Would the desert ecosystem be considered an open or closed system

A closed ecosystem is a type of ecosystem wherein it exchanges energy but not matter with its surroundings such as mesocosm. Thus it is self-contained or under controlled environment or controlled-condition. Meanwhile, an open ecosystem is a type of ecosystem wherein it exchanges both energy and matter with its surrounding environments.

A desert is a dry and arid environment that displays extreme temperature or  climate condition, that is hot or cold, in which most of the time it is hot. This occurs in region where there is less than 50 cm of rainfall in a year and have a specialized crops or  vegetation. It also has variety of animals that are self-sustaining-- can survive for days without water.

Based on the description, we can conclude that a desert is an OPEN ECOSYSTEM since it is not under a controlled-environment.

Ihaven't done that yet, so no idea,but this is not the right place to ask

When you are making a guess you are forming a hypothesis