Response of Diatoms to the Addition of Bamboo in the Eastern Arabian Sea

Nutrient availability limits phytoplankton growth throughout much of the global ocean, and this has led scientists to consider fertilizing the ocean with phytoplankton growth-limiting nutrients. We studied the response of phytoplankton to the addition of natural materials such as rice husk and bamboo leaves through field mesocosm experiments. Rice husk released only SiO₄⁴⁻ while the bamboo leaves released SiO₄⁴⁻ and also NH₄⁺, which led to a phytoplankton community shift from picophytoplankton to microphytoplankton. The bamboo addition led to a diatom bloom with an increase in diatom abundance, and the supply of nutrients particularly benefited Nitzschia spp., along with Navicula spp., Chaetoceros spp., Leptocylindrus spp., and Pseudo-nitzschia spp. Such a proliferation of diatoms triggered by bamboo addition lowered the partial pressure of carbon dioxide (pCO₂) by upto 60 μatm in 8 days. Our findings reveal that bamboo has high potential in ocean fertilization experiments, as it gave better pCO₂ reduction when compared to most global ocean fertilization experiments. Furthermore, the ecological success of bamboo in drawing down pCO₂ over other SiO₄⁴⁻ sources indicates that diatom proliferation is mainly regulated by nitrogen limitation in the Arabian Sea. This study has implications for CO₂ sequestration, the aquaculture industry, and broader environmental health.