Katana VentraIP

Human impact on marine life

Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.[3]

The ocean can be described as the world's largest ecosystem and it is home for many species of marine life. Different activities carried out and caused by human beings such as global warming, ocean acidification, and pollution affect marine life and its habitats. For the past 50 years, more than 90 percent of global warming resulting from human activity has been absorbed into the ocean. This results in the rise of ocean temperatures and ocean acidification which is harmful to many fish species and causes damage to habitats such as coral.[4] With coral producing materials such as carbonate rock and calcareous sediment, this creates a very unique and valuable ecosystem not only providing food/homes for marine creatures but also having many benefits for humans too. Ocean acidification caused by rising levels of carbon dioxide leads to coral bleaching where the rates of calcification is lowered affecting coral growth.[5] Additionally, another issue caused by humans which impacts marine life is marine plastic pollution, which poses a threat to marine life.[6] According to the IPCC (2019), since 1950 "many marine species across various groups have undergone shifts in geographical range and seasonal activities in response to ocean warming, sea ice change and biogeochemical changes, such as oxygen loss, to their habitats."[7]


It has been estimated only 13% of the ocean area remains as wilderness, mostly in open ocean areas rather than along the coast.[8]

Microplastics among sand and glass spheres in sediment from the Rhine. The white bar represents 1 mm.

Microplastics among sand and glass spheres in sediment from the Rhine. The white bar represents 1 mm.

Vast plastic garbage patches have accumulated at the centre of ocean gyres.[38]

Vast plastic garbage patches have accumulated at the centre of ocean gyres.[38]

Model results for the count density of small planktonic plastic particles.[39]
Red: more dense
Green: less dense

Model results for the count density of small planktonic plastic particles.[39] Red: more dense Green: less dense

Interactions between marine microorganisms and microplastics[40]

Interactions between marine microorganisms and microplastics[40]

Ocean warming is changing the distribution of the keystone species Antarctic krill[56][57]

Ocean warming is changing the distribution of the keystone species Antarctic krill[56][57]

In the Antarctic, limited-range shallow-water species, like this emerald rockcod, are under threat.[56][57]

In the Antarctic, limited-range shallow-water species, like this emerald rockcod, are under threat.[56][57]

Decreases in aragonite saturation make it more difficult for marine organisms like pteropods to build calcium shells

Decreases in aragonite saturation make it more difficult for marine organisms like pteropods to build calcium shells

Shells of pteropods dissolve in increasingly acidic conditions caused by increased amounts of atmospheric CO2

Shells of pteropods dissolve in increasingly acidic conditions caused by increased amounts of atmospheric CO2