The coastal zone is the point of entry of different elements that are generated in the land area of influence (waste of human activities, dragging of sediments by rain wash).

In arid or semi-arid areas, tropical rain is important because it takes organic material and sediments in its drainage to the coastal area. Drainage is capable of modifying, temporarily or permanently, the shape of the coastline (sediments) and the quality of the water that receives these contributions (nitrogen, phosphorus); at the same time it can promote changes in the populations of marine organisms (red tides).

Another process that is not evident but important is underground flow. Fresh water supply for the populations of arid areas comes from the water stored in aquifers exploited by wells. A fraction of this underground water is partially or constantly dumped into the sea, introducing higher concentrations of nitrogen and phosphorus. This process is practically unknown to arid areas, thus its study could value the importance of changes in coastal marine water quality.

Tropical storm over La Paz, BCS:
How does coastal water quality change after rainfall drainage?
Photograph from project file.

In this line of research, we study these four processes:

1. Growth or erosion pattern of the coastal area due to changes in the natural contribution of sand and by construction of coastal urban infrastructure;

2. Effects on environmental quality of the coastal area by nitrogen and phosphorus contributions that come from basin drainage and by the influence of human activities (agriculture, aquaculture, urban growth);

3. Changes in mangrove communities, and biomarkers of environmental trend, and

4. Effects of nitrogen and phosphorus contributions in the presence and probable increase of red tides and their consequences in other economically important marine organisms (toxins in mollusks, death of sea fish), as well as their consequences in human health (intoxication by toxin content consumption in mollusks and fish).