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88-738: The Bering Canyon is the longest of the Bering Sea submarine canyons ; it extends about 400 km across the Bering shelf and slope. It is confined at its eastern edge by the Aleutian Islands . The width of the canyon at the shelf break is about 65 km, only about two-thirds that of the Zhemchug Canyon and Navarin Canyons , but because of its great length, the Bering Canyon has the largest area. At

176-454: A carbon sink . Management strategies are being employed to prevent eutrophication -related coccolithophore blooms, as these blooms lead to a decrease in nutrient flow to lower levels of the ocean. The most abundant species of coccolithophore, Emiliania huxleyi , belongs to the order Isochrysidales and family Noëlaerhabdaceae . It is found in temperate , subtropical , and tropical oceans. This makes E. huxleyi an important part of

264-600: A in austral spring and summer in the Southern Ocean, plays an important role in climate fluctuations, accounting for over 60% of the Southern Ocean area (30–60° S). The region between 30° and 50° S has the highest uptake of anthropogenic carbon dioxide (CO 2 ) alongside the North Atlantic and North Pacific oceans. Recent studies show that climate change has direct and indirect impacts on Coccolithophore distribution and productivity. They will inevitably be affected by

352-552: A 2012 study estimated that the overall effect of coccolithophores on the increase in radiative forcing of the ocean is less than that from anthropogenic factors. Therefore, the overall result of large blooms of coccolithophores is a decrease in water column productivity, rather than a contribution to global warming. Their predators include the common predators of all phytoplankton including small fish, zooplankton, and shellfish larvae. Viruses specific to this species have been isolated from several locations worldwide and appear to play

440-469: A 30–40% decline in average seasonal primary productivity has occurred over the last 50 years. The implication is that the carrying capacity of the Bering Sea is much lower now than it has been in the past. The sea supports many whale species, including the beluga , humpback whale , bowhead whale , gray whale and blue whale , the vulnerable sperm whale , and the endangered fin whale , sei whale and

528-427: A coccosphere seems to be a protection against predators or viruses. Viral infection is an important cause of phytoplankton death in the oceans, and it has recently been shown that calcification can influence the interaction between a coccolithophore and its virus. The major predators of marine phytoplankton are microzooplankton like ciliates and dinoflagellates . These are estimated to consume about two-thirds of

616-604: A depth of 3200 m, the Bering Canyon thalweg reaches the Aleutian Basin , where a low-relief submarine channel-lobe system has developed. This article about a specific oceanic location or ocean current is a stub . You can help Misplaced Pages by expanding it . Bering Sea The Bering Sea is separated from the Gulf of Alaska by the Alaska Peninsula . It covers over 2,000,000 square kilometers (770,000 sq mi) and

704-427: A functional or vestigial haptonema is also present. This structure, which is unique to haptophytes , coils and uncoils in response to environmental stimuli. Although poorly understood, it has been proposed to be involved in prey capture. The complex life cycle of coccolithophores is known as a haplodiplontic life cycle , and is characterized by an alternation of both asexual and sexual phases. The asexual phase

792-414: A higher albedo , and 2) there is induced photoinhibition , meaning photosythetic production is diminished due to an excess of light. In case 1), a high concentration of coccoliths leads to a simultaneous increase in surface water temperature and decrease in the temperature of deeper waters. This results in more stratification in the water column and a decrease in the vertical mixing of nutrients. However,

880-478: A hypothetical gain in competitiveness due to altered carbonate chemistry conditions would not automatically lead to dinoflagellate dominance because a huge number of factors other than carbonate chemistry have an influence on species composition as well. Currently, the evidence supporting or refuting a protective function of the coccosphere against predation is limited. Some researchers found that overall microzooplankton predation rates were reduced during blooms of

968-449: A large meteor exploded above the Bering Sea. The meteor exploded at an altitude of 25.6km, releasing 49 kilotons of energy. The International Hydrographic Organization defines the limits of the Bering Sea as follows: Islands of the Bering Sea include: Regions of the Bering Sea include: The Bering Sea contains 16 submarine canyons including the largest submarine canyon in the world, Zhemchug Canyon . The Bering Sea shelf break

