International Journal of Marine Science, 2024, Vol.14, No.1, 6-13 http://www.aquapublisher.com/index.php/ijms 7 1 Seasonal Changes in the Composition and Diversity of Marine Surface Floating Biological 1.1 Seasonal variation in the composition of surface floating biological The composition of marine surface-floating biological on the surface of the ocean undergoes significant changes in different seasons, primarily influenced by seasonal environmental factors, including temperature, salinity, light and nutrient salts. Spring is one of the seasons when the marine surface-floating biological community is the most diverse and abundant. In warm spring, due to increased light and nutrient availability, phytoplankton (Figure 1) such as diatoms, dinoflagellates, and green algae proliferate rapidly. These phytoplankton are essential components of the surface-floating biological community, as they undergo photosynthesis, absorbing carbon dioxide and releasing oxygen, thereby providing energy and oxygen to the marine ecosystem. Furthermore, spring is also a season for the reproduction of zooplankton, including pelagic zooplankton and animal plankton such as jellyfish. They feed on phytoplankton, forming a complex food web. During spring, both the variety and abundance of zooplankton significantly increase, providing rich food resources for upper-level organisms in the marine food chain. Figure 1 Marine phytoplankton (Image source: https://cn.bing.com/) Summer is the peak season for marine surface-floating biological communities, with rising seawater temperatures and maximum light intensity, providing ideal conditions for the growth of phytoplankton. Large diatoms like diatomaceous diatoms, chain diatoms, and spiral diatoms reach their peak during summer, forming extensive phytoplankton communities known as algal blooms. These algal blooms play a crucial role in the photosynthesis and energy transfer within the marine ecosystem and also have a significant impact on the cycling of nutrients such as nitrogen and phosphorus in the marine ecosystem. Moreover, summer is a season of abundance for zooplankton, including pelagic zooplankton, animal plankton such as jellyfish, and pelagic shrimp. These zooplankton feed on phytoplankton and participate in the nutrient transfer within the marine food web. As autumn approaches, the composition of marine surface-floating biological communities begins to change. The temperature and light levels gradually decrease, leading to a slowdown in the growth of phytoplankton. Additionally, influenced by monsoons and ocean currents, the supply of nutrients also relatively diminishes. This results in a reduction in both the quantity and variety of phytoplankton, as well as a decline in zooplankton.Winter is one of the seasons when the marine surface-floating biological community reaches one of its lowest points. Seawater temperatures further decrease, and there is reduced light, causing almost a complete halt in the growth of phytoplankton. Only a small number of cold-tolerant diatoms and dinoflagellates can survive in these low-temperature conditions. Consequently, the number of zooplankton also decreases, with many species entering a dormant state or migrating to warmer regions. 1.2 Seasonal diversity changes in surface floating biological communities As the composition of seasonal marine surface-floating biological communities changes, their diversity also undergoes corresponding variations. Diversity typically involves species richness and the relative abundance of
RkJQdWJsaXNoZXIy MjQ4ODYzNA==