, is the lowest layer in the Ocean, existing below the Thermocline, at a depth of 1000 fathoms or more [1] An estimated 30,000 seamounts occur across the globe, with only a few having been studied. However, some seamounts are also unusual. For example, while the summits of seamounts are normally hundreds of meters below sea level, the Bowie Seamount rises from a depth of about 3,000 meters to within 24 meters of the sea surface. The Bowie Seamount is a Submarine volcano, located 180 kilometers west of the Queen Charlotte Islands, British Columbia, Canada.
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Geography
Seamounts are often found in groupings or submerged archipelagos, a classic example, being the Emperor Seamounts, which are an extension of the Hawaiian Islands, which were formed millions of years ago by volcanism, and have since subsided to below sea level. An archipelago (ɑrkəˈpɛləgoʊ is a chain or cluster of Islands The word archipelago literally means "chief Sea " from Italian The Hawaiian-Emperor seamount chain is composed of the Hawaiian Ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor The Hawaiian Islands, once known as the Sandwich Islands, form an Archipelago of 19 Islands and Atolls numerous smaller Plate tectonics and hotspots Divergent plate boundaries At the The long chain of islands and seamounts, extending thousands of kilometres northwest from the Big Island demonstrates the movement of a plate over the Hawaii hotspot. The Island of Hawaii, also called the Big Island or Hawaii Island, is a volcanic Island in the U Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere The Hawaii hotspot is perhaps the best known volcanic hotspot on Earth, responsible for the Hawaiian Islands in the Pacific Ocean.
Isolated seamounts and those without clear volcanic origins appear to be less common. Plate tectonics and hotspots Divergent plate boundaries At the In recent years, geologists have confirmed that a number of seamounts are active undersea volcanoes: Lo‘ihi in the Hawaiian Islands and Vailulu‘u in the Manu‘a Group (Samoa) are examples. Plate tectonics and hotspots Divergent plate boundaries At the Lōihi is a Seamount and undersea Volcano in the Hawaiian archipelago, located at 18 Vailulu'u is a volcanic Seamount that was discovered in 1975 It rises 4200 m from the sea floor to a depth of 590 m Manua or the Manua Islands Group (Samoan Manua tele) consists of three main islands Ta{{okina}}u, Ofu and Olosega.
Ecology
Seamounts often project upwards into shallower zones more hospitable to sea life, providing habitats for marine species that are not found on or around the surrounding deeper ocean bottom. A habitat (which is Latin for "it inhabits" is an Ecological or environmental area that is inhabited by a particular Species. Because seamounts are isolated from each other they form "undersea islands" creating the same biogeographical interest. Biogeography is the study of the distribution of Biodiversity over Space and Time. As they are formed from volcanic rock, the substrate is much harder than the surrounding sedimentary deep sea floor. This causes a different type of fauna to exist than on the seafloor, and leads to a higher degree of endemism. Endemism is the Ecological state of being unique to a place Endemic species are not naturally found elsewhere
In addition to simply providing physical presence in this zone, the seamount itself may deflect deep currents and create upwelling. Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense cooler and usually nutrient-rich water towards the ocean surface replacing the warmer This process can bring nutrients into the photosynthetic zone, producing an area of activity in an otherwise desert-like open ocean. Seamounts may thus be vital stopping points for some migratory animals such as whales. Whales are marine mammals which are neither Dolphins (ie members of the families Delphinidae or Platanistoidae) nor Porpoises Orcas Some recent research indicates whales may use such features as navigational aids throughout their migration. Due to the larger populations of fish in these areas overexpoitation by the fishing industry has caused some seamount fauna populations to decrease considerably.
The primary productivity of the epipelagic waters above the submerged peak can often be enhanced by the hydrographic conditions of the seamount. Any water in the sea that is not close to the bottom is in the pelagic zone. Hydrography focuses on the measurement of physical characteristics of Waters and marginal land [2] This increases the densities of the zooplankton and leads to the high concentrations of fish in these areas. Zooplankton are the Heterotrophic (sometimes detritivorous) type of Plankton. Another theory for this is that the fish are sustained on the diurnal migration of zooplankton being interrupted by the presence of the seamount, and causing the zooplankton to stay in the area. It is also possible that the high densities of fishes has more to do with the fish life histories and interaction with the benthic fauna of the seamount. [3] The benthic fauna of the seamounts is dominated by suspension feeders, including sponges and true corals. The sponges or poriferans (from Latin porus "pore" and ferre "to bear" are Animals Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many For some seamounts that peaks at 200-300 metres below the surface benthic macroalgae is common. The sedimentary infauna is dominated by polychaete worms. The Polychaeta or polychaetes are a class of Annelid worms generally marine
For a long time it has been surmised that many pelagic animals visit seamounts to gather food, but proof this of this aggregating effect has been lacking. The first demonstration of this conjecture has recently been published [4]
In 2005 a Census of Marine Life project "CenSeam" (a global census of marine life on seamounts) was formed. CenSeam is intended to provide the framework needed to prioritise, integrate, expand and facilitate seamount research efforts in order to significantly reduce the unknown and build towards a global understanding of seamount ecosystems, and the roles they have in the biogeography, biodiversity, productivity and evolution of marine organisms. CenSeam researchers have identified two core research themes – (1): What factors drive community composition and diversity on seamounts, including any differences between seamounts and other habitat types? And (2): What are the impacts of human activities on seamount community structure and function?
