What's the difference between 感謝している and 感謝する? Looking at http://www.tanos.co.uk/jlpt/skills/vocab/sentences/?vocabid=85961 , I get the impression that for the word 感謝, it is not as simple as one being the continuous tense and the other, the present tense. From the link, it seems that both has the meaning of "I am grateful" (in the state of being grateful), and that means both is in continuous tense rather than present. Sounds to me like 感謝する does not/cannot/will not mean "I will be grateful". A more concrete example:
食べ物に感謝する and 食べ物に感謝している both means "I am grateful for the food". The former cannot mean "I will be grateful for the food" and can only ever mean "I am grateful for the food"