Algo esta contaminando el agua en la playa. No estoy seguro de que esa cosa es, pero creo que es una especie de algas marinas.

No se si esa cosa es peligrosa o no, pero todo lo que veo esta cubierto de esa cosa.
Based on the information provided, it seems that the contaminant in the water is a species of marine algae. More specifically, it could be a type of dinoflagellate, which are single-celled organisms belonging to the superclass Dinoflagellata. Dinoflagellates have two flagella, one in the sulcus and one in the cingulum, and can be either naked ore.

To determine the specific type of dinoflagellate, we can look at its order. Based on the description, it sounds like the organism could be in the order Blastodiniales. However, without further observation or testing, we cannot be certain.

Therefore, the contaminant in the water could potentially be a species of dinoflagellate from the order Blastodiniales.

For further information, please refer to the following pages:

Dinoflagellata
Dinophyceae