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dot Foraminifera Video- Courtesy of  O. Roger Anderson and Allan W. H. Be, Columbia University, Lamont-Doherty Earth Observatory. (195 MB)

O. Roger Anderson and Allan W. H. Bé pioneered the study of foraminifera in culture while at Columbia University’s Lamont-Doherty Earth Observatory (LDEO).  Their experiments yielded insight on the feeding strategies of planktonic foraminifera, and on how environmental changes affect individuals.  For instance, they found that some species adopt a dual feeding strategy such that they capture prey if it is available (e.g., brine shrimp, copepods), and otherwise can utilize photosynthetic activity of symbiotic algae within the foraminiferal protoplasm for supplemental food (Anderson and Bé, 1976).  Some of the experiments leading to their findings are illustrated in selected time-lapse footage of planktonic foraminifera cultured by Anderson and Bé, available for download here.

Dr. Bé served as president of the Cushman Foundation (1983), the same year he passed away.  Dr. Anderson is still a researcher at LDEO, focusing on amoeboid protists, their ecological relationship to other protists, environmental physical and biogeochemical variables, and their role in food webs, habitat abundance and diversity, and role in carbon budgets of ecosystems.

When using the video, please include this acknowledgment:
"Courtesy of  O. Roger Anderson and Allan W. H. Bé, Columbia University, Lamont-Doherty Earth Observatory."

Anderson, O. R., and Bé, A. W. H., 1976, The ultrastructure of a planktonic foraminifer, Globigerinoides sacculifer (Brady), and its symbiotic dinoflagellates: Journal of Foraminiferal Research, v. 6, p. 1-21.

 

Video narrative

Most of the images were taken of foraminifera collected at the Bermuda Institute for Ocean Sciences (previously known as the Bermuda Biological Station).  The foraminifera were maintained in laboratory culture using open ocean seawater in glass vials; in some cases, they were transferred to an inverted microscope observation vessel with an optically clear glass base plate. The videos are time lapse (lapse rate is unknown).

0-2:20  Globorotalia truncatulinoides – new chamber formation showing the emergence of a cytoplasmic mass where the new chamber will be deposited.  This is a view from the ventral or flat spiral surface of the foraminifer.  The enlarging cytoplasmic mass emerges from the oral aperture of the existing final chamber.  Eventually, a thin outer envelope, or cytoplasmic anlage, is formed at the periphery of the cytoplasmic mass.  The anlage is the template where calcium carbonate is deposited, and thus the final shape of the new chamber is determined.

2:20  Globorotalia and brine shrimp altercation (don’t give away outcome!)

3:00  Three Globigerinoides – note reticulopods (anastomosing pseudopods), spines, symbionts, and particles drawn to test. Apparent cannibalism has been observed in cultures when individual foraminifers are in close contact – but we do not know if it occurs in the natural environment, where typically the floating planktonic foraminifera are more widely dispersed.

4:45  Globigerinoides close-up – note reticulopods, spines, and symbionts.

6:00  Gametogenesis, showing the emergence of the cytoplasmic bulge that contains developing gametes. The gamete-containing bulge emerges from the oral aperture of the test at an early stage of gamete release.  Eventually, the bulge ruptures as the gametes are fully released and swim away from the parent foraminifer.

6:30  Orbulina universa – note internal initial spiral chambers, visible through the thin final spherical chamber.  There is a spectacular close-up of dinoflagellate symbionts at 6:45.

6:47  Gametogenesis

7:00  Close-up of gametogenesis

8:50  Hastigerina pelagica – note bubble capsule and spines.  The foraminifer has ensnared two copepods.  H. pelagica harbors Pyrocystis noctiluca and P. robusta dinoflagellates, but there is no evidence that they are symbionts and may be only commensals.

9:22  Small Orbulina universa – note reticulopods, spines, dinoflagellate symbionts, particles drawn to test, and waste products expelled. 

12:05  Orbulina universa – initial chambers are visible through thin final chamber; symbionts are visible inside test. 

14:15 Algal symbionts are transported by cytoplasmic streaming within the rhizopodial network.  This streaming is controlled, such that symbionts are drawn to the surface of the test and incorporated into vacuoles within the test in the evening.  At dawn, the symbionts are exocytosed and distributed outward along the spines.  One set of frames shows the symbionts being distributed out along the spines, as typically occurs each day before sunrise.

 

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