scholarly journals Population-specific responses in physiological rates of <i>Emiliania huxleyi</i> to a broad CO<sub>2</sub> range

2018 ◽  
Author(s):  
Yong Zhang ◽  
Lennart T. Bach ◽  
Kai T. Lohbeck ◽  
Kai G. Schulz ◽  
Luisa Listmann ◽  
...  

Abstract. Although coccolithophore physiological responses to CO2-induced changes in seawater carbonate chemistry have been widely studied in the past, there is limited knowledge on the variability of physiological responses between populations. In the present study, we investigated the population-specific responses of growth, particulate organic (POC) and inorganic carbon (PIC) production rates of 17 strains of the coccolithophore Emiliania huxleyi from three regions in the North Atlantic Ocean (Azores, Canary Islands, and Norwegian coast near Bergen) to a CO2 partial pressure (pCO2) range from 120 µatm to 2630 µatm. Physiological rates of each population and individual strain displayed the expected optimum curve responses to the pCO2 gradient. Optimal pCO2 for growth and POC production rates and tolerance to low pH (i.e. high proton concentration) was significantly higher in an E. huxleyi population isolated from a Norwegian fjord than in those isolated near the Azores and Canary Islands. This may be due to the large pCO2 and pH variability in coastal waters off Bergen compared to the rather stable oceanic conditions at the other two sites. Maximum growth and POC production rates of the Azores and Bergen populations were similar and significantly higher than of the Canary Islands population. One of the reasons may be that the chosen incubation temperature (16 °C) is slightly below what strains isolated near the Canary Islands normally experience. Our results indicate adaptation of E. huxleyi to their local environmental conditions. Within each population, different growth, POC and PIC production rates at different pCO2 levels indicated strain-specific phenotypic plasticity. The existence of distinct carbonate chemistry responses between and within populations will likely benefit E. huxleyi to acclimate to rising CO2 levels in the oceans.

2018 ◽  
Vol 15 (12) ◽  
pp. 3691-3701 ◽  
Author(s):  
Yong Zhang ◽  
Lennart T. Bach ◽  
Kai T. Lohbeck ◽  
Kai G. Schulz ◽  
Luisa Listmann ◽  
...  

Abstract. Although coccolithophore physiological responses to CO2-induced changes in seawater carbonate chemistry have been widely studied in the past, there is limited knowledge on the variability of physiological responses between populations from different areas. In the present study, we investigated the specific responses of growth, particulate organic (POC) and inorganic carbon (PIC) production rates of three populations of the coccolithophore Emiliania huxleyi from three regions in the North Atlantic Ocean (Azores: six strains, Canary Islands: five strains, and Norwegian coast near Bergen: six strains) to a CO2 partial pressure (pCO2) range from 120 to 2630 µatm. Physiological rates of each population and individual strain increased with rising pCO2 levels, reached a maximum and declined thereafter. Optimal pCO2 for growth, POC production rates, and tolerance to low pH (i.e., high proton concentration) was significantly higher in an E. huxleyi population isolated from the Norwegian coast than in those isolated near the Azores and Canary Islands. This may be due to the large environmental variability including large pCO2 and pH fluctuations in coastal waters off Bergen compared to the rather stable oceanic conditions at the other two sites. Maximum growth and POC production rates of the Azores and Bergen populations were similar and significantly higher than that of the Canary Islands population. This pattern could be driven by temperature–CO2 interactions where the chosen incubation temperature (16 ∘C) was slightly below what strains isolated near the Canary Islands normally experience. Our results indicate adaptation of E. huxleyi to their local environmental conditions and the existence of distinct E. huxleyi populations. Within each population, different growth, POC, and PIC production rates at different pCO2 levels indicated strain-specific phenotypic plasticity. Accounting for this variability is important to understand how or whether E. huxleyi might adapt to rising CO2 levels.


