Spatial and temporal distribution of Trichodesmium spp. in the stratified Gulf of Aqaba, Red Sea

Post, A.; Dedej, Z; Gottlieb, Ronald H.; Li, H; Thomas, David N.; El-Absawi, M; El-Naggar, Ahmed M.; El-Gharabawi, M; Sommer, Ulrich

doi:10.3354/meps239241

Cited by 99 publications

(119 citation statements)

References 47 publications

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“…The two species have distinct morphometric characteristics and they displayed much 331 higher length variations at Sta. SM (Table 3) than those reported by Post et al (2002) in the Gulf of 332 Aqaba: 300 -800 µm for T. erythraeum and 1000 -2000 µm for T. thiebautii. 333…”

Section: Trichodesmium Population Characteristics 299mentioning

confidence: 64%

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Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Rodier

Borgne²

2008

Journal of Experimental Marine Biology and Ecology

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Abstract. The present description of Trichodesmium spp. population dynamics and associated 1 environmental variables is the first one using a very short sampling interval (2-3 days). Such a 2 strategy allows a fine description of changes involving the population density and characteristics. It 3 also lends itself to interpreting those changes from past environmental conditions. During the two 4 surveys, 2 and 5 month-long, T. erythraeum dominated the Trichodesmium population, with 5 temporary occurrence of T. thiebautii and five blooms could be described. These events appeared at 6 temperatures > 24°C and followed, in all cases, nitrate, soluble reactive phosphorus and chlorophyll 7 a enrichments, with a 3-7 day time lag. Low wind speed (< 4m s -1 ) was not a prerequisite for 8Trichodesmium bloom developments as long as temperatures exceeded 26°C. As abundance 9 increased during the bloom, so did the number of filaments (trichomes) in colonies and their 10 buoyancy, leading to a clear positive biomass gradient from the bottom to the surface. A simple 11 model, using variable growth rates, showed trichome ascent would be responsible for 87-99% of 12 concentrations at 0.5m, with Trichodesmium net growth rates ranging from 0.11 to 0.38 d -1 . Finally, 13 rapid trichome density declines could be ascribed to nutrient depletion and massive surface death 14 following ascent. 15 16 17

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Section: Trichodesmium Population Characteristics 299mentioning

confidence: 64%

“…col -1 . 353 But Carpenter et al (2004), Letelier and Karl (1996) and Post et al (2002) reported numbers > 100 354 for both T. erythraeum and T. thiebautii. 355…”

Section: Trichodesmium Population Characteristics 299mentioning

confidence: 99%

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Rodier

Borgne²

2008

Journal of Experimental Marine Biology and Ecology

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“…Trichodesmium spp. form blooms throughout the nitrogen-limited Atlantic and Pacific Oceans (21), as well as the Arabian and Red Seas (19,22), and in the North Pacific Subtropical Gyre, they dominate a recurrent annual phytoplankton bloom (23). The up-to-multimillimeter-sized Trichodesmium colony environment can be an oasis of fixed N and C in the oligotrophic oceans (24, 25) and has been observed to contain a varied assemblage of organisms, ranging from prokaryotes and unicellular eukaryotes to juvenile copepods and decapods (26-31) with metabolisms including heterotrophs and anoxygenic and oxygenic phototrophs, as well as mixotrophic eukaryotes.…”

mentioning

confidence: 99%

Trichodesmium genome maintains abundant, widespread noncoding DNA in situ, despite oligotrophic lifestyle

Walworth

Pfreundt

Nelson

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Understanding the evolution of the free-living, cyanobacterial, diazotroph Trichodesmium is of great importance because of its critical role in oceanic biogeochemistry and primary production. Unlike the other >150 available genomes of free-living cyanobacteria, only 63.8% of the Trichodesmium erythraeum (strain IMS101) genome is predicted to encode protein, which is 20-25% less than the average for other cyanobacteria and nonpathogenic, free-living bacteria. We use distinctive isolates and metagenomic data to show that low coding density observed in IMS101 is a common feature of the Trichodesmium genus, both in culture and in situ. Transcriptome analysis indicates that 86% of the noncoding space is expressed, although the function of these transcripts is unclear. The density of noncoding, possible regulatory elements predicted in Trichodesmium, when normalized per intergenic kilobase, was comparable and twofold higher than that found in the gene-dense genomes of the sympatric cyanobacterial genera Synechococcus and Prochlorococcus, respectively. Conserved Trichodesmium noncoding RNA secondary structures were predicted between most culture and metagenomic sequences, lending support to the structural conservation. Conservation of these intergenic regions in spatiotemporally separated Trichodesmium populations suggests possible genus-wide selection for their maintenance. These large intergenic spacers may have developed during intervals of strong genetic drift caused by periodic blooms of a subset of genotypes, which may have reduced effective population size. Our data suggest that transposition of selfish DNA, low effective population size, and high-fidelity replication allowed the unusual "inflation" of noncoding sequence observed in Trichodesmium despite its oligotrophic lifestyle. marine microbiology | oligotrophic | evolution genomics | nitrogen fixation T he low availability of N (and fixed carbon) in the midlatitude upper oceans provides an important niche for autotrophic organisms that can fix atmospheric nitrogen, which can exert control over global primary production (1-3). Nitrogen fixation is a prokaryotic process with a high-energy demand, and oceanic cyanobacteria are known to be significant sources of this "new" nitrogen (nitrogen that is fixed from the atmosphere or NO 3 advected from depth) (4, 5). Molecular field data have shown that a handful of cyanobacterial diazotrophs responsible for oligotrophic nitrogen fixation can reach relatively high cell numbers (6-12) and be of significant biogeochemical importance (13-16). These include photosynthetic free-living forms, such as the filamentous Trichodesmium and the unicellular Crocosphaera and Cyanothece, and photosynthetic and nonphotosynthetic symbiotic forms, such as heterocystous Richelia and Candidatus Atelocyanobacterium thalassa (3,5,17).Trichodesmium cells can grow either as trichomes (i.e., filaments) or aggregates and form three types of classically described colonies, including radial puffs, vertically aligned fusiform tufts, and bowties (...

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“…Following further onto this trend, Carmen composition and density of these species were very few ( Figure 3). Trichodesmium can either live in a colonial habitat dominated by extensive physical interactions with both sister cells and other taxa and/or as free trichomes that can constitute a significant fraction of the Trichodesmium water column biomass (Orcutt et al, 2001).Field populations of Trichodesmium have previously been enumerated using cell counts (Letelier and Karl, 1996;Post et al, 2002;Tyrrell et al, 2003).…”

Section: Densitymentioning

confidence: 99%

“…must be understood, to know the mechanics of the nitrogen inputs in the marine ecosystem. Cell counts, specifically trichome (filament) and colony counts, can be effective (Letelier and Karl, 1996;Post et al, 2002;Tyrrell et al, 2003). There is little study on Trichodesmium species identification in Central Visayas, Philippines.…”

Section: Introductionmentioning

confidence: 99%

Density Account of Cyanobacteria (Genus: Trichodesmium) in Selected Cebu Provinces, Philippines

2017

International Journal of Research Studies in Biosciences

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Spatial and temporal distribution of Trichodesmium spp. in the stratified Gulf of Aqaba, Red Sea

Cited by 99 publications

References 47 publications

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Trichodesmium genome maintains abundant, widespread noncoding DNA in situ, despite oligotrophic lifestyle

Density Account of Cyanobacteria (Genus: Trichodesmium) in Selected Cebu Provinces, Philippines

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