What do Skarner's Crystals do in patch 5.16?

Solution 1:

From the Patchnotes:

NEW Passive - Crystal Spires
Skarner's presence causes crystals to spawn in set locations around the map. Crystals can be captured by either team by standing on top of them. Capturing a crystal prevents them from being captured by the opposing team for 15 seconds.

While near active crystals, Skarner gains 70 - 120 Movement Speed (66 + 4 / 3 / 2 per champion level), 43~164% (34 + 9 / 7 / 5 per champion level) Attack Speed, and restores 2% of his maximum Mana per second.

So if the enemy team captures a crystal, it just means you can't get the buff there and you can't capture the crystal for 15 seconds. Nothing else from what i have seen.

For yourself, it is a buffzone. Also, if you capture the crystal on your own, you get 15 gold from it. If more than one champ participated in the capturing, 30 gold are split among the people who captured it.