A new study has found that human activity is having a drastic impact on the creatures under the sea, with many on the verge of extinction thanks to humans.  However, swift intervention could still prevent a "disaster of the magnitude observed on land."

The study published this week in the journal Science analyzes the impact humans are having on the oceans.  According to the group of researchers who developed the study, several marine species could soon be gone forever if changes are not quickly made.

With a growing concern that low extinction rates seen today "may be the prelude to a major extinction pulse, similar to that observed on land during the industrial revolution", the researchers investigated the wider implications that may have for humans and marine life, such as "imperiling food sustainability" for humans and a depleting "wide range of ecologically important marine fauna."

"Climate change is essentially making the oceans a warmer and more acidic place, and that's going to make it a more hostile place for ocean wildlife" coauthor of the study and professor at UC Santa Barbara, Dr. Douglas McCauley says. "We may be sitting on a precipice of a major extinction event."

Unsustainable fishing is the principal threat to marine life today, but the researchers revealed that there are also other dangers.  For example, while the great whales are no longer being hunted as they once were, they still face dangers from noise pollution and oil exploration.  Bottom trawling, an industrial fishing method, can alter or destroy underwater habitats also putting other species at risk.

The development of coastal cities and a practice known as "seasteading," or building artificial land in the ocean, also creates problems for marine habitats along with sea floor mining and gas extraction. But there is still time to change course and avoid the damaging repercussions already seen in land animals, the study notes. 

The authors say that there is time to "avert the kinds of defaunation disasters observed on land" through "efforts to slow climate change" and rebuild animal populations, while ensuring marine mining and energy development "take important marine wildlife habitats into consideration."  While there have been no recorded extinctions of marine animals in the past five decades, marine animal loss remains significant and changes that affect the bottom of the food chain could travel upward.

"Depletions of fauna such as anchovies, sardines, and krill cause reductions in food for higher-trophic level (position on the food chain) animals such as seabirds and marine mammals, potentially resulting in losses in reproduction or reductions in their population size," the authors said. 

This has troubling implications for humans as well, as the loss of many of these fish as a human food source could create food sustainability issues, leading to increased social conflict around the globe. It should be noted, however, that the report makes it clear that "we are not necessarily doomed to helplessly recapitulate the defaunation processes observed on land in the oceans."

There is still time to reverse this trend and reduce the threat to marine life if humans begin to mitigate their practices on land and how we care for the sea.