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The Acantharea (Acantharia) are a group of radiolarian protozoa, distinguished mainly by their strontium sulfate skeletons. Acantharians are heterotrophic marine microplankton that range in size from about 200 microns in diameter up to several millimeters. Some acantharians have photosynthetic endosymbionts and hence are considered mixotrophs.
Zooplankton are the animal component of the planktonic community. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers.
Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. Tests of chitin are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment, while a smaller number float in the water column at various depths, which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA.
Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mouth is fringed with tentacles. Although some species are solitary, most are colonial. The founding polyp settles and starts to secrete calcium carbonate to protect its soft body. Solitary corals can be as much as 25 cm (10 in) across but in colonial species the polyps are usually only a few millimetres in diameter. These polyps reproduce asexually by budding, but remain attached to each other, forming a multi-polyp colony of clones with a common skeleton, which may be up to several metres in diameter or height according to species.
The Rhizaria are a diverse and species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthethic, but many foraminifera and radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, Guttulinopsis vulgaris, a cellular slime mold, has been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon. Being described mainly from rDNA sequences, they vary considerably in form, having no clear morphological distinctive characters (synapomorphies), but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods. In the absence of an apomorphy, the group is ill-defined, and its composition has been very fluid. Some Rhizaria possess mineral exoskeletons, which are in different clades within Rhizaria made out of opal, celestite, or calcite. Certain species can attain sizes of more than a centimeter with some species being able to form cylindrical colonies approximately 1 cm in diameter and greater than 1 m in length. They feed by capturing and engulfing prey with the extensions of their pseudopodia; forms that are symbiotic with unicellular algae contribute significantly to the total primary production of the ocean.
The Globigerinina is a suborder of foraminiferans that are found as marine plankton. They produce hyaline calcareous tests, and are known as fossils from the Jurassic period onwards. The group has included more than 100 genera and over 400 species, of which about 30 species are extant. One of the most important genera is Globigerina; vast areas of the ocean floor are covered with Globigerina ooze, dominated by the shells of planktonic forms.
Gromia is a genus of protists, closely related to foraminifera, which inhabit marine and freshwater environments. It is the only genus of the family Gromiidae. Gromia are ameboid, producing filose pseudopodia that extend out from the cell's proteinaceous test through a gap enclosed by the cell's oral capsule. The test, a shell made up of protein that encloses the cytoplasm, is made up of several layers of membrane, which resemble honeycombs in shape — a defining character of this genus.
The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/Series, which spans the time between 13.82 Ma and 11.63 Ma. The Serravallian follows the Langhian and is followed by the Tortonian.
Quinqueloculina is a genus of foraminifera in the family Miliolidae.
Globigerina bulloides is a species of heterotrophic planktonic foraminifer with a wide distribution in the photic zone of the world's oceans. It is able to tolerate a range of sea surface temperatures, salinities and water densities, and is most abundant at high southern latitudes, certain high northern latitudes, and in low-latitude upwelling regions. The density or presence of G. bulloides may change as a function of phytoplankton bloom successions, and they are known to be most abundant during winter and spring months.
Shell growth in estuaries is an aspect of marine biology that has attracted a number of scientific research studies. Many groups of marine organisms produce calcified exoskeletons, commonly known as shells, hard calcium carbonate structures which the organisms rely on for various specialized structural and defensive purposes. The rate at which these shells form is greatly influenced by physical and chemical characteristics of the water in which these organisms live. Estuaries are dynamic habitats which expose their inhabitants to a wide array of rapidly changing physical conditions, exaggerating the differences in physical and chemical properties of the water.
Astrangia poculata, the northern star coral or northern cup coral, is a species of non-reefbuilding stony coral in the family Rhizangiidae. It is native to shallow water in the western Atlantic Ocean and the Caribbean Sea. It is also found on the western coast of Africa. The International Union for Conservation of Nature lists this coral as being of "least concern". Astrangia poculata is an emerging model organism for corals because it harbors a facultative photosymbiosis, is a calcifying coral, and has a large geographic range. Research on this emerging model system is showcased annually by the Astrangia Research Working Group, collaboratively hosted by Roger Williams University, Boston University, and Southern Connecticut State University
Nassellaria is an order of Rhizaria belonging to the class Radiolaria. The organisms of this order are characterized by a skeleton cross link with a cone or ring.
