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| Auteurs principaux: | , , , , , , , |
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| Format: | Artículo científico |
| Langue: | en |
| Publié: |
Marine environmental research
2026
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| Sujets: | |
| Accès en ligne: | https://pubmed.ncbi.nlm.nih.gov/42139988/ |
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Table des matières:
- Blue light stimulates the release of humic-like substances in a marine diatom Thalassiosira pseudonana. Chen, Bokun Liu, Jihua Xu, Ge Chen, Xiao Zhao, Wei Yang, Xue Ren, Hongwei Li, Gang Blue Light Diatoms Dissolved Organic Matter Humic Substances Phytoplankton Differential attenuation of various wavebands of solar irradiation makes the blue light spectrum (450-495 nm) to dominate the middle and lower euphotic zones of the oceans, where maximum phytoplankton biomass is often present. Yet, how these primary producers adjust their cellular composition and the release of dissolved organic matter (DOM) under such light conditions remains unclear, despite potential effects on marine biogeochemical cycles. In this study, we cultivated a model diatom Thalassiosira pseudonana under combinations of light intensity (optimal vs. limited) and light quality (white vs. blue) to investigate the effects of blue light on cellular metabolism and DOM characteristics across growth phases. Results showed that blue light increased the growth rate during the exponential phase by 10% at optimal light and by 12% at limited light, which is related to pigment reprogramming and increased particulate organic carbon (POC) content. Meanwhile, blue light increased dissolved organic carbon (DOC) concentration within the cultures at both optimal and limited light, with maximal enhancements in ΔDOC of 244% and 211% during the exponential phase, respectively. We identified five DOM components using excitation-emission matrix spectroscopy (EEMs) and found that cells under blue light convert a tryptophan-like component into two humic-like substances with lower molecular weight and rich in carboxyl and amino groups, ultimately doubling the humification index (HIX). This may be related to the phenomenon of "photosynthetic overflow" under blue light. Our results indicate that phytoplankton might contribute substantially more to the marine recalcitrant dissolved organic carbon (RDOC) pool than previously recognized.