Sampling bias misrepresents the biogeographical significance of constitutive mixotrophs across global oceans


Contact
Urban.Tillmann [ at ] awi.de

Abstract

Aim: Most protist plankton are mixotrophic, with potential to engage in photoautotrophy and phagotrophy; however, the ecology of these organisms has been misdiagnosed for over a century. A large proportion of these organisms are constitutive mixotrophs (CMs), with an innate ability to photosynthesize. Here, for the first time, an analysis is presented of the biogeography of CMs across the oceans. Location: Global marine ecosystems. Time period: 1970–2018. Major taxa studied: Marine planktonic protists. Methods: Records for CM species, primarily from the Ocean Biogeographic Information System (OBIS), were grouped by taxonomy and size to evaluate sampling efforts across Longhurst's oceanic provinces. Biases were evaluated through nonparametric tests and multivariate analysis. Biogeographies of CMs from OBIS data were compared with data from studies that specifically targeted these organisms. Results: Constitutive mixotrophs of different taxonomic groups, across all size ranges, are ubiquitous. However, strong database biases were detected with respect to organism size, taxonomic groups and region. A strong bias was seen towards dinophytes. Species < 20 µm, especially non-dinophytes, were least represented, with their recorded distribution limited to coastal regions and to temperate and polar seas. Studies specifically targeting these organisms revealed their distribution to be much wider. Such biases are likely to have occurred owing to a failure to capture and correctly identify these organisms in routine sampling protocols. Main conclusions: Constitutive mixotrophs are dominant members of organisms traditionally termed “phytoplankton”. However, lack of routine protocols for measuring phagotrophy in “phytoplankton” protists has led to widespread misrepresentation of the fundamental nature of marine planktonic primary producers; most express both “animal-like” and “plant-like” nutrition. Our results have implications for studies of the global biogeography of plankton, of food web dynamics (including models) and of biogeochemical cycling in the oceans.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
49218
DOI https://www.doi.org/10.1111/geb.12853

Cite as
Leles, S. G. , Mitra, A. , Flynn, K. J. , Tillmann, U. , Stoecker, D. , Jeong, H. J. , Burkholder, J. , Hansen, P. J. , Caron, D. A. , Glibert, P. M. , Hallegraeff, G. , Raven, J. A. , Sanders, R. W. and Zubkov, M. (2019): Sampling bias misrepresents the biogeographical significance of constitutive mixotrophs across global oceans , Global Ecology and Biogeography, 28 (4), pp. 418-428 . doi: https://www.doi.org/10.1111/geb.12853


Download
[thumbnail of 2019_Leles_GlobalEcologyBiogeography.pdf]
Preview
PDF
2019_Leles_GlobalEcologyBiogeography.pdf

Download (1MB) | Preview

Share


Citation

Geographical region
N/A

Research Platforms
N/A

Campaigns
N/A


Actions
Edit Item Edit Item