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Antarctic krill (Euphausia superba) acquire a UV-absorbing mycosporine-like amino acid from dietary algae

journal contribution
posted on 2023-05-16, 12:11 authored by Newman, SJ, Dunlap, WC, Nicol, S, Ritz, DA
We hypothesised that Antarctic krill acquire UV-absorbing mycosporine-like amino acids (MAAs) from dietary algae, which produce MAAs in response to ultraviolet (UV) irradiation. To test this hypothesis, we grew cultures of Phaeocystis antarctica that had been grown under either photosynthetically active radiation (PAR, 400-750 nm) plus UV irradiation (UVR, 280-400 nm), or else PAR-only. Algae grown under PAR-only produced high concentrations of porphyra-334, whereas additional UVR caused formation of high concentrations of mycosporine-glycine:valine and lower concentrations of porphyra-334. Krill were fed with either of these two cultures on eight occasions over 63 days. A third group was starved for the duration of the experiment. Animals were analysed after 36 and 63 days for MAA content. Remaining animals from all treatments were starved for a further 35 days and analysed to examine MAA retention characteristics. Our findings are that krill acquired different MAAs from dietary algae depending on the light conditions under which the algae were grown. Specifically, krill fed algae grown under PAR-only had higher concentrations of porphyra-334 than starved krill. Conversely, krill fed algae grown under PAR with additional UVR had high body concentrations of mycosporine-glycine:valine. MAA concentrations in starved krill remained static throughout the experiment. However, long term starvation (35 days) caused levels of certain acquired MAAs to decline. From this we can infer that MAA concentrations in krill are dependent on the MAA content of phytoplankton, and therefore the algae's response to UV exposure. This has implications for transfer of MAAs through marine trophic webs. (C) 2000 Elsevier Science B.V.

History

Publication title

Journal of Experimental Marine Biology and Ecology

Volume

255

Pagination

93-110

ISSN

0022-0981

Department/School

Institute for Marine and Antarctic Studies

Publisher

Elsevier-Science-BV

Place of publication

Netherlands

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences

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