The dry mountain ranges of the western United States contain rocks dating back 440 to 510 million years, to the Ordovician period, and teeming with evidence of tropical marine life.
But under sea ice, the attenuation coefficient of PAR is little bit different, as the spectrum of the light has been changed by selective absorption through the sea ice.
Aquariums provide the public with many chances to experience life under the sea. These fun and educational places can be found in most areas of the world.
The seas are full of the cast-offs of humanity, from tub toys that have fallen off container ships to boats swept away in storms to bottled messages deliberately set adrift.
Biological hypotheses include ecological changes brought about by the evolution of cooperation between insects and flowering plants or of bottom-feeding predators in the oceans.
We also need to consider the longer-term context and see if we need to build better sea defences at a particular location and assess how high dykes or walls need to be.