it looks like poloniex is digging for clams and also it sells it on the market. Imo this is a huge conflict of interests... Maybe they are the misterious digger.
The transaction you linked to is spending a bunch of 4.605
35574 CLAM outputs.
Digging gets you 4.605
45574 CLAM outputs.
The outputs being spent are each 0.0001 CLAM less than the dig amount. The 0.0001 was spent on a transaction fee as the digger moved the outputs from his wallet to his poloniex deposit address(es).
Check the address of the first input:
http://khashier.com/address/x9Va3QTU2Rtt9MJtv24ZY1ddUGX9tT6ypo
The digger sent 10 separate 4.6 amounts there. Outputs don't merge when they're sent to the same address. The same is true of every other Bitcoin-like coin I'm aware of.
Edit: of course, if you spend multiple outputs in a single transaction then they merge together. But he's sending them individually, in separate transactions, so they don't merge.