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123-515: Between the 1930s and '80s, it was hypothesized that iron is a limiting ocean micronutrient, but there were not sufficient methods reliably to detect iron in seawater to confirm this hypothesis. In 1989, high concentrations of iron-rich sediments in nearshore coastal waters off the Gulf of Alaska were detected. However, offshore waters had lower iron concentrations and lower productivity despite macronutrient availability for phytoplankton growth. This pattern

246-504: A ton of gold ). Prochlorococcus is ubiquitous between 40°N and 40°S and dominates in the oligotrophic (nutrient-poor) regions of the oceans. Prochlorococcus is mostly found in a temperature range of 10–33 °C and some strains can grow at depths with low light (<1% surface light). These strains are known as LL (Low Light) ecotypes, with strains that occupy shallower depths in the water column known as HL (High Light) ecotypes. Furthermore, Prochlorococcus are more plentiful in

369-648: A central lagoon . Important human migrations occurred in the Pacific in prehistoric times. Modern humans first reached the western Pacific in the Paleolithic , at around 60,000 to 70,000 years ago. Originating from a southern coastal human migration out of Africa, they reached East Asia , Mainland Southeast Asia , the Philippines, New Guinea , and then Australia by making the sea crossing of at least 80 kilometres (50 mi) between Sundaland and Sahul . It

492-406: A day in the subsurface layer or oligotrophic waters. Prochlorococcus is abundant in the euphotic zone of the world's tropical oceans. It is possibly the most plentiful genus on Earth: a single millilitre of surface seawater may contain 100,000 cells or more. Worldwide, the average yearly abundance is (2.8 to 3.0) × 10 individuals (for comparison, that is approximately the number of atoms in

615-459: A depth where blue light penetrates allows them to inhabit depths between 80 and 200 m. Their genomes can range from 1,650,000 to 2,600,000 basepairs in size. Prochlorococcus marinus subsp. pastoris is associated with high-light adapted types. It can be further classified by sub-ecotypes HLI-HLVI. HLIII, like LV, is also located in an iron-limited environment near the equator, with similar ferric adaptations. The high-light adapted subspecies

738-433: A difficult time digesting the sequestered algae. Biofuels, not sold and used as renewable fuel, could be sequestered in abandoned oil wells and coal mines. The volume of bio-diesel and mass of bio-char would provide an accurate figure for producing (when sequestering) and selling (when removing from wells or mines) carbon credits. Pacific Ocean Main five oceans division: Further subdivision: The Pacific Ocean

861-1026: A low, constant standing stock. Without this grazing pressure , some scientists believe small phytoplankton would produce blooms despite micronutrient depletion because smaller phytoplankton typically have lower iron requirements and can absorb nutrients at a slower rate. Current scientific consensus agrees that HNLC areas lack high productivity because of a combination of iron and physiological limitations, grazing pressure, and physical forcings. The extent to which each factor contributes to low production may differ in each HNLC region. Iron limitation allows for smaller, more iron-frugal phytoplankton to grow at rapid rates, while grazing by microzooplankton maintains stable stocks of these smaller phytoplankton. Once micronutrients become available, grazing may then limit bloom sizes. Additional micronutrient limitations from trace metals like zinc or cobalt may suppress phytoplankton blooms. Turbulent mixing at higher-latitude HNLC regions (North Pacific and Southern Ocean) may mix phytoplankton below

984-578: A major role in global marine new primary production . New production is a term used in biological oceanography to describe the way in which nitrogen is recycled within the ocean. In regions of enhanced new production, nitrate from the aphotic zone makes its way into surface waters, replenishing surface nitrate supply. Despite nitrogen availability in Equatorial Pacific waters, primary production and observed surface ocean biomass are considerably lower compared to other major upwelling regions of

1107-467: A proxy for primary production. Modern satellite observations monitor and track global chlorophyll α abundances in the ocean via remote sensing . Higher chlorophyll concentrations generally indicate areas of enhanced primary production, and conversely lower chlorophyll levels indicate low primary production. This co-occurrence of low chlorophyll and high macronutrient availability is why these regions are deemed "high-nutrient, low-chlorophyll." In addition to

1230-528: A subsurface supply of micronutrients, which can be used by primary producers during upwelling of deeper waters to the surface. Seafloor depth may also stimulate phytoplankton blooms in HNLC regions as iron diffuses from the seafloor and alleviates iron limitation in shallow waters. Research conducted in the Gulf of Alaska showed that areas with shallow waters, such as the south shelf of Alaska, have more intense phytoplankton blooms than offshore waters. Volcanic ash from

1353-542: Is 4,280 m (14,040 ft; 2,340 fathoms), putting the total water volume at roughly 710,000,000 km (170,000,000 cu mi). Due to the effects of plate tectonics , the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km (0.20 sq mi) a year. By contrast, the Atlantic Ocean is increasing in size. Along

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1476-563: Is a genus of very small (0.6  μm ) marine cyanobacteria with an unusual pigmentation ( chlorophyll a2 and b2 ). These bacteria belong to the photosynthetic picoplankton and are probably the most abundant photosynthetic organism on Earth. Prochlorococcus microbes are among the major primary producers in the ocean, responsible for a large percentage of the photosynthetic production of oxygen . Prochlorococcus strains, called ecotypes, have physiological differences enabling them to exploit different ecological niches. Analysis of

1599-555: Is completely theoretical. Testing would be required to determine feasibility, optimum iron concentration per unit area, carbon sequestration by area over time, need for other micro-nutrients, amount of energy required to maintain such a system, and the potential amount of energy produced by the system. This system considers economic feasibility (profitability of bio-fuel products and carbon credits) and risk management. Grazing results in algae being consumed by micro-zooplankton. This predation results in less than 7-10% of carbon being taken to

