scholarly journals The Influence of pCO2-Driven Ocean Acidification on Open Ocean Bacterial Communities during A Short-Term Microcosm Experiment in the Eastern Tropical South Pacific (ETSP) off Northern Chile

2020 ◽  
Vol 8 (12) ◽  
pp. 1924
Author(s):  
Paulina Aguayo ◽  
Víctor L. Campos ◽  
Carlos Henríquez ◽  
Francisca Olivares ◽  
Rodrigo De Ia Iglesia ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Bacterial Communities ◽  
South Pacific ◽  
Low Ph ◽  
Open Ocean ◽  
High Pco2 ◽  
Northern Chile ◽  
Microcosm Experiment ◽  
Short Term ◽  
Key Microorganisms

Due to the increasing anthropogenic CO2 emissions, Ocean Acidification (OA) is progressing rapidly around the world. Despite the major role that microorganisms play on the marine biogeochemical cycling and ecosystem functioning, the response of bacterial communities upon OA scenarios is still not well understood. Here, we have conducted a detailed characterization of the composition and relative abundance of bacterial communities in the water column of an open-ocean station in the Eastern Tropical South Pacific (ETSP) off northern Chile and their interactions with environmental factors. In addition, through a short-term microcosm experiment, we have assessed the effect of low pH/high pCO2 conditions over the abundance and genetic diversity of bacterial communities. Our results evidence a clear partitioning of community composition that could be attributed mostly to dissolved oxygen. However, our experimental approach demonstrated that low pH/high pCO2 conditions might modify the structure of the bacterial community, evidencing that small changes in pH may impact significantly the abundance and diversity of key microorganisms. This study constitutes a first step aiming to provide insight about the influence of changing carbonate chemistry conditions on natural bacterial communities and to shed light on the potential impact of OA in biogeochemical cycles on the ETSP region.

scholarly journals Ocean Acidification and Mollusc Settlement in Posidonia oceanica Meadows: Does the Seagrass Buffer Lower pH Effects at CO2 Vents?

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 311
Author(s):  
Alessandra Barruffo ◽  
Laura Ciaralli ◽  
Giandomenico Ardizzone ◽  
Maria Cristina Gambi ◽  
Edoardo Casoli
Keyword(s):  
Ocean Acidification ◽  
Benthic Communities ◽  
Plant Cover ◽  
Posidonia Oceanica ◽  
Low Ph ◽  
High Pco2 ◽  
Future Climate Change ◽  
Ph Effects ◽  
Ph Conditions ◽  
Mollusc Assemblages

Ocean acidification has been broadly recognised to have effects on the structure and functioning of marine benthic communities. The selection of tolerant or vulnerable species can also occur during settlement phases, especially for calcifying organisms which are more vulnerable to low pH–high pCO2 conditions. Here, we use three natural CO2 vents (Castello Aragonese north and south sides, and Vullatura, Ischia, Italy) to assess the effect of a decrease of seawater pH on the settlement of Mollusca in Posidonia oceanica meadows, and to test the possible buffering effect provided by the seagrass. Artificial collectors were installed and collected after 33 days, during April–May 2019, in three different microhabitats within the meadow (canopy, bottom/rhizome level, and dead matte without plant cover), following a pH decreasing gradient from an extremely low pH zone (pH < 7.4), to ambient pH conditions (pH = 8.10). A total of 4659 specimens of Mollusca, belonging to 57 different taxa, were collected. The number of taxa was lower in low and extremely low pH conditions. Reduced mollusc assemblages were reported at the acidified stations, where few taxa accounted for a high number of individuals. Multivariate analyses revealed significant differences in mollusc assemblages among pH conditions, microhabitat, and the interaction of these two factors. Acanthocardia echinata, Alvania lineata, Alvania sp. juv, Eatonina fulgida, Hiatella arctica, Mytilys galloprovincialis, Musculus subpictus, Phorcus sp. juv, and Rissoa variabilis were the species mostly found in low and extremely low pH stations, and were all relatively robust to acidified conditions. Samples placed on the dead matte under acidified conditions at the Vullatura vent showed lower diversity and abundances if compared to canopy and bottom/rhizome samples, suggesting a possible buffering role of the Posidonia on mollusc settlement. Our study provides new evidence of shifts in marine benthic communities due to ocean acidification and evidence of how P. oceanica meadows could mitigate its effects on associated biota in light of future climate change.

