Temperature and salinity limits for growth and survival of some planktonic foraminifers in laboratory cultures

• Main Authors: Bijma, Jelle, Faber, Walter W. Jr., Hemleben, Christoph
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cushman Foundation for Foraminiferal Research 1990
• Subjects: Planktonic foraminifera
• Online Access: https://oceanrep.geomar.de/id/eprint/29357/; https://oceanrep.geomar.de/id/eprint/29357/1/Bijma.pdf

The biological response to extreme temperatures and salinities is investigated in the laboratory for seven species of planktonic foraminifera: Globigerinoides sacculi/er (Brady), Globigerinoides ruber (d'Orbigny), Globigerinoides conglobatus (Brady), Globigerine/la siphonifera (d'Orbigny), Orbulina universa d'Orbigny, Neogloboquadrina dutertrei (d'Orbigny) and Globorotalia menardii (d'Orbigny). When one of the vital processes, food acceptance, growth or reproduction is inhibited by a culture variable, the absolute survival limit is reached. The measured in vitro temperature ranges compare well with the global temperature distribution patterns of these species, suggesting that this parameter plays a major role in their biogeographical distribution. The salinity ranges that are tolerated in laboratory cultures exceed the range encountered in modern oceans. Thus salinity does not limit the distribution of the species investigated herein. In general, larger mean final shell sizes are attained and the total shell length increase is larger at optimum temperatures and salinities than at extreme culture conditions, but the differences were not always statistically significant. Marginal temperature and salinity conditions do not induce contained growth in expatriated specimens. Under extreme culture conditions, the relative frequency of the different shell morphologies is altered relative to normal conditions. "Abnormal" phenotypes are more frequent under normal conditions and the "normal" morphology is found more often under extreme conditions. As opposed to previous reports, the frequency of kummerform chambers generally decreases toward extreme temperature and salinity culture conditions, indicating that kummerform phenotypes are not indicative of environmental stress. The incidence of sac-like chambers in G. sacculi/er and the formation of spherical chambers in adult 0. universa decrease toward extreme temperature and salinity culture conditions, demonstrating that maturation is suppressed in stress situations. SEM ...