Some people find the distinctive aroma of sea vegetables to be strong or off-putting. One reason that it smells so strong is because it's a highly concentrated, dehydrated food.  As long as there is no mold or other signs of deterioration (usually from being stored under damp and/or overly warm conditions) the product is fine to eat. Storing sea vegetables in a tightly sealed glass or plastic jar helps keep the odor from permeating the kitchen or pantry.