1722-526: Is in the correct bioavailable form of iron. Additionally, iron must be deposited during productive seasons and coincide with the appropriate RKR-ratios of surface nutrients. Aeolian dust has a larger influence on Northern Hemisphere HNLC regions because more land mass contributes to more dust deposition. Due to the Southern Ocean's isolation from land, upwelling related to eddy diffusivity provides iron to HNLC regions. Formulated by John Walsh in 1976,

1845-621: Is low, so most phytoplankton that are not consumed sink to the sea floor which provides nutrients to benthic organisms. Given the remote location of HNLC areas, scientists have combined modeling and observational data in order to study limits on primary production. Combining these two data sources allows for comparison between the North Pacific, Equatorial Pacific, and Southern Ocean. Two current explanations for global HNLC regions are growth limitations due to iron availability and phytoplankton grazing controls. In 1988, John Martin confirmed

1968-404: Is made up of lipids, carbohydrates, amino acids, and nucleic acids. Whole algae could be turned into animal feed, fertilizer, or bio-char . Separating the lipids from the algae could also create bio-diesel from the lipid content and bio-char from the rest. Of course, the algae could be pumped to the bottom of the ocean, below any grazing pressure for sequestration. In a controlled floating farm,

2091-491: Is not known with any certainty what level of maritime technology was used by these groups – the presumption is that they used large bamboo rafts which may have been equipped with some sort of sail. The reduction in favourable winds for a crossing to Sahul after 58,000 B.P. fits with the dating of the settlement of Australia, with no later migrations in the prehistoric period. The seafaring abilities of pre-Austronesian residents of Island South-east Asia are confirmed by

2214-426: Is otherwise known to have a low ratio of chlorophyll b2 to chlorophyll a2. High-light adapted strains inhabit depths between 25 and 100 m. Their genomes can range from 1,640,000 to 1,800,000 basepairs in size. Most cyanobacterium are known to have an incomplete tricarboxylic acid cycle (TCA). In this process, 2-oxoglutarate decarboxylase (2OGDC) and succinic semialdehyde dehydrogenase (SSADH), replace

2337-548: Is supplied to the North Pacific by dust storms that occur in Asia and Alaska as well as iron-rich waters advected from the continental margin, sometimes by eddies such as Haida Eddies . Concentrations of iron however vary throughout the year. Ocean currents are driven by seasonal atmospheric patterns which transport iron from the Kuril-Kamchatka margin into the western Subarctic Pacific. This introduction of iron provides

2460-616: Is the largest and deepest of Earth's five oceanic divisions . It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica ) in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with a southern Antarctic border), this largest division of

2583-497: Is the only known prokaryote with α-carotene. The genomes of several strains of Prochlorococcus have been sequenced. Twelve complete genomes have been sequenced which reveal physiologically and genetically distinct lineages of Prochlorococcus marinus that are 97% similar in the 16S rRNA gene. Research has shown that a massive genome reduction occurred during the Neoproterozoic Snowball Earth , which

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2706-642: The Americas , although evidence for this remains inconclusive. The first contact of European navigators with the western edge of the Pacific Ocean was made by the Portuguese expeditions of António de Abreu and Francisco Serrão , via the Lesser Sunda Islands , to the Maluku Islands , in 1512, and with Jorge Álvares 's expedition to southern China in 1513, both ordered by Afonso de Albuquerque from Malacca . The eastern side of

2829-424: The Americas , more than 25,000 islands, large and small, rise above the surface of the Pacific Ocean. Multiple islands were the shells of former active volcanoes that have lain dormant for thousands of years. Close to the equator, without vast areas of blue ocean, are a dot of atolls that have over intervals of time been formed by seamounts as a result of tiny coral islands strung in a ring within surroundings of

2952-520: The Bering Sea in the Arctic to the northern extent of the circumpolar Southern Ocean at 60°S (older definitions extend it to Antarctica 's Ross Sea ), the Pacific reaches its greatest east–west width at about 5°N latitude , where it stretches approximately 19,800 km (12,300 mi) from Indonesia to the coast of Colombia  – halfway around the world, and more than five times

3075-989: The Massachusetts Institute of Technology , Robert J. Olson of the Woods Hole Oceanographic Institution , and other collaborators in the Sargasso Sea using flow cytometry . Chisholm was awarded the Crafoord Prize in 2019 for the discovery. The first culture of Prochlorococcus was isolated in the Sargasso Sea in 1988 ( strain SS120) and shortly another strain was obtained from the Mediterranean Sea (strain MED). The name Prochlorococcus originated from

3198-601: The Pacific War ; however, by the end of that war, Japan was defeated and the U.S. Pacific Fleet was the virtual master of the ocean. The Japanese-ruled Northern Mariana Islands came under the control of the United States. Since the end of World War II, many former colonies in the Pacific have become independent states . The Pacific separates Asia and Australia from the Americas. It may be further subdivided by

3321-498: The Prochlorococcus make it a key organism in oligotrophic waters serving as an important primary producer to the open ocean food webs. Prochlorococcus has different "ecotypes" occupying different niches and can vary by pigments, light requirements, nitrogen and phosphorus utilization, copper, and virus sensitivity. It is thought that Prochlorococcus may occupy potentially 35 different ecotypes and sub-ecotypes within

3444-738: The Sirena Deep , is also located in the Mariana Trench. The western Pacific has many major marginal seas , including the Philippine Sea , South China Sea , East China Sea , Sea of Japan , Sea of Okhotsk , Bering Sea , Gulf of Alaska , Gulf of California , Mar de Grau , Tasman Sea , and the Coral Sea . In the early 16th century , Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama in 1513 and sighted

