The ice nucleating ability of macromolecules in immersion freezing decreases in the presence of salts: Implications for freezing point depression calculations

2021 ◽  
Author(s):  
Jon F. Went ◽  
Jeanette D. Wheeler ◽  
François J. Peaudecerf ◽  
Nadine Borduas-Dedekind
Keyword(s):  
Sea Water ◽  
Freezing Point ◽  
Pure Water ◽  
Salt Content ◽  
Mixed Phase ◽  
Cloud Formation ◽  
Sea Spray ◽  
Freezing Point Depression ◽  
Immersion Freezing ◽  
Mixed Phase Clouds

<p>Cloud formation represents a large uncertainty in current climate predictions. In particular, ice in mixed-phase clouds requires the presence of ice nucleating particles (INPs) or ice nucleating macromolecules (INMs). An influential population of INPs has been proposed to be organic sea spray aerosols in otherwise pristine ocean air. However, the interactions between INMs present in sea water and their freezing behavior under atmospheric immersion freezing conditions warrants further research to constrain the role of sea spray aerosols on cloud formation. Indeed, salt is known to lower the freezing temperature of water, through a process called freezing point depression (FPD). Yet, current FPD corrections are solely based on the salt content and assume that the INMs’ ice nucleation abilities are identical with and without salt. Thus, we measured the effect of salt content on the ice nucleating ability of INMs, known to be associated with marine phytoplankton, in immersion freezing experiments in the Freezing Ice Nuclei Counter (FINC) (Miller et al., AMTD, 2020). We measured eight INMs, namely taurine, isethionate, xylose, mannitol, dextran, laminarin, and xanthan as INMs in pure water at temperatures relevant for mixed-phase clouds (e.g. 50% activated fraction at temperatures above –23 °C at 10 mM concentration). Subsequently, INMs were analyzed in artificial sea water containing 36 g salt L<sup>-1</sup>. Most INMs, except laminarin and xanthan, showed a loss of ice activity in artificial sea water compared to pure water, even after FPD correction. Based on our results, we hypothesize sea salt has an inhibitory effect on the ice activity of INMs. This effect influences our understanding of how INMs nucleate ice as well as challenges our use of FPD correction and subsequent extrapolation to ice activity under mixed-phase cloud conditions.</p>

Osmoregulation in Ligia Oceanica and Idotea Granulosa

1963 ◽  
Vol 40 (2) ◽  
pp. 381-392
Author(s):  
MARY E. TODD
Keyword(s):  
Blood Concentration ◽  
Sea Water ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
External Concentration ◽  
Osmotic Concentration ◽  
Test Range ◽  
The Mean ◽  
The Difference ◽  
Idotea Granulosa

1. The osmoregulatory response of Ligia oceanica and Idotea granulosa to the range of the experimental variables was similar. They were both hyperosmotic relative to the medium and the difference between internal and external concentration increased as the salinity of the medium decreased. 2. In 100% sea water the osmotic concentration of the blood of Ligia oceanica was markedly above that of the medium, whereas in Idotea granulosa the blood was only marginally hyperosmotic. 3. In Ligia oceanica the blood concentration changed little in 100 and 75% sea water, but dropped significantly between 75 and 50% sea water, whereas blood concentration in Idotea granulosa dropped significantly throughout the test range of salinities. 4. The more efficient osmoregulation of Ligia oceanica in 25% sea water is reflected in the mean freezing-point depression of the blood, Δi = 1.65, compared with Δi = 0.90 in Idotea granulosa. 5. In both species the osmotic concentration of the blood was influenced by season, by temperature and by a temperature-salinity interaction. 6. Neither size nor sex of the animal influenced osmotic concentration of the blood.

