May be its related to their element contents such as chloride and calcium.

Maybe this paper about a comparison for sorption capacity of lanthanides in seaweeds could help. I found it very interesting

bets regards

stefania

Dear Siti Mashitah,

Try to look for other related REE studies especially in  Biological nutrient product in marine environment (e.g.biological silicate, silicate and opal) also to bio geochemical cycles (REE-trace metal-organic/ ligands (fulvic and humic acid)-water compartments-ions such ox hydroxide, hydrolyzed ). This should be very interested research.

Good luck

Best regard's

Zolhizir bin Daud

Fikrat Hassan - Thank You Sir, i'll have a look on their correlation with  REEs accumulation by seaweed. 

Stefania - Thank You Stefania for your attachment ^^V .. and that journal actually was one my best reference since beginning. Interesting indeed. 

Zolhizir - Thank You Zolhizir, aah..i found that u also in REEs field. Must be interesting to correlate REEs with geo studies. i've done some for my master and relate with radionuclides too. .great suggestion!, but for me to start a new scope now..its kinda TOO late already =P hehehee..but Tq