3567-725: The Southern Hemisphere . The North Equatorial Current , driven westward along latitude 15°N by the trade winds , turns north near the Philippines to become the warm Japan or Kuroshio Current . Turning eastward at about 45°N , the Kuroshio forks and some water moves northward as the Aleutian Current , while the rest turns southward to rejoin the North Equatorial Current. The Aleutian Current branches as it approaches North America and forms

3690-710: The Southwest Pacific around Oceania . The Pacific Ocean's mean depth is 4,000 meters (13,000 feet). Challenger Deep in the Mariana Trench , located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of 10,928 meters (35,853 feet). The Pacific also contains the deepest point in the Southern Hemisphere , the Horizon Deep in the Tonga Trench , at 10,823 meters (35,509 feet). The third deepest point on Earth,

3813-685: The Strait of Magellan to the Philippines , the explorer indeed found the ocean peaceful; however, the Pacific is not always peaceful. Many tropical storms batter the islands of the Pacific. The lands around the Pacific Rim are full of volcanoes and often affected by earthquakes . Tsunamis , caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns. The Martin Waldseemüller map of 1507

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3936-818: The Western Hemisphere . The Southern Pacific Ocean harbors the Southeast Indian Ridge crossing from south of Australia turning into the Pacific-Antarctic Ridge (north of the South Pole ) and merges with another ridge (south of South America) to form the East Pacific Rise which also connects with another ridge (south of North America) which overlooks the Juan de Fuca Ridge . For most of Magellan's voyage from

4059-673: The World Ocean and the hydrosphere covers about 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area (148,000,000 km (57,000,000 sq mi)). The centers of both the Water Hemisphere and the Western Hemisphere , as well as the oceanic pole of inaccessibility , are in the Pacific Ocean. Ocean circulation (caused by the Coriolis effect ) subdivides it into two largely independent volumes of water that meet at

4182-583: The crab claw sail ) – it is likely that the progressive development of these technologies were related to the later steps of settlement into Near and Remote Oceania. Starting at around 2200 BCE, Austronesians sailed southwards to settle the Philippines . From, probably, the Bismarck Archipelago they crossed the western Pacific to reach the Marianas Islands by 1500 BCE, as well as Palau and Yap by 1000 BCE. They were

4305-408: The critical depth needed to have community growth. Since past iron fertilization experiments have resulted in large phytoplankton blooms, some have suggested that large-scale ocean fertilization experiments should be conducted to draw down inorganic anthropogenic carbon dioxide in the form of particulate organic carbon . Fertilization would stimulate biological productivity, leading to a decrease in

4428-991: The equator , the North Pacific Ocean and the South Pacific Ocean (or more loosely the South Seas ). The Pacific Ocean can also be informally divided by the International Date Line into the East Pacific and the West Pacific , which allows it to be further divided into four quadrants, namely the Northeast Pacific off the coasts of North America , the Southeast Pacific off South America , Northwest Pacific off Far Eastern / Pacific Asia , and

4551-411: The genome sequences of Prochlorococcus strains show that 1,273 genes are common to all strains, and the average genome size is about 2,000 genes . In contrast, eukaryotic algae have over 10,000 genes. Although there had been several earlier records of very small chlorophyll- b -containing cyanobacteria in the ocean, Prochlorococcus was discovered in 1986 by Sallie W. (Penny) Chisholm of

4674-619: The neurotoxin domoic acid , poisoning grazing fish. If diatoms grow preferentially during iron fertilization experiments, sustained fertilizations could enhance domoic acid poisoning in the marine food web near fertilized patches. Iron enters remote HNLC regions through two primary methods: upwelling of nutrient-rich water and atmospheric dust deposition. Iron needs to be replenished frequently and in bioavailable forms because of its insolubility , rapid uptake through biological systems, and binding affinity with ligands . Dust deposition might not result in phytoplankton blooms unless settling dust

4797-433: The umuCD gene complex whose product, DNA polymerase V , functions in error-prone DNA replication. These cyanobacteria also have the gene lexA that regulates an SOS response system, probably a system like the well-studied E. coli SOS system that is employed in the response to DNA damage . Ancestors of Prochlorococcus contributed to the production of early atmospheric oxygen. Despite Prochlorococcus being one of

4920-645: The Aeolian Dust hypothesis which suggests that the atmospheric transport of iron-rich dust off Central and South America controls the intensity of primary production in the Equatorial Pacific. One study suggests that because EUC upwelling provides most of the bioavailable iron to the equatorial surface waters, the only method to reverse HNLC conditions is by enhancing upwelling. In other words, enhanced regional upwelling, rather than iron-rich atmospheric dust deposition, may explain why this region experiences higher primary productivity during glacial periods. Compared to

5043-908: The Atlantic, the Strait of Magellan was at times patrolled by fleets sent to prevent the entrance of non-Spanish ships. On the western side of the Pacific Ocean the Dutch threatened the Spanish Philippines . The 18th century marked the beginning of major exploration by the Russians in Alaska and the Aleutian Islands , such as the First Kamchatka expedition and the Great Northern Expedition , led by

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5166-533: The Atlantic. The andesite line is the most significant regional distinction in the Pacific. A petrologic boundary, it separates the deeper, mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of felsic igneous rock on its margins. The andesite line follows the western edge of the islands off California and passes south of the Aleutian arc , along

5289-466: The Atlantic. Because of low atmospheric dust inputs directly onto Southern Ocean surface waters, chlorophyll α concentrations are low. Light availability in the Southern Ocean changes dramatically seasonally, but it does not seem to be a significant constraint on phytoplankton growth. Macronutrients present in Southern Ocean surface waters come from upwelled deep water. While micronutrients such as zinc and cobalt may possibly co-limit phytoplankton growth in

5412-672: The Chilean coast, the South Equatorial Current divides; one branch flows around Cape Horn and the other turns north to form the Peru or Humboldt Current . The climate patterns of the Northern and Southern Hemispheres generally mirror each other. The trade winds in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on

