Great Calcite Belt
{{Short description|High-calcite region of the Southern Ocean}}
File:Great Calcite Belt of the Southern Ocean.webm. The belt appears during the southern hemisphere summer as a light teal stripe.]]
The Great Calcite Belt (GCB) refers to a region of the ocean where there are high concentrations of calcite, a mineral form of calcium carbonate. The belt extends over a large area of the Southern Ocean surrounding Antarctica. The calcite in the Great Calcite Belt is formed by tiny marine organisms called coccolithophores, which build their shells out of calcium carbonate. When these organisms die, their shells sink to the bottom of the ocean, and over time, they accumulate to form a thick layer of calcite sediment.
The Great Calcite Belt occurs in areas of the Southern ocean where the calcite compensation depth (CCD) is relatively shallow, meaning that calcite minerals from the shells of marine organisms dissolve at a shallower depth in the water column. This results in a higher concentration of calcium carbonate sediments in the ocean floor, which can be observed in the form of white chalky sediments.
The Great Calcite Belt plays a significant role regulating the global carbon cycle. Calcite is a form of carbon that is removed from the atmosphere and stored in the ocean, which helps to reduce the amount of carbon dioxide in the atmosphere and mitigate the effects of climate change. Recent studies suggest the belt sequesters something between 15 and 30 million tonnes of carbon per year.{{cite journal | last1=Anderson | first1=Robert F. | last2=Sachs | first2=Julian P. | last3=Fleisher | first3=Martin Q. | last4=Allen | first4=Katherine A. | last5=Yu | first5=Jimin | last6=Koutavas | first6=Athanasios | last7=Jaccard | first7=Samuel L. | title=Deep‐Sea Oxygen Depletion and Ocean Carbon Sequestration During the Last Ice Age | journal=Global Biogeochemical Cycles | publisher=American Geophysical Union (AGU) | volume=33 | issue=3 | year=2019 | issn=0886-6236 | doi=10.1029/2018gb006049 | pages=301–317| bibcode=2019GBioC..33..301A | hdl=1885/196693 | s2cid=134926685 | hdl-access=free }}
Scientists have further interest in the calcite sediments in the belt, which contain valuable information about past climate, ocean currents, ocean chemistry, and marine ecosystems. For example, variations in the CCD depth over time can indicate changes in the amount of carbon dioxide in the atmosphere and the ocean's ability to absorb it. The belt is also home to a diverse range of contemporary marine life, including deep-sea corals and fish that are adapted to the unique conditions found in this part of the ocean. The Great Calcite Belt is a region of elevated summertime upper ocean calcite concentration derived from coccolithophores, despite 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.
Overview
{{plankton sidebar|bloom}}
The Great Calcite Belt can be defined as an elevated particulate inorganic carbon (PIC) feature occurring alongside seasonally elevated chlorophyll a in austral spring and summer in the Southern Ocean.{{cite journal |doi = 10.1029/2004JC002560|title = Calcium carbonate measurements in the surface global ocean based on Moderate-Resolution Imaging Spectroradiometer data|year = 2005|last1 = Balch|first1 = W. M.|last2 = Gordon|first2 = Howard R.|last3 = Bowler|first3 = B. C.|last4 = Drapeau|first4 = D. T.|last5 = Booth|first5 = E. S.|journal = Journal of Geophysical Research|volume = 110|issue = C7|pages = C07001|bibcode = 2005JGRC..110.7001B|doi-access = free}} It plays an important role in climate fluctuations,{{cite journal |doi = 10.1038/30455|title = Simulated response of the ocean carbon cycle to anthropogenic climate warming|year = 1998|last1 = Sarmiento|first1 = Jorge L.|last2 = Hughes|first2 = Tertia M. C.|last3 = Stouffer|first3 = Ronald J.|last4 = Manabe|first4 = Syukuro|journal = Nature|volume = 393|issue = 6682|pages = 245–249|bibcode = 1998Natur.393..245S|s2cid = 4317429}}{{cite journal |doi = 10.1029/2003GB002134|title = Response of ocean ecosystems to climate warming|year = 2004|last1 = Sarmiento|first1 = J. L.|last2 = Slater|first2 = R.|last3 = Barber|first3 = R.|last4 = Bopp|first4 = L.|last5 = Doney|first5 = S. C.|last6 = Hirst|first6 = A. C.|last7 = Kleypas|first7 = J.|last8 = Matear|first8 = R.|last9 = Mikolajewicz|first9 = U.|last10 = Monfray|first10 = P.|last11 = Soldatov|first11 = V.|last12 = Spall|first12 = S. A.|last13 = Stouffer|first13 = R.|journal = Global Biogeochemical Cycles|volume = 18|issue = 3|pages = n/a|bibcode = 2004GBioC..18.3003S|hdl = 1912/3392| s2cid=15482539 |hdl-access = free}} accounting for over 60% of the Southern Ocean area (30–60° S).{{cite journal |doi = 10.1029/2011JC006941|title = The contribution of coccolithophores to the optical and inorganic carbon budgets during the Southern Ocean Gas Exchange Experiment: New evidence in support of the "Great Calcite Belt" hypothesis|year = 2011|last1 = Balch|first1 = W. M.|last2 = Drapeau|first2 = D. T.|last3 = Bowler|first3 = B. C.|last4 = Lyczskowski|first4 = E.|last5 = Booth|first5 = E. S.|last6 = Alley|first6 = D.|journal = Journal of Geophysical Research|volume = 116|issue = C4|pages = C00F06|bibcode = 2011JGRC..116.0F06B}} The region between 30° and 50° S has the highest uptake of anthropogenic carbon dioxide (CO2) alongside the North Atlantic and North Pacific oceans.{{cite journal |doi = 10.1126/science.1097403|title = The Oceanic Sink for Anthropogenic CO2|year = 2004|last1 = Sabine|first1 = C. L.|last2 = Feely|first2 = R. A.|last3 = Gruber|first3 = N.|last4 = Key|first4 = R. M.|last5 = Lee|first5 = K.|last6 = Bullister|first6 = J. L.|last7 = Wanninkhof|first7 = R.|last8 = Wong|first8 = C. S.|last9 = Wallace|first9 = D. W.