scholarly journals Abundances and morphotypes of the coccolithophore <i>Emiliania huxleyi</i> in southern Patagonia compared to neighbouring oceans and Northern Hemisphere fjords

2021 ◽  
Vol 18 (19) ◽  
pp. 5465-5489
Author(s):  
Francisco Díaz-Rosas ◽  
Catharina Alves-de-Souza ◽  
Emilio Alarcón ◽  
Eduardo Menschel ◽  
Humberto E. González ◽  
...  
Keyword(s):  
Niche Breadth ◽  
Minor Component ◽  
Emiliania Huxleyi ◽  
Early Spring ◽  
Saturation State ◽  
Southern Patagonia ◽  
Calcite Saturation ◽  
Chemical Conditions ◽  
Freshwater Inputs ◽  
Patagonian Fjords

Abstract. Coccolithophores are potentially affected by ongoing ocean acidification, where rising CO2 lowers seawater pH and calcite saturation state (Ωcal). Southern Patagonian fjords and channels provide natural laboratories for studying these issues due to high variability in physical and chemical conditions. We surveyed coccolithophore assemblages in Patagonian fjords during late spring 2015 and early spring 2017. Surface Ωcal exhibited large variations driven mostly by freshwater inputs. High-Ωcal conditions (max. 3.6) occurred in the Archipelago Madre de Dios. Ωcal ranged from 2.0–2.6 in the western Strait of Magellan and 1.5–2.2 in the inner channel and was subsaturating (0.5) in Skyring Sound. Emiliania huxleyi was the only coccolithophore widely distributed in Patagonian fjords (> 96 % of total coccolithophores), only disappearing in the Skyring Sound, a semi-closed mesohaline system. Correspondence analysis associated higher E. huxleyi biomasses with lower diatom biomasses. The highest E. huxleyi abundances in Patagonia were in the lower range of those reported in Norwegian fjords. Predominant morphotypes were distinct from those previously documented in nearby oceans but similar to those of Norwegian fjords. Moderately calcified forms of E. huxleyi A morphotype were uniformly distributed throughout Patagonia fjords. The exceptional R/hyper-calcified coccoliths, associated with low Ωcal values in Chilean and Peruvian coastal upwellings, were a minor component associated with high Ωcal levels in Patagonia. Outlying mean index (OMI) niche analysis suggested that pH and Ωcal conditions explained most variation in the realized niches of E. huxleyi morphotypes. The moderately calcified A morphotype exhibited the widest niche breadth (generalist), while the R/hyper-calcified morphotype exhibited a more restricted realized niche (specialist). Nevertheless, when considering an expanded sampling domain, including nearby southeast Pacific coastal and offshore waters, even the R/hyper-calcified morphotype exhibited a higher niche breadth than other closely phylogenetically related coccolithophore species. The occurrence of E. huxleyi in naturally low pH–Ωcal environments indicates that its ecological response is plastic and capable of adaptation.

scholarly journals Abundances and morphotypes of the coccolithophore <i>Emiliania huxleyi</i> in southern Patagonia compared to neighboring oceans and northern-hemisphere fjords

2021 ◽  
Author(s):  
Francisco Díaz-Rosas ◽  
Catharina Alves-de-Souza ◽  
Emilio Alarcón ◽  
Eduardo Menschel ◽  
Humberto E. González ◽  
...  
Keyword(s):  
Niche Breadth ◽  
Minor Component ◽  
Emiliania Huxleyi ◽  
Early Spring ◽  
Saturation State ◽  
Southern Patagonia ◽  
Calcite Saturation ◽  
Chemical Conditions ◽  
Freshwater Inputs ◽  
Patagonian Fjords

