Time-lapse recording of yearly activity of the sea star Odontaster validus and the sea urchin Sterechinus neumayeri in Tethys Bay (Ross Sea, Antarctica)

Abstract

One-year time-lapse images acquired via an autonomous photo imaging device positioned at a depth of 20 m in Tethys Bay (Ross Sea, Antarctica) on a rocky bottom colonized by the sponge Mycale (Oxymycale) acerata were analysed. Monthly changes in the abundance and activity of the sea star Odontaster validus and sea urchin Sterechinus neumayeri on the sponge and nearby rocky bottom were compared with respect to environmental variables such as pack-ice presence/absence, temperature, salinity and photosynthetically active radiation. Sea urchins were more abundant on the rocky bottom and sponge during the summer and winter, respectively. Sea stars showed a decrease in the number of individuals on the sponge from January to December. The grazing activity of both species reached its maximum in January–April, when increased sunlight contributed to the phytoplankton bloom. The winter months were critical both for O. validus and S. neumayeri; although the red sea star maintained its pattern of activity on the rocky bottoms in terms of searching for food, the sea urchin reduced its activity. Time-lapse monitoring systems coupled with physicochemical sensors showed potential for revealing species behaviour in polar environments, contributing to the elucidation of future changes in coastal communities facing climate change.

In situ observation of circadian rhythm of polyps’ opening and closing of the coral Dendrophyllia ramea (Linnaeus, 1758)

“…Time-lapse technology has been crucial in advancing research on coral polyps' rhythm and behavior because it allows the observation and analysis of slow processes or movements over an extended period, enabling the study of the polyps' daily activities and understanding how they interact with their environment over time. A similar approach was applied in a study of the occurrence and activity levels of macrozoobenthos in the Ross Sea, Antarctica, confirming its suitability as a tool for evaluating aspects of key macroinvertebrate foraging and behavior patterns in extreme environments such as marine caves (Cicogna & Pronzato, 1985) and polar habitats (Peirano et al, 2016(Peirano et al, , 2023.…”

Individual diet variability shapes the architecture of Antarctic benthic food webs

“…Third, we identified the core food web whose links and nodes remain unchanged. Comparisons were extended from the whole web to species level, by focusing on key Antarctic species in terms of abundance and distribution (the scallop Adamussium colbecki , the sea-urchin Sterechinus neumayeri and the sea star Odontaster validus 59 , 60 ).…”