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1056-560: A major role in spring bloom dynamics. No environmental evidence of coccolithophore toxicity has been reported, but they belong to the class Prymnesiophyceae which contain orders with toxic species. Toxic species have been found in the genera Prymnesium Massart and Chrysochromulina Lackey. Members of the genus Prymnesium have been found to produce haemolytic compounds, the agent responsible for toxicity. Some of these toxic species are responsible for large fish kills and can be accumulated in organisms such as shellfish; transferring it through

1144-635: A pod of beluga whales in the Bering Sea. One of the central characters in the 1949 film Down to the Sea in Ships has the given name "Bering" due to having been born in a ship crossing the Bering Sea. The 2002 supernatural thriller, Ghost Ship , directed by Steve Beck , follows a marine salvage crew in the Bering Sea who discover the lost Italian ocean liner, Antonia Graza that disappeared in 1962. Coccolithophore Coccolithophores , or coccolithophorids , are single-celled organisms which are part of

1232-414: A protective shell of coccoliths , calcified scales which make up its exoskeleton or coccosphere . The coccoliths are created inside the coccolithophore cell and while some species maintain a single layer throughout life only producing new coccoliths as the cell grows, others continually produce and shed coccoliths. The primary constituent of coccoliths is calcium carbonate, or chalk . Calcium carbonate

1320-408: A sharp increase in the population of coccolithophores. Coccolithophores are one of the more abundant primary producers in the ocean. As such, they are a large contributor to the primary productivity of the tropical and subtropical oceans, however, exactly how much has yet to have been recorded. The ratio between the concentrations of nitrogen , phosphorus and silicate in particular areas of

1408-547: A small subspecies of Canada goose, the Bering Canada goose ( Branta canadensis asiatica ) is extinct due to overhunting and the introduction of rats to their breeding islands. The Bering Sea supports many species of fish, some of which support large and valuable commercial fisheries. Commercial fish species include Pacific cod , several species of flatfish , sablefish , Pacific salmon , and Pacific herring . Shellfish include red king crab and snow crab . Fish biodiversity

1496-429: A smaller cell radius and lower cell volume than other types of phytoplankton. Giant DNA-containing viruses are known to lytically infect coccolithophores, particularly E. huxleyi . These viruses, known as E. huxleyi viruses (EhVs), appear to infect the coccosphere coated diploid phase of the life cycle almost exclusively. It has been proposed that as the haploid organism is not infected and therefore not affected by

1584-415: Is a coccolithophore. Coccolithophores are single-celled phytoplankton that produce small calcium carbonate (CaCO 3 ) scales ( coccoliths ) which cover the cell surface in the form of a spherical coating, called a coccosphere . Many species are also mixotrophs , and are able to photosynthesise as well as ingest prey. Coccolithophores have been an integral part of marine plankton communities since

1672-415: Is a single cell with membrane bound organelles . Two large chloroplasts with brown pigment are located on either side of the cell and surround the nucleus , mitochondria , golgi apparatus , endoplasmic reticulum , and other organelles. Each cell also has two flagellar structures, which are involved not only in motility, but also in mitosis and formation of the cytoskeleton . In some species,

1760-766: Is bordered on the east and northeast by Alaska , on the west by the Russian Far East and the Kamchatka Peninsula , on the south by the Alaska Peninsula and the Aleutian Islands and on the far north by the Bering Strait , which connects the Bering Sea to the Arctic Ocean 's Chukchi Sea . Bristol Bay is the portion of the Bering Sea between the Alaska Peninsula and Cape Newenham on mainland Southwest Alaska . The Bering Sea ecosystem includes resources within

1848-973: Is compacted serve as valuable microfossils . Calcification , the biological production of calcium carbonate (CaCO 3 ), is a key process in the marine carbon cycle . Coccolithophores are the major planktonic group responsible for pelagic CaCO 3 production. The diagram on the right shows the energetic costs of coccolithophore calcification: The diagram on the left shows the benefits of coccolithophore calcification. (A) Accelerated photosynthesis includes CCM (1) and enhanced light uptake via scattering of scarce photons for deep-dwelling species (2). (B) Protection from photodamage includes sunshade protection from ultraviolet (UV) light and photosynthetic active radiation (PAR) (1) and energy dissipation under high-light conditions (2). (C) Armor protection includes protection against viral/bacterial infections (1) and grazing by selective (2) and nonselective (3) grazers. The degree by which calcification can adapt to ocean acidification