Fishing
The main cause for the recent interest in seamounts is the discovery that they maintain large stocks of commercially important fishes and invertebrates. This began during the 1960s when Russia, Australia and New Zealand started to look for new stocks of fish and began to trawl the seamounts. Year 1960 ( MCMLX) was a Leap year starting on Friday (link will display full calendar of the Gregorian calendar. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending For a topic outline on this subject see List of basic Australia topics. New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island The majority of the invertebrates brought up are corals, and are mainly used for the jewelry trade. The two major fish species were the orange roughy (Hoplostethus atlanticus) and pelagic armourhead (Pseudopentaceros wheeleri), which were quickly overexploited due to lack of knowledge of the longevity of the fish, late maturity, low fecundity, small geographic range and recuitment to the fishery. The orange roughy, red roughy, or deep sea perch, Hoplostethus atlanticus, is a relatively large Deep-sea fish belonging to the Slimehead The pelagic armorhead, pelagic armourhead, Richardson's boarfish, or southern boarfish, Pseudopentaceros richardsoni, is an Armorhead Fecundity, derived from the word fecund, generally refers to the ability to Reproduce. As well as the fishes being overexploited the benthic communities were destroyed by the trawling gear.
One of the core research themes of CenSeam (a Census of Marine Life project - see link below) is the impact of human activities (e. g. fishing) on seamount community structure and function. CenSeam's Data Analysis Working Group recently assessed the vulnerability of deep-sea corals to fishing on seamounts beyond areas of national jurasdiction (Clark et al. 2006 - see external links).
Dangers
Some seamounts have not been mapped and thus pose a navigational danger. For instance, Muirfield Seamount is named after the ship that hit it in 1973. The Muirfield Seamount is a submarine mountain located in the Indian Ocean approximately 130 kilometers (70 nautical miles southwest of the Cocos (Keeling Islands More recently, the USS San Francisco (SSN-711) submarine ran into an uncharted seamount in 2005 at a speed of 35 knots, sustaining serious damage and killing one seaman. Collision with Seamount On 8 January 2005 at about 0200 GMT San Francisco collided with an undersea mountain about 560 kilometers (350 statute miles Volcanic eruptions at active seamounts offer navigational hazards, and the collapse of seamount (or island) flanks may cause major Tsunamis.
See also
References
- ^ Nybakken, James W. For the French viticulturist see Jules Guyot. For the Old French name see Guiot. and Bertness, Mark D. , 2005. Marine Biology: An Ecological Approach. Sixth Edition. Benjamin Cummings, San Francisco
- ^ Boehlert, G. W. and Genin, A. 1987. A review of the effects of seamounts on biological processes. 319-334. Seamount, islands and atolls. Geophysical Monograph 43, edited by B. H. Keating, P. Fryer, R. Batiza, and G. W. Boehlert.
- ^ Rogers, A. D. 1994. The biology of seamounts. Advances in Marine Biology 30:305-350
- ^ Morato, T. , Varkey, D. A. , Damaso, C. , Machete, M. , Santos, M. , Prieto, R. , Santos, R. S. and Pitcher, T. J. (2008) Evidence of a seamount effect on aggregating visitors. Marine Ecology Progress Series 357: 23-32.
Bibliography
- de Forges, Richer; J. Anthony Koslow and G. C. B. Poore (2000-06-22). 2000 ( MM) was a Leap year that started on Saturday of the Common Era, in accordance with the Gregorian calendar. Events 217 BC - Battle of Raphia: Ptolemy IV of Egypt defeats Antiochus III the Great of the Seleucid kingdom. "Diversity and endemism of the benthic seamount fauna in the southwest Pacific". Nature 405 (6789): 944-947. Nature Publishing Group.
- Keating, B. H. , Fryer, P. , Batiza, R. , Boehlert, G. W. (Eds. ), 1987: Seamounts, islands and atolls. Geophys. Monogr. 43:319-334.
- Koslow, J. A. (1997). Seamounts and the ecology of deep-sea fisheries. Am. Sci. 85:168-176.
- Menard, H. W. (1964). Marine Geology of the Pacific. International Series in the Earth Sciences. McGraw-Hill, New York, 271 pp.
- Pitcher, T. J. , Morato, T. , Hart, P. J. B. , Clark, M. R. , Haggan, N. and Santos, R. S. (eds) (2007) Seamounts: Ecology, Fisheries and Conservation. Fish and Aquatic Resources Series 12, Blackwell, Oxford, UK. 527pp. ISBN 978-1-4051-3343-2
External links
- Seamount Catalog, a database of seamount maps
- SeamountsOnline, a database of seamount biology
- Volcanic History of Seamounts in the Gulf of Alaska
- Hydrographic structure and circulation at the Great Meteor Seamount showing an example of an isolated seamount and the formation of a submerged island of life.
- Seamount Oasis
- CenSeam, Census of Marine Life project CenSeam: a global census of marine life on seamounts
- Vulnerability of deep sea corals to fishing on seamounts beyond areas of national jurisdiction Report authored by Clark et al. (2006)
- FeMO2007 Expedition, FeMO cruise to Loihi seamount
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