Abstract. Coccolithophores are potentially affected by ongoing ocean acidification, where rising CO2 lowers seawater pH and calcite saturation state (Ωcal). Southern Patagonian fjords and channels provide natural laboratories for studying these issues due to high variability in physical and chemical conditions. We surveyed coccolithophore assemblages in Patagonian fjords during late-spring 2015 and early-spring 2017. Surface Ωcal exhibited large variations driven mostly by freshwater inputs. High Ωcal conditions (max. 3.6) occurred in the Archipelago Madre de Dios. Ωcal ranged from 2.0–2.6 in the western Strait of Magellan, 1.5–2.2 in the Inner Channel, and was sub-saturating (0.5) in Skyring Sound. Emiliania huxleyi was the only coccolithophore widely distributed in Patagonian fjords (> 96 % of total coccolitophores), only disappearing in the Skyring Sound, a semi-closed mesohaline system. Correspondence analysis associated higher E. huxleyi biomasses with lower diatom biomasses. The highest E. huxleyi abundances in Patagonia were in the lower range of those reported in Norwegian fjords. Predominant morphotypes were distinct from those previously documented in nearby oceans but similar to those of Norwegian fjords. Moderate-calcified forms of E. huxleyi A morphotype were uniformly distributed throughout Patagonia fjords. The exceptional R/hyper-calcified coccoliths, associated with low Ωcal values in Chilean and Peruvian coastal upwellings, were a minor component associated with high Ωcal levels in Patagonia. Outlying mean index (OMI) niche analysis suggested that pH/Ωcal conditions explained most variation in the realized niches of E. huxleyi morphotypes. The moderate-calcified A morphotype exhibited the widest niche-breadth (generalist), while the R/hyper-calcified morphotype exhibited a more restricted realized niche (specialist). Nevertheless, when considering an expanded sampling domain, including nearby Southeast Pacific coastal and offshore waters, even the R/hyper-calcified morphotype exhibited a higher niche breadth than other closely phylogenetically-related coccolithophore species. The occurrence of E. huxleyi in naturally low pH/Ωcal environments indicates that its ecological response is plastic and capable of adaptation.

scholarly journals Morphology of <i>Emiliania huxleyi</i> coccoliths on the North West European shelf – is there an influence of carbonate chemistry?

2014 ◽  
Vol 11 (3) ◽  
pp. 4531-4561 ◽  
Author(s):  
J. R. Young ◽  
A. J. Poulton ◽  
T. Tyrrell
Keyword(s):  
Environmental Samples ◽  
Significant Variation ◽  
Emiliania Huxleyi ◽  
Morphometric Study ◽  
Saturation State ◽  
North West ◽  
The North ◽  
Microscope Images ◽  
Calcite Saturation ◽  
The Uk

Abstract. Within the context of the UK Ocean Acidification project, Emiliania huxleyi (type A) coccolith morphology was examined from samples collected during cruise D366. In particular, a morphometric study of coccolith size and degree of calcification was made on scanning electron microscope images of samples from shipboard CO2 perturbation experiments and from a set of environmental samples with significant variation in calcite saturation state (Ωcalcite). One bioassay in particular (E4 from the southern North Sea) yielded unambiguous results – in this bioassay exponential growth from a low level occurred with no artificial stimulation and coccosphere numbers increased ten-fold during the experiment. The samples with elevated CO2 saw significantly reduced coccolithophore growth. However, coccolithophore morphology was not significantly affected by the changing CO2 conditions even under the highest levels of perturbation (1000 μatm). Environmental samples similarly showed no correlation of coccolithophore morphology with calcite saturation state. Some variation in coccolith size and degree of calcification does occur but this seems to be predominantly due to genotypic differentiation between populations on the shelf and in the open ocean.

scholarly journals Carbon fixation prediction during a bloom of <i>Emiliania huxleyi</i> is highly sensitive to the assumed regulation mechanism

2009 ◽  
Vol 6 (3) ◽  
pp. 5339-5372 ◽  
Author(s):  
O. Bernard ◽  
A. Sciandra ◽  
S. Rabouille
Keyword(s):  
Large Scale ◽  
Carbon Fixation ◽  
Co2 Concentration ◽  
Carbon Fluxes ◽  
Emiliania Huxleyi ◽  
Regulation Mechanism ◽  
Fixation Rate ◽  
Saturation State ◽  
Calcite Saturation ◽  
Order Of Magnitude

