## 3 Results
### SEM Results  
Several microbial morphologies were observed under SEM, and associated EDS confirmed the chemical composition of the samples. Numerous microbial morphologies were observed in differing amounts across several morphological sample types (Figure 8). Most of the terms we use are self-explanatory, and demonstrated through the use of SEM images, but we felt we should define the term \"Biofilm\" in this context. We use the term biofilm to describe the amorphous matrix substance found between, below, and covering other morphologies. It has a high carbon peak when probed with EDS. Microbial mats and mineral crusts were the sample types that had the greatest diversity of microbial morphologies, followed closely by the ooze sample type. The least diversity of microbial morphologies was observed in coralloids. Spheroids and moonmilk sample types were the next least diverse in terms of microbial morphologies. There were several interesting and unique occurrences across the samples we imaged. First, microbial mats had the highest number of fuzzy cocci (Figure 9B). Moonmilk had the second-highest biofilm observations but had one of the lowest numbers of different morphologies present. There were two rare morphologies across the samples: beads-on-a-string (Figure 9E) were observed once in each of three sample types: one mineral crust, one moonmilk, and one ooze sample. Reticulated filaments (Figure 9F) were found exclusively in Hawaiian samples, especially in Maelstrom cave and especially in ooze samples. These two interesting, ornate morphologies were previously found in caves in other parts of the world [29; 51]. As for other morphologies found, cocci (Figure 9B) were observed both with putative pili or fimbiae and in large, aggregate groups. Microbial rods were observed but were not as common as other morphologies present in these samples. Filamentous microbes were found in most of our samples, generally falling into one of two categories: smooth filaments (Figure 9A) and what we have dubbed \"fuzzy\" filaments (Figure 9C). A common morphology observed is a mix between cocci and fuzzy filaments--we have dubbed such morphologies as \"fuzzy filaments with cocci\" (Figure 10C). Less often observed but somewhat related to filaments are what we call \"segmented filaments\", which are often flat  
Figure 8: Number of observations of different microbial morphologies across different sample types. “Number of Samples Analyzed” is a reference to the number of cave features placed under the SEM. “Number of Images” references the sum total of different scanning electron micrographs taken for all samples analyzed. The data are represented in two different heat maps. The microbial morphologies are color coded with dark blue representing extremely low numbers observed, and dark red representing high abundance; white is the intermediate. Sample size goes from white, representing a low number of samples analyzed, to dark green, representing a high number of samples analyzed. and come in a smooth, segmented filament variety as well as a \"spikey\", segmented variety, where the spikes are likely pili. Some spiral bacteria (Figure 9D) were observed as well, but much like the rods, spiral bacteria were relatively rare. Testate amoebas were commonplace, as well as diatoms. Biofilm (Figure 10B) is found on every sample we looked at, including bare rock, which was not included in this analysis. Finally, insect parts (Figure 11C) were also commonly found in both New Mexican and Hawaiian samples. We also looked at the surface morphologies of each microbe and mineral type of cave features. Coralloids varied in their appearance under SEM from mineral flakes at the surface, to smooth, almost crust-like surfaces on the samples (Figure 12A,B). All associated sample EDS spectra showed signals of silica, some gypsum and calcite in coralloid samples, which is to be expected [27]. Spheroids had macroscopically visible ridges across the sample, which were the main features noticed underneath the microscope (Figure 13A,B).