scholarly journals Impact of high pCO2 and warmer temperatures on the process of silica biomineralization in the sponge Mycale grandis

2015 ◽  
Vol 73 (3) ◽  
pp. 704-714 ◽  
Author(s):  
Jan Vicente ◽  
Nyssa J. Silbiger ◽  
Billie A. Beckley ◽  
Charles W. Raczkowski ◽  
Russell T. Hill
Keyword(s):  
Surface Temperature ◽  
Ocean Acidification ◽  
Sea Surface Temperature ◽  
Dry Weight ◽  
Sea Surface ◽  
High Pco2 ◽  
Short Term ◽  
Uptake Rates ◽  
Siliceous Sponges

Abstract Siliceous sponges have survived pre-historical mass extinction events caused by ocean acidification and recent studies suggest that siliceous sponges will continue to resist predicted increases in ocean acidity. In this study, we monitored silica biomineralization in the Hawaiian sponge Mycale grandis under predicted pCO2 and sea surface temperature scenarios for 2100. Our goal was to determine if spicule biomineralization was enhanced or repressed by ocean acidification and thermal stress by monitoring silica uptake rates during short-term (48 h) experiments and comparing biomineralized tissue ratios before and after a long-term (26 d) experiment. In the short-term experiment, we found that silica uptake rates were not impacted by high pCO2 (1050 µatm), warmer temperatures (27°C), or combined high pCO2 with warmer temperature (1119 µatm; 27°C) treatments. The long-term exposure experiments revealed no effect on survival or growth rates of M. grandis to high pCO2 (1198 µatm), warmer temperatures (25.6°C), or combined high pCO2 with warmer temperature (1225 µatm, 25.7°C) treatments, indicating that M. grandis will continue to prosper under predicted increases in pCO2 and sea surface temperature. However, ash-free dry weight to dry weight ratios, subtylostyle lengths, and silicified weight to dry weight ratios decreased under conditions of high pCO2 and combined pCO2 warmer temperature treatments. Our results show that rising ocean acidity and temperature have marginal negative effects on spicule biomineralization and will not affect sponge survival rates of M. grandis.

Impact of low pH/high pCO2 on the physiological response and fatty acid content in diatom Skeletonema pseudocostatum

2016 ◽  
Vol 97 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Bárbara G. Jacob ◽  
Peter von Dassow ◽  
Joe E. Salisbury ◽  
Jorge M. Navarro ◽  
Cristian A. Vargas
Keyword(s):  
Fatty Acids ◽  
Organic Carbon ◽  
Ocean Acidification ◽  
Dark Respiration ◽  
Essential Fatty Acids ◽  
Fatty Acid Content ◽  
Low Ph ◽  
Marine Diatom ◽  
High Pco2 ◽  
Ph Conditions

pCO2/pH perturbation experiments were carried out under two different pCO2 levels to evaluate effects of CO2-driven ocean acidification on semi-continuous cultures of the marine diatom Skeletonema pseudocostatum CSA48. Under higher pCO2/lowered pH conditions, our results showed that CO2-driven acidification had no significant impact on growth rate, chlorophyll-a, cellular abundance, gross photosynthesis, dark respiration, particulate organic carbon and particulate organic nitrogen between CO2-treatments, suggesting that S. pseudocostatum is adapted to tolerate changes of ~0.5 units of pH under high pCO2 conditions. However, dissolved organic carbon (DOC) concentration and DOC/POC ratio were significantly higher at high pCO2, indicating that a greater partitioning of organic carbon into the DOC pool was stimulated by high CO2/low pH conditions. Total fatty acids (FAs) were significantly higher under low pCO2 conditions. The composition of FAs changed from low to high pCO2, with an increase in the concentration of saturated and a reduction of monounsaturated FAs. Polyunsaturated FAs did not show significant differences between pCO2 treatments. Our results lead to the conclusion that the balance between negative or null effect on S. pseudocostatum ecophysiology upon low pH/high pCO2 conditions constitute an important factor to be considered in order to evaluate the global effect of rising atmospheric CO2 on primary productivity in coastal ocean. We found a significant decrease in total FAs, however no indications were found for a detrimental effect of ocean acidification on the nutritional quality in terms of essential fatty acids.

