Martian Mushrooms? If So, What Are They Feeding On?

A paper just published in the Journal of Astrobiology and Space Science Reviews, 1, 40–81, 2019, entitled Evidence of Life on Mars? begins with the words:

Presented here is a body of evidence and observations which do not prove but supports the hypothesis Mars was, and is, a living planet hosting prokaryotes, lichens, and fungi.

Among the data presented are the following photographs taken by NASA's Rover Opportunity.

Figure 8. Sol 1145-left v Sol 1148-right). Comparing Sol 1145-left vs Sol 1148-right. Growth of fifteen Martian specimens over three days. Specimens labeled 1-5 and marked with red circles have increased in size. Those specified by arrows--Sol 1148-right--demarcate the emergence of ten new specimens which were not visible in Sol 1145-left photographed three days earlier by NASA/JPL. Differences in photo quality are secondary to changes in camera-closeup-focus by NASA. The majority of experts in fungi, lichens, geomorphology, and mineralogy agreed these are likely living specimens, i.e. fungi, puffballs. An alternate explanation is a strong wind uncovered hematite which had been buried beneath sand and dirt.

The apparent growth and multiplication of objects reminiscent of mushrooms or puffball fungi is certainly remarkable, as are many other images presented in this paper, the full text of which is available here.

But if these are fungi, then a big puzzle remains: What do Martian fungi feed on?

Fungi are not autotrophic, meaning that they are unable to synthesize organic matter from inorganic substrates. They require a source of organic material to feed on: either dead material, if they saprophytes, or living material if they are parasites. But in either case, since dead organic material must once have been living, the existence of fungi on Mars would indicate the existence of autotrophic organisms, which are capable of synthesizing organic molecules photosynthetically or by other means from purely inorganic substrates. In other words, the presence of fungi on Mars would indicate the presence of an ecosystem of at least several different types of living organism.

The first botanist to set foot on Mars may be in for amazing discoveries.