Inflows of nitrate brought to the surface by coastal upwelling are essential for ocean life near the shore. Despite its importance, consistent long-term records of nitrate do not exist for much of the ocean. As a stand-in for direct nitrate concentration measurements, researchers have relied on water temperature measurements because research has shown that there is an inverse relationship between temperature and nitrate concentration. To investigate the viability of using temperature to estimate nitrate concentrations, Palacios et al. studied the region of the California Current, where long-term observations of nitrate going back to 1959 exist. Studies in this region also tracked properties such as temperature and salinity and the concentrations of oxygen, phosphorus, and silicate.