5535-844: The Danish-born Russian navy officer Vitus Bering . Spain also sent expeditions to the Pacific Northwest , reaching Vancouver Island in southern Canada, and Alaska. The French explored and colonized Polynesia , and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii , and the North American Pacific Northwest . In 1768, Pierre-Antoine Véron , a young astronomer accompanying Louis Antoine de Bougainville on his voyage of exploration, established

5658-400: The Equatorial Pacific may have been 2.5 times more productive than the modern equatorial ocean. During these glacial periods, the Equatorial Pacific increased its export of marine new production, thus providing a sink of atmospheric carbon dioxide. The science of paleoceanography attempts to understand the interplay of glacial cycles with ocean dynamics. Paleo-oceanographers currently challenge

5781-679: The Moluccas, between 1525 and 1527, Portuguese expeditions encountered the Caroline Islands , the Aru Islands , and Papua New Guinea . In 1542–43 the Portuguese also reached Japan. In 1564, five Spanish ships carrying 379 soldiers crossed the ocean from Mexico led by Miguel López de Legazpi , and colonized the Philippines and Mariana Islands . For the remainder of the 16th century, Spain maintained military and mercantile control, with ships sailing from Mexico and Peru across

5904-546: The North Atlantic is incorporated into North Atlantic Deep Water and is transported to the Southern Ocean via thermohaline circulation . Eventually mixing with the Antarctic Circumpolar Water , upwelling provides iron and macronutrients to the Southern Ocean surface waters. Therefore, iron inputs and primary production in the Southern Ocean are sensitive to iron-rich Saharan dust deposited over

6027-410: The North Pacific and Southern Ocean, Equatorial Pacific waters have relatively low levels of biogenic silica and thus do not support significant standing stocks of diatoms. Picoplankton are the most abundant marine primary producers in these regions due mainly to their ability to assimilate low concentrations of trace metals. Various phytoplankton communities within the Equatorial Pacific are grazed at

6150-579: The North Pacific is an HNLC region, it produces and exports to the ocean interior a relatively high amount of particulate biogenic silica compared to the North Atlantic, which supports significant diatom growth. The Equatorial Pacific is an oceanic province characterized by nearly year-round upwelling due to the convergence of trade winds from the northeast and southeast at the Intertropical Convergence Zone . The Equatorial Pacific spans nearly half of Earth’s circumference and plays

6273-498: The North Pacific), synechococcus , and various eukaryotes . Grazing protists likely control the abundance and distribution of these small phytoplankton. The generally lower net primary production in HNLC zones results in lower biological draw-down of atmospheric carbon dioxide and thus these regions are generally considered a net source of carbon dioxide to the atmosphere. HNLC areas are of interest to geoengineers and some in

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6396-631: The Pacific Ring of Fire is the world's foremost belt of explosive volcanism . The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones. The Pacific Ocean is the only ocean which is mostly bounded by subduction zones. Only the central part of the North American coast and the Antarctic and Australian coasts have no nearby subduction zones. Prochlorococcus Prochlorococcus

6519-802: The Pacific Ocean to the Philippines via Guam , and establishing the Spanish East Indies . The Manila galleons operated for two and a half centuries, linking Manila and Acapulco , in one of the longest trade routes in history. Spanish expeditions also arrived at Tuvalu , the Marquesas , the Cook Islands , the Solomon Islands , Vanuatu , the Marshalls and the Admiralty Islands in the South Pacific. Later, in

6642-399: The Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea , Coral Sea , East China Sea (East Sea), Philippine Sea , Sea of Japan , South China Sea (South Sea), Sulu Sea , Tasman Sea , and Yellow Sea (West Sea of Korea). The Indonesian Seaway (including the Strait of Malacca and Torres Strait ) joins the Pacific and the Indian Ocean to

6765-402: The Pacific in recorded history. They were part of a Spanish expedition to the Spice Islands that would eventually result in the first world circumnavigation . Magellan called the ocean Pacífico (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas off Cape Horn , the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until

6888-540: The Philippines already in 7000 BCE. Additional earlier migrations into Insular Southeast Asia, associated with Austroasiatic-speakers from Mainland Southeast Asia, are estimated to have taken place already in 15000 BCE. At around 1300 to 1200 BCE, a branch of the Austronesian migrations known as the Lapita culture reached the Bismarck Archipelago , the Solomon Islands , Vanuatu , Fiji , and New Caledonia . From there, they settled Tonga and Samoa by 900 to 800 BCE. Some also back-migrated northwards in 200 BCE to settle

7011-436: The South Sandwich Islands . These areas are adjacent to shelf regions of Antarctica and islands of the Southern Ocean. The micronutrients required for algal growth are believed to be supplied from the shelves themselves. Except in areas close to the Antarctic shelf, micronutrient deficiency severely limits productivity in the Southern Ocean. Iron availability is not the only regulator of phytoplankton productivity and biomass. In

7134-401: The Southern Ocean, iron appears to be a critical limiting micronutrient. Some regions of the Southern Ocean experience both adequate bioavailable iron and macronutrient concentrations yet phytoplankton growth is limited. Hydrographic studies and explorations of the Southern Drake Passage region have observed this phenomenon around the Crozet Islands , Kerguelen Islands , and South Georgia and

7257-444: The Southern Ocean, prevailing low temperatures are believed to have a negative impact on phytoplankton growth rates. Phytoplankton growth rate is very intense and short lived in open areas surrounded by sea ice and permanent sea-ice zones . Grazing by herbivores such as krill, copepods and salps is believed to suppress phytoplankton standing stock. Unlike the open waters of the Southern Ocean, grazing along continental shelf margins

