How does seawater alkalinity affect marine life?
Seawater alkalinity stabilizes pH levels, supporting marine life health by preventing harmful fluctuations. It ensures suitable conditions for calcium carbonate shell and skeleton formation in organisms like corals and mollusks. However, shifts in alkalinity, often due to ocean acidification, can impair these processes, threatening marine biodiversity.
How does seawater alkalinity impact the ocean's ability to absorb carbon dioxide?
Seawater alkalinity enhances the ocean's ability to absorb carbon dioxide by buffering pH changes and facilitating the conversion of CO2 into bicarbonate and carbonate ions. This process helps maintain stable ocean chemistry and increases the ocean's capacity to store carbon, mitigating atmospheric CO2 levels and climate change.
What causes changes in seawater alkalinity?
Changes in seawater alkalinity are primarily caused by processes such as weathering of rocks, riverine inputs, biological activity (e.g., shell and coral formation), and anthropogenic influences like CO2 emissions. These processes add or remove bicarbonate and carbonate ions, altering seawater's buffering capacity.
How is seawater alkalinity measured?
Seawater alkalinity is measured using titration with a strong acid, typically hydrochloric acid, to a specific pH endpoint. The total amount of acid used reflects the seawater's buffering capacity and allows calculation of alkalinity, often determined using an automatic titrator and spectrophotometric or potentiometric methods.
How does climate change influence seawater alkalinity?
Climate change affects seawater alkalinity primarily through ocean acidification, which results from increased atmospheric CO2 being absorbed by oceans, lowering pH levels and buffering capacity. Additionally, changes in temperature and ice melt can alter seawater composition and circulation, influencing alkalinity distribution and balance in marine environments.