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1936-416: Is high, and at least 419 species of fish have been reported from the Bering Sea. The Bering Sea is world-renowned for its productive and profitable fisheries, such as king crab , opilio and tanner crabs, Bristol Bay salmon, pollock and other groundfish. These fisheries rely on the productivity of the Bering Sea via a complicated and little understood food web. Commercial fishing is lucrative business in

2024-451: Is known as the haploid phase, while the sexual phase is known as the diploid phase. During the haploid phase, coccolithophores produce haploid cells through mitosis . These haploid cells can then divide further through mitosis or undergo sexual reproduction with other haploid cells. The resulting diploid cell goes through meiosis to produce haploid cells again, starting the cycle over. With coccolithophores, asexual reproduction by mitosis

2112-559: Is low in nutrient concentration, high in light intensity and penetration, and usually higher in temperature. The lower photic zone is high in nutrient concentration, low in light intensity and penetration and relatively cool. The middle photic zone is an area that contains the same values in between that of the lower and upper photic zones. The Great Calcite Belt of the Southern Ocean is a region of elevated summertime upper ocean calcite concentration derived from coccolithophores, despite

2200-594: Is now the Bering Strait. Other animals including megafauna migrated in both directions. This is commonly referred to as the " Bering land bridge " and is accepted by most, though not all scientists, to be the first point of entry of humans into the Americas . There is a small portion of the Kula Plate in the Bering Sea. The Kula Plate is an ancient tectonic plate that used to subduct under Alaska. On 18 December 2018,

2288-418: Is possible in both phases of the life cycle, which is a contrast with most other organisms that have alternating life cycles. Both abiotic and biotic factors may affect the frequency with which each phase occurs. Coccolithophores reproduce asexually through binary fission. In this process the coccoliths from the parent cell are divided between the two daughter cells. There have been suggestions stating

2376-446: Is possible within one year. Unraveling these fundamental constraints and the limits of adaptation should be a focus in future coccolithophore studies because knowing them is the key information required to understand to what extent the calcification response to carbonate chemistry perturbations can be compensated by evolution. Silicate- or cellulose-armored functional groups such as diatoms and dinoflagellates do not need to sustain

2464-494: Is presently unknown. Cell physiological examinations found the essential H efflux (stemming from the use of HCO 3 for intra-cellular calcification) to become more costly with ongoing ocean acidification as the electrochemical H inside-out gradient is reduced and passive proton outflow impeded. Adapted cells would have to activate proton channels more frequently, adjust their membrane potential , and/or lower their internal pH . Reduced intra-cellular pH would severely affect

2552-530: Is the dominant driver of primary productivity in the Bering Sea. This zone, where the shallower continental shelf drops off into the North Aleutians Basin is also known as the "Greenbelt". Nutrient upwelling from the cold waters of the Aleutian basin flowing up the slope and mixing with shallower waters of the shelf provide for constant production of phytoplankton . The second driver of productivity in

2640-418: Is transparent, so the organisms' photosynthetic activity is not compromised by encapsulation in a coccosphere. Coccoliths are produced by a biomineralization process known as coccolithogenesis. Generally, calcification of coccoliths occurs in the presence of light, and these scales are produced much more during the exponential phase of growth than the stationary phase. Although not yet entirely understood,

2728-416: Is widely accepted to affect the land-based fossil record . The coccolithophorids help in regulating the temperature of the oceans. They thrive in warm seas and release dimethyl sulfide (DMS) into the air whose nuclei help to produce thicker clouds to block the sun. When the oceans cool, the number of coccolithophorids decrease and the amount of clouds also decrease. When there are fewer clouds blocking

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2816-524: The Discovery Channel television program Deadliest Catch . Landings from Alaskan waters represents half the U.S. catch of fish and shellfish. Because of the changes going on in the Arctic, the future evolution of the Bering Sea climate and ecosystem is uncertain. Between 1979 and 2012, the region experienced small growth in sea ice extent, standing in contrast to the substantial loss of summer sea ice in

2904-526: The Jurassic . Today, coccolithophores contribute ~1–10% to inorganic carbon fixation (calcification) to total carbon fixation (calcification plus photosynthesis) in the surface ocean and ~50% to pelagic CaCO 3 sediments. Their calcareous shell increases the sinking velocity of photosynthetically fixed CO 2 into the deep ocean by ballasting organic matter. At the same time, the biogenic precipitation of calcium carbonate during coccolith formation reduces

