Relação entre a disponibilidade de ferro (Fe2+) e a capacidade de sequestração de CO2 pela espécie Tetraselmis chuii

Abstract

Iron has proven to be central to the biogeochemical balance of primary productivity in the euphotic zone of the oceans. Iron 'fertilisation' studies that have sought to establish this relationship have been conducted preferentially at meso- and macro- scales, although small-scale experiments accurately reflect processes occurring in situ. In this sense, the response of the microalgae Tetraselmis chuii to different concentrations of Iron (Fe²⁺) was studied, cultivating it in three experimental groups: control (F/2 medium), II (F/2 + 2x Fe²⁺) and III (F/2 + 4x Fe²⁺). The dry weight was calculated and allowed the determination of the algal biomass (ma, gL^-1) and the mass of sequestered inorganic carbon (mCi, gL^-1).
Compared with the control (ma=(1.7±0.58), mCi=0.85), Group II (ma=(2.6±0.58), mCi=1.3) and particularly Group III (ma=(4.0±1.0), mCi=2.0) there was a statistically significant difference in biomass production and carbon sequestration.
This study demonstrated the existence of higher algal growth in cultures exposed to a higher availability of Fe, concluding that CO₂ sequestration is enhanced using increasing concentrations of that metal. Further research should seek to understand the influence of iron fertilisation on the proliferation of other species, particularly harmful algal blooms (HBAs).