|Climate change will force marine organisms towards
the poles, but would they be safe there? |
Human activities such as emissions from the use of fossil fuels, rampant urbanisation, deforestation, and modern agricultural practices, are all altering the earth’s climate in an unprecedented scale. Climate change not only occurs in the land, but also in water bodies. Studies have indicated that since the 1950s, the amount of heat stored in the ocean (ocean heat) has increased considerably. Besides, ocean temperatures have increased throughout the world since the advent of the twentieth century, with the past three decades recording the highest temperatures since the measurements began.
A major consequence of increase in ocean temperatures is the corresponding decrease in dissolved oxygen levels. This phenomenon is predicted to significantly disturb marine ecosystems. Recent research by a group of American and German scientists revealed the consequences of oceanic climate change on a range of fish and crustacean species in the North Atlantic with different levels of tolerance towards heat and oxygen levels. The researchers' climate models predict substantial warming and deoxygenation throughout most of the upper ocean by the end of this century which in turn will affect the distribution of marine creatures. Their studies reveal that warming of water and oxygen depletion would force the organisms to migrate towards the pole due to deficiency of the original native waters to sustain their energy requirements. The scientists predict that even the waters towards the pole would have reduced oxygen levels, meaning the survival of the migrants could be precarious even there. Furthermore, this movement could alter the ecosystems in the polar waters due to many factors including competition from the migrants which may alter species ecologies.
http://www.sciencemag.org/content/348/6239/1132.abstractDeutsch C, Ferrel A, Seibel B, Pörtner HO, & Huey RB (2015). Ecophysiology. Climate change tightens a metabolic constraint on marine habitats. Science (New York, N.Y.), 348 (6239), 1132-5 PMID: 26045435