EAS201 Lecture Notes - Lecture 34: Ocean Acidification, Ecological Footprint, Overfishing
2 May 2020
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Document Summary
Ecological footprint of each human being on the limited resources the earth provides. Over the past 4000 years, humans have replaces natural vegetation with managed landscapes with far lower biodiversity. Deforestation impacts soil stability, the water cycle and biogeochemical reactions. 5. 2 million hectares of forest are added each year, but 14. 6 million hectares are lost. Marine systems are more difficult to study than terrestrial (challenging to place restrictions on fishing) >80% of marine fish stocks are fully fished or overfished and this continues to worsen. Particular concern are fish nets that capture non-target species (ex. dolphins) or damage seafloor habitants during net dragging. Coral reefs are colonies of tiny animals coexisting with photosynthetic algae called zooxanthellae. Zooxanthellae produce food from photosynthesis which is shared with corals and corals provide nitrogen to zooxanthellae (symbiotic relationship) Without these algae, corals do not build reefs. Can occur when there is too much sediment in water (inhibits photosynthesis)
