Boneccia viridis

Pettersen, Ragnhild, Johnsen, Geir, Bruheim, Per & Andreassen, Trygve, 2014, Development of hyperspectral imaging as a bio-optical taxonomic tool for pigmented marine organisms, Organisms Diversity & Evolution (New York, N. Y.) 14 (2), pp. 237-246 : 240-241

Boneccia viridis

Pigment analysis (LC-MS) detected only one pigment in B. viridis , and surprisingly this was not the expected bonellin, but a derivative of bonellin called neobonellin. Neobonellin (pigment 1) with maximum optical density [OD(λ)max] at 392 nm, 494 nm, 521 nm, 586 nm and 640 nm was identified from the body skin of B. viridis with LC-MS analysis and found to contribute to the deep green colour of the animal ( Fig. 2a , Table 1). The in vivo and in vitro OD absorption signatures ( Fig. 2b ) corresponded to the absorption spectra of neobonellin from 400 to 650 nm (in vivo and in vitro was only measured from 400 to 700 nm) except a shoulder at 488 nm that is not shown or reported for the neobonellin absorption spectra and a OD(λ) max at 538 nm that correspond both to the reported absorption max of neobonellin (536 nm) and bonellin (539 nm) absorption spectra but was not evident in the absorption spectra from LC-MS analysis. The bonellin absorption spectrum has been reported to have OD maxima at: 394– 488 (shoulder)–494–521–539–590–(620) and 641 nm ( Cariello et al. 1978), indicating that the shoulder at 488 nm in the in vivo and in vitro spectra were due to bonellin. LC-MS analysis did not detect bonellin, probably because the proboscis, which is the main source of bonellin, was not included in the extraction, only the body skin, which is the main source of neobonellin. When HI measurements were conducted, the animal had withdrawn its proboscis (probably because of being negatively phototactic) so that only the body skin was a b

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used also for HI reflection spectra. Therefore, the location of pigments in the OOI and also the behaviour and movement pattern of sessile and none sessile OOI is important knowledge and needs to be taken into consideration when using absorption and reflection signatures as taxonomic identification tools. For organisms living on the sea bottom, in situ UHI measurements have short exposure times and therefore animals that are negatively phototactic would not have time to withdraw their appendages or perform an escape. Sessile organisms that, by chance, have withdrawn their coloured appendages, have other body parts that can be used for identification. For burrowing organisms and organisms living within the sediments, the UHI technique might not be applicable.

The HI reflection spectra of B. viridis were found to be high in the 420–480 nm wavelength area with a R(λ) max at 441 nm ( Fig. 2b ). The corresponding low absorption in the same wavelength area led to the conclusion that, for B. viridis , R(λ) and OD(λ) spectra were inversely related.

Figures

Fig. 2 a, b Bio-optical signatures from B. viridis. a Specific absorbance spectra of neobonellin (pigment 1) detected from liquid chromatography– mass spectroscopy (LC-MS) analysis of the spoon worm B. viridis. b Absorbance spectra in vivo OD(λ) and in vitro OD(λ) plotted against reflection spectra in vivo R(λ) from the hyperspectral imager (HI),