Lignin's ability to nucleate ice via immersion freezing

2020 ◽  
Author(s):  
Sophie Bogler ◽  
Nadine Borduas-Dedekind
Keyword(s):  
Structural Changes ◽  
Dominant Role ◽  
Mixed Phase ◽  
Freezing Process ◽  
Radiative Balance ◽  
Ice Nuclei ◽  
Atmospheric Processing ◽  
Immersion Freezing ◽  
Mixed Phase Clouds ◽  
The Impact

<p>Uncertainties in current predictions for the atmosphere’s radiative balance are dominated by the impact of clouds. Ice nucleating particles (INPs) play a dominant role in the formation of mixed-phase clouds, however there is still a lack of understanding of how INPs interact with water in the freezing process. Detailed elucidations of the organic aerosol chemical composition from IN active atmospheric samples are scarce which is due to the analytical challenge of resolving their high complexity. We chose to reduce sample complexity by investigating the IN activity of a specific sub-component of organic aerosols, the biopolymer lignin. This approach facilitates connecting ice nucleating abilities to molecular properties. Ice nucleation experiments were conducted in our home-built Freezing Ice Nuclei Counter (FINC) to measure freezing temperatures in the immersion freezing mode which is the dominant IN mechanism in mixed-phase clouds. We find that lignin acts as an INP at temperatures relevant for mixed-phase cloud processes (e.g. 50% activated fraction at – 20 °C concentrated 20 mg C/L). Photochemistry and ozonation experiments were subsequently conducted to test the effect of atmospheric processing on lignin’s IN activity. We discovered that this activity was not susceptible to change under environmentally relevant conditions even though structural changes were introduced by monitoring UV/Vis absorbance. Additionally to atmospheric processing, laboratory treatments including heating, sonication and oxidation with hydrogen peroxide were done, where only the heating experiments had a decreasing effect on lignin’s IN activity.  Based on these results, we present a thorough INP characterization of lignin, a specific organic matter subcomponent, and contribute to the understanding of how organic material present in the atmosphere can nucleate ice.</p>

scholarly journals Sources and nature of ice-nucleating particles in the free troposphere at Jungfraujoch in winter 2017

2021 ◽  
Vol 21 (22) ◽  
pp. 16925-16953
Author(s):  
Larissa Lacher ◽  
Hans-Christian Clemen ◽  
Xiaoli Shen ◽  
Stephan Mertes ◽  
Martin Gysel-Beer ◽  
...  
Keyword(s):  
Time Series ◽  
Laser Ablation ◽  
Source Region ◽  
Mixed Phase ◽  
Dust Particles ◽  
Sea Spray ◽  
Free Troposphere ◽  
Mass Spectrometers ◽  
Air Masses ◽  
Mixed Phase Clouds

Abstract. Primary ice formation in mixed-phase clouds is initiated by a minute subset of the ambient aerosol population, called ice-nucleating particles (INPs). The knowledge about their atmospheric concentration, composition, and source in cloud-relevant environments is still limited. During the 2017 joint INUIT/CLACE (Ice Nuclei research UnIT/CLoud–Aerosol Characterization Experiment) field campaign, observations of INPs as well as of aerosol physical and chemical properties were performed, complemented by source region modeling. This aimed at investigating the nature and sources of INPs. The campaign took place at the High-Altitude Research Station Jungfraujoch (JFJ), a location where mixed-phase clouds frequently occur. Due to its altitude of 3580 m a.s.l., the station is usually located in the lower free troposphere, but it can also receive air masses from terrestrial and marine sources via long-range transport. INP concentrations were quasi-continuously detected with the Horizontal Ice Nucleation Chamber (HINC) under conditions representing the formation of mixed-phase clouds at −31 ∘C. The INP measurements were performed in parallel to aerosol measurements from two single-particle mass spectrometers, the Aircraft-based Laser ABlation Aerosol MAss Spectrometer (ALABAMA) and the laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF). The chemical identity of INPs is inferred by correlating the time series of ion signals measured by the mass spectrometers with the time series of INP measurements. Moreover, our results are complemented by the direct analysis of ice particle residuals (IPRs) by using an ice-selective inlet (Ice-CVI) coupled with the ALABAMA. Mineral dust particles and aged sea spray particles showed the highest correlations with the INP time series. Their role as INPs is further supported by source emission sensitivity analysis using atmospheric transport modeling, which confirmed that air masses were advected from the Sahara and marine environments during times of elevated INP concentrations and ice-active surface site densities. Indeed, the IPR analysis showed that, by number, mineral dust particles dominated the IPR composition (∼58 %), and biological and metallic particles are also found to a smaller extent (∼10 % each). Sea spray particles are also found as IPRs (17 %), and their fraction in the IPRs strongly varied according to the increased presence of small IPRs, which is likely due to an impact from secondary ice crystal formation. This study shows the capability of combining INP concentration measurements with chemical characterization of aerosol particles using single-particle mass spectrometry, source region modeling, and analysis of ice residuals in an environment directly relevant for mixed-phase cloud formation.