2992-455: The White Cliffs of Dover , and of other similar rocks in many other parts of the world. At the present day sedimented coccoliths are a major component of the calcareous oozes that cover up to 35% of the ocean floor and is kilometres thick in places. Because of their abundance and wide geographic ranges, the coccoliths which make up the layers of this ooze and the chalky sediment formed as it

3080-451: The carbon cycle . The production of coccoliths requires the uptake of dissolved inorganic carbon and calcium. Calcium carbonate and carbon dioxide are produced from calcium and bicarbonate by the following chemical reaction: Because coccolithophores are photosynthetic organisms, they are able to use some of the CO 2 released in the calcification reaction for photosynthesis . However,

3168-630: The phytoplankton , the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingdom Protista , according to Robert Whittaker 's five-kingdom system , or clade Hacrobia , according to a newer biological classification system. Within the Hacrobia, the coccolithophores are in the phylum or division Haptophyta , class Prymnesiophyceae (or Coccolithophyceae ). Coccolithophores are almost exclusively marine , are photosynthetic and mixotrophic , and exist in large numbers throughout

3256-475: The planktonic base of a large proportion of marine food webs . It is also the fastest growing coccolithophore in laboratory cultures. It is studied for the extensive blooms it forms in nutrient depleted waters after the reformation of the summer thermocline . and for its production of molecules known as alkenones that are commonly used by earth scientists as a means to estimate past sea surface temperatures . Coccolithophores (or coccolithophorids, from

3344-406: The sunlight zone of the ocean . Coccolithophores are the most productive calcifying organisms on the planet, covering themselves with a calcium carbonate shell called a coccosphere . However, the reasons they calcify remain elusive. One key function may be that the coccosphere offers protection against microzooplankton predation, which is one of the main causes of phytoplankton death in

3432-478: The white cliffs of Dover . Of particular interest are fossils dating back to the Palaeocene-Eocene Thermal Maximum 55 million years ago. This period is thought to correspond most directly to the current levels of CO 2 in the ocean. Finally, field evidence of coccolithophore fossils in rock were used to show that the deep-sea fossil record bears a rock record bias similar to the one that

3520-460: The Arctic Ocean to the north. 'The White Seal', one of many chapters on Rudyard Kipling 's The Jungle Book , features the Bering Sea as the birthplace and homeland of Kotick, a rare white fur seal . The film Harbinger Down , which was released on August 7, 2015, was about a group of grad students who booked passage on the crabbing boat Harbinger to study the effects of global warming on

3608-415: The Bering Sea is seasonal sea ice that, in part, triggers the spring phytoplankton bloom. Seasonal melting of sea ice causes an influx of lower salinity water into the middle and other shelf areas, causing stratification and hydrographic effects which influence productivity. In addition to the hydrographic and productivity influence of melting sea ice, the ice itself also provides an attachment substrate for

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3696-483: The Bering Sea, which is relied upon by the largest seafood companies in the world to produce fish and shellfish. On the U.S. side, commercial fisheries catch approximately $ 1 billion worth of seafood annually, while Russian Bering Sea fisheries are worth approximately $ 600 million annually. The Bering Sea also serves as the central location of the Alaskan king crab and snow crab seasons, which are chronicled on

3784-496: The European-based CALMARO are monitoring the responses of coccolithophore populations to varying pH's and working to determine environmentally sound measures of control. Coccolith fossils are prominent and valuable calcareous microfossils . They are the largest global source of biogenic calcium carbonate, and significantly contribute to the global carbon cycle . They are the main constituent of chalk deposits such as

3872-518: The Indian Ocean, are not as well studied as other locations in the Pacific and Atlantic Oceans. It is also very hard to explain distributions due to multiple constantly changing factors involving the ocean's properties, such as coastal and equatorial upwelling , frontal systems, benthic environments, unique oceanic topography, and pockets of isolated high or low water temperatures. The upper photic zone

3960-799: The Pacific Ocean was in an area of the ocean considered the Central North Zone which is an area between 30 N and 5 N, composed of the North Equatorial Current and the Equatorial Countercurrent. These two currents move in opposite directions, east and west, allowing for a strong mixing of waters and allowing a large variety of species to populate the area. In the Atlantic Ocean, the most abundant species are E. huxleyi and Florisphaera profunda with smaller concentrations of

