Long Term Seasonal Dynamics of Synechococcus Population Structure in the Gulf of Aqaba, Northern Red Sea

Abstract

Spatial patterns of marine Synechococcus diversity across ocean domains have been reported on extensively. However, much less is known of seasonal and multiannual patterns of change in Synechococcus community composition. Here we report on the genotypic diversity of Synechococcus populations in the Gulf of Aqaba, Northern Red Sea, over seven annual cycles of deep mixing and stabile stratification, using ntcA as a phylogenetic marker. Synechococcus clone libraries were dominated by clade II and XII genotypes and a total of eight different clades were identified. Inclusion of ntcA sequences from the Global Ocean Sampling database in our analyses identified members of clade XII from beyond the Gulf of Aqaba, extending its known distribution. Most of the Synechococcus diversity was attributed to members of clade II during the spring bloom, while clade III contributed significantly to diversity during summer stratification. Clade XII diversity was most prevalent in fall and winter. Clade abundances were estimated from pyrosequencing of the V6 hypervariable region of 16S rRNA. Members of clade II dominated Synechococcus communities throughout the year, whereas the less frequent genotypes showed a pattern of seasonal succession. Based on the prevailing nutritional conditions we observed that clade I members thrive at higher nutrient concentrations during winter mixing. Clades V, VI and X became apparent during the transition periods between mixing and stratification. Clade III became prominent during sumeer stratification. We propose that members of clades V, VI, and X, and clade III are Synechococcus ecotypes that are adapted to intermediate and low nutrient levels respectively. This is the first time that molecular analyses have correlated population dynamics of Synechococcus genotypes with temporal fluctuations in nutrient regimes. Since these Synechococcus genotypes are routinely observed in the Gulf of Aqaba we suggest that seasonal fluctuations in nutrient levels create temporal niches that sustain their coexistence.

A microarray for assessing transcription from pelagic marine microbial taxa

“…ALOHA. The presence of this clade has recently been reported in the open ocean and in the Mediterranean Sea, with higher abundances in warm, low-nutrient waters (MellaFlores et al, 2011;Post et al, 2011;Ahlgren and Rocap, 2012;Huang et al, 2012).…”

Distribution and expression of the cyanate acquisition potential among cyanobacterial populations in oligotrophic marine waters

“…1820 m deep waterbody (Wolf-Vecht et al 1992). It is subject to an annual cycle of stable summer stratification and deep winter mixing (Genin et al 1995;Post et al 2011). Early stratification in spring brings about a phytoplankton bloom that is dominated by Synechococcus, with typical mid-bloom chlorophyll a (Chl a) concentration , 0.73 mg L 21 (Genin et al 1995;Lindell et al 2005b).…”

Effects of low temperature on tropical and temperate isolates of marine Synechococcus

“…Clades I and IV are predominant in oceanic latitudes above 30°N and below 30°S. Clades II and III are found mostly within tropical and sub-tropical oceanic latitudes (Zwirglmaier et al, 2007(Zwirglmaier et al, , 2008Scanlan et al, 2009;Mella-Flores et al, 2011;Post et al, 2011;Ahlgren and Rocap, 2012;Mazard et al, 2012;Huang et al, 2012;Sohm et al, 2016). In relation to temperature, clades I and IV occur at higher abundances at 10 -20°C whereas clades II and III occur in the range of 20-28°C (Zwirglmaier et al, 2008) suggesting that temperature, among other environmental factors, may have a key role in their partitioning.…”

“…The largest, sub-cluster 5.1, is the dominant cluster in the marine environment (Urbach et al, 1998;Herdman et al, 2001;Fuller et al, 2003;Dufresne et al, 2008;Ahlgren and Rocap, 2012). Oceanic surveys indicate that these clades exhibit broad distribution from the equator to the polar regions having colonized habitats defined by a broad range of light, temperature and nutrient regimes (Fuller et al, 2003;Ahlgren and Rocap, 2006;Penno et al, 2006;Paerl et al, 2008;Zwirglmaier et al, 2008;Scanlan et al, 2009;Post et al, 2011;Huang et al, 2012;Mazard et al, 2012). The genomic complements of strains from different clades provide insights to preferential habitat niches .…”