|last10 = Tilbrook|first10 = B.|last11 = Millero|first11 = F. J.|last12 = Peng|first12 = T. H.|last13 = Kozyr|first13 = A.|last14 = Ono|first14 = T.|last15 = Rios|first15 = A. F.|journal = Science|volume = 305|issue = 5682|pages = 367–371|pmid = 15256665|bibcode = 2004Sci...305..367S|s2cid = 5607281|url = http://oceanrep.geomar.de/46251/1/1193.full.pdf}} Knowledge of the impact of interacting environmental influences on phytoplankton distribution in the Southern Ocean is limited. For example, more understanding is needed of how light and iron availability or temperature and pH interact to control phytoplankton biogeography.{{cite journal |doi = 10.4319/lo.2010.55.3.1353|title = Environmental control of open-ocean phytoplankton groups: Now and in the future|year = 2010|last1 = Boyd|first1 = Philip W.|last2 = Strzepek|first2 = Robert|last3 = Fu|first3 = Feixue|last4 = Hutchins|first4 = David A.|journal = Limnology and Oceanography|volume = 55|issue = 3|pages = 1353–1376|bibcode = 2010LimOc..55.1353B|doi-access = free}}{{cite journal |doi = 10.1029/2011JC007726|title = Mapping phytoplankton iron utilization: Insights into Southern Ocean supply mechanisms|year = 2012|last1 = Boyd|first1 = P. W.|last2 = Arrigo|first2 = K. R.|last3 = Strzepek|first3 = R.|last4 = Van Dijken|first4 = G. L.|journal = Journal of Geophysical Research: Oceans|volume = 117|issue = C6|pages = n/a|bibcode = 2012JGRC..117.6009B|doi-access = free}}{{cite journal |doi = 10.5194/bg-13-5917-2016|title = Environmental drivers of coccolithophore abundance and calcification across Drake Passage (Southern Ocean)|year = 2016|last1 = Charalampopoulou|first1 = Anastasia|last2 = Poulton|first2 = Alex J.|last3 = Bakker|first3 = Dorothee C. E.|last4 = Lucas|first4 = Mike I.|last5 = Stinchcombe|first5 = Mark C.|last6 = Tyrrell|first6 = Toby|journal = Biogeosciences|volume = 13|issue = 21|pages = 5917–5935|bibcode = 2016BGeo...13.5917C|doi-access = free|hdl = 11427/34237|hdl-access = free}} Hence, if model parameterizations are to improve to provide accurate predictions of biogeochemical change, a multivariate understanding of the full suite of environmental drivers is required.{{cite journal |doi = 10.1016/S0967-0637(98)00066-1|title = Does planktonic community structure determine downward particulate organic carbon flux in different oceanic provinces?|year = 1999|last1 = Boyd|first1 = P.W.|last2 = Newton|first2 = P.P.|journal = Deep Sea Research Part I: Oceanographic Research Papers|volume = 46|issue = 1|pages = 63–91|bibcode = 1999DSRI...46...63B}}
The Southern Ocean has often been considered as a microplankton-dominated (20–200 μm) system with phytoplankton blooms dominated by large diatoms and Phaeocystis sp.{{cite journal |doi = 10.1016/S0967-0645(96)00063-X|title = Spring development of phytoplankton biomass and composition in major water masses of the Atlantic sector of the Southern Ocean|year = 1997|last1 = Bathmann|first1 = U.V.|last2 = Scharek|first2 = R.|last3 = Klaas|first3 = C.|last4 = Dubischar|first4 = C.D.|last5 = Smetacek|first5 = V.|journal = Deep-Sea Research Part II: Topical Studies in Oceanography|volume = 44|issue = 1–2|pages = 51–67|bibcode = 1997DSRII..44...51B|url = https://epic.awi.de/id/eprint/193/1/Bat1997b.pdf}}{{cite journal |doi = 10.1016/j.dsr2.2007.06.005|title = Phytoplankton community composition around the Crozet Plateau, with emphasis on diatoms and Phaeocystis|year = 2007|last1 = Poulton|first1 = Alex J.|last2 = Mark Moore|first2 = C.|last3 = Seeyave|first3 = Sophie|last4 = Lucas|first4 = Mike I.|last5 = Fielding|first5 = Sophie|last6 = Ward|first6 = Peter|journal = Deep-Sea Research Part II: Topical Studies in Oceanography|volume = 54|issue = 18–20|pages = 2085–2105|bibcode = 2007DSRII..54.2085P}}{{cite journal |doi = 10.1046/j.1529-8817.2002.t01-1-01203.x|title = Environmental Factors Controlling Phytoplankton Processes in the Southern Ocean1|year = 2002|last1 = Boyd|first1 = Philip W.|journal = Journal of Phycology|volume = 38|issue = 5|pages = 844–861|s2cid = 53448178}} However, since the identification of the Great Calcite Belt (GCB) as a consistent feature{{cite journal |doi = 10.1002/2016GB005414|title = Factors regulating the Great Calcite Belt in the Southern Ocean and its biogeochemical significance|year = 2016|last1 = Balch|first1 = William M.|last2 = Bates|first2 = Nicholas R.|last3 = Lam|first3 = Phoebe J.|last4 = Twining|first4 = Benjamin S.|last5 = Rosengard|first5 = Sarah Z.|last6 = Bowler|first6 = Bruce C.|last7 = Drapeau|first7 = Dave T.|last8 = Garley|first8 = Rebecca|last9 = Lubelczyk|first9 = Laura C.|last10 = Mitchell|first10 = Catherine|last11 = Rauschenberg|first11 = Sara|journal = Global Biogeochemical Cycles|volume = 30|issue = 8|pages = 1124–1144|bibcode = 2016GBioC..30.1124B| s2cid=22536090 |doi-access = free|hdl = 1912/8609|hdl-access = free}} and the recognition of picoplankton (< 2 μm) and nanoplankton (2–20 μm) importance in high-nutrient, low-chlorophyll (HNLC) waters,{{cite journal |doi = 10.1029/2006GB002726|title = A rising tide lifts all phytoplankton: Growth response of other phytoplankton taxa in diatom-dominated blooms|year = 2006|last1 = Barber|first1 = R. T.|last2 = Hiscock|first2 = M. R.|journal = Global Biogeochemical Cycles|volume = 20|issue = 4|pages = n/a|bibcode = 2006GBioC..20.4S03B|doi-access = free}} the dynamics of small (bio)mineralizing plankton and their export need to be acknowledged. The two dominant biomineralizing phytoplankton groups in the GCB are coccolithophores and diatoms. Coccolithophores are generally found north of the polar front,{{cite journal |doi = 10.1016/j.marmicro.2007.08.005|title = Ecology of coccolithophores in the Indian sector of the Southern Ocean|year = 2008|last1 = Mohan|first1 = Rahul|last2 = Mergulhao|first2 = Lina P.