AME 56:227-239 (2009) - DOI: https://doi.org/10.3354/ame01357
Nitrogen and phosphorus limitation of oceanic microbial growth during spring in the Gulf of Aqaba
David J. Suggett1,*, Noga Stambler2, Ondrej Prášil3, Zbigniew Kolber4, Antonietta Quigg5, Evaristo Vázquez-Dominguez6, Tamar Zohary7, Tom Berman7, David Iluz8, Orly Levitan2, Tracy Lawson1, Efrat Meeder9,10, Boaz Lazar9,10, Edo Bar-Zeev2, Hana Medova3, Ilana Berman-Frank8
ABSTRACT: Bioassay experiments were performed to identify how growth of key groups within the microbial community was simultaneously limited by nutrient (nitrogen and phosphorus) availability during spring in the Gulf of Aqaba’s oceanic waters. Measurements of chlorophyll a (chl a) concentration and fast repetition rate (FRR) fluorescence generally demonstrated that growth of obligate phototrophic phytoplankton was co-limited by N and P and growth of facultative aerobic anoxygenic photoheterotropic (AAP) bacteria was limited by N. Phytoplankton exhibited an increase in chl a biomass over 24 to 48 h upon relief of nutrient limitation. This response coincided with an increase in photosystem II (PSII) photochemical efficiency (Fv/Fm), but was preceded (within 24 h) by a decrease in effective absorption cross-section (σPSII) and electron turnover time (τ). A similar response for τ and bacterio-chl a was observed for the AAPs. Consistent with the up-regulation of PSII activity with FRR fluorescence were observations of newly synthesized PSII reaction centers via low temperature (77K) fluorescence spectroscopy for addition of N (and N + P). Flow cytometry revealed that the chl a and thus FRR fluorescence responses were partly driven by the picophytoplankton (<10 µm) community, and in particular Synechococcus. Productivity of obligate heterotrophic bacteria exhibited the greatest increase in response to a natural (deep water) treatment, but only a small increase in response to N and P addition, demonstrating the importance of additional substrates (most likely dissolved organic carbon) in moderating the heterotrophs. These data support previous observations that the microbial community response (autotrophy relative to heterotrophy) is critically dependent upon the nature of transient nutrient enrichment.
KEY WORDS: Phytoplankton · Aerobic anoxygenic photoheterotroph · Bacterial · Fast repetition rate fluorometry · Chlorophyll a · Nutrient limitation · Gulf of Aqaba
Full text in pdf format  | Cite this article as: Suggett DJ, Stambler N, O Prášil, Kolber Z and others (2009) Nitrogen and phosphorus limitation of oceanic microbial growth during spring in the Gulf of Aqaba. Aquat Microb Ecol 56:227-239. https://doi.org/10.3354/ame01357 Export citation Share: Facebook - - linkedIn |
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