7380-528: The United States. Significant contributions to oceanographic knowledge were made by the voyages of HMS Beagle in the 1830s, with Charles Darwin aboard; HMS Challenger during the 1870s; the USS Tuscarora (1873–76); and the German Gazelle (1874–76). In Oceania, France obtained a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853, respectively. After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro negotiated

7503-451: The amount of inorganic surface carbon dioxide within a fertilized patch. The bloom would then die off and presumably sink to the deep ocean, taking much of the absorbed carbon dioxide to the seafloor and sequestering it from the short-term carbon cycle in the deep ocean or ocean sediments. To effectively remove anthropogenic carbon from the atmosphere, iron fertilization would need to result in significant removal of particulate carbon from

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7626-416: The andesite line and include New Guinea, the islands of New Zealand, and the Philippines. Some of these islands are structurally associated with nearby continents. High islands are of volcanic origin, and many contain active volcanoes. Among these are Bougainville , Hawaii, and the Solomon Islands. The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under

7749-408: The andesite line. Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the andesite line, volcanism is of the explosive type, and

7872-409: The arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December. A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. The Westerlies and associated jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between

7995-420: The bacteria's distribution across the oceans suggest that the colder waters could be fatal. This wide range of latitude along with the bacteria's ability to survive up to depths of 100 to 150 metres, i.e. the average depth of the mixing layer of the surface ocean, allows it to grow to enormous numbers, up to 3×10 individuals worldwide. This enormous number makes the Prochlorococcus play an important role in

8118-421: The base of a counter-clockwise circulation in the Bering Sea . Its southern arm becomes the chilled slow, south-flowing California Current . The South Equatorial Current , flowing west along the equator, swings southward east of New Guinea , turns east at about 50°S , and joins the main westerly circulation of the South Pacific, which includes the Earth-circling Antarctic Circumpolar Current . As it approaches

8241-407: The bottom of the ocean. Growing algae in floating farms could allow these HNLC areas to grow algae for harvest without the problem of predation. Algae grown in floating farms would be recycled through grazing if there was a catastrophic failure of a floating farm, which would limit any environmental damage. Algae grown in floating farms could be harvested and used for food or fuel. All biological life

8364-407: The convergence of subtropical water and the equatorial "cold tongue." The Equatorial Pacific contains the world's largest yellowfin tuna fisheries and is home to the spotted dolphin . The Southern Ocean is the largest HNLC region in the global ocean. The surface waters of the Southern Ocean have been widely identified as being rich in macronutrients despite low phytoplankton stocks. Iron deposited in

8487-702: The development of hypotheses such as grazing control which poses that HNLC regions are formed, in part, from the grazing of phytoplankton (e.g. dinoflagellates , ciliates ) by smaller organisms (e.g. protists ). Primary production is the process by which autotrophs use light to convert carbon from aqueous carbon dioxide to sugar for cellular growth. Light provides the energy for the photosynthetic process and nutrients are incorporated into organic material . For photosynthesis to occur, macronutrients such as nitrate and phosphate must be available in sufficient ratios and bioavailable forms for biological utilization. The molecular ratio of 106(Carbon):16(Nitrogen):1(Phosphorus)

8610-408: The diameter of the Moon. Its geographic center is in eastern Kiribati south of Kiritimati , just west from Starbuck Island at 4°58′S 158°45′W  /  4.97°S 158.75°W  / -4.97; -158.75 . The lowest known point on Earth – the Mariana Trench  – lies 10,911 m (35,797  ft ; 5,966 fathoms ) below sea level. Its average depth

8733-402: The difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active month. November is the only month in which all the tropical cyclone basins are active. The Pacific hosts the two most active tropical cyclone basins , which are

8856-493: The east and the islands of Kiribati in the southeast. Melanesia, to the southwest, includes New Guinea , the world's second largest island after Greenland and by far the largest of the Pacific islands. The other main Melanesian groups from north to south are the Bismarck Archipelago , the Solomon Islands , Santa Cruz , Vanuatu , Fiji and New Caledonia . The largest area, Polynesia , stretching from Hawaii in

8979-505: The east coast of Russia contrasting with the milder weather off British Columbia during the winter months due to the preferred flow of ocean currents . In the tropical and subtropical Pacific, the El Niño Southern Oscillation (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately 3,000 km (1,900 mi) to

9102-665: The eastern edge of the Kamchatka Peninsula , the Kuril Islands , Japan, the Mariana Islands , the Solomon Islands , and New Zealand's North Island . The dissimilarity continues northeastward along the western edge of the Andes Cordillera along South America to Mexico, returning then to the islands off California. Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside

9225-572: The eighteenth century. Magellan stopped at one uninhabited Pacific island before stopping at Guam in March 1521. Although Magellan himself died in the Philippines in 1521, Spanish navigator Juan Sebastián Elcano led the remains of the expedition back to Spain across the Indian Ocean and round the Cape of Good Hope , completing the first world circumnavigation in 1522. Sailing around and east of

9348-647: The equator into northern (North Pacific) and southern (South Pacific) portions. It extends from the Antarctic region in the South to the Arctic in the north. The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of 165,200,000 km (63,800,000 sq mi) – larger than Earth's entire landmass combined, 150,000,000 km (58,000,000 sq mi). Extending approximately 15,500 km (9,600 mi) from

9471-435: The equator, and as a result, have lost several ferric proteins. The low-light adapted subspecies is otherwise known to have a higher ratio of chlorophyll b2 to chlorophyll a2, which aids in its ability to absorb blue light. Blue light is able to penetrate ocean waters deeper than the rest of the visible spectrum, and can reach depths of >200 m, depending on the turbidity of the water. Their ability to photosynthesize at

9594-601: The equator, which can have a salinity as low as 34 parts per thousand, is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. The lowest counts of less than 32 parts per thousand are found in the far north as less evaporation of seawater takes place in these frigid areas. The motion of Pacific waters is generally clockwise in the Northern Hemisphere (the North Pacific gyre ) and counter-clockwise in

