What gives glacier algae their wild colors?

When a British expedition reported seeing pink mountain snow in 1818, the London Times said: “Our credulity is put to an extreme test upon this occasion, but we cannot learn that there is any reason to doubt the fact as stated.” Two hundred years later, we now can confirm that pink snow (“watermelon snow”) is real and it is caused by certain types of algae. But why is it that snow algae take on such distinctive red and purple colors? And how does this connect to melting glaciers or global sea level rise?

Read more

Out of balance: how climate change is altering ocean food webs

Climate change has a number of impacts on the ocean. Did you know that the ocean absorbs at least one quarter of the carbon dioxide that is released into the atmosphere? As the ocean absorbs carbon, the chemistry of the water itself is changed in a process known as ocean acidification. Ocean acidification can make it harder for organisms with shells to grow and thrive, but can benefit photosynthetic algae that need carbon dioxide to grow. Climate change is also warming the oceans, which impacts the metabolism of all organisms. A recent study from Southern Australia reported that ocean acidification boosted algae, herbivores, and fish predators in a trophic food chain, but when ocean warming was introduced, these impacts were reversed. This research highlights how the complex stressors of climate change may result in food webs that are out of balance.

Read more