A Climatic Gradient as a Proxy for Climate Change Effects

Climate models predict a hotter, drier climate in the southwestern USA: so what will change in estuaries? There is probably no better place on Earth to compare effects caused by altered inflow than the Texas coast, because the major estuarine systems lie in a climatic gradient where runoff decreases 56 fold from the Louisiana border in the northeast to the Mexico border in the southwest. This results in a gradient of four subregions where the inflow balance in estuaries ranges from strongly positive, moderately positive, neutral, to negative. Thus, nature has provided a perfect experimental design to compare estuarine processes that change in relation to freshwater inflow. Assuming change along the inflow gradient is analogous to effects of dewatering over time, we can identify ecosystem change as a function of dewatering. Over the past 30 years, it has been discovered that we can expect increased acidification and hypoxia, but decreased benthos.