4048-527: The added weight of multiple layers of coccoliths allows the organism to sink to lower, more nutrient rich layers of the water and conversely, that coccoliths add buoyancy, stopping the cell from sinking to dangerous depths. Coccolith appendages have also been proposed to serve several functions, such as inhibiting grazing by zooplankton. Coccoliths are the main component of the Chalk , a Late Cretaceous rock formation which outcrops widely in southern England and forms

4136-702: The adjective ) form a group of about 200 phytoplankton species. They belong either to the kingdom Protista , according to Robert Whittaker 's Five kingdom classification , or clade Hacrobia , according to the newer biological classification system. Within the Hacrobia, the coccolithophores are in the phylum or division Haptophyta , class Prymnesiophyceae (or Coccolithophyceae ). Coccolithophores are distinguished by special calcium carbonate plates (or scales) of uncertain function called coccoliths , which are also important microfossils . However, there are Prymnesiophyceae species lacking coccoliths (e.g. in genus Prymnesium ), so not every member of Prymnesiophyceae

4224-478: The alga, this additional source of gas is then available to the Coccolithophore for photosynthesis. It has been suggested that they may provide a cell-wall like barrier to isolate intracellular chemistry from the marine environment. More specific, defensive properties of coccoliths may include protection from osmotic changes, chemical or mechanical shock, and short-wavelength light. It has also been proposed that

4312-596: The area, which provides highly productive foraging habitat, particularly along the shelf edge and in other nutrient-rich upwelling regions, such as the Pribilof, Zhemchug , and Pervenets canyons. The Bering Sea is also home to colonies of crested auklets , with upwards of a million individuals. Two Bering Sea species, the Steller's sea cow ( Hydrodamalis gigas ) and spectacled cormorant ( Phalacrocorax perspicillatus ), are extinct because of overexploitation by man. In addition,

4400-412: The basis of its size or shape and through chemical signals and may thus favor other prey that is available and not protected by coccoliths. Coccolithophores are spherical cells about 5–100 micrometres across, enclosed by calcareous plates called coccoliths , which are about 2–25 micrometres across. Each cell contains two brown chloroplasts which surround the nucleus . Enclosed in each coccosphere

4488-418: The biomineralization process is tightly regulated by calcium signaling . Calcite formation begins in the golgi complex where protein templates nucleate the formation of CaCO 3 crystals and complex acidic polysaccharides control the shape and growth of these crystals. As each scale is produced, it is exported in a Golgi-derived vesicle and added to the inner surface of the coccosphere. This means that

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4576-655: The bottom of the ocean in the form of coccoliths and becomes part of sediment; thus, coccolithophores provide a sink for emitted carbon, mediating the effects of greenhouse gas emissions. Research also suggests that ocean acidification due to increasing concentrations of CO 2 in the atmosphere may affect the calcification machinery of coccolithophores. This may not only affect immediate events such as increases in population or coccolith production, but also may induce evolutionary adaptation of coccolithophore species over longer periods of time. For example, coccolithophores use H ion channels in to constantly pump H ions out of

4664-440: The calcification-related H efflux. Thus, they probably do not need to adapt in order to keep costs for the production of structural elements low. On the contrary, dinoflagellates (except for calcifying species; with generally inefficient CO 2 -fixing RuBisCO enzymes may even profit from chemical changes since photosynthetic carbon fixation as their source of structural elements in the form of cellulose should be facilitated by

4752-650: The cell during coccolith production. This allows them to avoid acidosis , as coccolith production would otherwise produce a toxic excess of H ions. When the function of these ion channels is disrupted, the coccolithophores stop the calcification process to avoid acidosis, thus forming a feedback loop . Low ocean alkalinity , impairs ion channel function and therefore places evolutionary selective pressure on coccolithophores and makes them (and other ocean calcifiers) vulnerable to ocean acidification. In 2008, field evidence indicating an increase in calcification of newly formed ocean sediments containing coccolithophores bolstered

4840-477: The cell. Heterococcoliths occur only in the diploid phase, have radial symmetry, and are composed of relatively few complex crystal units (fewer than 100). Although they are rare, combination coccospheres, which contain both holococcoliths and heterococcoliths, have been observed in the plankton recording coccolithophore life cycle transitions. Finally, the coccospheres of some species are highly modified with various appendages made of specialized coccoliths. While