2012 ◽  
Vol 9 (8) ◽  
pp. 3449-3463 ◽  
Author(s):  
L. T. Bach ◽  
C. Bauke ◽  
K. J. S. Meier ◽  
U. Riebesell ◽  
K. G. Schulz

Abstract. The coccolithophore Emiliania huxleyi is a marine phytoplankton species capable of forming small calcium carbonate scales (coccoliths) which cover the organic part of the cell. Calcification rates of E. huxleyi are known to be sensitive to changes in seawater carbonate chemistry. It has, however, not yet been clearly determined how these changes are reflected in size and weight of individual coccoliths and which specific parameter(s) of the carbonate system drive morphological modifications. Here, we compare data on coccolith size, weight, and malformation from a set of five experiments with a large diversity of carbonate chemistry conditions. This diversity allows distinguishing the influence of individual carbonate chemistry parameters such as carbon dioxide (CO2), bicarbonate (HCO3−), carbonate ion (CO32−), and protons (H+) on the measured parameters. Measurements of fine-scale morphological structures reveal an increase of coccolith malformation with decreasing pH suggesting that H+ is the major factor causing malformations. Coccolith distal shield area varies from about 5 to 11 μm2. Changes in size seem to be mainly induced by varying [HCO3−] and [H+] although influence of [CO32−] cannot be entirely ruled out. Changes in coccolith weight were proportional to changes in size. Increasing CaCO3 production rates are reflected in an increase in coccolith weight and an increase of the number of coccoliths formed per unit time. The combined investigation of morphological features and coccolith production rates presented in this study may help to interpret data derived from sediment cores, where coccolith morphology is used to reconstruct calcification rates in the water column.


2020 ◽  
Vol 7 ◽  
Author(s):  
Cleo L. Davie-Martin ◽  
Stephen J. Giovannoni ◽  
Michael J. Behrenfeld ◽  
William B. Penta ◽  
Kimberly H. Halsey

Marine-derived volatile organic compounds (VOCs) influence global carbon cycling, atmospheric reactions, and climate. Yet, the biogenic production (sources) and consumption (sink) rates of marine VOCs are not well-constrained and are currently excluded from global chemical transport models. We directly measured the net biogenic production rates of seven VOCs (acetaldehyde, acetone, acetonitrile, dimethylsulfide, isoprene, methanethiol, and methanol) in surface seawater during four field campaigns in the North Atlantic Ocean that targeted different stages of the phytoplankton annual cycle. All of the VOCs exhibited strong seasonal trends, with generally positive rates during May (peak spring bloom) and lower, sometimes negative rates (net consumption), during November and/or March (the winter bloom minimum transition). Strong latitudinal gradients were identified for most VOCs during May and September, with greater production observed in the northern regions compared to the southern regions. These gradients reflect the interplay between high phytoplankton and bacterial productivity. During the bloom transition stages (March and September), acetaldehyde and acetone exhibited net production rates that bracketed zero, suggesting that biogenic production was either very low or indicative of a tightly coupled system with more complex underlying microbial VOC cycling. Our data provides the first direct evidence for widespread biogenic acetonitrile production and consumption in the surface ocean and the first net biogenic production rates for methanethiol in natural seawater.


2012 ◽  
Vol 9 (5) ◽  
pp. 5849-5885 ◽  
Author(s):  
L. T. Bach ◽  
C. Bauke ◽  
K. J. S. Meier ◽  
U. Riebesell ◽  
K. G. Schulz

Abstract. The coccolithophore Emiliania huxleyi is a marine phytoplankton species capable of forming small calcium carbonate scales (coccoliths) which cover the organic part of the cell. Calcification rates of E. huxleyi are known to be sensitive to changes in seawater carbonate chemistry. It is, however, not yet understood how these changes are reflected in the morphology of coccoliths. Here, we compare data on coccolith size, weight, and malformation from a~set of five experiments with a large diversity of carbonate chemistry conditions. This diversity allows distinguishing the influence of individual carbonate chemistry parameters such as carbon dioxide (CO2), bicarbonate (HCO3−), carbonate (CO32−), and protons (H+) on the measured parameters. Measurements of fine-scale morphological structures reveal an increase of coccolith malformation with decreasing pH suggesting that H+ is the major factor causing malformations. Coccolith distal shield area varies from about 5 to 11 μm2. Changes in size seem to be mainly induced by varying [HCO3−] and [H+] although influence of [CO32−] cannot be entirely ruled out. Changes in coccolith weight were proportional to changes in size. Increasing CaCO3 production rates are reflected in an increase in coccolith weight and an increase of the number of coccoliths formed per unit time. The combined investigation of morphological features and coccolith production rates presented in this study may help to interpret data derived from sediment cores, where coccolith morphology is used to reconstruct calcification rates in the water column.


