Biochemical composition of Echinodermata (Ophiuroidea, Asteroidea) from the abyssal Clarion-Clipperton Fracture Zone

Echinodermata (Ophiuroidea and Asteroidea) were collected by the remotely operating vehicle (ROV) Kiel 6000 (Geomar, Kiel, Germany) and ROV HD14 (Ocean Infinity, Texas, USA) in the eastern Clarion-Clipperton Fracture Zone in 2019 and 2021. Total carbon, organic carbon, total nitrogen, δ13TC, δ13org. C, and δ15N content of freeze-dried, pulverized Ophiuroidea and Asteroidea were measured with a elemental analyzer coupled to an isotope ratio mass spectrometer (EA-IRMS). Phospholipid-derived fatty acids (PLFAs) were extracted from the Echinodermata pulver using a Bligh and Dyer extraction. Afterwards, PLFAs were derivatized to fatty acid methyl esters (FAMEs), and their concentrations and δ13 isotopic values measured on a gas chromatograph coupled to an isotope ratio mass spectrometer (GC-IRMS).