Freezing-induced acidification of sea ice brine

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985904%3A_____%2F24%3A00587907" target="_blank" >RIV/67985904:_____/24:00587907 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/24:00137406

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0048969724043420?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0048969724043420?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.scitotenv.2024.174194" target="_blank" >10.1016/j.scitotenv.2024.174194</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Freezing-induced acidification of sea ice brine

Popis výsledku v původním jazyce

The acidity of sea ice and snow plays a key role in the chemistry of the cryosphere, an important example lies in the photochemical catalytic release of reactive bromine in polar regions, facilitated at pHs below 6.5. We apply in-situ acid-base indicators to probe the microscopic acidity of the brine within the ice matrix in artificial sea water at a range of concentrations (0.35-70 PPT) and initial pHs (6-9). The results are supported by analogous measurements of the most abundant salts in seawater: NaCl, Na2SO4, and CaCO3. In the research herein, the acidity is expressed in terms of the Hammett acidity function, H2- . The obtained results show a pronounced acidity increase in sea water after freezing at -15 degrees C and during the subsequent cooling down to -50 degrees C. Importantly, we did not observe any significant hysteresis, the values of acidity upon warming markedly resembled those at the corresponding temperatures at cooling. The acidity increase is attributed to the minerals' crystallization, which is accompanied by a loss of the buffering capacity. Our observations show that lower salinity sea water samples (<= 3.5 PPT) reach pH values below 6.5 at the temperature of -15 degrees C, whereas higher salinity ices attain such values only at -30 degrees C. The ensuing implications for polar chemistry and the relevance to the field measurements are discussed.

Název v anglickém jazyce

Freezing-induced acidification of sea ice brine

Popis výsledku anglicky

The acidity of sea ice and snow plays a key role in the chemistry of the cryosphere, an important example lies in the photochemical catalytic release of reactive bromine in polar regions, facilitated at pHs below 6.5. We apply in-situ acid-base indicators to probe the microscopic acidity of the brine within the ice matrix in artificial sea water at a range of concentrations (0.35-70 PPT) and initial pHs (6-9). The results are supported by analogous measurements of the most abundant salts in seawater: NaCl, Na2SO4, and CaCO3. In the research herein, the acidity is expressed in terms of the Hammett acidity function, H2- . The obtained results show a pronounced acidity increase in sea water after freezing at -15 degrees C and during the subsequent cooling down to -50 degrees C. Importantly, we did not observe any significant hysteresis, the values of acidity upon warming markedly resembled those at the corresponding temperatures at cooling. The acidity increase is attributed to the minerals' crystallization, which is accompanied by a loss of the buffering capacity. Our observations show that lower salinity sea water samples (<= 3.5 PPT) reach pH values below 6.5 at the temperature of -15 degrees C, whereas higher salinity ices attain such values only at -30 degrees C. The ensuing implications for polar chemistry and the relevance to the field measurements are discussed.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10613 - Zoology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Science of the Total Environment

ISSN

0048-9697

e-ISSN

1879-1026

Svazek periodika

946

Číslo periodika v rámci svazku

OCT 10

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

14

Strana od-do

174194

Kód UT WoS článku

001266508700001

EID výsledku v databázi Scopus

2-s2.0-85196803827