As temperatures have increased, removing significant portions of sea ice, krill (a tiny shrimp-like crustacean) populations in certain areas have decreased significantly due to a reduction in the amount of their food source - algae - which grows on the bottom of sea ice.
(temperatures; have increased; ) (temperatures; removing; significant portions of sea ice, krill (a tiny shrimp-like crustacean) populations in certain areas) (a reduction in the amount of their food source - algae; grows; L:on the bottom of sea ice)
temperatures temperatures a reduction in the amount of their food source - algae
have increased removing grows
significant portions of sea ice, krill (a tiny shrimp-like crustacean) populations in certain areas
L:on the bottom of sea ice