Effects of Global Warming on the Growth and Proliferation of Attached Sargassum horneri in the Aquaculture Area near Gouqi Island, China

Abstract

With global warming, in recent years, golden tides have frequently occurred off the coasts of China. Sargassum horneri, which attach to aquaculture rafts, can float and form small-scale golden tides after falling off. Temperature will affect the growth and reproduction of algae. In order to explore whether the temperature is the potential influence factor of the golden tide outbreak, in this study, the effects of global warming on the growth and proliferation of S. horneri in the mussel aquaculture area of Gouqi Island will be discussed. Samples of the macroalgae were collected monthly from August 2021 to July 2022 at various stages of its life cycle, and the relationship between algal growth and temperature was analyzed based on the concept of effective accumulated temperature, combined with the parameters of sea surface temperature, photosynthetic rate, growth rate, and growth cycle. Based on the continuous temperature variation observed, the growth cycle could be divided into five stages: the decreasing temperature period (October to November), the low-temperature adaptation period (December), the second suitable low-temperature period (January to February), and the high-temperature decay period (February to May). The effective accumulated temperature stored by S. horneri from 2021 to 2022 was 2772.4 °C·d; compared with previous studies, it decreased by about 800 °C·d. The winter temperature in 2022 was higher than the average temperature in the previous 5 years, allowing the macroalgae to enter the reproductive period in advance. This had a significant impact on the blooming time of golden tides and led to an earlier outbreak and extinction. Therefore, in the future, we can set up a monitoring system for the early warning of golden tides according to the change of SST in winter.

La invasión de sargazo: de un problema ambiental a un área de oportunidad

“…La temperatura es un factor abiótico importante que afecta a las actividades biológicas de las algas marinas, de hecho, se ha identificado una correlación entre los cambios en la temperatura del mar y las etapas de desarrollo y distribución del sargazo (Ogawa, 1985;Wu et al, 2022). El aumento de la temperatura promueve su crecimiento y proliferación, con un rango óptimo de 18-30 ºC para especies como Sargasssum natans, Sargassum muticum y Sargassum patents (Bui et al, 2018;Jouanno et al, 2021).…”

“…En este sentido, se han propuesto diferentes hipótesis que intentan explicar las causas del incremento masivo de sargazo; incluyendo el aumento de nutrientes del agua, de la temperatura y cambios en el patrón climatológico (Wang et al, 2019). El cambio climático global representa una causa directa de este fenómeno, obligando al Mar de los Sargazos a trasladarse muy cerca del sur, provocando la distribución de las algas por todo el Mar Caribe (Louime et al, 2017;Wu et al, 2022).…”

Br doping-induced evolution of the electronic band structure in dimorphic and hexagonal SnSe2 thermoelectric materials

“…Global warming is disrupting ecosystems and reducing biodiversity, which is threatening food production and human wellbeing. 1,2 The emission of greenhouse gases, such as carbon dioxide (CO 2 ), is a major cause of global warming. Fossil fuels, such as coal, oil, and natural gas, are the main source of CO 2 emissions.…”

“…where S, s, T, k e , and k l are the Seebeck coefficient, electrical conductivity, absolute temperature, electronic thermal conductivity, and the lattice thermal conductivity, respectively. [7][8][9][10] As evident from eqn (1), to achieve a high zT, it is essential to increase the power factor (PF), which is the product of the S and the s, and simultaneously lower the k l (the k e is linked to the s). Unfortunately, the S and s are in a trade-off relationship.…”