Large benthic foraminifera (LBF) are marine calcifying protists that commonly harbor algae as symbionts. These organisms are major calcium carbonate producers and important contributors to primary production in the photic zones. Light is one of the main known factors limiting their distribution, and species of this group developed specific mechanisms that allow them to occupy different habitats across the light gradient. Operculina ammonoides (Gronovius, 1781) is a planispiral LBF that has two main shell morphotypes, thick involute and flat evolute. Earlier studies suggested morphologic changes with variation in water depth and presumably light. In this study, specimens of the two morphotypes were placed in the laboratory under artificial low light and near the sea floor at depths of 15 m, 30 m, and 45 m in the Gulf of Aqaba-Eilat for 23 days. Differences in growth and symbionts content were evaluated using weight, size, and chlorophyll a. Our results show that O. ammonoides exhibit morphological plasticity when constructing thinner chambers after relocation to low light conditions, and adding more weight per area after relocation to high light conditions. In addition, O. ammonoides exhibited chlorophyll content adaptation to a certain range of light conditions, and evolute specimens that were acclimatized to very low light did not survive relocation to a high light environment, possibly due to photo-oxidative stress.
|State||Published - 1 Dec 2018|
Bibliographical noteFunding Information:
We wish to express our gratitude to the Inter-University Institute (IUI) of Eilat for providing the facilities to carry out this study. We thank Gal Eyal for accompanying Shai Oron on her CCR diving sessions. The research was supported by the Israel Science Foundation grant No 587/2013. This research is a part of the first author’s PhD dissertation, and was also funded by the Department of Geological and Environmental Sciences at Ben-Gurion University of the Negev and by the Inter-University Institute of Marine Sciences in Eilat (IUI).
© 2018 The Author(s).