Sediment Phylogenetic archaeal tree.

<p>Reference sequences from GenBank (<b>in bold</b>). OTUs were defined by using a distance level of 3% by using the furthest neighbor algorithm in MOTHUR. The tree topology is based on maximum likelihood and bootstrap analysis was performed with 1000 replications. Bootstrap value <50 are not shown.</p

Tropical Aquatic Archaea Show Environment-Specific Community Composition

<div><p>The Archaea domain is ubiquitously distributed and extremely diverse, however, environmental factors that shape archaeal community structure are not well known. Aquatic environments, including the water column and sediments harbor many new uncultured archaeal species from which metabolic and ecological roles remain elusive. Some environments are especially neglected in terms of archaeal diversity, as is the case of pristine tropical areas. Here we investigate the archaeal composition in marine and freshwater systems from Ilha Grande, a South Atlantic tropical environment. All sampled habitats showed high archaeal diversity. No OTUs were shared between freshwater, marine and mangrove sediment samples, yet these environments are interconnected and geographically close, indicating environment-specific community structuring. Group II <i>Euryarchaeota</i> was the main clade in marine samples, while the new putative phylum Thaumarchaeota and LDS/RCV <i>Euryarchaeota</i> dominated freshwaters. Group III <i>Euryarchaeota</i>, a rare clade, was also retrieved in reasonable abundance in marine samples. The archaeal community from mangrove sediments was composed mainly by members of mesophilic Crenarchaeota and by a distinct clade forming a sister-group to Crenarchaeota and Thaumarchaeota. Our results show strong environment-specific community structuring in tropical aquatic Archaea, as previously seen for Bacteria.</p> </div

Venn diagram at 97% identity.

<p>A: Seawater, B: Freshwater, C: Sediment. IG1 – Parnaioca water spring; IG2 – Parnaioca river; IG5 – mangrove; IG3 – Parnaioca beach; IG7 – Aventureiros beach; IG8 – Meros; SedIG –mangrove channel; Leste – Leste lagoon center; Sul - Sul lagoon entrance. Asterisks shown for ∫-LIBSHUFF comparisons with p value >0.0001.</p

Freshwater Phylogenetic archaeal tree.

<p>Reference sequences from GenBank (<b>in bold</b>). OTUs were defined by using a distance level of 3% by using the furthest neighbor algorithm in MOTHUR. The tree topology is based on maximum likelihood and bootstrap analysis was performed with 1000 replications. Bootstrap value <50 are not shown.</p

Match between archaeal communities in freshwater, seawater and sediment libraries.

<p>Principal coordinates plots (PCoA) were generated using the pair wise unweighted UniFrac distances. Freshwater samples in circles, marine samples in squares, and sediments in triangles. Parnaioca Spring (green triangle); Parnaioca river (green circle); Mangrove water (green square); Parnaioca beach (blue triangle); Aventureiros beach (blue circle); Meros Island (blue square); SedIg (red triangle); SedLeste (red circle); SedSul (red square).</p

Marine Phylogenetic archaeal tree.

<p>Reference sequences from GenBank (<b>in bold</b>). OTUs were defined by using a distance level of 3% by using the furthest neighbor algorithm in MOTHUR. The tree topology is based on maximum likelihood and bootstrap analysis was performed with 1000 replications. Bootstrap value <50 are not shown.</p

Rarefaction analyses of 16S rDNA clone libraries at 97% (A, C and E) and 80% (B, D and F).

<p>In A and B each marine water library is plotted, in C and D, each freshwater and in E and F each sediment.</p

Map of the studied site and the nine sampled locations.

<p>IG1 – Parnaioca water spring; IG2 – Parnaioca river; IG5 – mangrove; IG3 – Parnaioca beach; IG7 – Aventureiros beach; IG8 – Meros; SedIG – sediment from mangrove channel; SedL – Leste lagoon entrance; SedS – Sul lagoon entrance.</p

Sponge <i>Crenarchaeota</i> communities.

<p>(A) Neighbour-joining 16S rRNA phylogenetic tree. Sponge archaeal clones (▪) HhP92, (□) HhCA, (▴) PmP92, (Δ) PmCA and (◊) PcCA Venn diagram with OTUs grouped at 97% similarity in (B) <i>Archaea</i> related to seawater and sponges from the Cagarras Archipelago and (C) <i>Archaea</i> related to seawater and sponges from P92. Hh, <i>Hymeniacidon heliophila</i>; Pm, <i>Paraleucilla magna</i>; Pc, <i>Petromica citrina</i>; CA, Cagarras Archipelago; P92, inner bay site.</p

Location of sampling sites, seawater trophic status and planktonic microbiological parameters in Rio de Janeiro.

<p>(A) The location of Guanabara Bay in South America is indicated on the map (upper left corner). The map on the upper right corner shows the location of Guanabara Bay in reference to Rio de Janeiro state. The lower panel shows a detailed map of Guanabara Bay and the location of the two sampling sites: the pillar 92 of the Rio-Niterói Bridge, the inner bay site (P92) and the Cagarras Archipelago (CA), the outer bay site. (B) Ammonium, phosphate and chlorophyll <i>a</i> concentrations in seawater inside (black bars) and outside Guanabara Bay (gray bars). (C) Planktonic prokaryotic abundance and production inside (black bars) and outside the bay (gray bars).</p