Are there any biological factors at play? For example, how do the toxins that some species involved in red waves release affect the organisms that eat them?
Yes, there are biological factors at play in the context of red tides. Red tides are caused by the rapid growth and accumulation of certain species of microscopic algae, called dinoflagellates, in marine or freshwater environments. These dinoflagellates can produce toxins as a byproduct of their metabolism.
When the dinoflagellate cells rupture or die, they release these toxins into the surrounding water. The specific types of toxins produced can vary depending on the species involved in the red tide. Some common types of toxins include saxitoxins, brevetoxins, domoic acid, and ciguatoxins.
The impact of these toxins on organisms that eat the affected organisms (such as filter-feeding shellfish or fish that consume the algae) can be detrimental. Consumption of toxin-contaminated seafood by humans can lead to various forms of shellfish poisoning, such as paralytic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning, or ciguatera fish poisoning.
These toxins can affect the nervous system, liver, or other organs of animals that ingest them, leading to sickness or even death. For example, harmful algal bloom toxins can cause neurotoxic symptoms like tingling, numbness, dizziness, or even paralysis in humans. The severity of the effects depends on the concentration and type of toxin, as well as individual susceptibilities.
Additionally, some marine organisms have developed resistance to these toxins, allowing them to feed on the affected organisms without being affected. This is an example of coevolution, as these organisms have developed strategies to counteract the harmful effects of the toxins over time.