A study was conducted to evaluate the impact of different concentrations of salt water on the growth of a particular species of marine algae. Researchers set up five tanks with varying salt concentrations: 0, 1, 2, 3, and 4 grams of salt per liter of water. Over a period of two weeks, they measured the growth of the algae in each tank in terms of biomass (grams).

At the end of the study, the results showed that the algae in tanks with 1 gram of salt per liter experienced the most growth, while those in the highest concentration (4 grams) had significantly less growth than all other groups.

Based on this study, what can be inferred about the effect of salt concentration on the growth of this marine algae?