Phytoplankton diversity and chemotaxonomy in contrasting North Pacific ecosystems

Antonija Matek; Sunčica Bosak; Luka Šupraha; Aimee Neeley; Hrvoje Višić; Ivona Cetinić; Zrinka Ljubešić

doi:10.7717/peerj.14501

Phytoplankton diversity and chemotaxonomy in contrasting North Pacific ecosystems

PeerJ. 2023 Jan 3:11:e14501. doi: 10.7717/peerj.14501. eCollection 2023.

Authors

Antonija Matek¹, Sunčica Bosak¹, Luka Šupraha^{2

3}, Aimee Neeley^{4

5}, Hrvoje Višić⁶, Ivona Cetinić^{4

7}, Zrinka Ljubešić¹

Affiliations

¹ Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia.
² Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
³ Section for Aquatic Biology and Toxicology (AQUA), Department of Biosciences, University of Oslo, Oslo, Norway.
⁴ Ocean Ecology Laboratory, NASA/Goddard Space Flight Center, Greenbelt, MD, United States of America.
⁵ Science Systems and Applications, Inc., Lanham, Maryland, United States of America.
⁶ Department of Geosciences, Faculty of Science, Eberhard Karls University Tübingen, Tübingen, Germany.
⁷ GESTAR II, Morgan State University, Baltimore, MD, United States of America.

Abstract

Background: Phytoplankton is the base of majority of ocean ecosystems. It is responsible for half of the global primary production, and different phytoplankton taxa have a unique role in global biogeochemical cycles. In addition, phytoplankton abundance and diversity are highly susceptible to climate induced changes, hence monitoring of phytoplankton and its diversity is important and necessary.

Methods: Water samples for phytoplankton and photosynthetic pigment analyses were collected in boreal winter 2017, along transect in the North Pacific Subtropical Gyre (NPSG) and the California Current System (CCS). Phytoplankton community was analyzed using light and scanning electron microscopy and photosynthetic pigments by high-performance liquid chromatography. To describe distinct ecosystems, monthly average satellite data of MODIS Aqua Sea Surface temperature and Chlorophyll a concentration, as well as Apparent Visible Wavelength were used.

Results: A total of 207 taxa have been determined, mostly comprised of coccolithophores (35.5%), diatoms (25.2%) and dinoflagellates (19.5%) while cryptophytes, phytoflagellates and silicoflagellates were included in the group "others" (19.8%). Phytoplankton spatial distribution was distinct, indicating variable planktonic dispersal rates and specific adaptation to ecosystems. Dinoflagellates, and nano-scale coccolithophores dominated NPSG, while micro-scale diatoms, and cryptophytes prevailed in CCS. A clear split between CCS and NPSG is evident in dendogram visualising LINKTREE constrained binary divisive clustering analysis done on phytoplankton counts and pigment concentrations. Of all pigments determined, alloxanthin, zeaxanthin, divinyl chlorophyll b and lutein have highest correlation to phytoplankton counts.

Conclusion: Combining chemotaxonomy and microscopy is an optimal method to determine phytoplankton diversity on a large-scale transect. Distinct communities between the two contrasting ecosystems of North Pacific reveal phytoplankton groups specific adaptations to trophic state, and support the hypothesis of shift from micro- to nano-scale taxa due to sea surface temperatures rising, favoring stratification and oligotrophic conditions.

Keywords: Particle abundance; Pigments; Trophic state; Phytoplankton taxonomy.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Chlorophyll A
Diatoms*
Dinoflagellida*
Ecosystem
Phytoplankton / chemistry

Substances

Chlorophyll A

Grants and funding

This work was funded by the Croatian Science Foundation under projects BIOTA (UIP-2013-11-6433), ISLAND (IP-2020-02-9524), the Schmidt Ocean Institute, NASA GSFC Ocean Ecology Lab, and NASA’s PACE mission. Jorijntje Henderiks provided financial support for SEM analyses at Uppsala University (Swedish Research Council grant 2011-4866 and other funding). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.