9717-593: The eruption of the Kasatochi volcano in August 2008 provided an example of natural iron fertilization in the Northeast Pacific Ocean. The region was fertilized by raining volcanic dust containing soluble iron. In the days following, phytoplankton blooms were visible from space. Limitations in trace metal concentrations in the North Pacific limit diatom blooms throughout the entire year. Even though

9840-480: The extra production gets incorporated into the food chain or falls to the deep ocean after a bloom dies off. Even if carbon is exported to depth, raining organic matter can be respired, potentially creating mid-column anoxic zones or causing acidification of deep ocean water. Pronounced community shifts to diatoms have been observed during fertilization, and it's still unclear if the change in species composition has any long-term environmental effects. The following

9963-508: The fact it was originally assumed that Prochlorococcus was related to Prochloron and other chlorophyll- b -containing bacteria, called prochlorophytes, but it is now known that prochlorophytes form several separate phylogenetic groups within the cyanobacteria subgroup of the bacteria domain. The only species within the genus described is Prochlorococcus marinus , although two subspecies have been named for low-light and high-light adapted niche variations. Marine cyanobacteria are to date

10086-488: The first HNLC region, the North Pacific , was formalized in a seminal paper published in 1988. The study concluded that surface waters of the eastern North Pacific are generally dominated by picoplankton despite the relative abundance of macronutrients. In other words, larger phytoplankton, such as diatoms which thrive in nutrient-rich waters, were not found. Instead, the surface waters were replete with smaller pico- and nanoplankton. Based on laboratory nutrient experiments, iron

10209-606: The first completely documented European landing in Australia (1606), in Cape York Peninsula , and Abel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and arrived at Tasmania and New Zealand in 1642. In the 16th and 17th centuries, Spain considered the Pacific Ocean a mare clausum  – a sea closed to other naval powers. As the only known entrance from

10332-474: The first humans to reach Remote Oceania , and the first to cross vast distances of open water. They also continued spreading southwards and settling the rest of Maritime Southeast Asia , reaching Indonesia and Malaysia by 1500 BCE, and further west to Madagascar and the Comoros in the Indian Ocean by around 500 CE. More recently, it is suggested that Austronesians expanded already earlier, arriving in

10455-493: The global carbon cycle and oxygen production. Along with Synechococcus (another genus of cyanobacteria that co-occurs with Prochlorococcus ) these cyanobacteria are responsible for approximately 50% of marine carbon fixation, making it an important carbon sink via the biological carbon pump (i.e. the transfer of organic carbon from the surface ocean to the deep via several biological, physical and chemical processes). The abundance, distribution and all other characteristics of

10578-403: The grazing hypothesis states that grazing by heterotrophs suppresses primary productivity in areas of high nutrient concentrations. Predation by microzooplankton primarily accounts for phytoplankton loss in HNLC regions. Grazing by larger zooplankton and advective mixing are also responsible for a small proportion of losses to phytoplankton communities. Constant grazing limits phytoplankton to

10701-533: The great "Southern Sea" which he named Mar del Sur (in Spanish). Afterwards, the ocean's current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favorable winds on reaching the ocean. He called it Mar Pacífico , which in Portuguese means 'peaceful sea'. Top large seas: Across the continents of Asia, Australia and

10824-521: The harvest could be sampled to record the amount of algae per unit volume which will indicate the amount of carbon being sequestered. If this carbon is sequestered at the bottom of the ocean, this figure could be used to accurately create carbon credits. Sequestering carbon dioxide on the ocean floor could destroy the unstudied ecosystem and cause undiscovered lifeforms to go extinct. Carbon sequestration on land does so with desiccated algae. Without sufficient sources of water, bacteria and other life will have

10947-513: The hypothesis that iron limits phytoplankton blooms and growth rates in the North Pacific. His work was extrapolated to other HNLC regions through evidence which linked low surface iron concentration with low chlorophyll. In response to iron fertilization experiments (IronEx, SOIREE, SEEDS, etc.) in HNLC areas, large phytoplankton responses such as decreased surface nutrient concentration and increased biological activity were observed. Iron fertilization studies conducted at repeated intervals over

11070-439: The incorporation of the island into Chile with native Rapanui in 1888. By occupying Easter Island, Chile joined the imperial nations. By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile. Although the United States gained control of Guam and the Philippines from Spain in 1898, Japan controlled most of the western Pacific by 1914 and occupied many other islands during

11193-483: The islands in the world. There are about 25,000 islands in the Pacific Ocean. The islands entirely within the Pacific Ocean can be divided into three main groups known as Micronesia , Melanesia and Polynesia . Micronesia, which lies north of the equator and west of the International Date Line , includes the Mariana Islands in the northwest, the Caroline Islands in the center, the Marshall Islands to

11316-636: The islands of eastern Micronesia (including the Carolines , the Marshall Islands , and Kiribati ), mixing with earlier Austronesian migrations in the region. This remained the furthest extent of the Austronesian expansion into Polynesia until around 700 CE when there was another surge of island exploration. They reached the Cook Islands , Tahiti , and the Marquesas by 700 CE; Hawaiʻi by 900 CE; Rapa Nui by 1000 CE; and finally New Zealand by 1200 CE. Austronesians may have also reached as far as

11439-472: The light-harvesting antennae phycobilisomes . However, Prochlorochoccus has evolved to use a unique light-harvesting complex, consisting predominantly of divinyl derivatives of chlorophyll a (Chl a2) and chlorophyll b (Chl b2) and lacking monovinyl chlorophylls and phycobilisomes. Prochlorococcus is the only known wild-type oxygenic phototroph that does not contain Chl a as a major photosynthetic pigment, and

