Publication Date:
2020-06-30
Description:
Six spinose species of planktonic foraminifera (Hastigerina pelagica (d'Orbigny), Globigerinella aequilateralis (Brady), Globigerinoides ruber (d'Orbigny), Globigerinoides sacculifer (Brady), Globigerinoides conglobatus (Brady) and Orbulina universa d'Orbigny) are routinely collected by scuba diving in the Sargasso Sea off Bermuda and are maintained in the laboratory. These and non-spinose species can also be collected with plankton nets for laboratory culture. H. pelagica recovers extremely well from the net-towing operation. The mean survival times of H. pelagica, G. aequilateralis, G. ruber, G. sacculifer, G. conglobatus and O. universa in laboratory cultures are 21.1, 10.6, 6.2, 6.7, 11.8 and 8.8 days, respectively. These figures reflect in part the onset of gametogenesis, which terminates the life of the mother cell. During gametogenesis, which occurs over a period of about thirteen hours, the mother shell sinks and sheds its spines, and hundreds of thousands of gametes are released. Gametogenesis has been observed in nine species. All six spinose species possess one or more types of associated algae, which vary widely in size and number. The external ones are large dinoflagellates, such as Pyrocystis fusiformis, P. noctiluca and Dissodinium spp., which occur with H. pelagica. The smaller ones (zooxanthellae) in G. sacculifer, G. ruber and O. universa exhibit a circadian periodicity of ingress into the shell in the evening and egress to the rhizopodial network and the distal parts of the spines during the day. Some planktonic foraminiferal species are herbivorous, others are carnivorous, and still others are omnivorous. Copepods appear to be the main diet of G. aequilateralis and H. pelagica, both of which are fed Artemia nauplii in the laboratory. Shell and spine growth have been observed, and the formation of a new chamber in G. ruber takes place in about 90 minutes.
Type:
Article
,
PeerReviewed
Format:
text
Permalink
