The inner structure of multitaxonomic boxwork rhodoliths from a seabed located off of the Northern Israeli coast was explored as a tool to understand past depositional environments of the shallow littoral zone. Studied rhodoliths consist of superimposed, successive growth stages formed by different encrusting biota. The types of growth stages include fruticose encrusting coralline algae layers, and layers of serpulid tubes, grainstone or encrusting coralline algae. Carbon dating of radial sections cut from along the growth axis of two large rhodoliths (~8 cm radial sections) suggests that the transition between these layers occurred at the same time, and that layers dominated by different phyla have significantly different growth rates, ≥0.3 ̶ ~0.8 mm yr−1 for the serpulid layers and 0.1–0.4 mm yr−1 for the coralline algae stages. Layers of sediment grains between some of the growth stages suggest that the successions occurred during high turbidity periods in the surrounding water, possibly induced by heavy rain or storm events. Radio-carbon dating of the largest rhodolith samples shows a record of such environmental influence in the area dating back 366 ± 57 years cal. B.P. Studies on boxwork rhodolith growth stages are a potential archive of past depositional environments in the shallow littoral zone.
Bibliographical noteFunding Information:
We are grateful for the kind help of Dr. Raziel Hoffman, Tel Aviv University, Israel, who assisted us in identifying the types of algae present in the rhodoliths; Dr. Boguslaw Kolodziej, Jagiellonian University, Poland who provided valuable comments regarding the formation of the rhodoliths and the carbon dating of samples taken from these; the Poznan Radiocarbon Laboratory, Poland for their kind assistance in dating the rhodoliths samples; Mr. JJ Gottlieb for his generous and patient help with the specimen photography and thin section petrography preparations; Dr. Mor Kanari of the Israel Oceanographic and Limnological Research Institute, who assisted with the drafting of maps and graphics; The Mediterranean Sea Research Center of Israel (MERCI) for a grant to enable the dating of the rhodoliths subsamples; the Recanati Institute for Maritime Studies and particularly Amir Yurman and Moshe Bachar for their assistance in collecting rhodoliths at sea; the Sir Maurice Hatter fund for a scholarship in support of this research.
- Coralline red algae
- Multitaxonomic rhodoliths
- Shallow littoral
- Southeast Mediterranean
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science