Abstract. Large scale precipitation of calcium carbonate in the oceans by coccolithophorids plays an important role in carbon sequestration. However, there is a controversy on the effect of an increase in atmospheric CO2 concentration on both calcification and photosynthesis of coccolithophorids. Indeed recent experiments, performed under nitrogen limitation, revealed that the associated fluxes may be slowed down, while other authors claim the reverse. We designed models to account for various scenarii of calcification and photosynthesis regulation in chemostat cultures of Emiliania huxleyi, based on different hypotheses on the regulation mechanism. These models consider that either carbon dioxide, bicarbonate, carbonate or calcite saturation state (Ω) is the regulating factor. All were calibrated to predict the same carbon fixation rate in nowadays pCO2, but they turn out to respond differently to an increase in CO2 concentration. Thus, using the four possible models, we simulated a large bloom of Emiliania huxleyi. It results that models assuming a regulation by CO32− or Ω predicted much higher carbon fluxes. The response when considering a doubled pCO2 was different and models controlled by CO2 or HCO3 − led to increased carbon fluxes. In addition, the variability between the various scenarii proved to be in the same order of magnitude than the response to pCO2 increase. These sharp discrepancies reveal the consequences of model assumptions on the simulation outcome.

scholarly journals Morphology of <i>Emiliania huxleyi</i> coccoliths on the northwestern European shelf – is there an influence of carbonate chemistry?

2014 ◽  
Vol 11 (17) ◽  
pp. 4771-4782 ◽  
Author(s):  
J. R. Young ◽  
A. J. Poulton ◽  
T. Tyrrell
Keyword(s):  
Environmental Samples ◽  
Significant Variation ◽  
Emiliania Huxleyi ◽  
Morphometric Study ◽  
Carbonate Chemistry ◽  
Saturation State ◽  
Initial Cell ◽  
Microscope Images ◽  
Calcite Saturation ◽  
The Uk

Abstract. Within the context of the UK Ocean Acidification project, Emiliania huxleyi (type A) coccolith morphology was examined from samples collected during cruise D366. In particular, a morphometric study of coccolith size and degree of calcification was made on scanning electron microscope images of samples from shipboard CO2 perturbation experiments and from a set of environmental samples with significant variation in calcite saturation state (Ωcalcite). One bioassay in particular (E4 from the southern North Sea) yielded unambiguous results – in this bioassay exponential growth from a low initial cell density occurred with no nutrient enrichment and coccosphere numbers increased tenfold during the experiment. The samples with elevated CO2 saw significantly reduced coccolithophore growth. However, coccolithophore morphology was not significantly affected by the changing CO2 conditions even under the highest levels of perturbation (1000 μatm CO2). Environmental samples similarly showed no correlation of coccolithophore morphology with calcite saturation state. Some variation in coccolith size and degree of calcification does occur but this seems to be predominantly due to genotypic differentiation between populations on the shelf and in the open ocean.

scholarly journals Processes determining the marine alkalinity and calcium carbonate saturation state distributions

2014 ◽  
Vol 11 (24) ◽  
pp. 7349-7362 ◽  
Author(s):  
B. R. Carter ◽  
J. R. Toggweiler ◽  
R. M. Key ◽  
J. L. Sarmiento
Keyword(s):  
Calcium Carbonate ◽  
The Arctic ◽  
Effect Of Temperature ◽  
Minor Role ◽  
Co2 Solubility ◽  
Saturation State ◽  
Marine System ◽  
Calcite Saturation ◽  
River Mouths ◽  
Arctic Surface

Abstract. We introduce a composite tracer for the marine system, Alk*, that has a global distribution primarily determined by CaCO3 precipitation and dissolution. Alk* is also affected by riverine alkalinity from dissolved terrestrial carbonate minerals. We estimate that the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk* in the Arctic surface and particularly near river mouths. Strong net carbonate precipitation results in low Alk* in subtropical gyres, especially in the Indian and Atlantic oceans. Upwelling of dissolved CaCO3-rich deep water elevates North Pacific and Southern Ocean Alk*. We use the Alk* distribution to estimate the variability of the calcite saturation state resulting from CaCO3 cycling and other processes. We show that regional differences in surface calcite saturation state are due primarily to the effect of temperature differences on CO2 solubility and, to a lesser extent, differences in freshwater content and air–sea disequilibria. The variations in net calcium carbonate cycling revealed by Alk* play a comparatively minor role in determining the calcium carbonate saturation state.

