Ancient myths imagined the world as being surrounded by a great ocean. Marine plankton play a key role in climate regulation through photosynthesis. Oceans cover over 70% of the planet and support vast biodiversity and ecosystems, but human activity like overfishing and pollution threaten marine life. Coral reefs encompass vast diversity despite covering less than 1% of ocean floors. Freshwater systems face degradation and 50% of people will face scarcity by 2025. Coastal regions are experiencing reduction and loss of ecosystems like mangroves and wetlands due to development and overfishing. Overfishing has depleted many fish stocks and climate change will raise sea levels and displace 150 million people from coastal areas by 2050.

1. Oceans

2. Mythology The original concept of "ocean" goes back to notions of Mesopotamian and Indo-European mythology, imagining the world to be encircled by a great river. Okeanos , "Ωκεανός" in Greek, reflects the ancient Greek observation that a strong current flowed off Gibraltar and their subsequent assumption that it was a great river. (Compare also Samudra from Hindu mythology and Jörmungandr from Norse mythology). The world was imagined to be enclosed by a celestial ocean above the heavens, and an ocean of the underworld below (compare Rasā, Varuna).

3. Marine Biosphere – Atmosphere Interactions Marine plankton ecosystems play a key role in the global geochemical cycles of elements relevant to climate. Photosynthesis by unicellular algae is the basis of ocean ecosystems. Physical interactions between marine animals and water, substrate and air determine the energetics of locomotion, acquisition of food and reproduction

4. Oceans & Marine Ecosystems The ocean covers 71 percent of the surface of our world and plays a vital role in maintaining biodiversity, regulating climate and weather patterns, and providing food and jobs for millions of people worldwide. As a result of destructive human activity the health of our oceans and the life they support is in jeopardy. Seabirds, hundreds of thousands of sea turtles and marine mammals are entangled and drowned by irresponsible fishing practices every year.

5. Coral Reefs Covering less than 0.2% of the ocean floor, coral reefs contain perhaps 1/4 of all marine species. Coral reefs in 93 of the 109 countries containing them have been damaged or destroyed by human activities. In addition, human impacts may have directly or indirectly caused the death of 5-10% of the world's living reefs, and if the pace of destruction is maintained, another 60% could be lost in the next 20-40 years.

6. Freshwater Systems The world's freshwater systems are so degraded that its ability to support human, plant and animal life is greatly in peril. By 2025, at least 3.5 billion people or nearly 50 percent of the world's population will face water scarcity. More than 20 percent of the world's known 10,000 freshwater fish species have become extinct, been threatened, or endangered in recent decades.

7. Coastal Ecosystems Forty percent of the world's population lives within 100 kilometers of a coastline, an area that accounts for only about 20 percent of the land mass. Population increase and conversion for development, agriculture, and aquaculture are reducing mangroves, coastal wetlands, seagrass areas, and coral reefs at an alarming rate. Coastal ecosystems have already lost much of their capacity to produce fish because of overfishing, destructive trawling techniques, and destruction of nursery habitats.

8. Over-fishing World fisheries face a grim forecast. Forty-five years of increasing fishing pressure have left many major fish stocks depleted or in decline. Sixty percent of the world's important fish stocks are "in urgent need of management" to rehabilitate them or keep them from being over-fished. 35 percent of the most important commercial fish stocks show a pattern of declining yields and require immediate action to halt over-harvesting.

9. Global Warming & Climate Change By 2050, the sea level will rise approximately 1.5 meters, flooding low lying areas. With as much as 50 percent of the world's population settled in coastal communities, it is estimated that by this time 150 million people will be driven from their homes and become environmental refugees.

10. Thank You