11562-465: The macronutrients needed for organic matter synthesis, phytoplankton need micronutrients such as trace metals for cellular functions. Micronutrient availability can constrain primary production because trace metals are sometimes limiting nutrients. Iron has been determined to be a primary limiting micronutrient in HNLC provinces. Recent studies have indicated that zinc and cobalt may be secondary and/or co-limiting micronutrients. HNLC regions cover 20% of

11685-601: The north to New Zealand in the south, also encompasses Tuvalu , Tokelau , Samoa , Tonga and the Kermadec Islands to the west, the Cook Islands , Society Islands and Austral Islands in the center, and the Marquesas Islands , Tuamotu , Mangareva Islands , and Easter Island to the east. Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs and uplifted coral platforms. Continental islands lie outside

11808-619: The northern Philippines , but also earlier groups associated with Austroasiatic-speakers , resulting in the modern peoples of Island Southeast Asia and Oceania. A later seaborne migration is the Neolithic Austronesian expansion of the Austronesian peoples . Austronesians originated from the island of Taiwan c.  3000 –1500 BCE. They are associated with distinctive maritime sailing technologies (notably outrigger boats , catamarans , lashed-lug boats, and

11931-575: The northwestern Pacific and the eastern Pacific. Pacific hurricanes form south of Mexico, sometimes striking the western Mexican coast and occasionally the Southwestern United States between June and October, while typhoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in the South Pacific basin , where they occasionally impact island nations. In

12054-399: The ocean was encountered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and reached a new ocean. He named it Mar del Sur ("Sea of the South" or "South Sea" ) because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. In 1520, navigator Ferdinand Magellan and his crew were the first to cross

12177-562: The ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia . The volume of the Pacific Ocean, representing about 50.1 percent of

12300-426: The ocean, HNLC zones have higher ratios of silicic acid to nitrate because larger diatoms , that require silicic acid to make their opal silica shells, are less prevalent. Unlike the Southern Ocean and the North Pacific, the Equatorial Pacific experiences temporal silicate availability which leads to large seasonal diatom blooms. The distribution of trace metals and relative abundance of macronutrients are reflected in

12423-480: The ocean. Thus the Equatorial Pacific is considered one of the three major HNLC regions. Like other major HNLC provinces, the Equatorial Pacific is considered nutrient-limited due to lack of trace metals such as iron. The Equatorial Pacific receives approximately 7-10 times more iron from Equatorial Undercurrent (EUC) upwelling than from inputs due to settling atmospheric dust. Climate reconstructions of glacial periods using sediment proxy records have revealed that

12546-464: The plankton community structure. For example, the selection of phytoplankton with a high surface area to volume ratio results in HNLC regions being dominated by nano- and picoplankton. This ratio allows for optimal utilization of available dissolved nutrients. Larger phytoplankton, such as diatoms, cannot energetically sustain themselves in these regions. Common picoplankton within these regions include genera such as prochlorococcus (not generally found in

12669-456: The presence of heterotrophs that have catalase abilities. Prochlorococcus do not have mechanisms to degrade reactive oxygen species and rely on heterotrophs to protect them. The bacterium accounts for an estimated 13–48% of the global photosynthetic production of oxygen , and forms part of the base of the ocean food chain . Prochlorococcus is closely related to Synechococcus , another abundant photosynthetic cyanobacteria, which contains

12792-581: The quest for Terra Australis ("the [great] Southern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigator Pedro Fernandes de Queirós , arrived at the Pitcairn and Vanuatu archipelagos, and sailed the Torres Strait between Australia and New Guinea, named after navigator Luís Vaz de Torres . Dutch explorers, sailing around southern Africa, also engaged in exploration and trade; Willem Janszoon , made

12915-536: The same rate as their growth rate, which further limits primary production. There is no current consensus regarding which of the two main hypotheses (grazing or micronutrients) controls production in these equatorial waters. It is likely that trace metal limitations select for smaller-celled organisms, which thereby increases the grazing pressure of protists. While the Equatorial Pacific maintains HNLC characteristics, productivity can be high at times. Productivity leads to an abundance of seabirds such as storm petrels near

13038-462: The scientific community who believe fertilizing large patches of these waters with iron could potentially lower dissolved carbon dioxide and offset increased anthropogenic carbon emissions. Analysis of Antarctic ice core data over the last million years shows correlation between high levels of dust and low temperature, indicating that addition of diffuse iron-rich dust to the sea has been a natural amplifier of climate cooling. The discovery and naming of

13161-505: The settlement of Buka by 32,000 B.P. and Manus by 25,000 B.P. Journeys of 180 kilometres (110 mi) and 230 kilometres (140 mi) are involved, respectively. The descendants of these migrations today are the Negritos , Melanesians , and Indigenous Australians . Their populations in maritime Southeast Asia , coastal New Guinea , and Island Melanesia later intermarried with the incoming Austronesian settlers from Taiwan and

13284-684: The smallest known photosynthetic organisms; Prochlorococcus is the smallest at just 0.5 to 0.7 micrometres in diameter. The coccoid shaped cells are non-motile and free-living. Their small size and large surface-area-to-volume ratio , gives them an advantage in nutrient-poor water. Still, it is assumed that Prochlorococcus have a very small nutrient requirement. Moreover, Prochlorococcus have adapted to use sulfolipids instead of phospholipids in their membranes to survive in phosphate deprived environments. This adaptation allows them to avoid competition with heterotrophs that are dependent on phosphate for survival. Typically, Prochlorococcus divide once

13407-531: The smallest types of marine phytoplankton in the world's oceans, its substantial number make it responsible for a major part of the oceans', world's photosynthesis, and oxygen production. The size of Prochlorococcus (0.5 to 0.7 μm) and the adaptations of the various ecotypes allow the organism to grow abundantly in low nutrient waters such as the waters of the tropics and the subtropics (c. 40°N to 40°S); however, they can be found in higher latitudes as high up as 60° north but at fairly minimal concentrations and