scholarly journals The Influence of Ocean Acidification and Warming on DMSP & DMS in New Zealand Coastal Water

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Alexia D. Saint-Macary ◽  
Neill Barr ◽  
Evelyn Armstrong ◽  
Karl Safi ◽  
Andrew Marriner ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Coastal Water ◽  
Phytoplankton Community ◽  
Dimethyl Sulfide ◽  
Temperature Treatment ◽  
Low Ph ◽  
Trace Gas ◽  
Mesocosm Experiments ◽  
Future Warming ◽  
Higher Temperature

The cycling of the trace gas dimethyl sulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) may be affected by future ocean acidification and warming. DMSP and DMS concentrations were monitored over 20-days in four mesocosm experiments in which the temperature and pH of coastal water were manipulated to projected values for the year 2100 and 2150. This had no effect on DMSP in the two-initial nutrient-depleted experiments; however, in the two nutrient-amended experiments, warmer temperature combined with lower pH had a more significant effect on DMSP & DMS concentrations than lower pH alone. Overall, this indicates that future warming may have greater influence on DMS production than ocean acidification. The observed reduction in DMSP at warmer temperatures was associated with changes in phytoplankton community and in particular with small flagellate biomass. A small decrease in DMS concentration was measured in the treatments relative to other studies, from −2% in the nutrient-amended low pH treatment to −16% in the year 2150 pH and temperature conditions. Temporal variation was also observed with DMS concentration increasing earlier in the higher temperature treatment. Nutrient availability and community composition should be considered in models of future DMS.

scholarly journals Dynamic response in the larval geoduck clam proteome to elevated pCO2

2019 ◽  
Author(s):  
Emma Timmins-Schiffman ◽  
José M. Guzmán ◽  
Rhonda Elliott ◽  
Brent Vadopalas ◽  
Steven B. Roberts
Keyword(s):  
Ocean Acidification ◽  
Pacific Coast ◽  
Low Ph ◽  
Molecular Physiology ◽  
Proteomics Analysis ◽  
Bivalve Larvae ◽  
Energetic Stress ◽  
The Pacific ◽  
Aquaculture Industry ◽  
Ph Conditions

AbstractPacific geoduck clams (Panopea generosa) are found along the Northeast Pacific coast where they are significant components of coastal and estuarine ecosystems and the basis of a growing and highly profitable aquaculture industry. The Pacific coastline, however, is also the sight of rapidly changing ocean habitat, including significant reductions in pH. The impacts of ocean acidification on invertebrate bivalve larvae have been widely documented and it is well established that many species experience growth and developmental deficiencies when exposed to low pH. As a native of environments that have historically lower pH than the open ocean, it is possible that geoduck larvae are less impacted by these effects than other species. Over two weeks in larval development (days 6-19 post-fertilization) geoduck larvae were reared at pH 7.5 or 7.1 in a commercial shellfish hatchery. Larvae were sampled at six time points throughout the period for a in-depth proteomics analysis of developmental molecular physiology. Larvae reared at low pH were smaller than those reared at ambient pH, especially in the prodissoconch II phase of development. Competency for settlement was also delayed in larvae from the low pH conditions. A comparison of proteomic profiles over the course of development reveal that these differing phenotypic outcomes are likely due to environmental disruptions to the timing of molecular physiological events as suites of proteins showed differing profiles of abundance between the two pH environments. Ocean acidification likely caused an energetic stress on the larvae at pH 7.1, causing a shift in physiological prioritization with resulting loss of fitness.

scholarly journals Carbon cycling in the North American coastal ocean: A synthesis

