Nitrogen enrichment and Ulva green tide dynamics on Jeju Island: insights from biomass, physiological traits, and stable isotopes signatures
6 affiliations
- 1Estuarine & Coastal Ecology Laboratory, Department of Marine Life Sciences, Jeju National University
- 2Marine Environmental Research Department, Korea Institute of Ocean Science and Technology (KIOST)
- 3Jeju Marine Research Center, Korea Institute of Ocean Science & Technology (KIOST)
- 4Oceanic Climates & Ecology Division, National Institute of Fisheries Science
- 5Molecular Ecology and Evolution Laboratory, Department of Biological Science, Sangji University
- 6Center for Climate Change Response, Jeju National University
Abstract
Green tides threaten coastal ecosystems worldwide, yet the physiological and environmental mechanisms driving their dynamics remain poorly resolved. On subtropical islands like Jeju, Korea, where nitrogen inputs are diverse, predicting bloom intensity is particularly challenging. Here we show that water column nutrient levels alone poorly correlated with bloom magnitude, whereas algal tissue nitrogen provides a more reliable indicator of nitrogen status and nutrient exposure history. Seasonal surveys across fourteen sites (2013–2015) revealed annual Ulva blooms exceeding 11,000 t, with stable isotope (δ15N) analysis indicating that blooms are likely sustained by mixed nitrogen sources rather than a single dominant source, although precise source attribution was not possible. Tissue nitrogen content closely tracked dissolved inorganic nitrogen, while nitrate reductase activity was decoupled from nitrate supply under nutrient-replete conditions and negatively associated with biomass accumulation; suppression of nitrogen reductase activity by ammonium feedback and self-shading within dense mats is inferred from these patterns but was not directly measured. By integrating environmental drivers with physiological traits, we provide mechanistic insights into bloom dynamics and highlight nitrogen management as a critical lever for mitigating green tides in vulnerable coastal ecosystems.
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BibTeX
@article{moon2026nitrogen,
title = {{Nitrogen enrichment and Ulva green tide dynamics on Jeju Island: insights from biomass, physiological traits, and stable isotopes signatures}},
author = {Kyeonglim Moon and Eun Ran Baek and Sun Kyeong Choi and Hyun Woo Jeong and Young Baek Son and Sangil Kim and Hyuk Je Lee and Yun Hee Kang and Sang Rul Park},
journal = {Scientific Reports},
year = {2026},
month = jul,
doi = {10.1038/s41598-026-63524-w},
url = {https://doi.org/10.1038/s41598-026-63524-w},
note = {CC BY},
}
RIS
TY - JOUR
TI - Nitrogen enrichment and Ulva green tide dynamics on Jeju Island: insights from biomass, physiological traits, and stable isotopes signatures
AU - Kyeonglim Moon
AU - Eun Ran Baek
AU - Sun Kyeong Choi
AU - Hyun Woo Jeong
AU - Young Baek Son
AU - Sangil Kim
AU - Hyuk Je Lee
AU - Yun Hee Kang
AU - Sang Rul Park
PY - 2026
DA - 2026/07/01
JO - Scientific Reports
DO - 10.1038/s41598-026-63524-w
UR - https://doi.org/10.1038/s41598-026-63524-w
AB - Green tides threaten coastal ecosystems worldwide, yet the physiological and environmental mechanisms driving their dynamics remain poorly resolved. On subtropical islands like Jeju, Korea, where nitrogen inputs are diverse, predicting bloom intensity is particularly challenging. Here we show that water column nutrient levels alone poorly correlated with bloom magnitude, whereas algal tissue nitrogen provides a more reliable indicator of nitrogen status and nutrient exposure history. Seasonal surveys across fourteen sites (2013–2015) revealed annual Ulva blooms exceeding 11,000 t, with stable isotope (δ15N) analysis indicating that blooms are likely sustained by mixed nitrogen sources rather than a single dominant source, although precise source attribution was not possible. Tissue nitrogen content closely tracked dissolved inorganic nitrogen, while nitrate reductase activity was decoupled from nitrate supply under nutrient-replete conditions and negatively associated with biomass accumulation; suppression of nitrogen reductase activity by ammonium feedback and self-shading within dense mats is inferred from these patterns but was not directly measured. By integrating environmental drivers with physiological traits, we provide mechanistic insights into bloom dynamics and highlight nitrogen management as a critical lever for mitigating green tides in vulnerable coastal ecosystems.
SN - 2045-2322
ER -