Soil moisture. Soil moisture affects the soil biota in two ways. Biologically water is essential for life and for enzyme activity and metabolism and, is a solvent for biological nutrients and other chemicals. Physically, soil moisture affects soil temperature (water is good conductor of heat) and soil aeration.oil moisture. Soil moisture affects the soil biota in two ways. Biologically water is essential for life and for enzyme activity and metabolism and, is a solvent for biological nutrients and other chemicals. Physically, soil moisture affects soil temperature (water is good conductor of heat) and soil aeration.
Your blood is actually always red! Blood in your veins has very little oxygen and is a dark red color that looks almost blue when covered by your skin. Your arteries have bright red blood because it has a lot of oxygen in it that is being carried throughout your body to be used by tissues.
You'll notice that the places that you see blue veins are in areas where the skin is thin and the blood vessel underneath is pushing up on it stretching the skin over it. Light hitting the dark color of the vein underneath the skin, in combination with the skin itself is what causes it to appear blue in these areas.