This article was originally published on the "China Aquatic Products" WeChat public account (ID: fishery1958), the author Liu Yadan, if you need to reprint, please indicate the source.
On the occasion of the 14th World Oceans Day, I would like to talk to my friends about the oceans on which we live. On December 5, 2008, the United Nations officially designated June 8 as World Oceans Day, providing a platform for cooperation for the international community to address ocean challenges. From focusing on the health of the oceans to protecting marine life, Ocean Day reminds everyone from different angles that the oceans are being destroyed, calls on people to protect the oceans, and seriously explores the reasons for the destruction of marine biodiversity, such as from climate change to the impact of human activities on the marine environment.
The mysterious and beautiful ocean is worth exploring
The ocean is a fascinating place, the largest ecosystem on Earth, it provides 99% of the living space for life, and the creatures it possesses range from microbes to the largest animals ever built on Earth. The ocean is also a magical place, with colors ranging from transparent and colorless to colorful, and the temperature difference from condensed icebergs to boiling ocean currents, showing a state ranging from sunny to stormy. The oceans are also affecting us in many different ways, her biodiversity provides us with important food and other natural resources, and her temperature changes affect the climate and weather conditions on which we depend.
As an aquatic worker, I have always had a deep feeling that we know too little about marine life compared to terrestrial life, and there are many more amazing creatures that we need to discover and explore. We just learned some interesting facts from the existing research. For example, 35 animal phylums (such as arthropods and molluscs, etc.) have been found in the ocean, of which 14 phylums can only be found in the ocean; The ocean is home to the largest mammal on Earth, the blue whale, and the largest invertebrate, the king squid; The fastest swimmer in the ocean is the sailfish, which can reach a speed of up to 100 kilometers per hour, almost catching up to the speed of your highway.
Beautiful creatures in the sea – seagrass, seaweed and coral
When we look at The Sea World, we don't know if we notice the beautiful "garden in the sea". The protagonist of the garden is the three beautiful creatures of the sea that I want to re-introduce today — seagrass, seaweed and coral.
Seagrass beds
Seagrass is the only higher angiosperm on Earth that can live entirely in seawater, and they can root, flower, and seed like land plants. Therefore, they can also be as colorful, colorful, and colorful as the flowers and plants on land. There are more than 70 known species of seagrass in the world, belonging to 6 families and 13 genera; There are 22 species of seagrass in China, belonging to 4 families and 10 genera. Scientists have confirmed that the plants on the earth originated in the ocean, and seagrass once survived on land, but in the process of evolution, it became a plant that "went to the sea" again, and its status in plant evolution was as important as that of whales and dolphins. Contiguous seagrasses with large areas are called "seagrass beds".
Morphology of seaweed (Titlyanov et al., 2016)
Seaweed is a large family of marine life. There are more than 8,000 species as small as single-celled diatoms and dinoflagellates that can only be seen under the microscope, and as large as giant algae up to several hundred meters. Brown algae are endemic to the ocean and are characterized by their large size. Macroalgae, mothballs, cystic algae, kelp, and sargassum are representative plants of brown algae. A typical inshore marine ecosystem formed by macrobenthic algae and other marine communities is specifically called "seaweed farms".
Seagrass and seaweed are both plants that grow in the sea, and people often confuse the two plants. How do you make a difference? Simply put, seaweed is a spore plant, usually fixed on the seabed or some solid structure, a single plant or a long string of simple aquatic plants composed of basal cells, and cannot distinguish stems or leaves when they appear in large quantities. Seagrass, on the other hand, is a flowering plant among higher plants, a monocotyledonous herb that lives in shallow waters along the coast of temperate seas, usually with well-developed root systems and underground stems.
Corals are fascinating creatures that sustain biodiversity. There are more than 7,000 species of Anthozoa, a family with many members, and only make their home in the sea. Among the polyps, they are divided into eight coral suborders and six coral subclasses. There are several types such as large hydra-bodied stone corals, small hydra-bodied stone corals, soft corals, and sea anemones. The beauty of corals is incredible, their color and form are not inferior to the various flowers on land, and some coral varieties can also emit amazing fluorescence. Coral reefs form one of the most biodiverse ecosystems on Earth and can be called "rainforests in the ocean".
What are the ecological functions of seagrass, seaweed and coral?
