Overfishing

Pollution covers a broad range but the biggest source of this stressor is non-point source pollution which occurs as a result of runoff from urbanised areas (cars, trucks, septic tanks, farms, livestock ranches, and timber harvest) adding chemicals, heavy metals, oil and other pollutants which greatly affect the water quality. Plastic has also a important impact on the ocean directly affecting all the biota in the ocean \cite{Koelmans_2014}.
Hipoxia The increasing frequency of blooms of nontoxic micro-algae and nuisance macro-algae is harmful because it dramatically reduces sunlight penetration in the water column. Large and long blooms can also draw a substantial amount of oxygen from the water column at night during respiration. Even though these events can occur seasonally, increasing water temperature and OA can change their frequency and intensity favouring the expansion of dead zones \cite{Sherman_2017}

Interaction between stressors

Interactions among ocean warming, decline in planktonic species, increase in smaller demersal species, and change in fishing practices has led to reduced stability and resilience of many ecosystems (Beaugrand et al. 2010). While interactions between stressor are highly complex to measure the prevailing view is that in a situation where three or more stressors (for example Ocean warming, OA, Overfishing) are affecting the ecosystem, synergies are expected to be the most prevalent interaction type (Paine et al. 1998). On other hand some interaction might also experience an antagonistic (reduced stress) or  additive (no additional stress) effects.