The upper ocean has lower concentrations of total carbon than the deep ocean as a result of this pump. Global climate models suggest that as temperatures rise, the interiors of continents will become hotter and drier, which would result in greater amounts of dust being blown out to sea. In turn, more iron dust settling in the ocean would greatly enhance phytoplankton productivity, thus slowing the rate of carbon dioxide increase in the atmosphere. In summary, in continental dust, nature may have a negative feedback mechanism that it uses to delay or even reverse global warming trends. As incoming sunlight warms the ocean's surface, water evaporates into a gas that rises up into the atmosphere.
Wind blowing across the face of the ocean produces a fine mist of sea spray in the lower atmosphere.
Later, when the surrounding air cools, or when the surrounding air can hold no more evaporated water, condensation occurs and water droplets begin to aggregate onto aerosol particles, forming clouds. Windblown dust from deserts, dry landscapes and pollution sources often settles into the ocean. This dust is rich in iron and other nutrients that, much like fertilizer, enhance phytoplankton growth. When phytoplankton die, their microscopic bodies settle to the bottom. But cold, upwelling currents carry some of this carbon back up toward the surface where it may again be used as a source of nutrition for phytoplankton, or even escape back into the atmosphere again in the form of carbon dioxide.