In this examination, we predetermined to investigate the consequence of prescribed gyrotactic microorganism, thermal radiation on unsteady mixed convention flow of Buogiorno model nanofluid inside the square cavity. The combination of suitable momentum, temperature, concentration and concentration of microorganism of nanofluid has been solved numerically via Finite Element method. Pictorial illustrations have been used to predict the sway of sophisticated parameters on fluid flow, temperature, concentration and gyrotactic microorganism set up: Radiation (Formula presented.), Brownian motion (Formula presented.), Rayleigh number (Formula presented.), Thermophoresis (Formula presented.), Buoyancy ratio (Formula presented.), Lewis number (Formula presented.), Peclet number (Formula presented.) and Bio-convection Rayleigh number (Formula presented.). Convergence analysis is presented via grid independence approach. The skin-friction coefficient, average Nusselt number, nanoparticle Sherwood number and microorganism Sherwood number of involved parameters are also plotted through graphs. It is observed through present investigation that isotherm patterns decline with higher choices of radiation parameter. Furthermore, the numerical codes of microorganism mass transport rate impede inside the cavity region with an intensifying values of thermophoresis parameter. © 2023 Informa UK Limited, trading as Taylor & Francis Group.