Understand brown algae
Brown algae is a genus of algae. The cells contain chlorophyll a, chlorophyll c, carotene, fucoxanthin and a large amount of lutein, etc. The color of the algae varies greatly due to the different proportions of various pigments contained, ranging from yellowish brown to dark brown. The products of photosynthesis are laminarin (also known as fucoidan/fucoidan/fucoidan) and mannitol. Most of them are seafood, with about 250 genera and 1,500 species existing, and only 8 species are freshwater products. There are about 80 genera and 250 species of Chinese seafood, and 2 species of freshwater species, namely lamellae and blackhead algae, were both found in the Jialing River in Beibei, Sichuan. Classification of brown algae
Members of the phylum Phaeophyta are a group of higher-level algae, with about 1,500 species distributed in cold water bodies along the coast of the continent. Freshwater species are rare. Its color depends on the ratio of brown pigment (fucoxanthin) and green pigment (chlorophyll), gradually appearing from dark brown to olive green. The inflated air bladders allow the photosynthetic portion of the frond to float at or near the water surface. Brown algae come in a variety of shapes and sizes, ranging from heterofilatric epiphytes (genus Hydroxylum) to complex, giant macro-brown algae ranging from 1 to 100 meters in length (genus Laminaria, Macrophysis and Nerocystis). Rockweed is a type of brown algae that grows floating (Sargassum) or epiphytes on rocky shores (Fucus, Ascophyllum). Brown algae reproduce asexually and sexually; both zoospores and gametes have two flagella of unequal length. Brown algae were once a major source of iodine and potassium, and are still an important source of algin, a gel used as a stabilizer in food baking and ice cream manufacturing. Some species are used as fertilizers, and several are used as vegetables in the East (Laminaria). Brown algae of the order Laminariales are commonly known as large brown algae (kelps).
Common algae in brown algae
There are about 250 genera and 1,500 species of Phaeophyta. Except for a few species that live in freshwater, most seafood is the main component of underwater forests. According to the presence and type of their generational alternation, they are generally divided into three classes, namely, the equal-generation class, the unequal-generation class and the aposporous class.
In the past, brown algae were divided into 3 classes and 11 orders based on the presence and type of generational alternation in the life history. Those with homomorphic generational alternation in the life history were classified into the homogenous class, and those with heteromorphic generational alternation in the life history were classified into The class Cyclospora, which only has sexual reproduction but no alternation of generations, belongs to the class Cyclospora. However, it is not comprehensive enough to only use life history as the basis for classification. For example, there are equal-generation types and unequal-generation types in the life history of Verdinophales.
Schefflera
In recent years, phycologists from various countries have not agreed on the classification of brown algae taxonomic units. Some still believe that it is a class of Chrysophyta, but most Most phycological workers believe that they are an independent phylum, divided into 1 class of Phaeophyceae, and are divided into 13 orders according to the type of life history, growth mode, structure of the algae, whether the chromatophore contains pyrenoids and other characteristics: Water Cloud Orders, Phytophthora, Phytophthora, Cherophyceales, Verdinales, Chaetocephalales, Dictophyceales, Hemeralales, Dictophyceales, Acidophyceales, Laminariales, Fucusales and Devi order. Except for Verdinales, Nematophorales and Deweyales, the other 10 orders are all found in China.
Ecological distribution of brown algae
Brown algae are mainly distributed in cold and temperate oceans, growing on rocks in the low tide zone and subtidal zone. They are found in all oceans of the world. They have many types and individuals. Large algae, such as tens of meters long, form dense macroalgae fields on the Pacific coast of the Americas.
Kelp is widely distributed on the southeastern coast of Kamchatka, the southern coast of the Kuril Islands, Sakhalin Island, Hokkaido and the north of Wonsan, North Korea. In China, it is mainly produced in the northern Yellow Sea. However, there are also some species such as Sargassum, which are mainly produced in tropical and subtropical oceans, and some species also grow in temperate oceans.
Kelp