Project description:An Autonomous Underwater Vehicle (AUV) and large volume underwater pumps were used to collect microbial biomass from offshore waters of the Sargasso Sea, from surface waters and into the deep ocean. Seawater collection was performed along a transect in the western North Atlantic Ocean beginning near Bermuda and ending off the coast of Massachusetts, capturing metabolic signatures from oligotrophic, continental margin, and productive coastal ecosystems.
Project description:The diversity and environmental distribution of the nosZ gene, which encodes the enzyme responsible for the consumption of nitrous oxide, was investigated in marine and terrestrial environments using a functional gene microarray. The microbial communities represented by the nosZ gene probes showed strong biogeographical separation, with communities from surface ocean waters and agricultural soils significantly different from each other and from those in oceanic oxygen minimum zones. Atypical nosZ genes, usually associated with incomplete denitrification pathways, were detected in all the environments, including surface ocean waters. The abundance of nosZ genes, as estimated by quantitative PCR, was highest in the agricultural soils and lowest in surface ocean waters.
2018-10-19 | GSE121473 | GEO
Project description:Microbial Diversity of Deep-Sea Ferromanganese Crust Field in the Rio Grande Rise, Southwestern Atlantic Ocean
Project description:Marine microbial communities are critical for biogeochemical cycles and the productivity of ocean ecosystems. Primary productivity, at the base of marine food webs, is constrained by nutrient availability in the surface ocean, and nutrient advection from deeper waters can fuel photosynthesis. In this study, we compared the transcriptional responses by surface microbial communities after experimental deep water mixing to the transcriptional patterns of in situ microbial communities collected with high-resolution automated sampling during a bloom in the North Pacific Subtropical Gyre. Transcriptional responses were assayed with the MicroTOOLs (Microbiological Targets for Ocean Observing Laboratories) marine environmental microarray, which targets all three domains of life and viruses. The experiments showed that mixing of deep and surface waters substantially affects the transcription of photosystem and nutrient response genes among photosynthetic taxa within 24 hours, and that there are specific responses associated with the addition of deep water containing particles (organisms and detritus) compared to filtered deep water. In situ gene transcription was most similar to that in surface water experiments with deep water additions, showing that in situ populations were affected by mixing of nutrients at the six sampling sites. Together, these results show the value of targeted metatranscriptomes for assessing the physiological status of complex microbial communities.
Project description:Comparative transcriptomics between prf3, Prf-SBP-FLAG complemented lines as controls and tft3 2-2 line (CRISPR/Cas9 tomato mutant line in Rio Grande-prf3 Prf-SBP-FLAG complemented background), treated with either buffer (as control) or P. syringae DC3000 6 hours post infiltration.
Project description:Seamounts, often rising hundreds of metres above the surrounding seafloor, obstruct the flow of deep-ocean water. While the resultant entrainment of deep-water by seamounts is predicted from ocean circulation models, its empirical validation has been hampered by the large scale and slow rate of the interaction. To overcome these limitations we use the growth of planktonic bacteria to assess the interaction rate. The selected study site, Tropic Seamount, in the North-Eastern Atlantic represents the majority of isolated seamounts, which do not affect the surface ocean waters. We prove deep-water is entrained by the seamount by measuring 2.3 times higher bacterial concentrations in the seamount-associated or ‘sheath’ water than in deep-ocean water unaffected by seamounts. Genomic analyses of the dominant sheath-water bacteria confirm their planktonic origin, whilst proteomic analyses indicate their slow growth. According to our radiotracer experiments, the doubling time of sheath-water bacterioplankton is 1.5 years. Therefore, for bacterioplankton concentration to reach 2.3 times higher in the ambient seawater, the seamount would need to retain deep-ocean water for more than 3.5 years. We propose that turbulent mixing of the retained sheath-water could stimulate bacterioplankton growth by increasing the cell encounter rate with the ambient dissolved organic molecules. If some of these molecules chelate hydroxides of iron and manganese, bacterioplankton consumption of the organic chelators would result in precipitation of insoluble hydroxides. Hence precipitated hydroxides would form ferromanganese deposits as a result of the bacterioplankton-mediated deep-water seamount interaction.
Project description:This project presents field metaproteomics data from Trichodesmium colonies collected from the surface ocean. Most were collected from the tropical and subtropical Atlantic ocean, but there is also data from the long term Bermuda Atlantic Time Series and Hawaii Ocean Time Series. Trichodesmium is a globally important marine microbe and its growth and nitrogen fixation activity is limited by nutrient availability in the surface ocean. This dataset was generated to answer questions about limitations on Trichodesmium's growth and activity in the nature.
Project description:Thiamine is often undetectable in ocean surface waters where Pelagibacter cells are numerically abundant. Despite this, Pelagibacter cells are missing de novo thiamine synthesis pathways. We show that an eogenous source of the thiamine precursor HMP is required for thiamine synthesis in Pelagibacter and that this precursor is abundant in the Sargasso sea.
Project description:The marine copepod Calanus finmarchicus is the most abundant zooplankton species in the northern regions of the Atlantic Ocean and the Barents Sea. Very little is known about the molecular mechanisms underlying critical processes associated with this species’ complex life history (e.g., ontogenetic development, reproduction, molting, diapause) and physiology (e.g., digestion, neural processes, and membrane physiology). This study analyzed patterns of gene expression of C. finmarchicus samples collected from the Gulf of Maine (Northwest Atlantic Ocean) using a 1,000 expressed sequence tag (EST) microarray designed to assay genes of known physiological function and hypothesized ecological importance for C. finmarchicus. Replicate analyses compared adult females and final-stage juveniles (Copepodite-5) collected from surface (0-30m) and deep (130-170m) layers. Environmental data include detailed characterization of biological, chemical, and physical oceanographic parameters in the sampled water packets. All data were screened for artifacts, normalized and selected using a fold-change filter prior to analysis. Replicate comparisons were analyzed by Significance Analysis of Microarrays (SAM; Stanford University Labs) with a control for False Discovery Rate (FDR) and with Principle Component Analysis with evaluation of significance by one- or two-sample t-test in Acuity Microarray Informatics Software (Molecular Devices, Inc.). Gene Ontology Enrichment Analysis was carried out using GOEAST (http://omicslab.genetics.ac.cn/GOEAST/index.php) to assess functional relationships of selected genes and/or proteins. The results indicated: up-regulation of genes involved in cell division, protein synthesis and mating in deep females and juveniles; up-regulation of genes related to cellular homeostasis, circadian behavior and nervous system development in surface females; and up-regulation of genes related to muscle development and protein catabolism in deep juveniles versus deep females. KEGG pathway analysis using the Blast2GO suite (http://www.blast2go.org/) indicated: up-regulation of genes encoding enzymes related to the citrate cycle and anaerobic metabolism in deep females and juveniles; and up-regulation of genes encoding enzymes related to energy metabolism and osmoregulation in surface females.