Archives: Bibliographies

Sordo L​, Santos R, Reis J, Shulika A, Silva J

Control system, Ocean acidification (OA), CO2 bubbling, Coralline algae

Ruocco M, Musacchia F, Olivé I, Costa MM, Barrote I, Santos R, Sanges R, Procaccini G, Silva J

carbohydrate metabolism, Cymodocea nodosa, ocean acidification, protein folding, seagrasses, transcriptome

Here, we report the first use of massive‐scale RNA‐sequencing to explore seagrass response to CO₂‐driven ocean acidification (OA). Large‐scale gene expression changes in the seagrass Cymodocea nodosa occurred at CO₂ levels projected by the end of the century. C. nodosa transcriptome was obtained using Illumina RNA‐Seq technology and de novo assembly, and differential gene expression was explored in plants exposed to short‐term high CO₂/low pH conditions. At high pCO₂, there was a significant increased expression of transcripts associated with photosynthesis, including light reaction functions and CO₂ fixation, and also to respiratory pathways, specifically for enzymes involved in glycolysis, in the tricarboxylic acid cycle and in the energy metabolism of the mitochondrial electron transport. The upregulation of respiratory metabolism is probably supported by the increased availability of photosynthates and increased energy demand for biosynthesis and stress‐related processes under elevated CO₂ and low pH. The upregulation of several chaperones resembling heat stress‐induced changes in gene expression highlighted the positive role these proteins play in tolerance to intracellular acid stress in seagrasses. OA further modifies C. nodosa secondary metabolism inducing the transcription of enzymes related to biosynthesis of carbon‐based secondary compounds, in particular the synthesis of polyphenols and isoprenoid compounds that have a variety of biological functions including plant defence. By demonstrating which physiological processes are most sensitive to OA, this research provides a major advance in the understanding of seagrass metabolism in the context of altered seawater chemistry from global climate change.

Sordo L, Santos R, Barrote I, Silva J

calcification, coralline algae, long-term, ocean acidification, photosynthesis, photosynthetic pigments, Phymatolithon lusitanicum, respiration, southern Portugal

Wahl M, Buchholz B, Winde V, Golomb D, Guy-Haim T, Müller J,
Rilov G, Scotti M, Böttcher ME

Biogenic, seasonal, and stochastic fluctuations at various scales characterize coastal marine habitats and modulate environmental stress. The relevance of most past studies into climate change impacts is weakened by the usually intentional  exclusion of fluctuations from the experimental design. We describe a new outdoor mesocosm system for benthic research (“benthocosms”) which permit the control and manipulation of several environmental variables while admitting all natural in situ fluctuations. This is achieved by continuously measuring the relevant variables (e.g., temperature, pH, O2, CO2) in situ, defining these in real time as reference values in the control software and simulating target climates by delta treatments. The latter constitute the manipulative addition of predefined changes (e.g., “warming”, “acidification”) to the reference values. We illustrate the performance of the system by presenting the environmental data of four seasonal experiments which together represent an entire year. The “Kiel Outdoor Benthocosms” allow realizing nearnatural climate change experiments on complex benthic communities under controlled scenarios.

Wyman M, Davies JT, Crawford DW, Purdie DA

mesocosm, Bergen, Espergend, 11 m3, nutrient addition, phytoplankton, DNA probes, RubisCO, Primary production, Norway

Vallino JJ

mesocosm, model, parameter estimation, DOM, 7 m3, Woods Hole Great Harbor, USA

Suchman CL, Sullivan BK

mesocosm, medusae, copepods, predator-prey, land based, 13 m3, Narragansett Bay, USA

Sondegaard M, Williams PJB, Cauwet G, Riemann B, Robinson C, Terzic S, Malcolm E, Woodward S, Worm J

mesocosm, nutrient addtion, Espegrend, Norway, 11 m3, DOC, DON, fluxes, plankton communities

Riebesell U, Zondervan I, Rost B, Tortell PD, Zeebe RE, Morel FMM

co2, acidification, Plankton, carbonate chemistry, mesocosm, Espegrend, Bergen, 11 m3, Norway

The formation of calcareous skeletons by marine planktonicorganisms and their subsequent sinking to depth generates acontinuous rain of calcium carbonate to the deep ocean andunderlying sediments1. This is important in regulating marinecarbon cycling and ocean±atmosphere CO2 exchange2. The presentrise in atmospheric CO2 levels3 causes signi®cant changes insurface ocean pH and carbonate chemistry4. Such changes havebeen shown to slow down calci®cation in corals and corallinemacroalgae5,6, but the majority of marine calci®cation occurs inplanktonic organisms. Here we report reduced calcite productionat increased CO2 concentrations in monospeci®c cultures of twodominant marine calcifying phytoplankton species, the coccolithophoridsEmiliania huxleyi and Gephyrocapsa oceanica. Thiswas accompanied by an increased proportion of malformedcoccoliths and incomplete coccospheres. Diminished calci®cationled to a reduction in the ratio of calcite precipitation toorganic matter production. Similar results were obtained inincubations of natural plankton assemblages from the northPaci®c ocean when exposed to experimentally elevated CO2levels. We suggest that the progressive increase in atmosphericCO2 concentrations may therefore slow down the production ofcalcium carbonate in the surface ocean. As the process of calci®cationreleases CO2 to the atmosphere, the response observed herecould potentially act as a negative feedback on atmospheric CO2levels

Mousseau L, Gosselin M, Levasseur M, Demers S, Fauchot J, Roy S, Villegas PZ, Mostajir B

Canada, mesocosm, 3.2 m3, Nitrogen transport, Photoinhibition, Photosynthesis, phytoplankton, St. Lawrence estuary, land based, Pointe au Pere research station Quebec, UVB