|last3 = Guptha|first3 = M.V.S.|last4 = Rajakumar|first4 = A.|last5 = Thamban|first5 = M.|last6 = Anilkumar|first6 = N.|last7 = Sudhakar|first7 = M.|last8 = Ravindra|first8 = Rasik|journal = Marine Micropaleontology|volume = 67|issue = 1–2|pages = 30–45|bibcode = 2008MarMP..67...30M}} though Emiliania huxleyi has been observed as far south as 58° S in the Scotia Sea,{{cite journal |doi = 10.1016/j.jmarsys.2010.05.007|title = Seasonal distributions of the coccolithophore, Emiliania huxleyi, and of particulate inorganic carbon in surface waters of the Scotia Sea|year = 2010|last1 = Holligan|first1 = P.M.|last2 = Charalampopoulou|first2 = A.|last3 = Hutson|first3 = R.|journal = Journal of Marine Systems|volume = 82|issue = 4|pages = 195–205|bibcode = 2010JMS....82..195H}} at 61° S across Drake Passage, and at 65°S south of Australia.{{cite journal |doi = 10.3354/meps07058|title = Calcification morphotypes of the coccolithophorid Emiliania huxleyi in the Southern Ocean: Changes in 2001 to 2006 compared to historical data|year = 2007|last1 = Cubillos|first1 = JC|last2 = Wright|first2 = SW|last3 = Nash|first3 = G.|last4 = De Salas|first4 = MF|last5 = Griffiths|first5 = B.|last6 = Tilbrook|first6 = B.|last7 = Poisson|first7 = A.|last8 = Hallegraeff|first8 = GM|journal = Marine Ecology Progress Series|volume = 348|pages = 47–54|bibcode = 2007MEPS..348...47C|doi-access = free}}
Diatoms are present throughout the GCB, with the polar front marking a strong divide between different size fractions.{{cite journal |doi = 10.1093/plankt/17.9.1791|title = Biogeographic structure of the microphytoplankton assemblages of the south Atlantic and Southern Ocean during austral summer|year = 1995|last1 = Froneman|first1 = P.W.|last2 = McQuaid|first2 = C.D.|last3 = Perissinotto|first3 = R.|journal = Journal of Plankton Research|volume = 17|issue = 9|pages = 1791–1802}} North of the polar front, small diatom species, such as Pseudo-nitzschia spp. and Thalassiosira spp., tend to dominate numerically, whereas large diatoms with higher silicic acid requirements (e.g., Fragilariopsis kerguelensis) are generally more abundant south of the polar front. High abundances of nanoplankton (coccolithophores, small diatoms, chrysophytes) have also been observed on the Patagonian Shelf{{hsp}} and in the Scotia Sea.{{cite journal |doi = 10.1016/j.dsr2.2011.09.002|title = Comparative seasonal biogeography of mineralising nannoplankton in the Scotia Sea: Emiliania huxleyi, Fragilariopsis SPP. And Tetraparma pelagica|year = 2012|last1 = Hinz|first1 = D.J.|last2 = Poulton|first2 = A.J.|last3 = Nielsdóttir|first3 = M.C.|last4 = Steigenberger|first4 = S.|last5 = Korb|first5 = R.E.|last6 = Achterberg|first6 = E.P.|last7 = Bibby|first7 = T.S.|journal = Deep-Sea Research Part II: Topical Studies in Oceanography|volume = 59-60|pages = 57–66|bibcode = 2012DSRII..59...57H}} Currently, few studies incorporate small biomineralizing phytoplankton to species level. Rather, the focus has often been on the larger and noncalcifying species in the Southern Ocean due to sample preservation issues (i.e., acidified Lugol’s solution dissolves calcite, and light microscopy restricts accurate identification to cells > 10 μm. In the context of climate change and future ecosystem function, the distribution of biomineralizing phytoplankton is important to define when considering phytoplankton interactions with carbonate chemistry,{{cite journal |doi = 10.1029/2005GC001227|title = Species-specific responses of calcifying algae to changing seawater carbonate chemistry|year = 2006|last1 = Langer|first1 = Gerald|last2 = Geisen|first2 = Markus|last3 = Baumann|first3 = Karl-Heinz|last4 = Kläs|first4 = Jessica|last5 = Riebesell|first5 = Ulf|last6 = Thoms|first6 = Silke|last7 = Young|first7 = Jeremy R.|journal = Geochemistry, Geophysics, Geosystems|volume = 7|issue = 9|pages = n/a|bibcode = 2006GGG.....7.9006L| s2cid=14774230 |url = https://epic.awi.de/id/eprint/14731/1/Lan2006e.pdf}}{{cite journal |doi = 10.1029/2007GL032583|title = CO2sensitivity of Southern Ocean phytoplankton|year = 2008|last1 = Tortell|first1 = Philippe D.|last2 = Payne|first2 = Christopher D.|last3 = Li|first3 = Yingyu|last4 = Trimborn|first4 = Scarlett|last5 = Rost|first5 = Björn|last6 = Smith|first6 = Walker O.|last7 = Riesselman|first7 = Christina|last8 = Dunbar|first8 = Robert B.|last9 = Sedwick|first9 = Pete|last10 = Ditullio|first10 = Giacomo R.|journal = Geophysical Research Letters|volume = 35|issue = 4|pages = L04605|bibcode = 2008GeoRL..35.4605T| s2cid=35741347 | url=https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1089&context=oeas_fac_pubs |doi-access = free}} and ocean biogeochemistry.{{cite journal |doi = 10.1029/2010GB003856|title = Causes and biogeochemical implications of regional differences in silicification of marine diatoms|year = 2010|last1 = Baines|first1 = Stephen B.|last2 = Twining|first2 = Benjamin S.|last3 = Brzezinski|first3 = Mark A.|last4 = Nelson|first4 = David M.|last5 = Fisher|first5 = Nicholas S.|journal = Global Biogeochemical Cycles|volume = 24|issue = 4|pages = n/a|bibcode = 2010GBioC..24.4031B|doi-access = }}{{cite journal |doi = 10.1073/pnas.1309345110|title = Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current|year = 2013|last1 = Assmy|first1 = P.|last2 = Smetacek|first2 = V.|last3 = Montresor|first3 = M.|last4 = Klaas|first4 = C.|last5 = Henjes|first5 = J.|last6 = Strass|first6 = V. H.|last7 = Arrieta|first7 = J. M.|last8 = Bathmann|first8 = U.|last9 = Berg|first9 = G. M.|last10 = Breitbarth|first10 = E.|last11 = Cisewski|first11 = B.|last12 = Friedrichs|first12 = L.|last13 = Fuchs|first13 = N.|last14 = Herndl|first14 = G. J.|last15 = Jansen|first15 = S.