Physiological functional traits explain morphological variation of Ulva prolifera during the drifting of green tides. Issue 1 (17th January 2022)

• Record Type: Journal Article
• Authors: Guan, Chen; Zhao, Xinyu; Qu, Tongfei; Zhong, Yi; Hou, Chengzong; Lin, Zhihao; Xu, Jinhui; Tang, Xuexi; Wang, Ying
• Is Part Of: Ecology and evolution. Volume 12:Issue 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-17
• Subjects: morphological variation -- photosynthetic system -- reproductive allocation -- surface area to volume ratio -- Ulva prolifera; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.8504
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Ulva prolifera green tides, one of the greatest marine ecological disasters, originate in the southern Yellow Sea of China and obtain the highest biomass in Haizhou Bay (latitude around 35° N) during northward drift. U . prolifera shows different morphologies from southern Haizhou Bay (SH) to northern Haizhou Bay (NH). Owing to the distinct nutrient environments between SH and NH, we hypothesized that thalli in NH with poor nutrients increased the surface area to volume ratio (SA:VOL) to better absorb nutrients. Here, we tested this hypothesis by comparing the SA:VOL of thalli in SH and NH. The results showed that the thalli in NH had a lower SA:VOL than those in SH, and SA:VOL had positive relationships with temperature and nutrients, contrary to the general hypothesis. The novel results suggested that morphological differences of U . prolifera were the result of developmental state rather than environmental acclimation. Indicators of reproduction (reproductive allocation ratio) were negatively related to variation in tissue contents of C, N, P, and crude protein, whereas indicators of growth (tissue contents of C, N, P, and crude protein) showed significant positive influences on SA:VOL. The results indicated that a trade‐off relationship between reproduction and growth existed in the northward drift. All the results suggested that physiological functional traits affected morphological variation of U . prolifera in different environmental conditions during the drifting of green tides. This study presents new insights into the opportunist species nature of U . prolifera through morphological variation and associated functional consequences. Abstract : This manuscript highlighted a trade‐off relationship between growth and reproduction existed in the northward drift of green tides caused by U. prolifera, and all the results suggested that physiological functional traits affected morphological variation of U. prolifera in different environmental conditions during the drifting. Principal findings of the manuscript: (1) previous studies demonstrated that large‐scale green tides, mainly the genus Ulva prolifera, have occurred in the Yellow Sea of China since 2007 and obtain the highest biomass in Haizhou Bay. U. prolifera displayed distinct morphological differences during the drift northward. In order to find the reason about morphological variation of U. prolifera, we hypothesized that the thalli of U. prolifera adapt to the environmental changes by the variation in morphology to enhance nutrient uptake in northern Haizhou Bay (NH), an area with relatively less nutrients. (2) However, by comparing the surface area to volume ratio (SA:VOL), we found that the thalli in NH had a lower SA:VOL than those in SH, and SA:VOL had positive relationships with temperature and nutrients, contrary to the general hypothesis. (3) The novel results suggested that morphological differences of U. prolifera were the result of developmental state rather than environmental acclimation. Indicators of growth (Fv/Fm, Y(II)) and relative growth rate showed positive correlations with SA:VOL, whereas indicators of reproduction (reproductive allocation ratio) exhibited an opposite result and were negatively related to variation in tissue contents of C, N, P, and crude protein.