here is some good info for those wondering about the variable Iodine content of different kelp species.

there are various species of sea vegetables all sold as "kelp." some of these species are higher in Iodine than others.

the "laminaria" species of kelp is the species highest in Iodine content. this includes any kelp product labeled laminaria digitata, l. japonica, l. saccharina, and l. longissima. the laminaria species of kelp can be 5% or more of iodine per dry weight.

"frontier" brand kelp is laminaria digitata, and therefore has a high iodine content.

any product labeled "kombu" is of the laminaria species and thus high in iodine.

bladder wrack (fucus vesiculosus)is the kelp variety that is next in line in iodine content. "nature's way" brand uses bladderwrack.

the next highest kelp variety in iodine content is ascophyllum nodosum. the "now" brand of kelp uses this species. this species can contain between .3% and .8% of iodine per dry weight.

however!! any specific batch of any type of kelp may be higher in iodine content than any other specific batch. why? because as the kelp grows it constanly is taking up and releasing iodine, thus the iodine content totally depends on exactly when during the iodine cycle the kelp is harvested.

the above iodine values are AVERAGE values. so generally speaking any laminaria species will be higher in iodine than any bladderwrack species, but that doesn't hold up all the time.