scholarly journals Carbonate saturation state of surface waters in the Ross Sea and Southern Ocean: controls and implications for the onset of aragonite undersaturation

2015 ◽  
Vol 12 (11) ◽  
pp. 8429-8465 ◽  
Author(s):  
H. B. DeJong ◽  
R. B. Dunbar ◽  
D. A. Mucciarone ◽  
D. A. Koweek
Keyword(s):  
Southern Ocean ◽  
Surface Waters ◽  
Ross Sea ◽  
Polar Front ◽  
Early Spring ◽  
Total Alkalinity ◽  
Saturation State ◽  
System Data ◽  
Algal Photosynthesis ◽  
Carbon System

Abstract. Predicting when surface waters of the Ross Sea and Southern Ocean will become undersaturated with respect to biogenic carbonate minerals is challenging in part due to the lack of baseline high resolution carbon system data. Here we present ~ 1700 surface total alkalinity measurements from the Ross Sea and along a transect between the Ross Sea and southern Chile from the austral autumn (February–March 2013). We calculate the saturation state of aragonite (ΩAr) and calcite (ΩCa) using measured total alkalinity and pCO2. In the Ross Sea and south of the Polar Front, variability in carbonate saturation state (Ω) is mainly driven by algal photosynthesis. Freshwater dilution and calcification have minimal influence on Ω variability. We estimate an early spring surface water ΩAr value of ~ 1.2 for the Ross Sea using a total alkalinity–salinity relationship and historical pCO2 measurements. Our results suggest that the Ross Sea is not likely to become undersaturated with respect to aragonite until the year 2070.

scholarly journals Biocalcification by Emiliania huxleyi in batch culture experiments

2008 ◽  
Vol 72 (1) ◽  
pp. 251-256 ◽  
Author(s):  
C. de Bodt ◽  
J. Harlay ◽  
L. Chou
Keyword(s):  
Organic Carbon ◽  
General Feature ◽  
Emiliania Huxleyi ◽  
Particle Aggregation ◽  
Strongly Correlated ◽  
Batch Experiments ◽  
Saturation State ◽  
Widespread Species ◽  
Surface Ocean ◽  
Deep Waters

AbstractCoccolithophores, among which Emiliania huxleyi is the most abundant and widespread species, are considered the most productive calcifying organism on earth. The export of organic carbon and calcification are the main drivers of the biological CO2 pump and are expected to change with oceanic acidification. Coccolithophores are further known to produce transparent exopolymer particles (TEP) that promote particle aggregation. As a result, the TEP and biogenic calcium carbonate (CaCO3) contribute to the export of carbon from the surface ocean to deep waters. In this context, we followed the development and the decline of E. huxleyi using batch experiments with monospecific cultures. We studied the link between different processes such as photosynthesis, calcification and the production of TEP. The onset of calcification was delayed in relation to photosynthesis. The timing and the general feature of the dynamics of calcification were closely related to the saturation state of seawater with respect to calcite, Ωcal. The production of TEP was enhanced after the decline of phytoplankton growth. After nutrient exhaustion, particulate organic carbon (POC) concentration increased linearly with increasing TEP concentration, suggesting that TEP contributes to the POC increase. The production of CaCO3 is also strongly correlated with that of TEP, suggesting that calcification may be considered as a source of TEP precursors.

scholarly journals Cements, Waters, and Scales: An Integrated Study of the Szeged Geothermal Systems (SE Hungary) to Characterize Natural Environmental Conditions of the Thermal Aquifer

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Andrea Varga ◽  
Gábor Bozsó ◽  
István Garaguly ◽  
Béla Raucsik ◽  
Attila Bencsik ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Thermal Water ◽  
Pannonian Basin ◽  
Integrated Approach ◽  
High Heat ◽  
Geothermal Systems ◽  
Geothermal Waters ◽  
Deep Aquifer ◽  
Saturation State ◽  
Calcite Saturation