We just focused on the beauty of these three creatures, in fact, they are all beautiful and soft, soft and rigid creatures. In the protection of ecological environment, they play a big role:
Creatures in the seagrass bed Courtesy photo/ Yang Hongsheng
Dugongs that eat seaweed
The seagrass bed can significantly reduce the impact of currents and waves, adjust the flow field characteristics of the sea area, and this inhibition of currents and waves can promote the deposition of the seabed substrate, which has the effect of stabilizing the substrate and the coast, and avoiding the erosion of the coast by the waves. In recent years, the number of bad weather has increased, and the effect of seagrass as a protective line for the coast has become more prominent in protecting the coast and alleviating the harm of natural disasters to humans. Seagrass beds, together with mangroves and coral reefs, make up three typical marine ecosystems. The seagrass bed is an important home for thousands of animals and plants and is a huge gene pool of marine life. Seagrass beds provide an attachment base for epiphytic communities and provide food and habitat for marine animals. In some marine areas, eels can reach a height of more than two meters, forming a vast seagrass bed that is a good habitat for sea cucumbers, shellfish, fish and so on. Seagrass beds can also attract creatures such as giant swans and "mermaid" dugongs.
Seaweed on the seabed Photo courtesy of Dalian Modern Marine Ranch Research Institute
Symbiosis of fish and algae Courtesy of Dalian Modern Marine Ranch Research Institute
Like seagrass beds, seaweed farms have many ecological functions. Algae farms are spawning grounds for many fish, shellfish and juvenile fish breeding grounds. Algae farms can provide natural food for aquatic organisms, some aquatic organisms live in the algae fields for life, and some aquatic organisms grow up and gradually move to the deep sea or the open sea. Seaweed produces oxygen in photosynthesis, and these dissolved oxygen not only provide oxygen for the growth of other organisms, but also regulate the oxygen-poor state of the middle and bottom water and the anaerobic state of the subsoil, so that the original deterioration of the substrate and water quality can be improved, thereby restoring the ecological environment. Algae farms can also alleviate the occurrence of red tides.
Corals are particularly prominent in their ecological function. Coral reefs are home to many marine life, providing a place for many fish and marine invertebrates to spawn, breed and escape predators, maintaining marine biodiversity. According to statistics, the world's coral reefs, with 0.25% of the ocean area, support more than 1/4 of the species of marine life. As a natural coastal barrier, coral reefs have the potential to dissipate wave energy, reduce coastal erosion, and protect subtropical coastlines, which is crucial to homeland security.
In addition, seagrass beds, seaweed farms, and coral reefs are the main forces of blue carbon. As a key link in the carbon and nitrogen cycle and energy flow, it has the ability to help improve the self-regulation of the marine environment.
What are the economic benefits of seagrass, seaweed and coral?
Delicious kelp shreds
First of all, compound feed with seagrass as raw material has become an important bait in the breeding of sea treasures, and will be further explored for use in livestock breeding. The seagrass bed has a strong ability to purify water quality, contributing to the green development of marine aquaculture. Seagrass resources have also led to the development of related processing industries, such as thermal insulation and rainproof products, and handicrafts woven with seagrass are also important products for export earnings. The edible and medicinal value of seaweed and seaweed is also being actively developed and utilized. Seaweed is a vegetable that is very nutritious to the human body. The health care products, medicines, beauty and skin care products processed by seaweed are loved by consumers. Scientists in the United States are even studying fungi and microbes on seagrass for active ingredients in the fight against cancer and other diseases.
Similarly, benthic organisms attached to the surface of coral reefs, such as algae and polychaetes, are important marine baits, attracting many marine fish to breed here, and are important producers of aquatic products. In addition, coral reefs are also a treasure trove of raw materials for some industrial and new marine medicines. Coral reefs also play a large economic role in recreational fisheries.
The most beautiful and fragile marine ecosystem
Seagrass, seaweed and coral are beautiful, sensitive and fragile, and they are one of the most sensitive environmental indicators of global climate change. Often, scientific studies have found that seagrass beds are gradually disappearing and seaweed species are decreasing. There are also studies that show that about 20% of the world's corals are extinct, and the world's well-preserved coral reef system is now difficult to find. Nearly 60% of the world's corals are expected to die by 2030.
The author shoots
On this special day, we remind everyone to pay attention to the "Garden in the Sea", hoping that everyone can work hard to protect and restore seagrass beds, seaweed fields and coral reefs to make them healthier and more beautiful! As aquatic workers, we also have to think about how to better play their marine ecological functions and economic benefits. Natural disasters have decreased, we have more edible aquatic products, more animals and plants in the water that can be admired, and the relationship between human beings and nature has become closer.
Author: Liu Yadan, Researcher, National Chief Science Communication Expert
Source: China Fisheries Magazine