Skeletal growth ring microanalysis and growth rates in sea pens from the Laurentian Channel MPA, Newfoundland

Abstract

Valuable information can be obtained through sea pen skeletons due to their high longevities and their annually deposited growth rings. Using Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM-EDX), elemental microanalyses were performed on sea pen skeletons to understand the physical basis of their growth rings. Here, the elemental composition and structure of growth bands in Anthoptilum grandiflorum, Anthoptilum murrayi, Pennatula aculeata, Funiculina quandrangularis, Protoptilum carpenteri, and Kophobelemnon stelliferum are shown. Samples were collected using the remotely operated vehicle (ROV) ROPOS in 2017 from the Laurentian Channel marine protected area (MPA) at depths of 400-600 m. Cross-sections of the axes were examined using SEM-EDX, presenting minor element variations within each growth ring (light: 2.64 cps Mg, 47.5 cps Ca; dark: Mg 2.25 cps, Ca 51.2 cps). The data suggests primary differences include large, abundant voids in dark growth rings, and fewer smaller voids in the light growth rings.