13530-504: The southeast of Hawaii is computed, and if the region is more than 0.5 °C (0.9 °F) above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when

13653-861: The span of a week have produced a larger biological response than a single fertilization event. The biological response size tends to depend on a site’s biological, chemical, and physical characteristics. In the Equatorial and North Pacific, silica is thought to constrain additional production after iron fertilization, while light limits additional production in the Southern Ocean. Native, smaller phytoplankton were initial responders to increased iron, but were quickly outcompeted by larger, coastal phytoplankton such as diatoms. The large bloom response and community shift has led to environmental concerns about fertilizing large sections of HNLC regions. One study suggests that diatoms grow preferentially during fertilization experiments. Some diatoms, such as pseudo-nitzschia , release

13776-582: The surface ocean and transport it to the deep ocean. Various studies estimated that less than 7-10% of carbon taken up during a bloom would be sequestered, and only a 15-25 ppm decrease in atmospheric carbon dioxide would result with sustained global iron fertilization. The amount of carbon dioxide removed may be offset by the fuel cost of acquiring, transporting, and releasing significant amounts of iron into remote HNLC regions. Many environmental concerns exist for large-scale iron fertilization. While blooms can be studied and traced, scientists still do not know if

13899-804: The tropics and Antarctica, which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated with extratropical cyclones riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude. The ocean was first mapped by Abraham Ortelius ; he called it Maris Pacifici following Ferdinand Magellan 's description of it as "a pacific sea" during his circumnavigation from 1519 to 1522. To Magellan, it seemed much more calm (pacific) than

14022-586: The west, and Drake Passage and the Strait of Magellan link the Pacific with the Atlantic Ocean on the east. To the north, the Bering Strait connects the Pacific with the Arctic Ocean . As the Pacific straddles the 180th meridian , the West Pacific (or western Pacific , near Asia) is in the Eastern Hemisphere , while the East Pacific (or eastern Pacific , near the Americas) is in

14145-534: The width of the Pacific with precision for the first time in history. One of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Growing imperialism during the 19th century resulted in the occupation of much of Oceania by European powers, and later Japan and

14268-434: The world's oceanic water, has been estimated at some 714 million cubic kilometers (171 million cubic miles). Surface water temperatures in the Pacific can vary from −1.4 °C (29.5 °F), the freezing point of seawater, in the poleward areas to about 30 °C (86 °F) near the equator. Salinity also varies latitudinally, reaching a maximum of 37 parts per thousand in the southeastern area. The water near

14391-547: The worlds' oceans. They can be differentiated on the basis of the sequence of the ribosomal RNA gene. It has been broken down by NCBI Taxonomy into two different subspecies, Low-light Adapted (LL) or High-light Adapted (HL). There are six clades within each subspecies. Prochlorococcus marinus subsp. marinus is associated with low-light adapted types. It is also further classified by sub-ecotypes LLI-LLVII, where LLII/III has not been yet phylogenetically uncoupled. LV species are found in highly iron scarce locations around

14514-615: The world’s oceans and are characterized by varying physical, chemical, and biological patterns. These surface waters have annually varying, yet relatively abundant macronutrient concentrations compared to other oceanic provinces. While HNLC broadly describes the biogeochemical trends of these large ocean regions, all three zones experience seasonal phytoplankton blooms in response to global atmospheric patterns. On average, HNLC regions tend to be growth-limited by iron and variably, zinc. This trace metal limitation leads to communities of smaller sized phytoplankton. Compared to more productive regions of

14637-848: Was deduced by Redfield, Ketcham, and Richards (RKR) and is known as the Redfield Ratio . Photosynthesis (forward) and respiration (reverse) is represented by the equation: Photosynthesis can be limited by deficiencies of certain macronutrients. However, in the North Pacific, the Equatorial Pacific, and the Southern Ocean macronutrients are found in sufficient ratios, quantities and bioavailable forms to support greater levels of primary production than found. Macronutrient availability in HNLC regions in tandem with low standing stocks of phytoplankton suggests that some other biogeochemical process limits phytoplankton growth. Since primary production and phytoplankton biomass cannot currently be measured over entire ocean basins, scientists use chlorophyll α as

14760-551: Was followed by population bottlenecks . The high-light ecotype has the smallest genome (1,657,990 basepairs, 1,716 genes) of any known oxygenic phototroph, but the genome of the low-light type is much larger (2,410,873 base pairs, 2,275 genes). Marine Prochlorococcus cyanobacteria have several genes that function in DNA recombination , repair and replication . These include the recBCD gene complex whose product, exonuclease V, functions in recombinational repair of DNA, and

14883-441: Was hypothesized to be a key limiting micronutrient. The Pacific Ocean is the largest and oldest body of water on Earth. The North Pacific is characterized by the general clockwise rotation of the North Pacific gyre , which is driven by trade winds . Spatial variations in tradewinds result in cooler air temperatures in the western North Pacific and milder air temperatures in the eastern North Pacific (i.e., Subarctic Pacific). Iron

15006-564: Was observed in other oceanic regions and led to the naming of three major HNLC zones: the North Pacific Ocean , the Equatorial Pacific Ocean, and the Southern Ocean . The discovery of HNLC regions has fostered scientific debate about the ethics and efficacy of iron fertilization experiments which attempt to draw down atmospheric carbon dioxide by stimulating surface-level photosynthesis. It has also led to

15129-583: Was the first to show the Americas separating two distinct oceans. Later, the Diogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size. (Inhabited dependent territories are denoted by the asterisk (*), with names of the corresponding sovereign states in round brackets. Associated states in the Realm of New Zealand are denoted by the hash sign (#).) Territories with no permanent civilian population. The Pacific Ocean has most of

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