Adapting your skills for under water combat in a new [Guide:] thread might seem like retelling information already posted on the forum, but the BWE3 has introduced this little icon , which makes taking a second look at your skill bar worth it, as it tells us which skills are not available under water - and that are quite a few.
Here is the link to all the Drowned & Trident skills of the Elementalist, which will replace your weapon skills #1 to #5 anyway, so we won't take a closer look at them. Please follow the link to the latest revision of skills for the Trident weapon.
What we will be looking at now, are the general slot skills, the healing slot and the elite skills, which can all be found on the right side of your health globe. The upcoming skills are not available to you under water.
1. Where is my heal!
A little surprise is the fact, that "Ether Renewal" is not available under water (making this heal even worse compared to the others, but that's another topic), limiting the three self heal skills you can use. So if you happen to take "Ether Renewal" as your healing skill below the surface, you are trapped there without any means of regenerating in combat.
2. No Conjures, when it's wet!
Those are pretty obvious to be not working under water, as they change the weapon slots, which are fixed to the aquatic Trident weapon.
3. Where are my Glyphs?
You can not summon an Elemental ally (whether normal or elite and they die, when you enter the water) and the lack of Glyph of Storms takes away an ability to create a massive field of elemental damage, probably due to the ground targeted use on a flat surface. It would just not work in the 3D environment of under water combat.
4. And this is your Elite
Whirlpool is the only profession Elite that is working under water.
If you know that you have to do adventuring for e.g. a Heart Quest or an DE (perhaps even a late game dungeon we don't know about?), prepare another set of skills. Change your skill bar, which is possible now (unlike the BWEs) and face the perils of the sea.
The Arcane skills are now all available and most of the Cantrip skills are working. People running Signet builds do not have to switch out anything compared to fighting on land.