Microbial rhodopsins are increasingly favoured over chlorophyll in High Nutrient Low Chlorophyll waters

Author(s)
B Hassanzadeh, B Thomson, F Deans, J Wenley, S Lockwood, K Currie, SE Morales, L Steindler, SA Sañudo-Wilhelmy, F Baltar, L Gómez-Consarnau
Abstract

Microbial rhodopsins are simple light-harvesting complexes that, unlike chlorophyll photosystems, have no iron requirements for their synthesis and phototrophic functions. Here, we report the environmental concentrations of rhodopsin along the Subtropical Frontal Zone off New Zealand, where Subtropical waters encounter the iron-limited Subantarctic High Nutrient Low Chlorophyll (HNLC) region. Rhodopsin concentrations were highest in HNLC waters where chlorophyll-a concentrations were lowest. Furthermore, while the ratio of rhodopsin to chlorophyll-a photosystems was on average 20 along the transect, this ratio increased to over 60 in HNLC waters. We further show that microbial rhodopsins are abundant in both picoplankton (0.2–3 μm) and in the larger (>3 μm) size fractions of the microbial community containing eukaryotic plankton and/or particle-attached prokaryotes. These findings suggest that rhodopsin phototrophy could be critical for microbial plankton to adapt to resource-limiting environments where photosynthesis and possibly cellular respiration are impaired.

Organisation(s)
Functional and Evolutionary Ecology
External organisation(s)
University of Southern California, University of Otago, National Institute of Water and Atmospheric Research, University of Haifa, Departamento de Innovación Biomédica División de Biología Experimental y Aplicada Centro de Investigación Científica y de Educación Superior de Ensenada, B.C.
Journal
Environmental Microbiology Reports
Volume
13
Pages
401-406
ISSN
1758-2229
DOI
https://doi.org/10.1111/1758-2229.12948
Publication date
04-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology
Portal url
https://ucris.univie.ac.at/portal/en/publications/microbial-rhodopsins-are-increasingly-favoured-over-chlorophyll-in-high-nutrient-low-chlorophyll-waters(197a4981-9105-46de-aa07-fe15b61c5294).html