We have even less information regarding the actual cycling of P by marine biota. Atmospheric Phosphorus deposition One aspect of my research involves understanding the temporal and spatial distribution of atmospheric P deposition. There are currently few measurements of atmospheric P deposition to either terrestrial or oceanic ecosystems. In the open ocean, there are only two ways of introducing P into the upper ocean, via upwelling of P rich waters from below and from the atmospheric deposition of P from above. If there is a transition from N to P limitation of plankton in surface waters, then understanding the sources of P becomes increasingly important.
Terrestrial systems obtain nutrients from either the soil or from atmospheric deposition.
The Hawaiian Island Chain has been used as a model ecosystem for elucidating changing nutrient sources over time. The Hawaiian Islands are a volcanically produced island chain remotely located in the middle of the North Pacific Ocean. One of the greatest obstacles in terrestrial ecosystem research today is understanding not only nutrient sources, but also the flux of nutrients between various atmospheric and terrestrial reservoirs. Often there are too many variables to fully constrain which nutrient uptake and removal processes are the most important within an ecological region. As a result, increasing dependence on atmospheric nutrient deposition results in a more P-limited ecosystem as the substrate ages.