|last16 = Kragefsky|first16 = S.|last17 = Latasa|first17 = M.|last18 = Peeken|first18 = I.|last19 = Rottgers|first19 = R.|last20 = Scharek|first20 = R.|last21 = Schuller|first21 = S. E.|last22 = Steigenberger|first22 = S.|last23 = Webb|first23 = A.|last24 = Wolf-Gladrow|first24 = D.|journal = Proceedings of the National Academy of Sciences|volume = 110|issue = 51|pages = 20633–20638|pmid = 24248337|pmc = 3870680|bibcode = 2013PNAS..11020633A|doi-access = free}}{{cite journal |doi = 10.1002/2013GB004641|title = The 2008Emiliania huxleyibloom along the Patagonian Shelf: Ecology, biogeochemistry, and cellular calcification|year = 2013|last1 = Poulton|first1 = Alex J.|last2 = Painter|first2 = Stuart C.|last3 = Young|first3 = Jeremy R.|last4 = Bates|first4 = Nicholas R.|last5 = Bowler|first5 = Bruce|last6 = Drapeau|first6 = Dave|last7 = Lyczsckowski|first7 = Emily|last8 = Balch|first8 = William M.|journal = Global Biogeochemical Cycles|volume = 27|issue = 4|pages = 1023–1033|bibcode = 2013GBioC..27.1023P| s2cid=129706569 |doi-access = free}}
File:Ecological-zones-of-the-Southern-Ocean.png
The Great Calcite Belt spans the major Southern Ocean circumpolar fronts: the Subantarctic front, the polar front, the Southern Antarctic Circumpolar Current front, and occasionally the southern boundary of the Antarctic Circumpolar Current.{{cite journal |doi = 10.1357/0022240943076759|title = Water-mass distributions in the western South Atlantic; A section from South Georgia Island (54S) northward across the equator|year = 1994|last1 = Tsuchiya|first1 = Mizuki|last2 = Talley|first2 = Lynne D.|last3 = McCartney|first3 = Michael S.|journal = Journal of Marine Research|volume = 52|pages = 55–81}}{{cite journal |doi = 10.1016/0967-0637(95)00021-W|title = On the meridional extent and fronts of the Antarctic Circumpolar Current|year = 1995|last1 = Orsi|first1 = Alejandro H.|last2 = Whitworth|first2 = Thomas|last3 = Nowlin|first3 = Worth D.|journal = Deep Sea Research Part I: Oceanographic Research Papers|volume = 42|issue = 5|pages = 641–673|bibcode = 1995DSRI...42..641O}}{{cite journal |doi = 10.1029/95JC02750|title = Southern Ocean fronts from the Greenwich meridian to Tasmania|year = 1996|last1 = Belkin|first1 = Igor M.|last2 = Gordon|first2 = Arnold L.|journal = Journal of Geophysical Research: Oceans|volume = 101|issue = C2|pages = 3675–3696|bibcode = 1996JGR...101.3675B}} The subtropical front (at approximately 10 °C) acts as the northern boundary of the GCB and is associated with a sharp increase in PIC southwards. These fronts divide distinct environmental and biogeochemical zones, making the GCB an ideal study area to examine controls on phytoplankton communities in the open ocean. A high PIC concentration observed in the GCB (1 μmol PIC L−1) compared to the global average (0.2 μmol PIC L−1) and significant quantities of detached E. huxleyi coccoliths (in concentrations > 20,000 coccoliths mL−1) both characterize the GCB. The GCB is clearly observed in satellite imagery{{hsp}} spanning from the Patagonian Shelf{{hsp}}{{cite journal |doi = 10.1029/2006GL026592|title = Seasonal and interannual variability of calcite in the vicinity of the Patagonian shelf break (38°S–52°S)|year = 2006|last1 = Signorini|first1 = Sergio R.|last2 = Garcia|first2 = Virginia M. T.|last3 = Piola|first3 = Alberto R.|last4 = Garcia|first4 = Carlos A. E.|last5 = Mata|first5 = Mauricio M.|last6 = McClain|first6 = Charles R.|journal = Geophysical Research Letters|volume = 33|issue = 16|pages = L16610|bibcode = 2006GeoRL..3316610S|doi-access = }}{{cite journal |doi = 10.1016/j.csr.2010.08.013|title = The COPAS'08 expedition to the Patagonian Shelf: Physical and environmental conditions during the 2008 coccolithophore bloom|year = 2010|last1 = Painter|first1 = Stuart C.|last2 = Poulton|first2 = Alex J.|last3 = Allen|first3 = John T.|last4 = Pidcock|first4 = Rosalind|last5 = Balch|first5 = William M.|journal = Continental Shelf Research|volume = 30|issue = 18|pages = 1907–1923|bibcode = 2010CSR....30.1907P}} across the Atlantic, Indian, and Pacific oceans and completing Antarctic circumnavigation via the Drake Passage.
File:Four phytoplankton species.png, (b) Fragilariopsis pseudonana, (c) Fragilariopsis nana, and (d) Pseudo-nitzschia spp.]]
{{clear}}
Coccolithophores versus the diatom
File:Coccolithophores and diatoms in the Southern Ocean 2.png Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License]. Biomass distributions for the four months from December to March. Mean top 50 metres of coccolithophore (left) and diatom (right) carbon biomass (mmol/m3) using a regional high-resolution model for the Southern Ocean. Coccolithophore and diatom biomass observations from the top 50 metres are indicated by coloured dots. (Note difference in scales.)]]
The biogeography of Southern Ocean phytoplankton controls the local biogeochemistry and the export of macronutrients to lower latitudes and depth. Of particular relevance is the competitive interaction between coccolithophores and diatoms, with the former being prevalent along the Great Calcite Belt (40–60°S), while diatoms tend to dominate the regions south of 60°S, as illustrated in the diagram on the right.{{cite journal |doi = 10.5194/bg-15-6997-2018|title = Factors controlling coccolithophore biogeography in the Southern Ocean|year = 2018|last1 = Nissen|first1 = Cara|last2 = Vogt|first2 = Meike|last3 = Münnich|first3 = Matthias|last4 = Gruber|first4 = Nicolas|last5 = Haumann|first5 = F. Alexander|journal = Biogeosciences|volume = 15|issue = 22|pages = 6997–7024|bibcode = 2018BGeo...15.6997N|hdl = 20.500.11850/304764|s2cid = 203137081|hdl-access = free | doi-access=free }} 50px Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].
