BIO-8 Lecture Notes - Lecture 28: Hemoglobin, Thermal Pollution, Body Plan
Document Summary
The uptake of gases from water is limited by diffusion. Co2 rapidly converts to bicarbonate (hco3-) or carbonate (co3-) ions, which can be used for photosynthesis. Even when co2 and bicarbonate ions are abundant in water, the slow rate at which these carbon sources diffuse through the water prevents organisms from getting access to them they diffuse slowly and limit plant growth. Carbonic acid can increase to high concentrations and provide a reservoir of carbon required for photosynthesis. Bicarbonate ions dissolve readily in water, so bicarbonate ion is the most common form of inorganic carbon in aquatic habitats. Boundary layer - a region of unstirred air or water that surrounds the surface of an object. Removed gases from this region are slow to be replaced; this further limits carbon availability. Oxygen (o2) in air is 21% by volume; in water only 1% Low solubility and slow diffusion of oxygen can limit metabolism of organisms that obtain oxygen from the water.
