Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Our riparian forest was little affected after the first 10 hours of saltwater exposure in June 2022 and grew normally for the rest of the year. We increased the exposure time to 20 hours in June 2023 and the forest still looks very unaffected, tulip poplar trees they drew water from the soil more slowly, which could be an early warning signal.
After a 30-hour exposure in June 2024, the situation changed. The tulip poplar leaves in the forests began to turn brown in mid-August, several weeks earlier than normal. In mid-September, the forest canopy was bare, as if winter had begun. These changes occurred with fresh water and not with seawater, but not in a nearby area that we treated similarly.
The initial stability of our forest can be partly explained by the relatively low salt content in this estuary, where the waters of freshwater rivers and the salty ocean mix. After the experiments in 2022 and 2023, rain washed away the salts in the soil.
But after the 2024 experiment, there was a major drought, so the salts remained in the soil at that time. Longer exposure of trees to saline soils after our 2024 experiment may have exceeded their ability to tolerate these conditions.
The seawater dumped on Southern California fires is full-strength, salty ocean water. And the conditions there they are very dryespecially compared to our East Coast forest area.
Obvious Changes on Earth
Our research team is still trying to understand all the factors that limit the forest’s saltwater tolerance and how our findings apply to other ecosystems, such as those in the Los Angeles area.
While it was a surprise to see the tree leaves turn from green to brown before autumn, there were other surprises hidden in the ground beneath our feet.
Rainwater seeping into the soil is normally clear, but in 2022, about a month after being exposed to the first and only 10 hours of saline water, the soil water turned brown and remained that way for two years. The brown color comes from carbon-based compounds leached from dead plant material. It is similar to the process of making tea.