4928-469: The coccolithophore Emiliania huxleyi , while others found high microzooplankton grazing rates on natural coccolithophore communities. In 2020, researchers found that in situ ingestion rates of microzooplankton on E. huxleyi did not differ significantly from those on similar sized non-calcifying phytoplankton. In laboratory experiments the heterotrophic dinoflagellate Oxyrrhis marina preferred calcified over non-calcified cells of E. huxleyi , which

5016-673: The coccolithoviruses and diploid organism. Coccolithophores are members of the clade Haptophyta , which is a sister clade to Centrohelida , which are both in Haptista . The oldest known coccolithophores are known from the Late Triassic, around the Norian - Rhaetian boundary. Diversity steadily increased over the course of the Mesozoic, reaching its apex during the Late Cretaceous . However, there

5104-433: The coccosphere prevents ingestion by the grazer. Instead, ingestion rates were dependent on the offered genotype of E. huxleyi. Altogether, these two studies suggest that the genotype has a strong influence on ingestion by the microzooplankton species, but if and how calcification protects coccolithophores from microzooplankton predation could not be fully clarified. Coccolithophores have both long and short term effects on

5192-473: The dinoflagellate shell, should rather be favored at high H concentrations because these usually coincide with high [CO 2 ]. Under these conditions dinoflagellates could down-regulate the energy-consuming operation of carbon concentrating mechanisms to fuel the production of organic source material for their shell. Therefore, a shift in carbonate chemistry conditions toward high [CO 2 ] may promote their competitiveness relative to coccolithophores. However, such

5280-463: The entire cellular machinery and require other processes (e.g. photosynthesis ) to co-adapt in order to keep H efflux alive. The obligatory H efflux associated with calcification may therefore pose a fundamental constraint on adaptation which may potentially explain why "calcification crisis" were possible during long-lasting (thousands of years) CO 2 perturbation events even though evolutionary adaption to changing carbonate chemistry conditions

5368-429: The exact function of the coccosphere is unclear, many potential functions have been proposed. Most obviously coccoliths may protect the phytoplankton from predators. It also appears that it helps them to create a more stable pH . During photosynthesis carbon dioxide is removed from the water, making it more basic. Also calcification removes carbon dioxide, but chemistry behind it leads to the opposite pH reaction; it makes

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5456-490: The first ever experimental data showing that an increase in ocean CO 2 concentration results in an increase in calcification of these organisms. Decreasing coccolith mass is related to both the increasing concentrations of CO 2 and decreasing concentrations of CO 2− 3 in the world's oceans. This lower calcification is assumed to put coccolithophores at ecological disadvantage. Some species like Calcidiscus leptoporus , however, are not affected in this way, while

5544-490: The food chain. In laboratory tests for toxicity members of the oceanic coccolithophore genera Emiliania, Gephyrocapsa, Calcidiscus and Coccolithus were shown to be non-toxic as were species of the coastal genus Hymenomonas , however several species of Pleurochrysis and Jomonlithus , both coastal genera were toxic to Artemia . Coccolithophorids are predominantly found as single, free-floating haploid or diploid cells. Most phytoplankton need sunlight and nutrients from

5632-414: The genotype of E. huxleyi that was offered, rather than on their degree of calcification. In the same study, however, the authors found that predators which preyed on non-calcifying genotypes grew faster than those fed with calcified cells. In 2018, Strom et al. compared predation rates of the dinoflagellate Amphidinium longum on calcified relative to naked E. huxleyi prey and found no evidence that

5720-526: The growth of algae as well as interstitial ice algae. Some evidence suggests that great changes to the Bering Sea ecosystem have already occurred. Warm water conditions in the summer of 1997 resulted in a massive bloom of low energy coccolithophorid phytoplankton (Stockwell et al. 2001). A long record of carbon isotopes , which is reflective of primary production trends of the Bering Sea, exists from historical samples of bowhead whale baleen . Trends in carbon isotope ratios in whale baleen samples suggest that

5808-436: The increasing temperatures and thermal stratification of the top layer of the ocean, since these are prime controls on their ecology, although it is not clear whether global warming would result in net increase or decrease of coccolithophores. As they are calcifying organisms, it has been suggested that ocean acidification due to increasing carbon dioxide could severely affect coccolithophores. Recent CO 2 increases have seen

