The effect of flow speed and food size on the capture efficiency and feeding behaviour of the cold-water coral Lophelia pertusa

Orejas Saco del Valle, Covadonga; Gori, Andrea; Rad-Menéndez, Cecilia; Last, Kim S.; Davies, Andrew J.; Beveridge, Christine M.; Sadd, Daniel; Kiriakoulakis, Konstadinos; Witte, Ursula; Roberts, John Murray

The effect of flow speed and food size on the capture efficiency and feeding behaviour of the cold-water coral Lophelia pertusa

2016

The capture efficiency and feeding behaviour of the cold-water coral (CWC) Lophelia pertusa (Linnaeus, 1758) were investigated considering: (1) different food types, (2) different food sizes and (3) different current speeds and temperatures. This study used two different multifactorial experimental approaches: (1) Corals were subjected to three different flow speeds (2, 5 and 10cms−1) in 5l volume tanks, and three different food types (alive zooplankton, alive algae, and dry particulate organic carbon) were offered to the corals under each current regime, analysing the capture rates of the corals under these different flow velocities. (2) In a flume, the feeding behaviour of the coral polyps was studied under different current speed regimes (1, 7, 15 and 27cms−1) and a temperature change over a range of 8–12°C. The obtained results confirm that low flow speeds (below 7cms−1) appear optimal for a successful prey capture, and temperature did not have an effect on polyp expansion behaviour for L. pertusa. In conclusion, flow speeds clearly impact food capture efficiency in L. pertusa, with zooplankton predominantly captured prey at low flow velocities (2cms−1) and phytoplankton captured at higher flow velocities of 5cms−1. This split in capture efficiency may allow corals to exploit different food sources under different tidal and flow conditions.

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