seawaterlike

Seawaterlike is an adjective used to describe a material, environment, or growth medium that resembles natural seawater, particularly in salinity, ionic composition, and chemical behavior. The term is common in oceanography, marine biology, chemistry, and materials testing when precise seawater–like conditions are needed without using actual seawater.

Natural seawater typically has a salinity of about 34 to 37 practical salinity units (psu), corresponding to roughly 35 grams of dissolved salts per liter. Its major ions, in approximate order of abundance, are chloride, sodium, sulfate, magnesium, calcium, and potassium, with chloride and sodium accounting for the largest fractions. Seawater also contains bicarbonate, borate, and trace elements, as well as dissolved organic matter and nutrients. The pH is around 8.1, and the density near the surface is about 1.025 g/mL, both of which vary with temperature and salinity.

Seawaterlike materials include artificial seawater (ASW) formulations used in aquaculture and laboratory culture of marine organisms, as well as testing environments for corrosion, ballast-water studies, and marine environmental simulations. In research and industry, adjusting salinity and ion ratios allows scientists to reproduce seawater conditions, study organism tolerance, or evaluate material performance under oceanic conditions.

Measurement and standardization of seawaterlike properties rely on established methods for salinity, such as conductivity-based scales, refractometry, and titration. Ionic composition is assessed by ion chromatography or inductively coupled plasma mass spectrometry, while reference seawater compositions provide benchmarks for calibration and comparison.