Sargassum Is Stressed

For years, the Caribbean has been stressing about Sargassum. Now it turns out Sargassum has been stressing too. And, like many of us under pressure, she starts making questionable dietary choices. The problem appears to involve phosphorus. Phosphorus is essential for growth, and pelagic Sargassum can become phosphorus-limited when there isn’t enough available in the waters where it grows. Scientists have even shown that adding phosphate to phosphorus-limited Sargassum can increase growth and photosynthesis. So our ugly sister is stressed. She’s hungry. And unfortunately, she’s also terrible at grocery shopping. Phosphate has a chemical lookalike: arsenate. They’re similar enough that the biological mechanisms involved in acquiring phosphorus can also interact with arsenate. Research has found a relationship between phosphorus stress and arsenic accumulation in Atlantic Sargassum. Basically, she’s looking for phosphorus and occasionally comes home with arsenic. “They looked similar on the label.” Which makes the arsenic problem even more interesting. What Sargassum accumulates can be influenced by the nutrient conditions it experiences while drifting across the Atlantic. Researchers have even proposed arsenic levels in Sargassum as an indicator of phosphorus limitation. Working with Sargassum keeps getting more interesting. Now we find out she’s stressed too. At Thalasso AS, we’ll work on the processing. We’ll leave the therapy to someone else.