Light and growth in marine phytoplankton: allometric, taxonomic, and environmental variation. (30th January 2015)

• Record Type: Journal Article
• Authors: Edwards, Kyle F.; Thomas, Mridul K.; Klausmeier, Christopher A.; Litchman, Elena
• Is Part Of: Limnology and oceanography. Volume 60:Number 2(2015:Mar.)
• Page Start: 540
• Page End: 552
• Publication Date: 2015-01-30
• Subjects: Limnology -- Periodicals; Oceanography -- Periodicals; Océanographie; Limnologie; Limnology; Oceanography; Computer network resources; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); Periodicals; 551.4805
• DOI: 10.1002/lno.10033
• Languages: English
• ISSNs: 0024-3590

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Light‐dependent growth of phytoplankton is a fundamental process in marine ecosystems, but we lack a comprehensive view of how light utilization traits vary across genotypes and species, and how this variation is structured by cell size, taxonomy, and environmental gradients. Here, we compile 308 growth‐irradiance experiments performed on 119 species of marine phytoplankton from all major functional groups, and characterize growth‐irradiance relationships in terms of the initial slope of the growth‐irradiance curve (<italic>α</italic>), the optimal irradiance above which growth declines (<italic>I</italic><sub>opt</sub>), and the maximum growth rate (<italic>μ</italic><sub>max</sub>). We find that <italic>α</italic> declines with increasing cell size, although cell size appears to be a weak constraint on this trait. There are significant differences across taxa in <italic>α</italic> and <italic>μ</italic><sub>max</sub>, with dinoflagellates, raphidophytes, and diazotrophs having the lowest values for both traits, and <italic>Phaeocystis</italic> spp. and diatoms having relatively high values. <italic>I</italic><sub>opt</sub> does not vary among taxonomic groups, and all traits exhibit large variation within most groups. Open‐ocean isolates tend to have higher <italic>α</italic>, lower <italic>I</italic><sub>opt</sub>, and lower <italic>μ</italic><sub>max</sub> than coastal isolates, implying adaptation to low light and low productivity. The three traits are correlated across species such that <italic>α</italic> and <italic>I</italic><sub>opt</sub> are negatively related while <italic>μ</italic><sub>max</sub> is positively correlated with both of these traits. There is some evidence that high <italic>α</italic> carries a cost of high N demand even when nitrogen (not light) is limiting. The results elucidate contrasting light‐related ecological strategies across phytoplankton and should help improve the parameterization of major functional groups in biogeochemical models.</p> </abstract>