The ocean is changing at an unprecedented rate as a consequence of increasing anthropogenic CO2 emissions and related climate change. Changes in density stratification and nutrient supply, as well as ocean acidification, lead to changes in phytoplankton community composition and consequently ecosystem structure and function. Some of these changes are already observable today{{hsp}}{{cite journal |doi = 10.3390/rs8050420|doi-access = free|title = Diatom Phenology in the Southern Ocean: Mean Patterns, Trends and the Role of Climate Oscillations|year = 2016|last1 = Soppa|first1 = Mariana|last2 = Völker|first2 = Christoph|last3 = Bracher|first3 = Astrid|journal = Remote Sensing|volume = 8|issue = 5|page = 420|bibcode = 2016RemS....8..420S}}{{cite journal |doi = 10.1093/plankt/fbt110|title = Poleward expansion of the coccolithophore Emiliania huxleyi|year = 2014|last1 = Winter|first1 = Amos|last2 = Henderiks|first2 = Jorijntje|last3 = Beaufort|first3 = Luc|last4 = Rickaby|first4 = Rosalind E. M.|last5 = Brown|first5 = Christopher W.|journal = Journal of Plankton Research|volume = 36|issue = 2|pages = 316–325|doi-access = free}} and may have cascading effects on global biogeochemical cycles and oceanic carbon uptake.{{cite journal |doi = 10.1073/pnas.0811302106|title = The role of nutricline depth in regulating the ocean carbon cycle|year = 2008|last1 = Cermeno|first1 = P.|last2 = Dutkiewicz|first2 = S.|last3 = Harris|first3 = R. P.|last4 = Follows|first4 = M.|last5 = Schofield|first5 = O.|last6 = Falkowski|first6 = P. G.|journal = Proceedings of the National Academy of Sciences|volume = 105|issue = 51|pages = 20344–20349|pmid = 19075222|pmc = 2603260|bibcode = 2008PNAS..10520344C|doi-access = free}}{{cite journal |doi = 10.1002/2014GL062769|title = Decreased calcification in the Southern Ocean over the satellite record|year = 2015|last1 = Freeman|first1 = Natalie M.|last2 = Lovenduski|first2 = Nicole S.|journal = Geophysical Research Letters|volume = 42|issue = 6|pages = 1834–1840|bibcode = 2015GeoRL..42.1834F| s2cid=131003925 | url=https://archimer.ifremer.fr/doc/00292/40371/ |doi-access = free}}{{cite journal |doi = 10.5194/bg-13-4023-2016|title = Projected decreases in future marine export production: The role of the carbon flux through the upper ocean ecosystem|year = 2016|last1 = Laufkötter|first1 = Charlotte|last2 = Vogt|first2 = Meike|last3 = Gruber|first3 = Nicolas|last4 = Aumont|first4 = Olivier|last5 = Bopp|first5 = Laurent|last6 = Doney|first6 = Scott C.|last7 = Dunne|first7 = John P.|last8 = Hauck|first8 = Judith|last9 = John|first9 = Jasmin G.|last10 = Lima|first10 = Ivan D.|last11 = Seferian|first11 = Roland|last12 = Völker|first12 = Christoph|journal = Biogeosciences|volume = 13|issue = 13|pages = 4023–4047|bibcode = 2016BGeo...13.4023L| s2cid=20577901 |doi-access = free|hdl = 20.500.11850/118663|hdl-access = free}} Changes in Southern Ocean (SO) biogeography are especially critical due to the importance of the Southern Ocean in fuelling primary production at lower latitudes through the lateral export of nutrients{{hsp}}{{cite journal |doi = 10.1038/nature02127|title = High-latitude controls of thermocline nutrients and low latitude biological productivity|year = 2004|last1 = Sarmiento|first1 = J. L.|last2 = Gruber|first2 = N.|last3 = Brzezinski|first3 = M. A.|last4 = Dunne|first4 = J. P.|journal = Nature|volume = 427|issue = 6969|pages = 56–60|pmid = 14702082|bibcode = 2004Natur.427...56S|s2cid = 52798128}} and in taking up anthropogenic CO2.{{cite journal |doi = 10.1175/JCLI-D-14-00117.1|title = Dominance of the Southern Ocean in Anthropogenic Carbon and Heat Uptake in CMIP5 Models|year = 2015|last1 = Frölicher|first1 = Thomas L.|last2 = Sarmiento|first2 = Jorge L.|last3 = Paynter|first3 = David J.|last4 = Dunne|first4 = John P.|last5 = Krasting|first5 = John P.|last6 = Winton|first6 = Michael|journal = Journal of Climate|volume = 28|issue = 2|pages = 862–886|bibcode = 2015JCli...28..862F| s2cid=140665037 |doi-access = free}} For the carbon cycle, the ratio of calcifying and noncalcifying phytoplankton is crucial due to the counteracting effects of calcification and photosynthesis on seawater pCO2, which ultimately controls CO2 exchange with the atmosphere, and the differing ballasting effect of calcite and silicic acid shells for organic carbon export.
File:Seasonal progression occurring in the Great Calcite Belt.png Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].]]
Calcifying coccolithophores and silicifying diatoms are globally ubiquitous phytoplankton functional groups.{{cite journal |doi = 10.5194/essd-4-149-2012|title = A global diatom database – abundance, biovolume and biomass in the world ocean|year = 2012|last1 = Leblanc|first1 = K.|last2 = Arístegui|first2 = J.|last3 = Armand|first3 = L.|last4 = Assmy|first4 = P.|last5 = Beker|first5 = B.|last6 = Bode|first6 = A.|last7 = Breton|first7 = E.|last8 = Cornet|first8 = V.|last9 = Gibson|first9 = J.|last10 = Gosselin|first10 = M.-P.|last11 = Kopczynska|first11 = E.|last12 = Marshall|first12 = H.|last13 = Peloquin|first13 = J.|last14 = Piontkovski|first14 = S.|last15 = Poulton|first15 = A. J.|last16 = Quéguiner|first16 = B.|last17 = Schiebel|first17 = R.|last18 = Shipe|first18 = R.|last19 = Stefels|first19 = J.|last20 = Van Leeuwe|first20 = M. A.|last21 = Varela|first21 = M.|last22 = Widdicombe|first22 = C.|last23 = Yallop|first23 = M.|journal = Earth System Science Data|volume = 4|issue = 1|pages = 149–165|bibcode = 2012ESSD....4..149L| s2cid=3515924 |doi-access = free|hdl = 20.500.12210/72907|hdl-access = free}}{{cite journal |doi = 10.5194/essd-5-259-2013|title = Global marine plankton functional type biomass distributions: Coccolithophores|year = 2013|last1 = O'Brien|first1 = C. J.|last2 = Peloquin|first2 = J. A.|last3 = Vogt|first3 = M.|last4 = Heinle|first4 = M.|last5 = Gruber|first5 = N.|last6 = Ajani|first6 = P.|last7 = Andruleit|first7 = H.|last8 = Arístegui|first8 = J.|last9 = Beaufort|first9 = L.|last10 = Estrada|first10 = M.|last11 = Karentz|first11 = D.|last12 = Kopczyńska|first12 = E.|last13 = Lee|first13 = R.|last14 = Poulton|first14 = A. J.|last15 = Pritchard|first15 = T.|last16 = Widdicombe|first16 = C.|journal = Earth System Science Data|volume = 5|issue = 2|pages = 259–276|bibcode = 2013ESSD....5..259O|hdl = 20.500.11850/163366| s2cid=55146651 |hdl-access = free | doi-access=free }} Diatoms are a major contributor to global phytoplankton biomass{{hsp}}{{cite journal |doi = 10.5194/essd-5-227-2013|title = MAREDAT: Towards a world atlas of MARine Ecosystem DATa|year = 2013|last1 = Buitenhuis|first1 = E. T.|last2 = Vogt|first2 = M.|last3 = Moriarty|first3 = R.|last4 = Bednaršek|first4 = N.|last5 = Doney|first5 = S. C.|last6 = Leblanc|first6 = K.|last7 = Le Quéré|first7 = C.|last8 = Luo|first8 = Y.-W.|last9 = O'Brien|first9 = C.|last10 = O'Brien|first10 = T.|last11 = Peloquin|first11 = J.|last12 = Schiebel|first12 = R.|last13 = Swan|first13 = C.|journal = Earth System Science Data|volume = 5|issue = 2|pages = 227–239|bibcode = 2013ESSD....5..227B|hdl = 20.500.11850/60385|hdl-access = free | doi-access=free }} and annual net primary production.{{cite journal |doi = 10.1016/j.seares.2004.01.007|title = Growth physiology and fate of diatoms in the ocean: A review|year = 2005|last1 = Sarthou|first1 = Géraldine|last2 = Timmermans|first2 = Klaas R.|last3 = Blain|first3 = Stéphane|last4 = Tréguer|first4 = Paul|journal = Journal of Sea Research|volume = 53|issue = 1–2|pages = 25–42|bibcode = 2005JSR....53...25S}} In comparison, coccolithophores contribute less to biomass{{hsp}} and to global NPP.{{cite journal |doi = 10.1016/j.dsr2.2006.12.007|title = Modeling coccolithophores in the global oceans|year = 2007|last1 = Gregg|first1 = Watson W.|last2 = Casey|first2 = Nancy W.|journal = Deep-Sea Research Part II: Topical Studies in Oceanography|volume = 54|issue = 5–7|pages = 447–477|bibcode = 2007DSRII..54..447G}}{{cite journal |doi = 10.1029/2005GB002532|title = Diagnosing the contribution of phytoplankton functional groups to the production and export of particulate organic carbon, CaCO3, and opal from global nutrient and alkalinity distributions|year = 2006|last1 = Jin|first1 = X.|last2 = Gruber|first2 = N.|last3 = Dunne|first3 = J. P.|last4 = Sarmiento|first4 = J. L.|last5 = Armstrong|first5 = R. A.|journal = Global Biogeochemical Cycles|volume = 20|issue = 2|pages = n/a|bibcode = 2006GBioC..20.2015J|doi-access = free}}{{cite journal |doi = 10.1029/2004GB002220|title = Upper ocean ecosystem dynamics and iron cycling in a global three-dimensional model|year = 2004|last1 = Moore|first1 = J. Keith|last2 = Doney|first2 = Scott C.|last3 = Lindsay|first3 = Keith|journal = Global Biogeochemical Cycles|volume = 18|issue = 4|pages = n/a|bibcode = 2004GBioC..18.4028M| s2cid=3575218 |hdl = 1912/3396|hdl-access = free}}O'Brien, C. J. (2015) "Global-scale distributions of marine haptophyte phytoplankton", PhD thesis, ETH Zürich.