5896-472: The jurisdiction of the United States and Russia , as well as international waters in the middle of the sea (known as the "Donut Hole" ). The interaction between currents, sea ice, and weather makes for a vigorous and productive ecosystem. Most scientists think that during the most recent ice age , sea level was low enough to allow humans to migrate east on foot from Asia to North America across what

5984-502: The life cycle of coccolithophores occur seasonally, where more nutrition is available in warmer seasons and less is available in cooler seasons. This type of life cycle is known as a complex heteromorphic life cycle. Coccolithophores occur throughout the world's oceans. Their distribution varies vertically by stratified layers in the ocean and geographically by different temporal zones. While most modern coccolithophores can be located in their associated stratified oligotrophic conditions,

6072-503: The life cycle of different coccolithophore species, there is often alternation between a motile, haploid phase, and a non-motile diploid phase. In both phases, the organism's dispersal is largely due to ocean currents and circulation patterns. Within the Pacific Ocean, approximately 90 species have been identified with six separate zones relating to different Pacific currents that contain unique groupings of different species of coccolithophores. The highest diversity of coccolithophores in

6160-474: The most abundant areas of coccolithophores where there is the highest species diversity are located in subtropical zones with a temperate climate. While water temperature and the amount of light intensity entering the water's surface are the more influential factors in determining where species are located, the ocean currents also can determine the location where certain species of coccolithophores are found. Although motility and colony formation vary according to

6248-530: The most abundant coccolithophore species, E. huxleyi might be (study results are mixed). Also, highly calcified coccolithophorids have been found in conditions of low CaCO 3 saturation contrary to predictions. Understanding the effects of increasing ocean acidification on coccolithophore species is absolutely essential to predicting the future chemical composition of the ocean, particularly its carbonate chemistry. Viable conservation and management measures will come from future research in this area. Groups like

6336-424: The most inexpensive armor under all circumstances because diatoms typically outcompete all other groups when silicate is available. The coccosphere is relatively inexpensive under sufficient [CO 2 ], high [HCO 3 ], and low [H ] because the substrate is saturating and protons are easily released into seawater. In contrast, the construction of thecal elements, which are organic ( cellulose ) plates that constitute

6424-441: The most recently produced coccoliths may lie beneath older coccoliths. Depending upon the phytoplankton's stage in the life cycle, two different types of coccoliths may be formed. Holococcoliths are produced only in the haploid phase, lack radial symmetry, and are composed of anywhere from hundreds to thousands of similar minute (ca 0.1 μm) rhombic calcite crystals. These crystals are thought to form at least partially outside

6512-472: The ocean acidification-associated CO 2 fertilization. Under the assumption that any form of shell/exoskeleton protects phytoplankton against predation non-calcareous armors may be the preferable solution to realize protection in a future ocean. The diagram on the right is a representation of how the comparative energetic effort for armor construction in diatoms, dinoflagellates and coccolithophores appear to operate. The frustule (diatom shell) seems to be

6600-786: The ocean dictates competitive dominance within phytoplankton communities. Each ratio essentially tips the odds in favor of either diatoms or other groups of phytoplankton, such as coccolithophores. A low silicate to nitrogen and phosphorus ratio allows coccolithophores to outcompete other phytoplankton species; however, when silicate to phosphorus to nitrogen ratios are high coccolithophores are outcompeted by diatoms. The increase in agricultural processes lead to eutrophication of waters and thus, coccolithophore blooms in these high nitrogen and phosphorus, low silicate environments. The calcite in calcium carbonate allows coccoliths to scatter more light than they absorb. This has two important consequences: 1) Surface waters become brighter, meaning they have

6688-521: The ocean to survive, so they thrive in areas with large inputs of nutrient rich water upwelling from the lower levels of the ocean. Most coccolithophores require sunlight only for energy production, and have a higher ratio of nitrate uptake over ammonium uptake (nitrogen is required for growth and can be used directly from nitrate but not ammonium). Because of this they thrive in still, nutrient-poor environments where other phytoplankton are starving. Trade-offs associated with these faster growth rates include

6776-428: The ocean. Coccolithophores are ecologically important, and biogeochemically they play significant roles in the marine biological pump and the carbon cycle . Depending on habitat, they can produce up to 40 percent of the local marine primary production . They are of particular interest to those studying global climate change because, as ocean acidity increases, their coccoliths may become even more important as

