Estuarine_acidification
Estuarine acidification
Reducing pH values in coastal marine ecosystems
Estuarine acidification happens when the pH balance of water in coastal marine ecosystems, specifically those of estuaries, decreases. Water, generally considered neutral on the pH scale, normally perfectly balanced between alkalinity and acidity. While ocean acidification occurs due to the ongoing decrease in the pH of the Earth's oceans, caused by the absorption of carbon dioxide (CO2) from the atmosphere,[1] pH change in estuaries is more complicated than in the open ocean due to direct impacts from land run-off, human impact, and coastal current dynamics. In the ocean, wave and wind movement allows carbon dioxide (CO2) to mixes with water (H2O) forming carbonic acid (H2CO3). Through wave motion this chemical bond is mixed up, allowing for the further break of the bond, eventually becoming carbonate (CO3) which is basic and helps form shells for ocean creatures, and two hydron molecules. This creates the potential for acidic threat since hydron ions readily bond with any Lewis Structure to form an acidic bond. [2] This is referred to as an oxidation-reduction reaction.
This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)
|
The basic chemical equation is as follows:
- CO2 + H2O ⇌ H2CO3 ⇌ HCO3 + H+ ⇌ CO3 + 2 H+
When this pattern of absorption is transferred into an estuary, however, acidity increases simply due to relative volume. Ocean water counts for the absorption of 30-40 percent of all CO2 emitted into the atmosphere and yet, due to its immense volume, it remains relatively resilient. [3] Estuaries - being smaller by volume, sheltered from wave motion, and victim to human impact when in an urban setting - do not readily support the mixing of water, and thereby prevents basic breakdown. [4] When this is combined with CO2 from human impact such as car emissions or fertilizers, oxidation more readily occurs due to the overabundance of hydron ions and additional cation, increasing the rate of occurrence and duration of acidification taking place. [5] As the acidity of estuarine water levels continues to fluctuate, several species who use estuaries as spawning nurseries have seen decreases in reproduction levels. [6]