However, coccolithophores are the major phytoplanktonic calcifier.{{cite journal |doi = 10.1029/2002EO000267|title = Progress made in study of ocean's calcium carbonate budget|year = 2002|last1 = Iglesias-Rodriguez|first1 = M. Debora|last2 = Armstrong|first2 = Robert|last3 = Feely|first3 = Richard|last4 = Hood|first4 = Raleigh|last5 = Kleypas|first5 = Joan|last6 = Milliman|first6 = John D.|last7 = Sabine|first7 = Christopher|last8 = Sarmiento|first8 = Jorge|journal = Eos, Transactions American Geophysical Union|volume = 83|issue = 34|pages = 365–375|doi-access = }} thereby significantly impacting the global carbon cycle. Diatoms dominate the phytoplankton community in the Southern Ocean,{{cite journal |doi = 10.1016/j.dsr.2015.12.002|title = A global seasonal surface ocean climatology of phytoplankton types based on CHEMTAX analysis of HPLC pigments|year = 2016|last1 = Swan|first1 = Chantal M.|last2 = Vogt|first2 = Meike|last3 = Gruber|first3 = Nicolas|last4 = Laufkoetter|first4 = Charlotte|journal = Deep Sea Research Part I: Oceanographic Research Papers|volume = 109|pages = 137–156|bibcode = 2016DSRI..109..137S|hdl = 20.500.11850/208709|hdl-access = free}}{{cite journal |doi = 10.5194/bg-15-31-2018|title = Distribution of planktonic biogenic carbonate organisms in the Southern Ocean south of Australia: A baseline for ocean acidification impact assessment|year = 2018|last1 = Trull|first1 = Thomas W.|last2 = Passmore|first2 = Abraham|last3 = Davies|first3 = Diana M.|last4 = Smit|first4 = Tim|last5 = Berry|first5 = Kate|last6 = Tilbrook|first6 = Bronte|journal = Biogeosciences|volume = 15|issue = 1|pages = 31–49|bibcode = 2018BGeo...15...31T|doi-access = free}}{{cite journal |doi = 10.1016/j.dsr2.2009.06.015|title = Phytoplankton community structure and stocks in the Southern Ocean (30–80°E) determined by CHEMTAX analysis of HPLC pigment signatures|year = 2010|last1 = Wright|first1 = Simon W.|last2 = Van Den Enden|first2 = Rick L.|last3 = Pearce|first3 = Imojen|last4 = Davidson|first4 = Andrew T.|last5 = Scott|first5 = Fiona J.|last6 = Westwood|first6 = Karen J.|journal = Deep-Sea Research Part II: Topical Studies in Oceanography|volume = 57|issue = 9–10|pages = 758–778|bibcode = 2010DSRII..57..758W}} but coccolithophores have received increasing attention in recent years. Satellite imagery of particulate inorganic carbon (PIC, a proxy for coccolithophore abundance) revealed the "Great Calcite Belt",{{cite journal |doi = 10.1029/2011JC006941|title = The contribution of coccolithophores to the optical and inorganic carbon budgets during the Southern Ocean Gas Exchange Experiment: New evidence in support of the "Great Calcite Belt" hypothesis|year = 2011|last1 = Balch|first1 = W. M.|last2 = Drapeau|first2 = D. T.|last3 = Bowler|first3 = B. C.|last4 = Lyczskowski|first4 = E.|last5 = Booth|first5 = E. S.|last6 = Alley|first6 = D.|journal = Journal of Geophysical Research|volume = 116|issue = C4|bibcode = 2011JGRC..116.0F06B}} an annually reoccurring circumpolar band of elevated PIC concentrations between 40 and 60°S. In situ observations confirmed coccolithophore abundances of up to 2.4×103 cells mL−1 in the Atlantic sector (blooms on the Patagonian Shelf), up to 3.8×102 cells mL−1 in the Indian sector,{{cite journal |doi = 10.1002/2016GB005414|title = Factors regulating the Great Calcite Belt in the Southern Ocean and its biogeochemical significance|year = 2016|last1 = Balch|first1 = William M.|last2 = Bates|first2 = Nicholas R.|last3 = Lam|first3 = Phoebe J.|last4 = Twining|first4 = Benjamin S.|last5 = Rosengard|first5 = Sarah Z.|last6 = Bowler|first6 = Bruce C.|last7 = Drapeau|first7 = Dave T.|last8 = Garley|first8 = Rebecca|last9 = Lubelczyk|first9 = Laura C.|last10 = Mitchell|first10 = Catherine|last11 = Rauschenberg|first11 = Sara|journal = Global Biogeochemical Cycles|volume = 30|issue = 8|pages = 1124–1144|bibcode = 2016GBioC..30.1124B| s2cid=22536090 |doi-access = free|hdl = 1912/8609|hdl-access = free}} and up to 5.4×102 cells mL−1 in the Pacific sector of the Southern Ocean{{hsp}}{{cite journal |doi = 10.3354/meps07058|title = Calcification morphotypes of the coccolithophorid Emiliania huxleyi in the Southern Ocean: Changes in 2001 to 2006 compared to historical data|year = 2007|last1 = Cubillos|first1 = JC|last2 = Wright|first2 = SW|last3 = Nash|first3 = G.|last4 = De Salas|first4 = MF|last5 = Griffiths|first5 = B.|last6 = Tilbrook|first6 = B.|last7 = Poisson|first7 = A.|last8 = Hallegraeff|first8 = GM|journal = Marine Ecology Progress Series|volume = 348|pages = 47–54|bibcode = 2007MEPS..348...47C|doi-access = free}} with Emiliania huxleyi being the dominant species.{{cite journal |doi = 10.1016/j.marmicro.2014.03.003|title = Biogeographic distribution of living coccolithophores in the Pacific sector of the Southern Ocean|year = 2014|last1 = Saavedra-Pellitero|first1 = Mariem|last2 = Baumann|first2 = Karl-Heinz|last3 = Flores|first3 = José-Abel|last4 = Gersonde|first4 = Rainer|journal = Marine Micropaleontology|volume = 109|pages = 1–20|bibcode = 2014MarMP.109....1S}} However, the contribution of coccolithophores to total Southern Ocean phytoplankton biomass and NPP has not yet been assessed. Locally, elevated coccolithophore abundance in the GCB has been found to turn surface waters into a source of CO2 for the atmosphere, emphasising the necessity to understand the controls on their abundance in the Southern Ocean in the context of the carbon cycle and climate change. While coccolithophores have been observed to have moved polewards in recent decades,{{cite journal |doi = 10.1038/nclimate1753|title = Long-term responses of North Atlantic calcifying plankton to climate change|year = 2013|last1 = Beaugrand|first1 = Gregory|last2 = McQuatters-Gollop|first2 = Abigail|last3 = Edwards|first3 = Martin|last4 = Goberville|first4 = Eric|journal = Nature Climate Change|volume = 3|issue = 3|pages = 263–267|bibcode = 2013NatCC...3..263B}}{{cite journal |doi = 10.1126/science.aaa8026|title = Multidecadal increase in North Atlantic coccolithophores and the potential role of rising CO2|year = 2015|last1 = Rivero-Calle|first1 = S.