Can kelp be used to make pork rib soup? It's too small! It can also "capture" carbon dioxide!

Humans have never stopped exploring the ocean. How much do you know about large offshore algae, such as kelp? Let's explore the brown "forest" in the blue ocean and see the great role of small kelp!

Algae is a complex concept of biological groups. It refers to organisms that can carry out photosynthesis in water. According to their size, they can be divided into large algae and microalgae. The well-known marine delicacy - kelp, is a representative of large algae.

Algae come in a variety of forms, including single-celled, "grouped", filamentous and thallus-like, and some advanced algae already have simple organizational structures.

Algae vary greatly in size, with small algae being only a few micrometers in size and visible only under a microscope, while large algae can be seen with the naked eye and can reach a maximum length of over 100 meters.

Algae is a complex biological group , which includes multiple taxonomic units of photosynthetic organisms. First, they are divided into prokaryotes and eukaryotes. Secondly, they can be subdivided from the evolutionary lineage, including cyanobacteria, naked algae, dinoflagellates, golden algae, yellow algae, diatoms, green algae, red algae, brown algae and other different categories. Among them, kelp belongs to the brown algae.

Kelp is one of the important algae products in China . In 2022, China's total algae production was 2.71 million tons, of which 1.74 million tons were kelp, accounting for 64.21% of the total algae production. Although China has abundant seaweed resources and a wide variety of species, with more than 900 species of seaweed distributed in the coastal waters, only 2% of the species have been developed and utilized. The development of seaweed resources is far from being fully utilized.

Although the scale of my country's seaweed industry is small, the industrial chain is complete and widely extended vertically and horizontally. At the same time, the research and development and wide application of seaweed gel products have had a positive impact on the textile industry, food manufacturing industry, cosmetics and other industries, greatly promoting the sustainable development of my country's coastal fishery economy.

However, in recent years, with the development of social economy and the expansion of human activities, problems such as degradation of seaweed germplasm resources, backward production models, deterioration of breeding environment, and frequent diseases have become increasingly serious, bringing new challenges to the algae industry.

A new variety of kelp "Zhongbao No. 1"

Image source: China Society of Oceanology and Limnology WeChat Official Account

At present, we can solve the problem of declining seaweed quality by collecting and evaluating seaweed germplasm and creating new germplasm, and improve the yield per unit area and carbon neutrality capacity of seaweed farming. To develop my country's algae farming industry, we need to broaden our horizons, obtain wild germplasm resources worldwide, improve traditional cultivation techniques, and break through new seaweed germplasm creation technologies to cultivate new varieties with independent intellectual property rights and outstanding quality. Achieving the goal of "improving quality and efficiency, reducing quantity and increasing income" will provide a new direction for the economic value and carbon sink function of algae farming.

Image source: Global Zero Carbon Public Account

We often mention the carbon sink function of algae, so what is algae carbon sink ?

In fact, in addition to meeting our nutritional and food needs, algae farmed in seawater also has an important role, which is to absorb carbon.

Chinese scientists have been studying the carbon sink function of large-scale seaweed farming for more than ten years. Current research shows that farmed algae have the ability to efficiently absorb carbon dioxide and fix carbon in their bodies, thereby prompting the ocean to absorb more carbon dioxide from the atmosphere.

At the same time, the particulate organic carbon produced during the growth of kelp will settle and be buried on the seabed, and the dissolved organic carbon will be converted into inert organic carbon that is difficult to be decomposed by bacteria and will be preserved in the ocean for a long time.

Both factors suggest that kelp farming has an important carbon sink effect.
According to the industry standard "Marine Carbon Sink Accounting Method" implemented on January 1, 2023, large algae such as kelp are included. Based on the calculation method of this standard, the Carbon Neutrality Committee believes that seaweed farming can reduce carbon emissions by 2.6 billion tons per year. It plays a very important role in regulating the global carbon cycle, reducing the concentration of CO2 in the atmosphere, and alleviating global warming.
Therefore, the algae industry provides many natural energy sources for the human world, and we humans should develop, utilize and protect algae to safeguard our future together.

Produced by: Popular Science in China to Benefit Farmers

Scientific Advisor: Associate Researcher Xu Dong, Assistant Researcher Wang Yitao, and Associate Researcher Fan Xiao from the Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences

Co-ordinators: Liao Danfeng, Zheng Fengmao, Wang Changhai, Zhang Ruijie

Planning: Wu Yuetong and Lin Jiaxin

Editor: Yan Shuo (internship)