Modeling the life cycle of four types of phytoplankton and their bloom mechanisms in a benthic-pelagic coupled ecosystem

Akio Sohma, Riku Imada, Tetsuya Nishikawa and Hisashi Shibuki

Ecological Modelling, 2022, vol. 467, issue C

Abstract: Harmful diatom (Coscinodiscus waillesi and Eucampia zodiacus) blooms frequently occur in the western coastal area of Japan from late autumn to early spring, causing discoloration of edible seaweed nori (Pyropia yezoensis). One of the causes of the discoloration is thought to be nutrient depletion (oligotrophication) due to nutrient uptake by diatoms. The goal of our study was to elucidate the mechanisms underlying phytoplankton blooms and the effects of such blooms on comprehensive nutrient cycles in the benthic-pelagic ecosystem. We developed a new ecosystem model, EMAGIN-L.P., simultaneously representing phytoplankton life cycle and the benthic-pelagic ecosystem. The life cycles of four types of phytoplankton—dinoflagellates (DFL), small diatoms (SDA), Coscinodiscus wailesii (CDW), and Eucampia zodiacus (EZ)—were numerically modeled and incorporated into an existing ecosystem model, ECOHYM (Sohma et al., 2008a), representing the food web among the benthic and pelagic systems and carbon-nitrogen-phosphorus-oxygen-coupled cycles driven by biogeochemical and physical processes. The model was applied to the Harima-Nada Sea where the discoloration of nori frequently occurs. The model reproduced the differences in timing and scale of the four phytoplankton blooms, and each bloom could be explained by a combination of temperature suitability, light availability, nutrient limitation, and vertical mixing within the water column. Furthermore, through a sensitivity analysis, competition for nutrient uptake among different types of phytoplankton was observed in the model. That is, from June to October, when DFL and SDA blooms occur, the SDA nutrient uptake rate is high and SDA suppresses the DFL bloom, while from November to March, when CDW and EZ blooms occur, the nutrient uptake rate of EZ is high and the CDW bloom is slightly suppressed. The developed model representing the phytoplankton bloom mechanisms in the whole benthic-pelagic coupled ecosystem will be a useful tool for revealing the mechanisms underlying the nutrient cycle and the contribution of harmful diatom blooms to the discoloration of nori. The modeling approach presented in this paper (i.e., categorizing different types of major phytoplankton and incorporating their life cycle into the entire benthic-pelagic coupling ecosystem) can be an effective method to understand, predict, and manage the problems caused by harmful diatom blooms across different damage types, harmful diatom species, and ocean areas.

Keywords: Phytoplankton life cycle; Ecosystem model; Benthic-pelagic coupling; Eucampia zodiacus; Coscinodiscus wailesii; Nutrient cycle (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0304380022000102
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:ecomod:v:467:y:2022:i:c:s0304380022000102

DOI: 10.1016/j.ecolmodel.2022.109882

Access Statistics for this article

Ecological Modelling is currently edited by Brian D. Fath

More articles in Ecological Modelling from Elsevier
Bibliographic data for series maintained by Catherine Liu ().