For those without a green thumb, it takes several things to make plants (or algae grow). These are sunlight, nutrients, and water. In the middle of the ocean there is plenty of water and on the surface plenty of sunlight, the problem is lack of nutrients. For almost three decades, oceanographers have been puzzled by the ability of microscopic algae to grow in mid-ocean areas where there is very little nitrate, an essential algal nutrient. In a recent issue of Nature, oceanographer Ken Johnson, along with coauthors Stephen Riser at the University of Washington and David Karl at the University of Hawaii, show that mid-ocean algae obtain nitrate from deep water, as much as 800 feet below the surface.