scholarly journals Sources and nature of ice-nucleating particles in the free troposphere at Jungfraujoch in winter 2017

2021 ◽  
Author(s):  
Larissa Lacher ◽  
Hans-Christian Clemen ◽  
Xiaoli Shen ◽  
Stephan Mertes ◽  
Martin Gysel-Beer ◽  
...  
Keyword(s):  
Time Series ◽  
Laser Ablation ◽  
Source Region ◽  
Mixed Phase ◽  
Dust Particles ◽  
Sea Spray ◽  
Free Troposphere ◽  
Mass Spectrometers ◽  
Air Masses ◽  
Mixed Phase Clouds

Abstract. Primary ice formation in mixed-phase clouds is initiated by a minute subset of the ambient aerosol population, called ice-nucleating particles (INPs). The knowledge about their atmospheric concentration, their composition, and source in cloud-relevant environments is still limited. During the joint INUIT/CLACE (Ice Nuclei research UnIT/ CLoud–Aerosol Characterization Experiment) 2017 field campaign, observations of INPs, as well as of aerosol physical and chemical properties were performed, complemented by source region modelling. This aimed at investigating the nature and sources of INPs. The campaign took place at the High-Altitude Research Station Jungfraujoch (JFJ), a location where mixed-phase clouds frequently occur. Due to its altitude of 3580 m a.s.l., the station is usually located in the lower free troposphere, but can also receive air masses from terrestrial and marine sources via long-range transport. INP concentrations were quasi-continuously detected with the Horizontal Ice Nucleation Chamber (HINC) under conditions representing the formation of mixed-phase clouds at −31 °C. The INP measurements were performed in parallel to aerosol measurements from two single particle mass spectrometers, the Aircraft-based Laser ABlation Aerosol MAss Spectrometer (ALABAMA) and the Laser Ablation Aerosol Particle Time-Of-Flight mass spectrometer (LAAPTOF). The chemical identity of INPs is inferred by correlating the time series of ion signals measured by the mass spectrometers with the time series of INP measurements. Moreover, our results are complemented by the direct analysis of ice particle residuals (IPRs) by using an ice-selective inlet (Ice-CVI) coupled with the ALABAMA. Mineral dust particles and aged sea spray particles showed the highest correlations with the INP time series. Their role as INP is further supported by source emission sensitivity analysis using atmospheric transport modelling, which confirmed that air masses were advected from the Saharan desert and marine environments during times of elevated INP concentrations and ice-active surface site densities. Indeed, the IPR analysis showed that by number, mineral dust particles dominated the IPR composition (~58 %), and also biological and metallic particles are found to a smaller extent (~10 %). Sea spray particles are also found as IPRs (17 %), and their fraction in the IPRs strongly varied according to the increased presence of small IPRs, which is likely due to an impact from secondary ice crystal formation. This study shows the capability of combining INP concentration measurements with chemical characterization of aerosol particles using single particle mass spectrometry, source region modelling, and analysis of ice-residuals in an environment directly relevant for mixed-phase cloud formation.

scholarly journals Effects of marine organic aerosols as sources of immersion-mode ice-nucleating particles on high-latitude mixed-phase clouds

2021 ◽  
Vol 21 (4) ◽  
pp. 2305-2327
Author(s):  
Xi Zhao ◽  
Xiaohong Liu ◽  
Susannah M. Burrows ◽  
Yang Shi
Keyword(s):  
Southern Ocean ◽  
High Latitude ◽  
Ice Nucleation ◽  
Surface Energy Budget ◽  
Mixed Phase ◽  
Sea Spray ◽  
Earth System ◽  
Cloud Forcing ◽  
Model Version ◽  
Mixed Phase Clouds

