How Sea Life Is Affected By Rising Temperatures

Earth's oceans can absorb a tremendous amount of heat. Covering 71% of the surface, they act as a buffer, absorbing over 90% of the heat produced by global warming. But there's a limit.  

Although they may absorb enough heat to keep the planet from becoming completely uninhabitable, the oceans themselves nurture a complex and delicate web of sea life. Here are five ways that rising temperatures threaten to upset the balance, eliminating important species and threatening the food sources and livelihoods of hundreds of millions of people.

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Rising Temperatures Directly Affect Sea Life

Rising temperatures have direct adverse effects on sea life. A warmer habitat can stunt the growth of many fish and other sea creatures like squid and octopus. As with land animals, the smaller size of farmed species can devastate the ability of farmed species to provide much-needed nutrition to a growing human population.

Changing water temperature can also induce marine species to migrate in search of their preferred temperatures and oxygen levels. The effects can be devastating when this movement is away from human populations that rely on sea life as a source of income or food. For example, tuna have moved away from the Pacific Islands, threatening the economies of Fiji and other island nations. 

Finally, warming water threatens to bleach coral reefs, destroying a complex ecosystem and reducing ocean biodiversity. Coral reefs are home to many ocean species and food sources for other wildlife or people. Like sea life migration, decaying coral reefs disproportionately impact developing countries, threatening the food supply.

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Water Chemistry Is Changing

Ocean water is a massive carbon sink. Unfortunately, when carbon enters the water, it reacts chemically to form carbonic acid. Altering the pH of ocean water has a devastating effect on a wide array of marine species, particularly those with shells. Acid leeches out minerals, and most shells are composed of calcium carbonate. Lobsters, scallops, crabs, and other shellfish require their shells for protection, while corals become much less resilient when they don't have enough calcium to maintain their structure.  

Even many species of plankton, the foundation of the marine food chain, need high calcium levels to survive. Without plankton to feed larger organisms, chemical changes in the ocean's water may lead to a collapse of the oceans as a food source.

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High Temps Change Currents And Harm Reproduction

As ocean temperatures and wind patterns change, so do water currents. This change can impact fish migration, potentially redirecting important species away from the human populations that need them for protein. In addition, many forms of marine life rely on currents to aid reproduction. If these species have trouble maintaining their numbers, the impact on the ecosystem could be catastrophic.

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Polar Ice Is An Integral Part Of The Ecosystem

Melting polar ice has negative effects on sea life and people. For example, many types of algae, the foundation of the arctic food chain, require ice cover to propagate. As the ice cover recedes, fewer algae mean less food for Arctic cod, whales, seals, polar bears, and others. Ice also forms a vital part of the habitat for seals, whales, penguins, walruses, and other animals.

As the arctic marine life habitat falls apart, it also affects humans. For instance, Cod fisheries have experienced lower yields, causing economic displacement. Furthermore, without enough food or ice, polar bears must range further afield to secure food, increasing the likelihood of conflict with people.

In the Antarctic, less ice means fewer krill, the primary food source for mammals and sea birds alike. Unfortunately, krill populations have been falling precipitously, leading to a decline in numbers among the species that depend on them.

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Rising Sea Levels Threaten More Than Just Human Settlements

According to a UN report, rising sea levels could threaten over half a billion people living in coastal cities worldwide. Resulting from a mix of melting ice and thermal expansion, they also affect a tremendous number of marine plant and animal species. For example, many sea turtles lay their eggs on low-lying beaches. As these beaches disappear, man-made and other barriers prevent them from migrating inland to find new places to nest.

Many species of sea life inhabit narrow strips of shallow water near coastlines. Coral reefs and mangroves are biologically diverse ecosystems, home to thousands of species. Unfortunately, the corals, sea grasses, and other immobile lifeforms are highly unlikely to be able to migrate effectively to accommodate higher water levels - their immobility leaves them under serious threat.

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Rising Temperatures Threaten To Harm Our Greatest Resource

Rising temperatures have direct effects on the development of many marine species. However, the indirect consequences can be equally devastating. Water chemistry, changing currents, less polar ice, and rising sea levels threaten many species in the delicate ecosystem. The effects on nature are undoubtedly tragic, but we should feel particular urgency about how these changes impact humans. Well-maintained oceans could provide an abundance of food for the growing population. But as it is, we need to curtail global warming to ensure we have this fantastic resource when we need it most.

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Key Takeaways

• Lower emissions—CO2 is warming the oceans, so do your part by making less of it. Of course, it's not easy – but buying an EV, switching to green energy, and buying products from sustainable businesses are all great ideas.
• Reduce pollutants—make sure to dispose of all waste properly. Chemical pesticides, herbicides, fertilizers, and other compounds create highly damaging runoff that pollutes waterways and eventually makes it to the ocean.
• Reuse when possible—sadly, much "recycled" material ends up in the ocean. Avoid single-use plastic as much as possible. Bringing your own bag, bottle, or container can go a long way.