Phaeocystis is a genus of algae belonging to the Prymnesiophyte class and to the larger division of Haptophyta. It is a widespread marine phytoplankton and can function at a wide range of temperatures (eurythermal) and salinities (euryhaline). Members of this genus live in the open ocean, as well as in sea ice. It has a polymorphic life cycle, ranging from free-living cells to large colonies.
"Monothalamea" is a grouping of foraminiferans, traditionally consisting of all foraminifera with single-chambered tests. Recent work has shown that the grouping is paraphyletic, and as such does not constitute a natural group; nonetheless, the name "monothalamea" continues to be used by foraminifera workers out of convenience.
Marine biogenic calcification is the process by which marine organisms such as oysters and clams form calcium carbonate. Seawater is full of dissolved compounds, ions and nutrients that organisms can use for energy and, in the case of calcification, to build shells and outer structures. Calcifying organisms in the ocean include molluscs, foraminifera, coccolithophores, crustaceans, echinoderms such as sea urchins, and corals. The shells and skeletons produced from calcification have important functions for the physiology and ecology of the organisms that create them.
Pelagodinium béii is a photosynthetic dinoflagellate that forms a symbiotic relationship with planktonic foraminifera.
Vital effects are biological impacts on geochemical records. Many marine organisms, ranging from zooplankton to phytoplankton to reef builders, create shells or skeletons from chemical compounds dissolved in seawater. This process, which is also called biomineralization, therefore records the chemical signature of seawater during the time of shell formation. However, different species have different metabolism and physiology, causing them to create their shells in different ways. These biological distinctions cause species to record slightly different chemical signatures in their shells; these differences are known as vital effects.
Hantkenina is a genus of planktonic foraminifera that lived from the Middle Eocene up to late Eocene, cirka 49 Ma-33.9 Ma. There have been 11 morphospecies described, including one of Cribrohantkenina
Foraminiferal tests are the tests of Foraminifera.
References
- ↑ Hayward, B. W.; Cedhagen, T.; Kaminski, M.; Gross, O. (2013). "Globigerinoides Cushman, 1927". World Foraminifera Database. Retrieved 2013-11-05.
- 1 2 3 4 5 6 7 Gupta, Barun K. Sen (2003). Modern Foraminifera. Kluwer Academic Publishers. pp. 15, 19, 24, 32, 48, 108–122, 245–247. ISBN 0-412-82430-2.
- ↑ Hemleben, CH; Erson, OR; Berthold, W & Spindler, M (1986). "Calcification and chamber formation in Foraminifera-a brief overview". In BSC Leadbeater & R Riding (eds.). Biomineralization in Lower Plants and Animals. Oxford: Clarendon Press. pp. 237–249.
- 1 2 Spero, Howard J; Lea, David W (1993). "Intraspecific stable isotope variability in the planktic foraminifera Globigerinoides sacculifer: Results from laboratory experiments". Marine Micropaleontology. 22 (3): 221–234. Bibcode:1993MarMP..22..221S. doi:10.1016/0377-8398(93)90045-y.
- ↑ Bé, A.W.H.; Spero, H.J. & Anderson, O.R. (1982). "Effects of symbiont elimination and reinfection on the life processes of the planktonic foraminifer Globigerinoides sacculifer". Marine Biology. 70: 73–86. doi:10.1007/bf00397298. S2CID 84793475.
- ↑ Bé, A.W.H.; Spero, H.J (1981). "Shell regeneration and biological recovery of planktonic foraminifera after physical injury induced in laboratory culture". Micropaleontology. 27 (3): 305–316. doi:10.2307/1485240. JSTOR 1485240.
- ↑ Thompson, Peter R; Be, Allan WH; Duplessy, Jean-Claude & Shackleton, Nicholas J (1979). "Disappearance of pink-pigmented Globigerinoides ruber at 120,000 yr BP in the Indian and Pacific Oceans". Nature. 280 (5723): 554–558. Bibcode:1979Natur.280..554T. doi:10.1038/280554a0. S2CID 4279013.
- ↑ Be, A.W.H; Tolderund, D.S. (1971). "Distribution and ecology of living planktonic foraminifera in surface waters of the Atlantic and Indian Oceans". The Micropalaeontology of Oceans: 103–149.
- ↑ Ogg, Gabi. "GSSP for Tortonian Stage". Geologic Timescale Foundation. Retrieved 8 November 2013.
- ↑ Ogg, Gabi. "GSSP Table - Cenozoic Era". Geologic Timescale Foundation. Retrieved 8 November 2013.