Global Warming Can Lead to Depletion of Oxygen by Disrupting Phytoplankton Photosynthesis: A Mathematical Modelling Approach

Abstract

Abstract:We consider the effect of global warming on the coupled plankton-oxygen dynamics in the ocean. The net oxygen production by phytoplankton is known to depend on the water temperature and hence can be disrupted by warming. We address this issue theoretically by considering a mathematical model of the plankton-oxygen system. The model is generic and can account for a variety of biological factors. We first show that sustainable oxygen production by phytoplankton is only possible if the net production rate is above a certain critical value. This result appears to be robust to the details of model parametrization. We then show that, once the effect of zooplankton is taken into account (which consume oxygen and feed on phytoplankton), the plankton-oxygen system can only be stable if the net oxygen production rate is within a certain intermediate range (i.e., not too low and not too high). Correspondingly, we conclude that a sufficiently large increase in the water temperature is likely to push the system out of the safe range, which may result in ocean anoxia and even a global oxygen depletion. We then generalize the model by taking into account the effect of environmental stochasticity and show that, paradoxically, the probability of oxygen depletion may decrease with an increase in the rate of global warming.

Variation of Aulacoseira granulata as an eco-pollution indicator in subtropical large river Ganga in India: a multivariate analytical approach

“…Similarly, the density has been positively in uenced by depth during winter, higher depths were observed in the river as similar to the Gharraf river of Iraq (Al-Husseini et al, 2020). A signi cant positive correlation with Dissolved oxygen was also observed, during the daytime with sunlight, the photosynthetic activities of the phytoplankton get enhanced, and relatively more oxygen is released in the aquatic system when the numbers of Phytoplankton are higher and is also depending on water temperature (Sekerci et al, 2018). The higher dissolved oxygen in the riverine system has also been reported during the post-monsoon and winter season.…”

Pattern Formation in a Model Oxygen-Plankton System

“…The decrease was previously linked to purely physical mechanisms such as the decrease of oxygen solvability in warmer waters [23,24]. More recently, however, it was shown that global warming can significantly affect the amount of dissolved oxygen also through a biological mechanism as it can disrupt the oxygen production by phytoplankton potentially leading to global ocean anoxia [10,12,25]. Moreover, since it is estimated that about 70% of the atmospheric oxygen is produced in the ocean, such a global disruption of oxygen production would eventually lead to a significant decrease of the oxygen concentration in the air and could hence lead to mass mortality of animals and humans.…”

Confession and Hope: Ekklesia’s Task in the Global Emergency

“…This is responsible for around 60% of our oxygen, but warming seas are destroying it. If present trends continue it is predicted that oxygen depletion will mean that we will all effectively be living in the kind of atmosphere we associate with the summit of Everest (Sekerci and Petrovskii 2018).…”