Project description:Dataset of metazoan identification using 18s eDNA metabarcoding from seawater in the Hybrid-Ocean Thermal Energy Conversion (H-OTEC) site of Peninsular Malaysia.
Project description:The available energy and carbon sources for prokaryotes in the deep ocean remain still largely enigmatic. Reduced sulfur compounds, such as thiosulfate, are a potential energy source for both auto- and heterotrophic marine prokaryotes. Shipboard experiments performed in the North Atlantic using Labrador Sea Water (~2000 m depth) amended with thiosulfate led to an enhanced prokaryotic dissolved inorganic carbon (DIC) fixation.
Project description:Porcelain crabs, Petrolisthes cinctipes, live in the marine intertidal zone and routinely experience thermal stress. Genes involved in heat shock responses are generally upregulated following heat stress and genes involved in oxidative energy production are downregulated following heat stress We used microarrays to detail the global programme of gene expression underlying responses to thermal stress and identified distinct classes of up-regulated and down-regulated genes during this process. Keywords: time course
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:Although N2 fixation can occur in free-living cyanobacteria, the unicellular endosymbiotic cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN-A) is considered to be a dominant N2-fixing species in marine ecosystems. Four UCYN-A sublineages are known from partial nitrogenase (nifH) gene sequences. However, few studies have investigated their habitat preferences and regulation by their respective hosts in open-ocean versus coastal environments. Here, we compared UCYN-A transcriptomes from oligotrophic open-ocean versus nutrient-rich coastal waters. UCYN-A1 metabolism was more impacted by habitat changes than UCYN-A2. However, across habitats and sublineages genes for nitrogen fixation and energy production were highly transcribed. Curiously these genes, critical to the symbiosis for the exchange of fixed nitrogen for fixed carbon, maintained the same schedule of diel expression across habitats and UCYN-A sublineages, including UCYN-A3 in the open-ocean transcriptomes. Our results undersore the importance of nitrogen fixation in UCYN-A symbioses across habitats, with consequences for community interaction and global biogeochemical cycles.
Project description:Studies have demonstrated that marine phytoplankton can adapt to the warmer environment. However, the underlying mechanisms remain largely unknown. Here, we quantified the capacity of a globally distributed marine diatom Skeletonema dohrnii, for rapid evolution under the moderate (24 ℃) and severe (28 ℃) warming scenarios. Whole-genome re-sequencing analysis revealed that the evolutionary adaptation of S. dohrnii to moderate warming was slow (i.e., 700 generations), whereas it was rapid (i.e., 300 generations) under severe warming but suffered a substantial loss of genetic diversity within the population. Genes associated with energy production and lipid metabolism evolved rapidly, particularly under severe warming, suggesting their vital roles in thermal adaptation. Proteomic results also showed the enhanced expression of proteins involved in energy production and lipid metabolism, especially under severe warming. Furthermore, particulate organic carbon and nitrogen production was greatly enhanced in the moderate warming-selected population but increased insignificantly in the severe warming-selected population, indicating more rapid adaptation driven by severe warming. Our results provide molecular insights into the rapid but limited evolution of thermal adaptation in marine diatoms and highlight energy production and lipid metabolism as the most important adaptive strategy. Future warming will affect genetic diversity and population dynamics of diatoms in the ocean.
Project description:In this research we present a transcriptomics analysis of the physiological response of a marine calcifier, Strongylocentrotus purpuratus, to ocean acidification, a decline in ocean pH that results from the absorption of anthropogenic carbon dioxide (CO2). Larvae were raised from fertilization to prism stage in seawater with elevated CO2 conditions based upon IPCC emissions scenario B1 (540ppm CO2) and A1FI (1020ppm CO2).
Project description:Hypoxia is an important environmental stressor in aquatic ecosystems, with increasingly impacts on global biodiversity. Yellow catfish is an economically important farmed fish in China, which has increased dramatically. We investigated the response of hybrid yellow catfish to hypoxia under experimental conditions and focused on the analysis of the differential expression patterns of specific genes associated with hypoxia response by RNA-seq and qPCR analysis. A total of 1556 genes were captured significantly differentially expressed, and were categorized into immune response and energy metabolism. Functional enrichment analysis revealed the NLR signaling pathway play pivotal roles in hypoxia tolerance and resistance. Our study provides important insights into the physiological acclimation, immune response and defense activity of hybrid yellow catfish under hypoxia challenge.
Project description:Marine cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity, yet little is known of the transcriptional response of marine Synechococcus to copper shock. Global transcriptional response to two levels of copper shock was assayed in both a coastal and an open ocean strain of marine Synechococcus using whole genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus. The two strains additionally showed a reduction in photosynthetic gene transcripts. Contrastingly, the open ocean strain showed a typical stress response whereas the coastal strain exhibited a more specific oxidative or heavy metal type response. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus may in part be a result of an increased ability to sense and respond in a more specialized manner.
Project description:Porcelain crabs, Petrolisthes cinctipes, live in the marine intertidal zone and routinely experience thermal stress. Genes involved in heat shock responses are generally upregulated following heat stress and genes involved in oxidative energy production are downregulated following heat stress We used microarrays to detail the global programme of gene expression underlying responses to thermal stress and identified distinct classes of up-regulated and down-regulated genes during this process. Keywords: time course Crabs were collected from the field and returned to the laboratory where they were given a heat stress or held under control conditions for the period of time during the heat stress. Samples from both heat stressed and control crabs were taken after crabs were placed into a common recovery tank for periods of time ranging from 0.5 to 30h