In this paper, we study the lake eutrophication by using a stochastic model that includes both input noise
and recycling noise. The effects of the input noise (a), the recycling noise (D) and the cross-correlation
between two noises (l) in the model are discussed, respectively. Our results show: (i) the noise-induced
ecological bistability (EB) expands in comparison with the deterministic case; (ii) noises still can induce
EB when the recycling parameter r < 0.5; (iii) the noises can cause the regime shifts from the eutrophic
state to the oligotrophic one (noise-induced oligotrophy); and (iv) the input noise can accelerate regime
shifts from the oligotrophic state to the eutrophic one for the case of zero or small cross-correlation.
Moreover, for the case of higher cross-correlation intensity, the mean first passage time (MFPT) as a
function of a exhibits a maximum, which identifies the input noise-enhanced stability (NES) of the
oligotrophic state. Finally, for whatever value of cross-correlation intensity, the theoretical results show
that the recycling noise can accelerate regime shifts from the oligotrophic state to the eutrophic one