Tag Archives: Foraminifera

Friday Fellow: Pink Miniacina

by Piter Kehoma Boll

It’s time  for the next foraminifer, which is always a problematic time, but I managed to find a suitable fellow for this Friday. Called Miniacina miniacea in the scientific community, it obviously lacks a common name, so I decided to call it the pink miniacina.

Differently from the previously introduced foraminifers, the pink miniacina is a sessile and colonial species. It usually grows attached to other lifeforms, especially algae and corals. Due to its colonial nature, added to the already bigger-than-average size of foramnifers when compared to other unicellular organisms, the pink miniacina is easily visible to the naked eye and can be seen as a series of small branched organisms with an intense pink color. It is particulary common in the Mediterranean Sea, although it can be found in other places as well.

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Several pink colonies of Miniacina miniacea growing in the Mediterranean Sea. Photo by Stefano Guerrieri.

Due to its habit of living on the surface of other sessile organisms, the pink miniacina competes with many other organisms that have the same behavior. As a result, its abundance tends to increase in deeper water, where many of such organisms find the conditions too unsuitable to live. In a few areas, the abundance of the pink miniacina may be high enough to create a “pink sand” from the shells of dead specimens.

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References:

Di Camillo, C.; Bo, M.; Lavorato, A.; Morigi, C.; Reinach, M. S.; Puce, S.; Bavestrello, G. (2008) Foraminifers epibiontic on Eudendrium (Cnidaria: Hydrozoa) from the Mediterranean Sea. Journal of the Marine Biological Association of the United Kingdom88(3): 485–489. https://doi.org/10.1017/S0025315408001045

Milliman, J. D.(1976) Miniacina miniacea: modern foraminiferal sands on the Outer Moroccan shelf. Sedimentology23: 415–419. https://doi.org/10.1111/j.1365-3091.1976.tb00059.x

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Friday Fellow: Bubble Globigerina

by Piter Kehoma Boll

A little more than a year ago I introduced the first foraminifer here, the tepid ammonia. Now it is time to bring the second one, this time a planctonic species that is rather famous and whose scientific name is Globigerina bulloides, or the bubble globigerina as I call it.

Globigerina_bulloides

A live specimen of Globigerina bulloides. Photo extracted from Words in mOcean.

This species can be found throughout the world, but it’s more common in cold subantarctic waters and a little less common in subarctic waters. The most common areas are the North and South Atlantic and the Indian Oceans, but the tropical records are most likely a misidentification of other closely related species.

The bubble globigerina usually lives in the upper 60 m of the water column, at least while reproducing, and feeds on other planktonic organisms, especially microscopic algae. In oder to maximize the ability of their gametes to meet in the vast extension of the ocean, the bubble globigerina synchronizes its sexual cycle with the moon cycle, reproducing during the first week after the new moon. It is, therefore, a kind of biological calendar.

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ResearchBlogging.orgReferences:

Bé, A. W. H.; Tolderlund, D. S. 1972. Distribution and ecology of living planktonic Foraminifera in surface waters of the Atlantic and Indian Oceans. In: Funnell, B. M.; Riedel, R. (Eds.) The Micropaleontology of Oceans, Cambridge University Press, pp. 105–150.

Schiebel, R., Bijma, J., & Hemleben, C. (1997). Population dynamics of the planktic foraminifer Globigerina bulloides from the eastern North Atlantic Deep Sea Research Part I: Oceanographic Research Papers, 44 (9-10), 1701-1713 DOI: 10.1016/S0967-0637(97)00036-8

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Friday Fellow: Tepid ammonia

by Piter Kehoma Boll

One of the few groups of living being not yet featured in Friday Fellow is Rhizaria, a group of single-celled organisms that includes the famous foraminifers. So today I decided to bring you just that, a foraminifer. And I think a good species to start with is Ammonia tepida, or the “tepid ammonia” as I decided to call it.

A live Ammonia tepida. Credits to Scott Fay.*

A live Ammonia tepida. Credits to Scott Fay.*

The tepid ammonia is found worldwide in brackish waters, or more precisely in the sediments deposited in brackish waters worlwide. It is able to tolerate a wide range of temperatures and degrees of salinity and is considered an ideal species of laboratory studies. As most foraminifers, the tepid ammonia secrets a shell of calcium carbonate, which is deposited on the cell’s surface in the form of a chain of chambers forming a spiral path, thus making it look like a snail shell.

Living in the sediments, the tepid ammonia feeds mainly on algae, but also consumes bacteria. In the laboratory, it demonstrated to have the ability to prey on small animals, such as nematodes, copepods and molluk larvae.

This kid got talent!

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References:

Dupuy, C.; Rossignol, L.; Geslin, E.; Pascal, P.-Y. (2010) Predation of mudflat meio-macrofaunal metazoans by a calcareous foraminifer, Ammonia tepida (Cushman, 1926). The Journal of Foraminiferal Research 40 (4): 305–312.

Munsel, D.; Kramar, U.; Dissard, D.; Nehrke, G.; Berner, Z.; Bijma, J.; Reichart, G.-J.; Neumann, T. (2010) Heavy metal incorporation in foraminiferal calcite: results from multi-element enrichment culture experiments with Ammonia tepida. Biogeosciences 7 (8): 2339–2350.

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*Creative Commons License
This image is licensed under a Creative Commons Attribution 2.5 Generic License.

 

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