In this blog post, we will look at the causes of red tides and the damage they cause to marine ecosystems, and learn about the fundamental solutions to prevent and mitigate them.
The sea has been closely linked to human life. It has played an important role in providing food, transportation, and even influencing the climate. However, recently, abnormal signals from the sea have become more frequent. One of them is the phenomenon of the sea turning red, or red tide. Red tide is one of the most representative examples of the negative impact of human activity on the marine ecosystem, and it is being exacerbated not only by natural factors but also by human activity. We need to understand this phenomenon of the sea turning red in detail and find the root causes and solutions.
What is red tide, why does it occur, and how can it be prevented? Red tide can be caused by red algae, bacteria, and dinoflagellates. In most cases, this phenomenon refers to the rapid increase in the number of phytoplankton, which causes the color of the sea, rivers, lakes, etc. to turn red or brown. This phenomenon does not stop at a simple change in water color, but has a variety of effects across the ecosystem.
Red tide may not change color if the phytoplankton are widely dispersed even if the number of phytoplankton increases rapidly. However, when the volume density of red tide organisms is 3 ppm or higher, the color change is so pronounced that the red tide phenomenon can be seen with the naked eye. When red tide organisms gather in such a concentrated manner, the redness of the sea becomes even more intense, and this leads to environmental problems that are not just biological phenomena.
So how does red tide occur? There are various theories, but the theories on red tide all point to adequate insolation, water temperature, and eutrophication as the causes of red tide. Phytoplankton obtain energy through photosynthesis, so the number of plankton increases rapidly in water bodies where photosynthesis is active. These conditions naturally coincide mainly in spring and summer, and in particular, water temperatures between 15°C and 25°C are optimal for the growth of red tide organisms. Although red tide can occur in the natural cycle, human activity is considered to be the main cause of its frequency.
Just as we fertilize plants to promote their growth, eutrophication in the ocean supplies more nutrients than necessary to red tide organisms such as plankton. Eutrophication can occur naturally, but it is mainly caused by the increase in the amount of nitrate or phosphate in the ocean due to waste from human activities. This eutrophication is the main factor that causes red tides to occur more frequently and more intensely.
When red tides occur, various damages occur. The death of aquatic organisms is one of the most representative damages. When red tide organisms overgrow, the amount of dissolved oxygen decreases, causing aquatic organisms such as fish to suffocate, or they may be directly harmed by toxic red tide organisms. In particular, algae such as coccolodinium secrete mucous substances in the gills, which can interfere with the fish’s breathing, or cause paralysis of the nerves due to toxic substances, resulting in death. Such damage does not stop at the death of the fish, but has adverse effects on the entire ecosystem.
Red tides are also deadly to underwater plants. When red tide organisms cover the surface of the water, sunlight cannot penetrate into the water, inhibiting the photosynthesis of underwater plants, which ultimately leads to the death of the plants. This acts as an important factor in the breakdown of the ecosystem and can lead to the collapse of the marine ecosystem in the long term.
To reduce damage from red tide, a red tide warning system should be introduced and practical prevention measures should be put in place. A red tide warning system can minimize damage by moving farmed fish to a safe place in advance, or by installing a shading net to suppress the growth of red tide organisms. However, these methods are only temporary solutions and cannot be a fundamental solution.
Therefore, in order to fundamentally prevent the red tide phenomenon, it is necessary to regulate human activities. It is necessary to regulate the discharge of nitrogen and phosphorus and prevent the over-supply of nutrients by dredging the low-quality soil. In addition, organic matter and heavy metals must not be released into the sea by improving sewage treatment facilities and manure treatment facilities. These measures will not only prevent red tides, but also play an important role in restoring the marine ecosystem and protecting the global environment.
In this blog post, we looked at the causes of red tides, the damage they cause, and the measures to prevent them. The right amount of red tide organisms become food for predators in the ecosystem and are part of the cycle. However, excessive amounts can disrupt the ecosystem and destroy the balance of the ocean. We must recognize that red tides are not just a natural phenomenon, but a problem caused by human activity. If we make efforts to prevent red tides, the ocean will once again return its blue color to us.