2018 ◽  
Author(s):  
Katja Fennel ◽  
Simone Alin ◽  
Leticia Barbero ◽  
Wiley Evans ◽  
Timotheé Bourgeois ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
North American ◽  
Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Fluxes ◽  
Coastal Ocean ◽  
Open Ocean ◽  
The Arctic ◽  
The North ◽  
Anthropogenic Carbon

Abstract. A quantification of carbon fluxes in the coastal ocean and across its boundaries, specifically the air-sea, land-to-coastal-ocean and coastal-to-open-ocean interfaces, is important for assessing the current state and projecting future trends in ocean carbon uptake and coastal ocean acidification, but is currently a missing component of global carbon budgeting. This synthesis reviews recent progress in characterizing these carbon fluxes with focus on the North American coastal ocean. Several observing networks and high-resolution regional models are now available. Recent efforts have focused primarily on quantifying net air-sea exchange of carbon dioxide (CO2). Some studies have estimated other key fluxes, such as the exchange of organic and inorganic carbon between shelves and the open ocean. Available estimates of air-sea CO2 flux, informed by more than a decade of observations, indicate that the North American margins act as a net sink for atmospheric CO2. This net uptake is driven primarily by the high-latitude regions. The estimated magnitude of the net flux is 160 ± 80 Tg C/y for the North American Exclusive Economic Zone, a number that is not well constrained. The increasing concentration of inorganic carbon in coastal and open-ocean waters leads to ocean acidification. As a result conditions favouring dissolution of calcium carbonate occur regularly in subsurface coastal waters in the Arctic, which are naturally prone to low pH, and the North Pacific, where upwelling of deep, carbon-rich waters has intensified and, in combination with the uptake of anthropogenic carbon, leads to low seawater pH and aragonite saturation states during the upwelling season. Expanded monitoring and extension of existing model capabilities are required to provide more reliable coastal carbon budgets, projections of future states of the coastal ocean, and quantification of anthropogenic carbon contributions.

scholarly journals Variation in brachiopod microstructure and isotope geochemistry under low pH–ocean acidification–conditions

2018 ◽  
Author(s):  
Facheng Ye ◽  
Hana Jurikova ◽  
Lucia Angiolini ◽  
Uwe Brand ◽  
Gaia Crippa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ocean Acidification ◽  
Isotope Geochemistry ◽  
Shell Growth ◽  
Low Ph ◽  
Secondary Layer ◽  
Ph Conditions ◽  
One Year ◽  
The Impact ◽  
Δ13c And Δ18o

Abstract. Throughout the last few decades and in the near future CO2–induced ocean acidification is potentially a big threat to marine calcite-shelled animals (e.g., brachiopods, bivalves, corals and gastropods). Despite the great number of studies focusing on the effects of acidification on shell growth, metabolism, shell dissolution and shell repair, the consequences on biomineral formation remain poorly understood, and only few studies addressed contemporarily the impact of acidification on shell microstructure and geochemistry. In this study, a detailed microstructure and stable isotope geochemistry investigation was performed on nine adult brachiopod specimens of Magellania venosa (Dixon, 1789), grown in the natural environment as well as in controlled culturing experiments at different pH conditions (ranging 7.35 to 8.15 ± 0.05) over different time intervals (214 to 335 days). Details of shell microstructural features, such as thickness of the primary layer, density and size of endopunctae and morphology of the basic structural unit of the secondary layer were analysed using scanning electron microscopy (SEM). Stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves. Based on our comprehensive dataset, we observed that, under low pH conditions, M. venosa produced a more organic-rich shell with higher density of and larger endopunctae, and smaller secondary layer fibres, when subjected to about one year of culturing. Also, increasingly negative δ13C and δ18O values are recorded by the shell produced during culturing and are related to the CO2–source in the culture setup. Both the microstructural changes and the stable isotope results are similar to observations on brachiopods from the fossil record and strongly support the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past.

scholarly journals N<sub>2</sub> fixation in eddies of the eastern tropical South Pacific Ocean

