Erica Mannis summarises the findings of a recent study into the repercussions climate change has on marine life.
Climate change and its effects are becoming increasingly well-known and understood. However, so often our focus is on dry land. We experience weather and can observe the effect its turbulence has on the local species, but climate change’s impact affects more than what is in plain sight.
Researchers at the University of Bristol have recently discovered movements in the distribution of marine species, finding higher numbers close to the poles, further from the equator. The research team compared previously known species’ ranges to what they found experimentally. They discovered almost all species examined had shifted to their most poleward limits. The sheer volume of species this theory applied to was a shocking result to the scientists.
They discovered almost all species examined had shifted to their most poleward limits.
The equator is the Earth’s warmest latitude, and as it warms even further due to global warming, marine species are moving away. It is unknown if this is because the species’ physiological limits cannot function in the increasing temperature, or if the movement is due to their interdependence on one another.
While this may seem like a trivial consequence of climate change, it will have a much bigger effect than many anticipate; the greatest of these will be on our fisheries, which will have to shift where they farm to supply common species. This is already occurring, for example, most of the fish we now harvest are exported to Europe as they are species more commonly eaten further south.
In addition to distribution, species abundance is also greatly affected. Emperor penguins are suffering as the water warms at their equatorial edge, decreasing their habitat limits. However, other species such as sea bass are thriving like never before at their poleward limit, where previously they have been uncommon.
If the temperature of the seas continues to rise, it is plausible to assume that this shift in marine species will also continue. Sea temperatures have risen by 1°C since pre-industrialisation, and this trend is predicted to continue with a further 1.5°C rise by 2050. The University of Bristol’s study is proof species are not adapting to the warmer temperatures which could lead to extinctions. Despite this, it would be crude to come to such conclusions without further research, especially into precisely why distribution patterns have changed.
If the temperature of the seas continues to rise, it is plausible to assume that this shift in marine species will also continue.
The change in distribution outlined in this study may affect our fisheries and marine eating habits, but the wider point to take from this research is that climate change is affecting the whole planet. Almost every species sampled experienced this shift in distribution; although it is most prominent in bony fish and sea birds, even phytoplankton and marine mammals are experiencing movement.
Our climate change impact is experienced globally, and now it is difficult to know where we will find Nemo.