6864-717: The possible presence of a sexual reproduction process due to the diploid stages of the coccolithophores, but this process has never been observed. K or r- selected strategies of coccolithophores depend on their life cycle stage. When coccolithophores are diploid, they are r-selected. In this phase they tolerate a wider range of nutrient compositions. When they are haploid they are K- selected and are often more competitive in stable low nutrient environments. Most coccolithophores are K strategist and are usually found on nutrient-poor surface waters. They are poor competitors when compared to other phytoplankton and thrive in habitats where other phytoplankton would not survive. These two stages in

6952-412: The primary production in the ocean and microzooplankton can exert a strong grazing pressure on coccolithophore populations. Although calcification does not prevent predation, it has been argued that the coccosphere reduces the grazing efficiency by making it more difficult for the predator to utilise the organic content of coccolithophores. Heterotrophic protists are able to selectively choose prey on

7040-596: The production of calcium carbonate drives surface alkalinity down, and in conditions of low alkalinity the CO 2 is instead released back into the atmosphere. As a result of this, researchers have postulated that large blooms of coccolithophores may contribute to global warming in the short term. A more widely accepted idea, however, is that over the long term coccolithophores contribute to an overall decrease in atmospheric CO 2 concentrations. During calcification two carbon atoms are taken up and one of them becomes trapped as calcium carbonate. This calcium carbonate sinks to

7128-558: The rarest in the world, the North Pacific right whale . Other marine mammals include walrus , Steller sea lion , northern fur seal , orca and polar bear . The Bering Sea is very important to the seabirds of the world. Over 30 species of seabirds and approximately 20 million individuals breed in the Bering Sea region. Seabird species include tufted puffins , the endangered short-tailed albatross , spectacled eider , and red-legged kittiwakes . Many of these species are unique to

7216-471: The region being known for its diatom predominance. The overlap of two major phytoplankton groups, coccolithophores and diatoms, in the dynamic frontal systems characteristic of this region provides an ideal setting to study environmental influences on the distribution of different species within these taxonomic groups. The Great Calcite Belt, defined as an elevated particulate inorganic carbon (PIC) feature occurring alongside seasonally elevated chlorophyll

7304-445: The species Umbellosphaera irregularis , Umbellosphaera tenuis and different species of Gephyrocapsa . Deep-dwelling coccolithophore species abundance is greatly affected by nutricline and thermocline depths. These coccolithophores increase in abundance when the nutricline and thermocline are deep and decrease when they are shallow. The complete distribution of coccolithophores is currently not known and some regions, such as

7392-431: The total alkalinity of seawater and releases CO 2 . Thus, coccolithophores play an important role in the marine carbon cycle by influencing the efficiency of the biological carbon pump and the oceanic uptake of atmospheric CO 2 . As of 2021, it is not known why coccolithophores calcify and how their ability to produce coccoliths is associated with their ecological success. The most plausible benefit of having

7480-412: The virus, the co-evolutionary " arms race " between coccolithophores and these viruses does not follow the classic Red Queen evolutionary framework, but instead a "Cheshire Cat" ecological dynamic. More recent work has suggested that viral synthesis of sphingolipids and induction of programmed cell death provides a more direct link to study a Red Queen-like coevolutionary arms race at least between

7568-403: The water more acidic. The combination of photosynthesis and calcification therefore even out each other regarding pH changes. In addition, these exoskeletons may confer an advantage in energy production, as coccolithogenesis seems highly coupled with photosynthesis. Organic precipitation of calcium carbonate from bicarbonate solution produces free carbon dioxide directly within the cellular body of

7656-624: Was a sharp drop during the Cretaceous-Paleogene extinction event , when more than 90% of coccolithophore species became extinct. Coccoliths reached another, lower apex of diversity during the Paleocene-Eocene thermal maximum , but have subsequently declined since the Oligocene due to decreasing global temperatures, with species that produced large and heavily calcified coccoliths most heavily affected. Each coccolithophore encloses itself in

7744-407: Was hypothesised to be due to size selective feeding behaviour, since calcified cells are larger than non-calcified E. huxleyi . In 2015, Harvey et al. investigated predation by the dinoflagellate O. marina on different genotypes of non-calcifying E. huxleyi as well as calcified strains that differed in the degree of calcification. They found that the ingestion rate of O. marina was dependent on

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