Is Enteromorpha a a biological invasion?

Enteromorpha belongs to the genus Ulva in the phylum Chlorophyta. There are about 40 species of Enteromorpha, and there are about 1 1 species in China. Most kinds of seafood are widely distributed in the oceans all over the world, often growing on rocks or swamps in intertidal zones, or on gravel in mudflats, and sometimes attached to algae bodies of large algae. Enteromorpha prolifera is a worldwide temperate seaweed, which is grass green, tubular, membranous, clustered, with obvious main branches and slender branches, and the height can reach 1 m. The base is attached to the rock with a fixer and grows on the beach and gravel in the mid-tidal zone. 65438+ February to April of the following year is the peak period of growth. The common species in China are Enteromorpha prolifera, Enteromorpha prolifera, Enteromorpha oblata and Enteromorpha prolifera. Enteromorpha prolifera is mainly produced in the coastal areas of Fujian, Zhejiang and Jiangsu, and is the dominant species in the coastal areas of Zhejiang, with Xiangshan Port and Sanmen Bay as the main producing areas. In recent years, Enteromorpha prolifera broke out periodically in the sea area east of Yancheng 100 km, and the outbreak time was from May to June. Some analysts believe that the provenance of Enteromorpha comes from discarded materials (bamboo poles, etc.). ) contains Enteromorpha. The earliest outbreak area of Enteromorpha prolifera was the eutrophic area near the sea. From the source, distribution area and influence of Enteromorpha prolifera, compared with the North Yellow Sea ecosystem, Enteromorpha prolifera has obvious species invasion characteristics. (1) No Enteromorpha prolifera grows in the northern part of the Yellow Sea. (2) Enteromorpha prolifera appeared in the northern part of the Yellow Sea in recent summer (06, 07 and 08); (3) Enteromorpha prolifera grows and breeds in some parts of the North Yellow Sea, which makes Enteromorpha prolifera continue to occur in the North Yellow Sea; (4) In recent years, the large-scale cultivation of Porphyra yezoensis in Jiangsu coastal areas has provided a large number of Enteromorpha provenances [1 2]. (5) The explosive growth of Enteromorpha has brought a serious impact on the ecological environment in Shandong coastal areas. The periodic outbreak of Enteromorpha prolifera in the Yellow Sea is closely related to climate change, regional marine ecological imbalance and species diffusion. Preliminary assessment of the invasion risk of Enteromorpha prolifera provides technical basis for effective management of green algae such as Enteromorpha prolifera and early warning of marine invasion. 1 risk calculation and risk grade evaluation According to the established marine organism invasion risk evaluation model and analysis software [6], the invasion risk of Enteromorpha prolifera is preliminarily evaluated, and the risk grade is calculated and divided. See table 1 for the results. Table 1 risk grade evaluation Enteromorpha prolifera invasion probability 0.728 impact degree 0.567 risk value 0.4 13 risk grade advanced 2 invasion risk early warning analysis The results of Enteromorpha prolifera risk early warning evaluation are shown in Table 2. The results show that Enteromorpha prolifera has exceeded the critical value in four groups: invasion ability, damage to indigenous organisms and damage to ecosystem, which is the focus of early warning. This paper is indicated by *. In terms of environmental damage, there is no actual specific data, so this analysis believes that the overall economic value loss has not exceeded the critical value. Table 2 Invasion Risk Early Warning Analysis Index Grouping Critical Index Early Warning Analysis Index Early Warning Result Invasion Ability 0.500 0.728 * Indigenous Biological Damage 0.200 0.2 17- Environmental Damage 0. 150 0. 175 * Ecosystem Damage 0.100 0 0.092-Economic Loss Conclusion Comprehensive analysis and evaluation of the biological, ecological characteristics, environmental impact, economic and social impact of Enteromorpha prolifera shows that the risk level of Enteromorpha prolifera invasion is medium. Enteromorpha prolifera has a variety of breeding methods, strong reproductive growth ability and strong invasion ability, which exceeds the set critical value and should be paid attention to. Enteromorpha prolifera explosively grows and drifts in summer, gathering along the northern coast of the Yellow Sea, which has a great impact on coastal landscape and tourism. The cleaning and treatment of Enteromorpha requires a lot of manpower and material resources, and brings huge economic losses. Climate change and regional marine ecological imbalance may be the important reasons for the periodic outbreak of Enteromorpha prolifera in the Yellow Sea in spring and summer.