All of the following are abiotic factors in an ecosystem except:

Algae

pH

Salinity

Climate

The answer is Algae.

Abiotic factors are non-living things of an ecosystem. Abiotic factors include landscape, climate, pH, salinity and other physical features of the ecosystem. On the other hand, there are b iotic factors. Biotic factors are living things in the ecosystem. Those are plants, animals, and other organisms. Since Algae are living-things, they are biotic factors unlike pH, salinity, and climate which are abiotic factors.