When hearing the term “red tide”, you might picture a beautiful red sea that belongs to a magical world, out of a fantasy novel. Or maybe it could seem like it belongs in a horror movie instead. However, it is not quite either of those. It is a very real natural phenomenon that occurs in our oceans and affects ocean life, has deep ecological impact, and can sometimes impact people too.
In this article, we will discuss a little bit about the red tide that happens in the Pacific ocean of Costa Rica as well as in other parts of the world. What is it that you should know when visiting the country during red tide season?
What Is the Red Tide?
The National Ocean Service from the U.S. National Oceanic and Atmospheric Administration explains the natural phenomenon, known as the “red tide”, as a proliferation in the growth of certain harmful algae in the oceans. While most algae are harmless, even beneficial for the ecosystems in which they exist, the microscopic algae responsible for this red tide phenomenon cause detrimental effects for both the fish and shellfish and for the humans who consume them.
According to this article by National Geographic, there are four algae species that cause red tide. Three species known as dinoflagellates and one species from the diatom group. While the dinoflagellate species are responsible for a lot of oxygen production in the oceans, when they overgrow, they end up releasing toxins.
The red tide is problematic because it causes a lot of chain effects. Dinoflagellates and diatoms, as well as some other species of phytoplankton, are the main source of food for a lot of oceanic wildlife. The toxins these algae release, as a result of their abundant growth, affect their main predator’s fish and shellfish, and some even die. Then poisoned fish also intoxicate the species that feed on them, such as some bigger types of fish or turtles. Eventually, if people eat those shellfish and fish, they can also get intoxicated and sick.
Other issues related to red tide are the damaging effects this phenomenon has on corals. As algae multiply rapidly, they cover the ocean surface and block the sunlight from reaching deeper regions. Since corals survive by photosynthesis, this lack of sunlight severely affects their living cycle. When they become unable to get the resources they need for survival, the corals eventually die.
Where does the name red tide come from?
When some of the species of algae mentioned above grow, they can make some areas of the ocean take on a reddish tint, and when the waves crash to the coast, they may look reddish. However, “red tide” doesn’t always mean red oceans. Sometimes, they turn brownish instead, and sometimes they don’t change color at all. However, the term “red tide” was coined to refer to this phenomenon anyway, all due to the few species that do cause a transformation in the oceanic color. While this term has become common, some experts argue it’s quite misconceiving. A better term to refer to it would be Harmful Algae Bloom (HAB).
What Causes Harmful Algal Bloom (HAB)?
As mentioned before, HABs are caused by the multiplication of certain algae species at an abnormal rate on the ocean surface. While it is a phenomenon that can occur naturally and has been happening even before humans could create a lasting effect on the ecosystems, some experts from the Marine Conservation & Education Center (MCEC) say it has been happening more frequently and lasting for longer periods than it should.
The reasons behind this long-lasting period of HABs could be both environment and human-related. Recently in Costa Rica there has been an abundant amount of rainfall. In addition, traces of pesticides and agrochemical products used in agriculture eventually reach the oceans. Both the heavy rainfall and the agrochemicals provide the algae with an excessive amount of nutrients that result in the overgrown phytoplankton population.
In Costa Rica, HABs can usually take place at some point in the country’s dry season, from December to March.
What Precautions Can Be Taken Against HABs?
It is not necessarily easy to tell if a particular portion of water is affected by HABs just by looking at it. In some cases, there is some algae growth that is not harmful like HABs, but telling the two apart is difficult without more in-depth examinations.
HABs happen worldwide and they can affect humans and animals differently depending on the type of exposure they have to the phenomenon. On one hand, it is recommended to avoid swimming in affected waters. While HABs aren’t necessarily toxic to humans upon skin contact, they can cause skin irritation. Other symptoms like throat, eye, and ear irritation could also take place. On the other hand, if you ingest either contaminated seafood or water, it could lead to more severe effects and sickness, including food poisoning.
Even if you happen to visit the country during a period of “red tide” or HABs, there is no need to worry. Costa Rica has more than 600 beaches you can visit both in the Caribbean and the Pacific coasts. Even with HABs, a trip to the beach can be perfectly enjoyable and relaxing, and not every beach is affected by “red tide”.
Costa Rica is not only a great vacation destination, but it is also one of the best in the world to visit. You can also opt for other alternatives to sea activities, like visiting National Parks, animal watching, or even packing up for an unforgettable road trip.
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