Occurrence of UVA- and UVB-absorbing compounds in 152 species (206 strains) of marine microalgae

Abstract

Marine microalgae (152 species, 206 strains) from 12 classes were exam~ned for the presence of UVA-and UVB-absorbing compounds. Cultures were grown under white fluorescent light without supplementary UVA or UVB radiation and were extracted after harvest m tetrahydrofuran:methanol (20:80, v/v). Ratios of UV absorbance (280 to 390 nm) to chlorophyll a (chl a) (665 nm) obtained by spectrophotometry ranged from 0.18 to 6.75. Three groups of species were distinguished: those with low UV:chl a ratios (0.18 to 0.9, diatoms, green algae, cyanophytes, euglenophytes, eustlgmatophytes, rhodophytes, some dinoflagellates, some prymnesiophytes], those with intermed~ate ratlos (0.9 to 1.4, chrysophytes, some prasinophytes, some prymnesiophytes) and those with very high ratios (1.4 to 6.75, surface bloom-forming dinoflagellates, cryptoinonads, prymnesiophytes and raphidophytes). UV-absorbing pigments varied across species of the same algal class and strains of the same species. HPLC analysis of extracts of 5 species (1 diatom, 2 bloom-forming raphidophytes and 2 bloomforming dinoflagellates) showed suites of mycosporine-like amino acids in 4 of them, which included mycosporine-glycine, asterina-330, shinorme, porphyra-334 and palythine. The dinoflagellate Gymnodin~um catenatum also contained major quantities of unknown UV-absorbing compounds.

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

“…5). Although diatom species generally contain low concentrations of MAAs, some species are reported to lack MAAs (Riegger & Robinson, 1997;Jeffrey et al, 1999;Laurion et al, 2003). In coincidence with previous reports (Riegger & Robinson, 1997;Hernando et al, 2002) Thalassiosira sp.…”

Influence of mycosporine‐like amino acids (MAAs) on UV absorption by particulate and dissolved organic matter in La Jolla Bay

“…The possibility also exists that these unknown compounds may be hereto unidentified MAAs, as several new MAAs are identified each year (Jeffrey et al 1999;Karsten and Wiencke 1999;Sommaruga et al 1999;Xiong et al 1999), but it is unlikely that all 14 unknowns are novel MAAs, especially the unknowns detected in the DOM samples. Several mechanisms may be responsible for the conversion of known MAAs to unknown UV-absorbing compounds.…”

“…These compounds have been identified in a wide phyletic assortment of marine organisms and may provide partial photoprotection from ultraviolet (UV) radiation (Karentz et al 1991;Bandaranayake 1998;Jeffrey et al 1999). L. polyedrum produces seven types of MAAs with absorption maxima ranging between 310 and 364 nm (Vernet and Whitehead 1996).…”

Production of chromophoric dissolved organic matter (CDOM) in the open ocean by zooplankton and the colonial cyanobacterium Trichodesmium spp.

“…MAAs are thought to be the major class of UV absorbing compounds in the marine environment (Bandaranayake 1998, Shick & Dunlap 2002, and important in the attenuation of UV radiation. These compounds are found in a wide range of marine organisms (including phytoplankton and zooplankton) and may provide photoprotection from, or minimize deleterious effects of UV radiation (Karentz et al 1991, Bandaranayake 1998, Jeffrey et al 1999, Karentz 2001, Shick & Dunlap 2002.…”