Dinitrogen-fixing cyanobacteria in microbial mats of two shallow coral reef ecosystems.
Dinitrogen-fixing organisms in cyanobacterial mats were studied in two shallow coral reef ecosystems: La Reunion Island, southwestern Indian Ocean, Sesoko (Okinawa) Island, and northwestern Pacific Ocean. Rapidly expanding benthic miniblooms, frequently dominated by a single cyanobacterial taxon, were identified by microscopy and molecular tools. In addition, nitrogenase activity by these blooms was measured in situ. Dinitrogen fixation and its contribution to mat primary production were calculated using (15)N(2) and (13)C methods. Dinitrogen-fixing cyanobacteria from mats in La Reunion and Sesoko showed few differences in taxonomic composition. Anabaena sp. among heterocystous and Hydrocoleum majus and Symploca hydnoides among nonheterocystous cyanobacteria occurred in microbial mats of both sites. Oscillatoria bonnemaisonii and Leptolyngbya spp. occurred only in La Reunion, whereas Hydrocoleum coccineum dominated in Sesoko. Other mats dominated by Hydrocoleum lyngbyaceum, Phormidium laysanense, and Trichocoleus tenerrimus occurred at lower frequencies. The 24-h nitrogenase activity, as measured by acetylene reduction, varied between 11 and 324 nmoles C(2)H(2) reduced microg(-1) Chl a. The highest values were achieved by heterocystous Anabaena sp. performed mostly during the day. Highest values for nonheterocystous cyanobacteria were achieved by H. coccineum mostly during the night. Daily nitrogen fixation varied from nine (Leptolyngbya) to 238 nmoles N(2) microg(-1) Chl day(-1) (H. coccineum). Primary production rates ranged from 1,321 (S. hydnoides) to 9,933 nmoles C microg(-1) Chl day(-1) (H. coccineum). Dinitrogen fixation satisfied between 5% and 21% of the nitrogen required for primary production.
Charpy
Loic
L
IRD, COM, Rue de la Batterie des Lions, 13007, Marseille, France. loic.charpy@univmed.fr
Palinska
Katarzyna A
KA
Casareto
Beatriz
B
Langlade
Marie José
MJ
Suzuki
Yoshimi
Y
Abed
Raeid M M
RM
Golubic
Stjepko
S
D000818:Animals; D037421:Anthozoa; D001483:Base Sequence; D018441:Biofilms / Q000145:classification*; D000458:Cyanobacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D017753:Ecosystem; D004784:Environmental Monitoring; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism; D010802:Phylogeny; D012623:Seawater / Q000737:chemistry / Q000382:microbiology
D009591:Nitrogenase; D009584:Nitrogen
Proc Natl Acad Sci U S A. 1967 Nov;58(5):2071-8
5237501
FEMS Microbiol Lett. 2006 Jul;260(2):171-7
16842341
Res Microbiol. 2003 Apr;154(3):157-64
12706503
Microbiology (Reading). 2002 Feb;148(Pt 2):481-496
11832512
Appl Environ Microbiol. 1996 Mar;62(3):986-93
16535283
Appl Environ Microbiol. 1983 Apr;45(4):1331-7
16346272
New Phytol. 1998 Nov;140(3):531-538
33862883
Ambio. 2002 Dec;31(7-8):602-5
12572829
J Bacteriol. 1988 Aug;170(8):3584-92
3136142
Nature. 2003 Oct 2;425(6957):504-7
14523445
Nucleic Acids Res. 1994 Nov 11;22(22):4673-80
7984417
Biomol Eng. 2003 Jul;20(4-6):191-7
12919797
Int J Syst Evol Microbiol. 2005 Mar;55(Pt 2):555-568
15774625