Abstract. Mixed-phase clouds are frequently observed in high-latitude regions and have important impacts on the surface energy budget and regional climate. Marine organic aerosol (MOA), a natural source of aerosol emitted over ∼ 70 % of Earth's surface, may significantly modify the properties and radiative forcing of mixed-phase clouds. However, the relative importance of MOA as a source of ice-nucleating particles (INPs) in comparison to mineral dust, and MOA's effects as cloud condensation nuclei (CCN) and INPs on mixed-phase clouds are still open questions. In this study, we implement MOA as a new aerosol species into the Community Atmosphere Model version 6 (CAM6), the atmosphere component of the Community Earth System Model version 2 (CESM2), and allow the treatment of aerosol–cloud interactions of MOA via droplet activation and ice nucleation. CAM6 reproduces observed seasonal cycles of marine organic matter at Mace Head and Amsterdam Island when the MOA fraction of sea spray aerosol in the model is assumed to depend on sea spray biology but fails when this fraction is assumed to be constant. Model results indicate that marine INPs dominate primary ice nucleation below 400 hPa over the Southern Ocean and Arctic boundary layer, while dust INPs are more abundant elsewhere. By acting as CCN, MOA exerts a shortwave cloud forcing change of −2.78 W m−2 over the Southern Ocean in the austral summer. By acting as INPs, MOA enhances the longwave cloud forcing by 0.35 W m−2 over the Southern Ocean in the austral winter. The annual global mean net cloud forcing changes due to CCN and INPs of MOA are −0.35 and 0.016 W m−2, respectively. These findings highlight the vital importance for Earth system models to consider MOA as an important aerosol species for the interactions of biogeochemistry, hydrological cycle, and climate change.

scholarly journals Salt and Water Balance in the East African Fresh-Water Crab, Potamon Niloticus (M. Edw.)

1959 ◽  
Vol 36 (1) ◽  
pp. 157-176 ◽  
Author(s):  
J. SHAW
Keyword(s):  
Water Balance ◽  
Fresh Water ◽  
Sea Water ◽  
Freezing Point ◽  
Salt Content ◽  
The Body ◽  
Sodium Balance ◽  
East African ◽  
Sodium Loss ◽  
Salt And Water Balance

1. The mechanisms of salt and water balance in the East African fresh-water crab, Potamon niloticus, have been investigated. 2. The freezing-point depression of the blood is equivalent to that of a 271 mM./l. NaCl solution. 3. The animals cannot survive in solutions more concentrated than 75% sea water. Above the normal blood concentration, the blood osmotic pressure follows that of the medium. 4. The urine is iso-osmotic with the blood and is produced at a very slow rate. The potassium content is only half that of the blood. 5. The animal loses sodium at a rate of 8 µM./10 g./hr. mainly through the body surface. Potassium loss occurs at one-sixteenth of this rate. 6. Sodium balance can be maintained at a minimum external concentration of 0.05 mM./l. Potassium requires a concentration of 0.07 mM./l. 7. Active absorption of both sodium and potassium occurs. The rate of uptake of sodium depends on the extent of previous sodium loss. The rate of sodium uptake may be affected by such environmental factors as the salt content of the water, temperature and oxygen tension. 8. The normal oxygen consumption rate is 0.72 mg./10 g./hr. A minimum of 2.3% is used in doing osmotic work to maintain salt balance. 9. The salt and water balance in Potamon is discussed in relation to the adaptation of the Crustacea to fresh water. The importance of permeability changes is stressed.

scholarly journals Enhanced ice nucleation efficiency of microcline immersed in dilute NH<sub>3</sub> and NH<sub>4</sub><sup>+</sup>-containing solutions

2018 ◽  
Author(s):  
Anand Kumar ◽  
Claudia Marcolli ◽  
Beiping Luo ◽  
Thomas Peter
Keyword(s):  
Volume Fraction ◽  
Pure Water ◽  
Freezing Temperature ◽  
Ice Nucleation ◽  
Ice Melting ◽  
Salt Solutions ◽  
Point Curve ◽  
Mineral Dusts ◽  
Immersion Freezing ◽  
Mixed Phase Clouds

