Factors such as agriculture runoff, loss of protective mangroves and climate change are all factors that contribute to stressors on coral ecosystems. Are we doing enough as a Force For Good to mitigate and reduce these stressors? 

Depending on location and facility you will come across one or both of these cylinder valve connections and it's prudent that if travelling with a DIN connection regulator from temperate climates to tropical waters to carry a convertor just in case the facility you're diving with on holiday has Yoke only cylinders.  

Generally, veins carry deoxygenated blood flow back towards the heart for reoxygenation and will then be transported back through the body to tissues and organs via the arterial system. 

If each halftime is 5 minutes long it will take that amount of time to load the available space in the tissue compartment. This means it will take 5 minutes to load 50%, 10 minutes to load 75% and 15 minutes to reach the third halftime, loading the tissue compartment 87.5%

Firstly let's work out the partial pressure of oxygen in air at sea level. This will give us a good baseline going forward.

It's a general agreement that we can say that the air we breath is approximately 21% oxygen and 79% nitrogen. To convert those percentages to their partial pressure we move the decimal place 2 places to the left. This gives us 0.21 ppO2 and 0.79 ppN2.

All gases in a mix must add up to the pressure exerted against them, 0.21 + .079 = 1.0, which is the ambient pressure at sea level.

If this pressure drops, such as at altitude, we must multiply the ppO2 by the new ambient pressure to get the answer, 0.21 X 0.7. This gives us the new ppO2 at this altitude,