The study area, Pannonian Basin (Central Europe), is characterized by high heat flow and presence of low-enthalpy geothermal waters. In the Szeged Geothermal Systems (Hungary), having Miocene to Pliocene sandstone aquifers with dominantly Na–HCO3-type thermal water, unwanted carbonate scaling was observed. An integrated approach consisting of host rock and scale mineralogical and petrographic analyses as well as water chemistry led to a better understanding of the characteristic natural (geogenic) environmental conditions of the geothermal aquifers and to highlight their technical importance. Analyses of the reservoir sandstones showed that they are mineralogically immature mixed carbonate-siliciclastic rocks with significant macroporosity. Detrital carbonate grains such as dolomite and limestone fragments appear as important framework components (up to ~20–25%). During water–rock interactions, they could serve as a potential source of the calcium and bicarbonate ions, contributing to the elevated scaling potential. Therefore, this sandstone aquifer cannot be considered as a conventional siliciclastic reservoir. In mudrocks, a significant amount of organic matter also occurs, triggering CO2producing reactions. Correspondingly, framboidal pyrite and ferroan calcite are the main cement minerals in all of the studied sandstone samples which can suggest that calcite saturation state of the thermal fluid is close to equilibrium in oxygen-depleted pore water. Analysis of the dominant carbonate crystals in the scale can suggest that growth of the feather dendrites of low-Mg calcite was probably driven by rapid CO2degassing of CO2-rich thermal water under far-from-equilibrium conditions. Based on hydrogeochemical data and related indices for scaling and corrosion ability, the produced bicarbonate-rich (up to 3180 mg/l) thermal water has a significant potential for carbonate scaling which supports the aforementioned statement. Taking into consideration our present knowledge of geological setting of the studied geothermal systems, temporal changes in chemical composition and temperature of the thermal water during the heating period can indicate upwelling fluids from a deep aquifer. Regarding the pre-Neogene basement, hydrologic contact with a Triassic carbonate aquifer might be reflected in the observed chemical features such as decreased total dissolved solids and increased bicarbonate content with high scale-forming ability. The proposed upflow of basin-derived water could be channeled by Neogene to Quaternary fault zones, including compaction effects creating fault systems above the elevated basement high. The results may help to understand the cause of the high carbonate scale precipitation rates in geothermal systems tapping sandstone aquifers.

scholarly journals Implications of observed inconsistencies in carbonate chemistry measurements for ocean acidification studies

2012 ◽  
Vol 9 (2) ◽  
pp. 1781-1792 ◽  
Author(s):  
C. J. M. Hoppe ◽  
G. Langer ◽  
S. D. Rokitta ◽  
D. A. Wolf-Gladrow ◽  
B. Rost
Keyword(s):  
Ocean Acidification ◽  
High Pco2 ◽  
Small Scale ◽  
Ecological Data ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Severe Problem ◽  
Important Approach ◽  
Calcite Saturation

Abstract. The growing field of ocean acidification research is concerned with the investigation of organisms' responses to increasing pCO2 values. One important approach in this context is culture work using seawater with adjusted CO2 levels. As aqueous pCO2 is difficult to measure directly in small scale experiments, it is generally calculated from two other measured parameters of the carbonate system (often AT, CT or pH). Unfortunately, the overall uncertainties of measured and subsequently calculated values are often unknown. Especially under high pCO2, this can become a severe problem with respect to the interpretation of physiological and ecological data. In the few datasets from ocean acidification research where all three of these parameters were measured, pCO2 values calculated from AT and CT are typically about 30 % lower (i.e. ~300 μatm at a target pCO2 of 1000 μatm) than those calculated from AT and pH or CT and pH. This study presents and discusses these discrepancies as well as likely consequences for the ocean acidification community. Until this problem is solved, one has to consider that calculated parameters of the carbonate system (e.g. pCO2, calcite saturation state) may not be comparable between studies, and that this may have important implications for the interpretation of CO2 perturbation experiments.

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