Red tide is a phenomenon in which the color of the ocean turns red due to an increase in plankton and other red tide organisms, and is primarily caused by insolation, water temperature, and eutrophication. It destroys marine ecosystems and harms underwater life, and requires nutrient discharge regulations and environmental improvements to prevent it.
The oceans are intimately connected to human life. They have played an important role in feeding us, providing transportation, and even influencing our climate. However, in recent years, the oceans have been sending us more and more abnormal signals. One of them is red tide, a phenomenon where the ocean turns red. Red tide is one of the most prominent examples of humanity’s negative impact on ocean ecosystems, exacerbated not only by natural factors but also by human activities. We need to better understand this phenomenon, which turns the ocean red, to find its underlying causes and solutions.
What is red tide, why does it happen, and how can it be prevented? Red tides can be caused by red tide organisms such as plankton, bacteria, and ciliates. In most cases, it’s a rapid increase in the number of phytoplankton that causes the color of the ocean, rivers, lakes, etc. to turn red or brown. This phenomenon is more than just a change in water color; it has a wide range of effects on the ecosystem as a whole.
Red tides can be caused by a rapid increase in the number of phytoplankton, which may not change color if they are widely dispersed. However, when the density of red tide organisms reaches 3 parts per million (ppm) or more, the color change becomes noticeable enough to be visible to the naked eye. In this case, the red color of the ocean becomes even more intense, and it’s not just a biological phenomenon, but an environmental issue.
So, how does red tide happen? There are many theories, but they all point to the same factors: the right amount of insolation, water temperature, and eutrophication. Phytoplankton get their energy from photosynthesis, so the number of plankton increases dramatically in waters where photosynthesis is active. These conditions naturally align during spring and summer, when water temperatures between 15 and 25 degrees Celsius are optimal for the growth of red tide organisms. While red tide can occur as part of a natural cycle, human activity is a major contributor to its increasing frequency.
Just as we fertilize our plants to encourage growth, eutrophication in the ocean provides more nutrients to red tide organisms, such as plankton, than they need. Eutrophication can occur naturally, but it is mainly caused by an increase in the amount of nitrates or phosphates in the ocean due to waste from human activities. With this eutrophication as the main factor, red tides become more frequent and intense.
Red tides cause a variety of damages. One of the most common is the death of aquatic life. Overgrowth of red tide can lead to a decrease in dissolved oxygen, which can suffocate aquatic organisms such as fish, or they can be directly harmed by toxic red tide algae. In particular, algae such as Cochlodinium can cause fish to secrete a mucous substance on their gills that impedes their breathing, or toxic substances can paralyze them, resulting in death. The damage isn’t just limited to fish kills; it can have a negative impact on the entire ecosystem.
Red tides are also deadly to underwater plants. When red tide covers the water’s surface, sunlight cannot penetrate the water, inhibiting photosynthesis in underwater plants, which leads to their death. This is a major factor in unbalancing the ecosystem and can lead to the collapse of marine ecosystems in the long run.
To reduce the damage caused by red tide, we need to introduce red tide warnings and take practical measures to prevent it. Red tide warnings can be used to minimize the damage by moving farmed fish to safer areas in advance, or shading can be used to inhibit the growth of red tide algae. However, these are only temporary measures and are not a permanent solution.
Therefore, to prevent red tide from occurring in the first place, human activities need to be regulated. Regulating nitrogen and phosphorus emissions and dredging low-quality soils to prevent nutrient overloads are necessary. In addition, sewage and manure treatment facilities need to be improved to prevent organic matter and heavy metals from entering the ocean. These measures will not only prevent red tide, but will also play an important role in restoring ocean ecosystems and protecting the global environment.
In this blog post, we’ve discussed the causes of red tide, its effects, and how to prevent it. In the right amounts, red tide organisms become food for predators in the ecosystem and are part of the cycle. But in excessive amounts, it can disrupt the ecosystem and upset the balance of the ocean. It’s important to recognize that red tide is not just a natural phenomenon, but a problem caused by human activity. If we make efforts to prevent red tide, the ocean will return its blue color to us once again.
