It doesn't sound plausible. The thyroid does not produce iodine. It needs it; and collects it from the blood that passes through it. The kelp is good for providing Iodine for the thyroid. Maybe that is what the article meant. Kelp is a good source of Iodine and other minerals.

It is my understanding that elemental Iodine rarely exists naturally. it usually comes in some form or another of an iodide. the human body is able to convert Iodide into iodine. For example if you eat kelp, the Iodine is in the form of iodide.

http://findarticles.com/p/articles/mi_m0ISW/is_252/ai_n6110597
Iodine: Why You Need It, Why You Can't Live Without It by David Brownstein, MD
Chapter 3 reviews the different forms of Iodine found in the body--iodine and its reduced form, iodide. This Chapter shows you which tissues concentrate which form of iodine. The breasts primarily concentrate iodine while the thyroid concentrates iodide. Dr. Brownstein carefully explains why the body is unable to convert between iodine and iodide. Therefore, he feels it is best to use a combination of iodine and Iodide when correcting an iodine deficiency.