Modelling Delayed Bloom Dynamics of Entomoneis sp. in İzmir Bay Using Spectral Collocation
OCEAN MODELLING, sa.1, ss.1-25, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.ocemod.2026.102811
- Dergi Adı: OCEAN MODELLING
- Derginin Tarandığı İndeksler: Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Science Citation Index Expanded (SCI-EXPANDED), Artic & Antarctic Regions, Compendex, Geobase, INSPEC
- Sayfa Sayıları: ss.1-25
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
İzmir Bay, a eutrophic semi-enclosed coastal basin in the eastern Aegean Sea, has experienced recurrent phytoplankton blooms associated with increasing nutrient enrichment. Among bloom-forming species, Entomoneis sp. is of particular ecological interest because of its anomalous cold-adapted physiology, exhibiting maximum growth at approximately 13°C rather than the monotonic temperature dependence commonly assumed in standard Eppley-type formulations. Despite its ecological importance, quantitative modelling studies incorporating both species-specific growth behaviour and physiological delay effects for this species remain limited.
In this study, a nutrient–phytoplankton delay differential equation (NP-DDE) model is developed to investigate the bloom dynamics of Entomoneis sp. in İzmir Bay. The growth function is calibrated using a 144-point Box–Behnken experimental dataset and is driven by realistic seasonal irradiance and temperature forcing representative of İzmir Bay. The delayed system is solved using a Lucas polynomial spectral collocation method with an algebraic delay-shift formulation, providing an efficient computational framework for delay-dependent bloom analysis.
The observed winter dominance of Entomoneis sp. is successfully reproduced by the calibrated growth function, and its strong sensitivity to low-temperature conditions is captured. Maturation delay is further shown to play an important role in bloom regime transitions: a single seasonal bloom is produced for short delay values, whereas a bimodal bloom structure with prolonged duration is produced for larger delay values. A transition threshold between τ₁ ≈ 1.0 and 1.5 d is identified, suggesting a potential link between nutrient-driven physiological delay and bloom stability.
The proposed modelling framework provides a quantitative basis for analysing delay-induced bloom transitions in eutrophic coastal systems and offers a practical tool for understanding phytoplankton dynamics in İzmir Bay.