| 研究課題/領域番号 |
17K17622
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| 研究機関 | 筑波大学 |
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研究代表者 |
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| 研究期間 (年度) |
2017-04-01 – 2020-03-31
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| キーワード | Ocean Acidification / CO2 Seeps / Community Succession / Biodiversity / Ecosystem Functioning |
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| 研究実績の概要 |
The proposed research seeks to characterise how biodiversity and ecosystem-functioning of whole communities will be altered by ocean acidification. FY2017 predominantly involved the setup and deployment of the experiment. After 2 and 4 months, the initial recruitment greatly differed between the reference- and elevated-CO2 sites with a highly reduced abundance of macroalgae (particularly calcified algae) in the elevated-CO2 site; which led to reduced gross primary production and calcification rates. Such a pattern persisted at 9 months, where community succession had clearly progressed in the reference-CO2 sites, with tiles now exhibiting a highly diverse macroalgae community with near total coverage. The elevated-CO2 sites in comparison, showed reduced coverage (similar to the reference site at 4 months) and reduced rates of gross primary production and calcification in comparison to the reference site. FY2018 focussed on investigating these longer-term patterns, and it was found that these same patterns further persisted after 18 and 24 months, with the communities showing a major divergence between the reference and high CO2 sites, and community production beginning to show a greater difference (with reference-CO2 sites showed enhanced gross primary production). Overall, this suggests that the development and community succession during ocean acidification may be slowed, requiring more time to reach their climax communities, with the suggestion that future communities may not be able to provide the same ecosystem functions as present-day communities.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The recruitment substrates (130 x 130 mm volcanic rock tiles) were deployed in Shikine-Jima (Izu Islands, Japan) in two zones: (i) near to the natural CO2 seeps (High-CO2, 900 ppm), and (ii) in a nearby bay for control conditions (reference-CO2, 300 ppm). A total of 50 tiles were deployed (n = 25 per zone) with a subset of five tiles collected and analysed after 2, 4, 9, 18, and 24 months. Each tile had photographs taken of it in the laboratory (topside and underside) in order to perform initial species identification and % cover; the tiles were then measured for gross primary production and calcification in a measure of the tiles community production rate; and finally preserved at -20 °C for DNA extraction.
The DNA has been extracted for half of the tiles using a Powermax Soil DNA Isolation Kit (MO-BIO) on homogenised tissue scraped from each tile. The remaining half will be extracted over the next two months. The extracted DNA is being stored at -20 °C until being used for DNA meta-barcoding.
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| 今後の研究の推進方策 |
PCR amplification, tagging, and sequencing will be carried out following an established protocol. In brief, three replicate PCR assays will be used to amplify an >300-bp of universal primers - COI and 18S (eukaryotic organisms) and 16S (prokaryotic organisms) fragments - in each replicate sample. A combination of tailed PCR primers and barcode adapters will be used (hierarchical tagging approach), with amplicons being sent for sequencing. Data analysis will use a pre-established bioinformatics pipeline. FY2019 will also include the majority of publication writing and dissemination of results.
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| 次年度使用額が生じた理由 |
For the meta-barcoding analysis of communities on the tiles, DNA extraction took longer than planned, and therefore the sequencing costs had to be moved into the final fiscal year.
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