Author(s):  
Robin Pingree ◽  
Carlos Garcia-Soto

Seasonal changes in altimeter data are derived for the North Atlantic Ocean. Altimeter data are then used to examine annually propagating structure along 26°N. By averaging the altimeter data into monthly values or by Fourier analysis, a positive anomaly can be followed from 17°W to ∼50°W along ∼26°N. The methods give a westward travel speed of 1° of longitude a month and a half-life of one year for the average decaying structure. At ∼50°W 26°N, the average structure is about 2·8 years old with an elevation signal of ∼1 cm, having travelled ∼3300 km westward. The mean positive anomaly results from the formation of anticyclonic eddies which are generally formed annually south of the Canary Islands by late summer and which then travel westward near 26°N. Individual eddy structure along 26°N is examined and related to in situ measurements and anomalies in the annual seasonal concentration cycle of SeaWiFS chlorophyll-a.


Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2616
Author(s):  
Christian Tamburini ◽  
Marc Garel ◽  
Aude Barani ◽  
Dominique Boeuf ◽  
Patricia Bonin ◽  
...  

In the dark ocean, the balance between the heterotrophic carbon demand and the supply of sinking carbon through the biological carbon pump remains poorly constrained. In situ tracking of the dynamics of microbial degradation processes occurring on the gravitational sinking particles is still challenging. Our particle sinking simulator system (PASS) intends to mimic as closely as possible the in situ variations in pressure and temperature experienced by gravitational sinking particles. Here, we used the PASS to simultaneously track geochemical and microbial changes that occurred during the sinking through the mesopelagic zone of laboratory-grown Emiliania huxleyi aggregates amended by a natural microbial community sampled at 105 m depth in the North Atlantic Ocean. The impact of pressure on the prokaryotic degradation of POC and dissolution of E. huxleyi-derived calcite was not marked compared to atmospheric pressure. In contrast, using global O2 consumption monitored in real-time inside the high-pressure bottles using planar optodes via a sapphire window, a reduction of respiration rate was recorded in surface-originated community assemblages under increasing pressure conditions. Moreover, using a 16S rRNA metabarcoding survey, we demonstrated a drastic difference in transcriptionally active prokaryotes associated with particles, incubated either at atmospheric pressure or under linearly increasing hydrostatic pressure conditions. The increase in hydrostatic pressure reduced both the phylogenetic diversity and the species richness. The incubation at atmospheric pressure, however, promoted an opportunistic community of “fast” degraders from the surface (Saccharospirillaceae, Hyphomonadaceae, and Pseudoalteromonadaceae), known to be associated with surface phytoplankton blooms. In contrast, the incubation under increasing pressure condition incubations revealed an increase in the particle colonizer families Flavobacteriaceae and Rhodobacteraceae, and also Colwelliaceae, which are known to be adapted to high hydrostatic pressure. Altogether, our results underline the need to perform biodegradation experiments of particles in conditions that mimic pressure and temperature encountered during their sinking along the water column to be ecologically relevant.


Author(s):  
Deborah Steinberg

The structure of planktonic communities profoundly affects particle export and sequestration of organic material (the biological pump) and the chemical cycling of nutrients. This chapter describes the integral and multifaceted role zooplankton (both protozoan and metazoan) play in the export and cycling of elements in the ocean, with an emphasis on the North Atlantic Ocean and adjacent seas. Zooplankton consume a significant proportion of primary production across the world's oceans, and their metabolism plays a key role in recycling carbon, nitrogen, and other elements. The chapter also addresses how human or climate-influenced changes in North Atlantic zooplankton populations may in turn drive changes in zooplankton-mediated biogeochemical cycling.


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