|last2 = Gnanadesikan|first2 = A.|last3 = Del Castillo|first3 = C. E.|last4 = Balch|first4 = W. M.|last5 = Guikema|first5 = S. D.|journal = Science|volume = 350|issue = 6267|pages = 1533–1537|pmid = 26612836|bibcode = 2015Sci...350.1533R|s2cid = 206635970|doi-access = free}} their response to the combined effects of future warming and ocean acidification is still subject to debate.{{cite journal |doi = 10.1038/nature10295|title = Sensitivity of coccolithophores to carbonate chemistry and ocean acidification|year = 2011|last1 = Beaufort|first1 = L.|last2 = Probert|first2 = I.|last3 = De Garidel-Thoron|first3 = T.|last4 = Bendif|first4 = E. M.|last5 = Ruiz-Pino|first5 = D.|last6 = Metzl|first6 = N.|last7 = Goyet|first7 = C.|last8 = Buchet|first8 = N.|last9 = Coupel|first9 = P.|last10 = Grelaud|first10 = M.|last11 = Rost|first11 = B.|last12 = Rickaby|first12 = R. E. 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P.|journal = Science|volume = 320|issue = 5874|pages = 336–340|pmid = 18420926|bibcode = 2008Sci...320..336I|s2cid = 206511068}}{{cite journal |doi = 10.1038/35030078|title = Reduced calcification of marine plankton in response to increased atmospheric CO2|year = 2000|last1 = Riebesell|first1 = Ulf|last2 = Zondervan|first2 = Ingrid|last3 = Rost|first3 = Björn|last4 = Tortell|first4 = Philippe D.|last5 = Zeebe|first5 = Richard E.|last6 = Morel|first6 = François M. M.|journal = Nature|volume = 407|issue = 6802|pages = 364–367|pmid = 11014189|bibcode = 2000Natur.407..364R|s2cid = 4426501|url = https://epic.awi.de/id/eprint/3784/1/Rie2000a.pdf}}{{cite journal |doi = 10.1038/nclimate2379|title = Adaptation of a globally important coccolithophore to ocean warming and acidification|year = 2014|last1 = Schlüter|first1 = Lothar|last2 = Lohbeck|first2 = Kai T.|last3 = Gutowska|first3 = Magdalena A.|last4 = Gröger|first4 = Joachim P.|last5 = Riebesell|first5 = Ulf|last6 = Reusch|first6 = Thorsten B. H.|journal = Nature Climate Change|volume = 4|issue = 11|pages = 1024–1030|bibcode = 2014NatCC...4.1024S}} As their response will also crucially depend on future phytoplankton community composition and predator–prey interactions,{{cite journal |doi = 10.1038/nclimate2722|title = Impact of ocean acidification on the structure of future phytoplankton communities|year = 2015|last1 = Dutkiewicz|first1 = Stephanie|last2 = Morris|first2 = J. Jeffrey|last3 = Follows|first3 = Michael J.|last4 = Scott|first4 = Jeffery|last5 = Levitan|first5 = Orly|last6 = Dyhrman|first6 = Sonya T.|last7 = Berman-Frank|first7 = Ilana|journal = Nature Climate Change|volume = 5|issue = 11|pages = 1002–1006|bibcode = 2015NatCC...5.1002D}} it is essential to assess the controls on their abundance in today's climate.
Top-down and bottom-up approaches
{{biomineralization sidebar|calcification}}
Coccolithophore biomass is controlled by a combination of bottom-up (physical–biogeochemical environment) and top-down factors (predator–prey interactions), but the relative importance of the two has not yet been assessed for coccolithophores in the Southern Ocean. Bottom-up factors directly impact phytoplankton growth, and diatoms and coccolithophores are traditionally discriminated based on their differing requirements for nutrients, turbulence, and light. Based on this, Margalef's mandala predicts a seasonal succession from diatoms to coccolithophores as light levels increase and nutrient levels decline.Margalef, R. (1978) "Life-forms of phytoplankton as survival alternatives in an unstable environment", Oceanol. Acta, 1: 493–509. In situ studies assessing Southern Ocean coccolithophore biogeography have found coccolithophores under various environmental conditions,{{cite journal |doi = 10.5194/bg-13-5917-2016|title = Environmental drivers of coccolithophore abundance and calcification across Drake Passage (Southern Ocean)|year = 2016|last1 = Charalampopoulou|first1 = Anastasia|last2 = Poulton|first2 = Alex J.|last3 = Bakker|first3 = Dorothee C. E.|last4 = Lucas|first4 = Mike I.|last5 = Stinchcombe|first5 = Mark C.|last6 = Tyrrell|first6 = Toby|journal = Biogeosciences|volume = 13|issue = 21|pages = 5917–5935|bibcode = 2016BGeo...13.5917C|doi-access = free|hdl = 11427/34237|hdl-access = free}}{{cite journal |doi = 10.1016/j.dsr2.2011.09.002|title = Comparative seasonal biogeography of mineralising nannoplankton in the Scotia Sea: Emiliania huxleyi, Fragilariopsis SPP. And Tetraparma pelagica|year = 2012|last1 = Hinz|first1 = D.J.|last2 = Poulton|first2 = A.J.|last3 = Nielsdóttir|first3 = M.C.|last4 = Steigenberger|first4 = S.|last5 = Korb|first5 = R.E.|last6 = Achterberg|first6 = E.P.|last7 = Bibby|first7 = T.S.|journal = Deep-Sea Research Part II: Topical Studies in Oceanography|volume = 59-60|pages = 57–66|bibcode = 2012DSRII..59...57H}} thus suggesting a wide ecological niche, but all of the mentioned studies have almost exclusively focused on bottom-up controls.
