Shot in the Foot: Unintended Consequences of Using Inorganic Fertilizer in Commercial Tropical Eucheumatoid Seaweed Farming

Seaweeds, like all primary producers, require macronutrients (C, N, P) for the synthesis of organic molecules through photosynthesis to support growth and accumulation of storage compounds, including cell wall polysaccharides, for example, agar, carrageenan, and alginates, that have numerous industrial applications. The commercial production of tropical eucheumatoids has been reliant on natural streams of inorganic nutrients. Recently, the prevalent use of inorganic fertilizer in seaweed farming in the southern Philippines was allegedly initiated to boost seaweed health and avert crop failure due to pests and diseases; however, it may also be economically driven to increase biomass production with a shorter crop period that is vital for the livelihood of the marginalized coastal inhabitants. Consequently, the harvest of fast-growing but immature crops whose tissues are replete with nutrients could compromise the carrageenan yield and rheology, and, more importantly, its organic status. Moreover, the indiscriminate use and disposal of inorganic fertilizer in algoculture pose the potential for ecological disaster.