Abstract. Potassium containing feldspars (K-feldspars) have been considered key mineral dusts for ice nucleation (IN) in mixed-phase clouds. To investigate the effect of solutes on their IN efficiency, we performed immersion freezing experiments with the K-feldspar microcline, which is highly IN active. Freezing of emulsified droplets with microcline suspended in aqueous solutions of NH3, (NH4)2SO4, NH4HSO4, NH4NO3, NH4Cl, Na2SO4, H2SO4, K2SO4 and KCl, with solute concentrations corresponding to water activities aw = 0.9–1.0, were investigated by means of a differential scanning calorimeter (DSC). The measured heterogeneous ice nucleation onset temperatures, Thet (aw) deviate strongly from Thet∆awhet (aw), the values calculated from the water-activity-based approach (where Thet∆awhet (aw) = Tmelt (aw + ∆awhet) with a constant offset ∆awhet with respect to the ice melting point curve). Surprisingly, for very dilute solutions of NH3 and NH4+-salts (molalities  ~ 0.96), we find IN temperatures raised by up to 4.5 K above the onset freezing temperature of microcline in pure water (Thet (aw = 1)) and 5.5 K above Thet∆awhet (aw), revealing NH3 and NH4+ to significantly enhance the IN of the microcline surface. Conversely, more concentrated NH3 and NH4+ solutions show a depression of the onset temperature below Thet∆awhet (aw) by as much as 13.5 K caused by a decline in IN ability accompanied with a reduction in the volume fraction of water frozen heterogeneously. All salt solutions not containing NH4+ as cation exhibit nucleation temperatures Thet (aw)  ~ 0.96) at warm (252–257 K) and NH3/NH4+-rich conditions.

Studies on Salt and Water Balance in Myxine Glutinosa (L.)

1965 ◽  
Vol 42 (2) ◽  
pp. 359-371
Author(s):  
R. MORRIS
Keyword(s):  
Water Balance ◽  
Sea Water ◽  
External Medium ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
High Concentration ◽  
After Effects ◽  
Monovalent Ions ◽  
Calcium Magnesium ◽  
Salt And Water Balance

1. Measurements of freezing-point depression and chemical analysis have been made of the plasma and urine of Myxine. 2. The plasma is generally slightly hypertonic to sea water whilst the urine tends to be slightly hypotonic to the blood. 3. The urinary output is low (5·4±1·6 ml./kg./day) and the majority of animals do not swallow sea water. 4. Analyses of plasma and urine indicate that the kidney participates in ionic regulation by reducing the concentrations of calcium, magnesium and sulphate in the plasma relative to sea water. Chloride seems to be conserved whilst potassium may be conserved or excreted. The high concentration of magnesium in the plasma of animals kept in static sea water may be caused by the after effects of urethane. These animals continue to excrete magnesium at normal rates. 5. The rates at which calcium, magnesium and sulphate enter an animal which does not swallow sea water are proportional to the diffusion gradients which exist between the external medium and the plasma. The situation is more complicated for monovalent ions, but there is no evidence of specialized ion-transporting cells within the gill epithelium. 6. In those animals which swallow sea water the amounts of ions absorbed from the gut are very large compared with the renal output and it would therefore seem unlikely that swallowing is part of the normal mechanism of salt and water balance. 7. It is argued that the mechanism of salt and water balance in Myxine is likely to be primitive and that the vertebrate glomerulus was probably developed originally in sea water as an ion-regulating device.

scholarly journals The phenomenon of absorption in its relation to soils: A résumé of the subject

1916 ◽  
Vol 8 (1) ◽  
pp. 111-130 ◽  
Author(s):  
James Arthur Prescott
Keyword(s):  
Specific Gravity ◽  
Sea Water ◽  
Pure Water ◽  
Salt Content ◽  
Garden Soil ◽  
The Subject

Ithas been known from the earliest times that soils would remove salts and colouring matters from solution and the problems arising out of the observations made on this phenomenon were among the earliest to be attacked by agricultural chemists. It was known to Aristotle that sea water lost some of its taste by filtration through sand and this observation seems to have been confirmed and applied in many ways. Lord Bacon in hisSylva Sylvarumdiscussed the question of making sea water potable by filtering through sand. Le Comte de Marsilli made quantitative experiments. Sea water was filtered through fifteen successive vessels of garden soil and a diminution in the salt content was proved by evaporation and by the change in specific gravity. Similar results were obtained with sand. Boyle Godfrey discussed the question of making sea water fit for use on ships and observed that if sea water be put into a stone straining cistern the first pint that runs through will be like pure water, having no taste of salt, but the next pint will be as salt as usual. Stephen Hales in dealing with the same question refers to the use of a soft stone by the Dutch as a filtering material, but he points out that this method has no practical value as only the first portions of the filtrate are free from salt.

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