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THREAD: There’s another huge anoxic event happening in Wheatley River Estuary right now. This is one of the PEI estuaries most impacted by agriculture. How does this happen? 
When an estuary is highly impacted by nutrients, we get algae blooms. Big mats of sea lettuce form and float to the surface. They block out all of the light and prevent plants like seagrass from photosynthesizing. Without photosynthesis, oxygen levels plummet.
Soon the sea lettuce grows so thick it starts to shade itself and decompose. The bacteria breaking it down also use oxygen. Oxygen levels plummet further.
When oxygen levels reach 0, we call it anoxia - meaning there is no oxygen left in the water. Fish swim to the surface to gulp air. Sedentary animals like clams unfortunately come out of the sediment and die. If you look closely you can see fish gulping in this photo
