Project description:In recent years, increasing levels of dissolved carbon dioxide in seawater have led to an increase of ocean acidification (OA), which constitutes a major threat to marine ecosystems. As an important economically marine bivalve, Mactra veneriformis is highly susceptible to ocean acidification. In this study, we recorded and observed the mortality rate, oxygen consumption rate and ammonia excretion rate of different shell colour groups of M. veneriformis under the stress of ocean acidification (pH=7.6), and conducted transcriptome analysis of the mantle tissues of M. veneriformis with white and purple shell colours in the acidified group (pH=7.6) and the control group (pH=8.1) under the two conditions, which showed that there was a significant difference in mortality rate between the acidified group and the control group at day 30, but there was a significant difference in mortality rate between the white colors group and the purple colors group at day 30, which was not significant. The results showed that there was a significant difference in mortality between the acidified and control groups at day 30, but the difference in mortality between the white and purple shell colour groups at day 30 was not significant. In the transcriptome analysis, fatty acid synthase gene was up-regulated in two shell colours of M. veneriformis under acidification stress, which may be a molecular compensatory mechanism to reduce the susceptibility of organisms to oxidative damage of lipids; tyrosinase gene was up-regulated, which may be a compensatory mechanism of Tyr's regulatory mechanism to the formation of shell damages under acidification; carbonic anhydrase gene was up-regulated in the purple group of M. veneriformis under acidification stress, which may be a compensatory mechanism for the acidity of M. veneriformis to cope with environmental stress; the white group of M. veneriformis under acidification stress was up-regulated. The carbonic anhydrase gene was up-regulated in the purple group under acidification stress, which may be an acidity compensation mechanism of M. veneriformis in response to the environmental stress.
Project description:The comparision between gradual ocean acidification (GC) and one way ocean acidification (HC) of physiological and molecular responses on diatom Skeletonema costatum
Project description:Sargassum is one of the most diverse brown algal genus with more than 150 known species, mostly benthic and few pelagic species. They contribute significantly to global primary production and serve as important habitat for wide range of marine organisms. Sargassum vulgare is one of the dominant habitat forming species along Mediterranean coast. Despite their huge ecological importance, it is relatively unknown how they will respond under future global climate change scenario. This work used de novo transcriptome sequencing approach to understand the molecular response of S. vulgare to chronic acidification at the shallow underwater volcanic CO2 vents off Ischia Island, Italy. Keywords: brown algae, Sargassum, de novo transcriptome, ocean acidification, CO2 vents.
Project description:The filamentous diazotrophic cyanobacteria Trichodesmium spp. supply fixed nitrogen (N) to the N-depleted oligotrophic oceans where their growth is often limited by the low availability of phosphorus(P) and/or iron. Previous studies have mostly been focused on the effects of ocean acidification on Trichodesmium under nutrient sufficient or iron-limited conditions. Only a few studies have examined the impacts of ocean acidification on Trichodesmium grown at low P concentrations using non-steady-state batch cultures. Here we cultured Trichodesmium using P-limited continuous cultures (chemostat) to mimic steady-state oceanic low P condition, and used comparative NGS-derived Trichodesmium transcriptome profiling (RNA-seq) analysis to find differentially expressed genes and cellular pathways in response to acidification.
Project description:Crustose coralline algae (CCA) are calcifying red macroalgae that play important ecological roles including stabilisation of reef frameworks and provision of settlement cues for a range of marine invertebrates. Previous research into the responses of CCA to ocean warming (OW) and ocean acidification (OA) have found magnitude of effect to be species-specific. Response to OW and OA could be linked to divergent underlying molecular processes across species. Here we show Sporolithon durum, a species that exhibits low sensitivity to climate stressors, had little change in metabolic performance and did not significantly alter the expression of any genes when exposed to temperature and pH perturbations. In contrast, Porolithon onkodes, a major coral reef builder, reduced photosynthetic rates and had a labile transcriptomic response with over 400 significantly differentially expressed genes, with differential regulation of genes relating to physiological processes such as carbon acquisition and metabolism. The differential gene expression detected in P. onkodes implicates possible key metabolic pathways, including the pentose phosphate pathway, in the stress response of this species. We suggest S. durum is more resistant to OW and OA than P. onkodes, which demonstrated a high sensitivity to climate stressors and may have limited ability for acclimatisation. Understanding changes in gene expression in relation to physiological processes of CCA could help us understand and predict how different species will respond to, and persist in, future ocean conditions predicted for 2100.
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:The razor clam Sinonovacula constricta (Lamarck 1818) is a famous marine bivalve species that widely distributed along the western Pacific coast with important economical and nutritional values. During the evolution, S. constricta has formed specific biological features to adapt to its living habit. To clarify the underlying molecular mechanism in forming the specific biological features, the tissues of siphon, gill, labial palp, foot, mantle, and intestine of S. constricta were subjected to RNA-sequencing. The results showed significant differences existed in gene expression among different tissues, which provided a molecular framework for understanding the differentiation of S. constricta tissues and their underlying specific biological functions.
Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification This experiment is part of a much larger experiment. We have produced 4 454 metatranscriptomic datasets and 6 454 metagenomic datasets. These were derived from 4 samples. The experiment is an ocean acidification mesocosm set up in a Norwegian Fjord in 2006. We suspended 6 bags containing 11,000 L of sea water in a Coastal Fjord and then we bubbled CO2 through three of these bags to simulate ocean acidification conditions in the year 2100. The other three bags were bubbled with air. We then induced a phytoplankton bloom in all six bags and took measurements and performed analyses of phytoplankton, bacterioplankton and physiochemical characteristics over a 22 day period. We took water samples from the peak of the phytoplankton bloom and following the decline of the phytoplankton bloom to analyses using 454 metagenomics and 454 metatranscriptomics. Day 1, High CO2 Bag and Day 1, Present Day Bag, refer to the metatranscriptomes from the peak of the bloom. Day 2, High CO2 Bag and Day 2, Present Day Bag, refer to the metatranscriptomes following the decline of the bloom. Obviously High CO2 refers to the ocean acidification mesocosm and Present Day refers to the control mesocosm. Raw data for both the metagenomic and metatranscriptomic components are available at NCBI's Short Read Archive at ftp://ftp.ncbi.nlm.nih.gov/sra/Studies/SRP000/SRP000101
Project description:Pacific geoduck (Panopea generosa) clams are found along the Northeast Pacific coast where they are significant components of coastal and estuarine ecosystems and the basis of a highly profitable aquaculture industry. The Pacific coastline, however, is also the sight of rapidly changing ocean habitat, including significant reductions in pH. To better understand the physiological impact of ocean acidification on geoduck clams, we characterized for the first time the proteomic profile of this bivalve during early larval development and compared it to that of larvae exposed to low pH.Geoduck larvae wer reared at pH 7.5 (ambient) or 7.1 in a commercial shellfish hatchery from day 6 to 19 post-fertilization , and sampled at six time points for an in-depth proteomics analysis using high-resolution data dependent analysis. We found that larvae reared at low pH were smaller than those reared at ambient pH, especially in the prodissoconch II phase of development, and displayed a delay in their competency for settlement. Proteomic profiles revealed that metabolic, cell cycle, and protein turnover pathways differed between the two pH, suggesting that differing phenotypic outcomes between pH 7.5 and 7.1 are likely due to environmental disruptions to the timing of molecular physiological events. In summary, ocean acidification likely caused an energetic stress on geoduck larvae, casuing a shift in physiological prioritization.