Spatiotemporal dynamics of bacterial populations in the anoxic Cariaco Basin

Abstract

Distributions of bacterial populations in the anoxic Cariaco Basin were studied over 2 yr (five cruises) at three stations using fluorescence in situ hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP) of 16S ribosomal ribonucleic acid (rRNA) genes. FISH results demonstrate that the contribution of eproteobacterial abundances to total prokaryotic inventories was relatively constant among cruises, and this group was dominant in the redoxcline, accounting for 18% of DAPI (496-diamidino-2-phenylindole)-stained counts on average. In contrast, b-proteobacteria were more variable. Sulfate reducers, a-, and c-proteobacteria accounted for minor components of the anaerobic microbial communities. T-RFLP fingerprinting also showed significant temporal shifts in bacterial community composition. The greatest variations in bacterial community structure were evident among oxic, transitional, and anoxic zones, but significant horizontal variations were also evident within redoxclines of three different stations. A statistical analysis of T-RFLP patterns revealed clear spatiotemporal patterns in bacterial community structure along the redox gradient among sites and over time.

Microbial Eukaryotes in Marine Oxygen Minimum Zones

“…1 ). This fi nding validates previous observations of oxygen and sul fi de concentrations in fl uencing microbial distributions in marine environments, such as the Cariaco Basin (Taylor et al, 2001 ;Li et al, 2008 ;Lin et al, 2008 ;Edgcomb et al, 2011a ;Orsi et al, 2011 ) and the Framvaren Fjord (Behnke et al, 2006 ;Stoeck et al, 2009Stoeck et al, , 2010 . The multivariate statistical analysis of protists in Saanich Inlet (Fig.…”

“…Also, unlike Saanich Inlet and Cariaco, the oxic/ anoxic interface of Framvaren Fjord lies in the photic zone and contains signi fi cantly higher sul fi de levels. The Cariaco Basin has remained anoxic for millions of years (Schubert, 1982 ) and experiences only limited oxygen intrusion events (Lin et al, 2008 ) , while the Saanich Inlet experiences only seasonal anoxia. Because Cariaco has been anoxic for a longer period of time, this likely allowed for a higher amount of speciation of anaerobic protists relative to Saanich Inlet.…”

Protistan microbial observatory in the Cariaco Basin, Caribbean. I. Pyrosequencing vs Sanger insights into species richness

“…This is because the Basin is a mosaic of dramatically different biogeochemical niches, and has existed as such for millions of years (Robertson and Burke, 1989), though it likely went through periods of oxidation (Peterson et al, 2000). (Taylor et al, 2001;Scranton et al, 2006;Li et al, 2008;Lin et al, 2008). This transition zone exhibits a peak in prokaryotic metabolic activity and cell numbers, which often coincides with peaks in protist cell numbers.…”

Subsurface ecosystem resilience: long-term attenuation of subsurface contaminants supports a dynamic microbial community

“…The key habitats examined for temporal microbial dynamics have included the mid-Atlantic bight (Nelson et al, 2008), the Cariaco Basin (Lin et al, 2008), epilithic biofilms in a freshwater stream (Anderson-Glenna et al, 2008), landfill leachate (Sundberg et al, 2007), an estuarine harbor (Kan et al, 2006), the Mediterranean Sea (Ghiglione et al, 2005) and the coastal California sea water (Fuhrman et al, 2006). Each community fingerprinting approach has its own strengths and weaknesses.…”