Tropical ocean waters have become dramatically saltier over the past 40 years, while oceans closer to Earth's poles have become fresher, scientists reported today in the journal Nature. Earth's ...

Notes: the subfigure shows an example of acidic soil areas defined by the World Reference Base for Soil Resources; the scatterplot shows the salt content of soil samples in five climate regions. A ...

A salt is a compound composed of positively and negatively charged ions (e.g., sodium (Na⁺) and chloride (Cl⁻)). While plants require soluble salts as nutrients, excessive amounts—referred to as soil ...