Dendrophyllia ramea specimens, collected during the CYCLAMEN cruise, were found in the continental shelf of Cyprus (~ 130 m depth), at a temperature of 16°C, which is considered as a relatively high temperature for the so called cold water corals (CWC).
To have a better understanding of D. ramea’s physiology, we are maintaining specimens at 4 different temperatures (12, 16, 20 and 24°C) for several weeks.

We are feeding the corals 5 times a week with Mysis (2 Mysis per polyp), and measuring the main physiological processes, such as respiration, calcification, release of dissolved and particulate organic carbon and nitrogen. We also conduct feeding experiments to calculate the capture rates using Artemia salina adults as prey. In addition, we will use in further experiments stable isotopes 13C and 15N labeled prey to feed the corals, in order to monitor the amount of prey actually assimilated under the different temperatures.
Experiments are currently being conducted and we expect the first results in the coming summer. We expect to disseminate these first results in the International Cold-water coral symposium, which will be held in Boston (USA) in September 2016.

Text and images by Stéphanie Reynaud (CSM)

1:D. ramea specimen during experiment of prey capture. Note that the polyp is full of Artemia salina.

2: Specimens of D. cornigera (the yellow specimen in the first road) and D. ramea (behind, orange colour) in the incubation tank with a temperature of 20 °C

3: View of the same tank of figure 2

4: Specimen of D. cornigera during prey capture experiment. Note the expansion of the polyp due to the large amount of prey captured

5: Incubation of Dendrophyllia cornigera and D. ramea to measure calcification and respiration rates, Total Organic Carbon & Nitrogen and Dissolved Organic Carbon & Nitrogen.

6: Specimen of D. ramea in the aquaria facilities of the CSM