The UK, Ireland, Norway, North and South America, New Zealand etc. all have most of their mountains and glacial "jagged "coastline on their west.  Eastern coastlines seem to be generally much "smoother" and generally less hilly.

What is the reason for this and are there any exceptions?

Assuming that rivers continuously feed minerals into the oceans, and that they are not yet saturated, is the salinity increasing? Hs it changed much on geological timescales? And are there any long-term consequences for ocean life?

The ocean's are great stores of CO2, especially at the high pressure seen at depths of over 1000m, or so I am informed. So are they fizzy down there, whats it like for a fish, do they basically live in a soda stream?

As a young child, I used to love putting the shells like the ones in the picture, into my ear to listen to them. I remember being told that you hear the waves in them. I know that's not entirely true, but what exactly causes the sound we hear? And why don't we hear such sounds if we put other objects like it up to our ear?

While swimming one morning across Coogee Bay in New South Wales, we came across thousands of these strange creatures (see photo) floating at depths down to about 2 metres.

They were hard but also flexible, with water inside and a small hole at one end. Their length varied from about 3 to 30 centimetres and their walls were between 2 and 5 millimetres thick. Their skin was marked with many small protrusions, the size of which varied from one creature to another. Unlike jellyfish they appeared to be completely harmless.

No one I've spoken to from the area has ever come across anything like this. So what were they and why were they there?

Philippe Wilmotte, Maroubra, New South Wales, Australia

Peter Buckley, Toronto, Canada

Does the sea have a meniscus? If you looked at a shoreline, would you see it rise towards the edge? If there is a meniscus, could you harness it for anything useful?