2016 ◽  
Vol 13 (10) ◽  
pp. 2889-2899 ◽  
Author(s):  
Carolin R. Löscher ◽  
Annie Bourbonnais ◽  
Julien Dekaezemacker ◽  
Chawalit N. Charoenpong ◽  
Mark A. Altabet ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
N2 Fixation ◽  
South Pacific ◽  
Open Ocean ◽  
Cyclonic Eddy ◽  
Geochemical Data ◽  
Intermediate Water ◽  
N Loss ◽  
Mode Water ◽  
South Pacific Ocean

Abstract. Mesoscale eddies play a major role in controlling ocean biogeochemistry. By impacting nutrient availability and water column ventilation, they are of critical importance for oceanic primary production. In the eastern tropical South Pacific Ocean off Peru, where a large and persistent oxygen-deficient zone is present, mesoscale processes have been reported to occur frequently. However, investigations into their biological activity are mostly based on model simulations, and direct measurements of carbon and dinitrogen (N2) fixation are scarce.We examined an open-ocean cyclonic eddy and two anticyclonic mode water eddies: a coastal one and an open-ocean one in the waters off Peru along a section at 16° S in austral summer 2012. Molecular data and bioassay incubations point towards a difference between the active diazotrophic communities present in the cyclonic eddy and the anticyclonic mode water eddies.In the cyclonic eddy, highest rates of N2 fixation were measured in surface waters but no N2 fixation signal was detected at intermediate water depths. In contrast, both anticyclonic mode water eddies showed pronounced maxima in N2 fixation below the euphotic zone as evidenced by rate measurements and geochemical data. N2 fixation and carbon (C) fixation were higher in the young coastal mode water eddy compared to the older offshore mode water eddy. A co-occurrence between N2 fixation and biogenic N2, an indicator for N loss, indicated a link between N loss and N2 fixation in the mode water eddies, which was not observed for the cyclonic eddy. The comparison of two consecutive surveys of the coastal mode water eddy in November 2012 and December 2012 also revealed a reduction in N2 and C fixation at intermediate depths along with a reduction in chlorophyll by half, mirroring an aging effect in this eddy. Our data indicate an important role for anticyclonic mode water eddies in stimulating N2 fixation and thus supplying N offshore.

scholarly journals Ocean acidification and high irradiance stimulate the photo-physiological fitness, growth and carbon production of the Antarctic cryptophyte <i>Geminigera cryophila</i>

2019 ◽  
Vol 16 (15) ◽  
pp. 2997-3008 ◽  
Author(s):  
Scarlett Trimborn ◽  
Silke Thoms ◽  
Pascal Karitter ◽  
Kai Bischof
Keyword(s):  
Ocean Acidification ◽  
Coastal Waters ◽  
High Irradiance ◽  
High Pco2 ◽  
Experimental Conditions ◽  
Phytoplankton Assemblages ◽  
Beneficial Effects ◽  
Carbon Production ◽  
Geminigera Cryophila ◽  
The Antarctic

Abstract. Ecophysiological studies on Antarctic cryptophytes to assess whether climatic changes such as ocean acidification and enhanced stratification affect their growth in Antarctic coastal waters in the future are lacking so far. This is the first study that investigates the combined effects of the increasing availability of pCO2 (400 and 1000 µatm) and irradiance (20, 200 and 500 µmol photons m−2 s−1) on growth, elemental composition and photophysiology of the Antarctic cryptophyte Geminigera cryophila. Under ambient pCO2, this species was characterized by a pronounced sensitivity to increasing irradiance with complete growth inhibition at the highest light intensity. Interestingly, when grown under high pCO2 this negative light effect vanished, and it reached the highest rates of growth and particulate organic carbon production at the highest irradiance compared to the other tested experimental conditions. Our results for G. cryophila reveal beneficial effects of ocean acidification in conjunction with enhanced irradiance on growth and photosynthesis. Hence, cryptophytes such as G. cryophila may be potential winners of climate change, potentially thriving better in more stratified and acidic coastal waters and contributing in higher abundance to future phytoplankton assemblages of coastal Antarctic waters.

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