However, phytoplankton growth rates do not necessarily covary with biomass accumulation rates. Using satellite data from the North Atlantic, Behrenfeld stressed in 2014 the importance of simultaneously considering bottom-up and top-down factors when assessing seasonal phytoplankton biomass dynamics and the succession of different phytoplankton types owing to the spatially and temporally varying relative importance of the physical–biogeochemical and the biological environment.{{cite journal |doi = 10.1038/nclimate2349|title = Climate-mediated dance of the plankton|year = 2014|last1 = Behrenfeld|first1 = Michael J.|journal = Nature Climate Change|volume = 4|issue = 10|pages = 880–887|bibcode = 2014NatCC...4..880B}}
File:Sediments-southerocean.pngs in the Southern Ocean: (1) calcareous ooze/mud, (2, 3) biosiliceous/mud, (4) coarse lithogenic sediments, (5, 6) lithogenic sand/mud]]
In the Southern Ocean, previous studies have shown zooplankton grazing to control total phytoplankton biomass,{{cite journal |doi = 10.5194/bg-13-4111-2016|title = Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles|year = 2016|last1 = Le Quéré|first1 = Corinne|last2 = Buitenhuis|first2 = Erik T.|last3 = Moriarty|first3 = Róisín|last4 = Alvain|first4 = Séverine|last5 = Aumont|first5 = Olivier|last6 = Bopp|first6 = Laurent|last7 = Chollet|first7 = Sophie|last8 = Enright|first8 = Clare|last9 = Franklin|first9 = Daniel J.|last10 = Geider|first10 = Richard J.|last11 = Harrison|first11 = Sandy P.|last12 = Hirst|first12 = Andrew G.|last13 = Larsen|first13 = Stuart|last14 = Legendre|first14 = Louis|last15 = Platt|first15 = Trevor|last16 = Prentice|first16 = I. 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W.|last2 = Boyd|first2 = Philip W.|last3 = Coale|first3 = Kenneth H.|last4 = Landry|first4 = Michael R.|last5 = Tsuda|first5 = Atsushi|last6 = Assmy|first6 = Philipp|last7 = Bakker|first7 = Dorothee C. E.|last8 = Bozec|first8 = Yann|last9 = Barber|first9 = Richard T.|last10 = Brzezinski|first10 = Mark A.|last11 = Buesseler|first11 = Ken O.|last12 = Boyé|first12 = Marie|last13 = Croot|first13 = Peter L.|last14 = Gervais|first14 = Frank|last15 = Gorbunov|first15 = Maxim Y.|last16 = Harrison|first16 = Paul J.|last17 = Hiscock|first17 = William T.|last18 = Laan|first18 = Patrick|last19 = Lancelot|first19 = Christiane|last20 = Law|first20 = Cliff S.|last21 = Levasseur|first21 = Maurice|last22 = Marchetti|first22 = Adrian|last23 = Millero|first23 = Frank J.|last24 = Nishioka|first24 = Jun|last25 = Nojiri|first25 = Yukihiro|last26 = Van Oijen|first26 = Tim|last27 = Riebesell|first27 = Ulf|last28 = Rijkenberg|first28 = Micha J. 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C.|journal = Biogeosciences|volume = 10|issue = 11|pages = 6833–6850|bibcode = 2013BGeo...10.6833H|hdl = 20.500.11850/60387| s2cid=54551044 |hdl-access = free | doi-access=free }}{{cite journal |doi = 10.1016/j.ecolmodel.2013.04.006|title = Comparing food web structures and dynamics across a suite of global marine ecosystem models|year = 2013|last1 = Sailley|first1 = S.F.|last2 = Vogt|first2 = M.|last3 = Doney|first3 = S.C.|last4 = Aita|first4 = M.N.|last5 = Bopp|first5 = L.|last6 = Buitenhuis|first6 = E.T.|last7 = Hashioka|first7 = T.|last8 = Lima|first8 = I.|last9 = Le Quéré|first9 = C.|last10 = Yamanaka|first10 = Y.|journal = Ecological Modelling|volume = 261-262|pages = 43–57|hdl = 1912/7238| s2cid=85212727 |hdl-access = free}} and the impact of different grazing formulations on phytoplankton biogeography and diversity is subject to ongoing research.{{cite journal |doi = 10.1016/j.pocean.2011.11.016|title = Top-down control of marine phytoplankton diversity in a global ecosystem model|year = 2012|last1 = Prowe|first1 = A.E. Friederike|last2 = Pahlow|first2 = Markus|last3 = Dutkiewicz|first3 = Stephanie|last4 = Follows|first4 = Michael|last5 = Oschlies|first5 = Andreas|journal = Progress in Oceanography|volume = 101|issue = 1|pages = 1–13|bibcode = 2012PrOce.101....1P}}{{cite journal |doi = 10.1016/j.pocean.2013.08.001|title = Maximal feeding with active prey-switching: A kill-the-winner functional response and its effect on global diversity and biogeography|year = 2014|last1 = Vallina|first1 = S.M.|last2 = Ward|first2 = B.A.|last3 = Dutkiewicz|first3 = S.|last4 = Follows|first4 = M.J.|journal = Progress in Oceanography|volume = 120|pages = 93–109|bibcode = 2014PrOce.120...93V}}
The diagram on the left shows the spatial distribution of different types of marine sediments in the Southern Ocean. The greenish area south of the Polar Front shows the extension of the subpolar opal belt where sediments have a significant portion of silicous plankton frustules. Sediments near Antarctica mainly consist of glacial debris in any grain size eroded and delivered by the Antarctic Ice.Diekmann, B. (2007). Sedimentary patterns in the late Quaternary Southern Ocean, Deep-Sea Res. II, 54, 2350-2366, {{doi|10.1016/j.dsr2.2007.07.025}}.Grobe, H., Diekmann, B., Hillenbrand, C.-D.(2009). The memory of the Polar Oceans, In: Hempel, G. (ed) Biology of Polar Oceans, hdl:10013/epic.33599.d001, pdf 0.4 MB.
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See also
References
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