Physiological effects of ultraviolet radiation on the subtidal red macroalga Laurencia obtusa
Regional Studies in Marine Science, cilt.102, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 102
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.rsma.2026.105394
- Dergi Adı: Regional Studies in Marine Science
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Zoological Record
- Anahtar Kelimeler: Laurencia obtusa, Nitrate reductase, Sublittoral macroalgae, Ultraviolet radiation
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
Ozone depletion has led to increasing levels of ultraviolet radiation (UVR) reaching the Earth’s surface, with sublittoral macroalgae predicted to be particularly vulnerable due to their adaptation to stable light environments. This study investigated the physiological responses of the sublittoral red macroalga Laurencia obtusa to three irradiance treatments- PAR (P), PAR + UVA (PA), PAR + UVA + UVB (PAB) – applied over three weeks, followed by a one-week recovery period. UVR stimulated the synthesis of chlorophyll-a, phycobiliproteins and UV-absorbing compounds, while nitrate reductase activity was significantly elevated under both UV treatments relative to PAR alone. Despite increased nitrogen assimilation, neither growth rate nor protein content increased under UV exposure, suggesting that assimilated nitrogen was preferentially directed towards the synthesis of photoprotective compounds. The persistence of elevated pigment contents, UV-absorbing compound levels and nitrate reductase activity during the recovery period indicates that the physiological effects of UVR were not reversed within one week. Overall, L. obtusa maintained its growth performance throughout the experiment, demonstrating that this sublittoral species possesses sufficient photoprotective capacity to tolerate sustained UV exposure. These results suggest that L. obtusa retains sufficient physiological capacity to tolerate an acute, field-realistic surface-level UVB dose, despite naturally inhabiting a UVB-attenuated sublittoral environment in the Marmara Sea.