The phrase "a marked decrease of" is correct and usable in written English.
It can be used to describe a significant reduction in quantity, quality, or intensity of something.
Example: "There was a marked decrease of productivity in the last quarter, prompting management to investigate the underlying issues."
Alternatives: "a significant reduction in" or "a notable decline in".
However, there has been a marked decrease of that in recent years.
In my own experience, the addition of newborns to our household resulted in a marked decrease of robustness, from which none of the adults have recovered.
Lower oxygen concentrations resulted in a marked decrease of the catalytic activity.
The placebo again provoked a marked decrease of experienced disgust and enhanced the number of fixations for disgusting images.
In these studies, Sirt3 knockout resulted in a marked decrease of basal ATP level in vivo[58].
Our series of experiments showed a marked decrease of silver-activity in biological fluids which corresponds with the controversial clinical results obtained with silver coated urinary catheters.
Correlatively, despite conserved intrinsic lectin activity of the CRD, avidity property of Lg-ECD is affected as shown by a marked decrease of gp120 binding.
At longer times, a marked decrease of these bands is observed, which can be explained on the basis of subsequent ester hydrolysis under ageing conditions.
In particular, we observed a significant increase of the total meiofauna and nematodes abundances, and a marked decrease of kinorhynchs diversity and density at the sites beneath and near the farming 'Cage'.
The discrete holes, arranged in rows aligned in the pitchwise direction, gave rise to relative maxima of film-cooling effectiveness downstream of each row, followed by a marked decrease of effectiveness along the gap between adjacent rows of holes.
Either sciatic nerve ligation or intraplantar injection of a complete Freund's adjuvant caused a marked decrease of the paw-withdrawal latency only on the ipsilateral, but not on the contralateral side of the paw in wild-type mice.
