Xianbiao Lin

Nov 29, 2023 | frontiersin.org | Xianbiao Lin |Xuebo Zhang |Jiawang Chen

1 IntroductionThe sound velocity and acoustic attenuation coefficient of seafloor sediments are crucial parameters in the fields of underwater acoustics, geo-acoustics, and sedimentary acoustics (Kim et al., 2018a; Buckingham, 2020; Yang and Jackson, 2020). They determine wave speed, acoustic impedance, path and distance of sound wave propagation. They are closely related to the sediment physical and mechanical properties, as well as to the measurement methods and environmental conditions.

Jun 8, 2023 | frontiersin.org | Guangdong Ocean |Meilin WU |Xianbiao Lin |Yingxian He

1 IntroductionThe oceans cover 71% of the Earth’s surface area, and marine primary productivity is an important foundation of marine ecosystems. Phytoplankton in the ocean are one of the primary producers of the ocean. They use light energy to absorb nutrients from seawater and convert inorganic carbon into organic carbon, while releasing oxygen, thus directly or indirectly providing the material base on which other organisms in the ocean depend.

May 9, 2023 | frontiersin.org | Zhejiang Ocean |Xianbiao Lin |Yuanyuan Feng |Run Zhang

1. IntroductionDiazotrophs convert N2 into bioavailable ammonia (NH3) catalyzed by the enzyme nitrogenase (nifH), which substantially relieves nitrogen limitation for primary production over most of the surface ocean (Zehr, 2011). N2 fixation is an important new bioavailable nitrogen source and thereby is crucial to marine nitrogen biogeochemical cycle and biological pump function (Falkowski, 1997; Capone et al., 2008).