The Galveston Island is a barrier island that has finished it's growth phase and is starting to erode naturally. There's not much you can do about this. To make matters worse the east jetty along the ship channel is robbing the rest of the island of its natural littoral drift sand. The trucking of this sand, because of grain size, is actually better than the previous method of pumping dredge material. The sea wall itself will cause the beach to erode.
Barrier islands try to maintain an equilibrium.
To address the subject at hand the sea weed is good to have on the beach because it will catch the sand that is brought to the beach by wave action. As bad as it smells it is really very good for the beach. I think the seaweed should be pulled farther up the beach and re-covered with sand. The way it stands right now, the seaweed is more of a con than a pro. That seaweed as we all know will never make it any farther up on the beach where it is needed most.