The Sacramento Mountains area, in addition with the Guadalupe Mountains, can be grouped into the southern end of the Rocky Mountains of the Western United States. The Sacramento Mountains are part of what is called the Rio Grande Rift, which is located at the east side of the pulling-apart rift. The Sacramento river, which is the main objective pathway for this analysis, starts about 15 miles southeast of Alamogordo, New Mexico. (See figure 1). As the Sacramento high range coexist with the Chihuahuan desert, extreme conditions are always present. Very cold with snow during winter and very hot and dry during the summer, although the raining season is during the summer.
With the opening of Sunspot National Solar Observatory, on September 1947, the area took quite relevance and some hydrogeologic studies were performed. This occurred during the 1950’s and 60’s. From there until now, not much else has been done. On regards the chemical analysis only one published paper was found, but none was found on the biological area.
This report gives a general idea of what kind of organisms exist along the complete system. The analysis of this local system consists of sampling the recharge, and discharge areas, some intermediate sample points in between, and one sample point at the subsurface. The chemical and biological results are discussed later on the report, as well as several other hydrogeological facts of the area. The study pretend to cover this very localized area, into what a karstic subsurface environment can be for microbes, and also their interaction with the surface runoff of the Sacramento river, and related water reservoirs.
The existence of carbonate rocks on the area, like the San Andres Formation, Hondo Member and the Yeso Formation, makes from the Sacramento River drainage system an almost certain karstic aquifer on the subsurface. Because of the young stage of the drainage (Bates, 1961), and the low recharge rate, this aquifer can be considered as a "Diffuse to Free flow carbonate aquifer," according to the classification of types of karstified carbonate rocks defined by White in 1969. The presence of folded strata increase the possibility for broken rocks, which give opportunity to more openings into the aquifer. The interconnectivity of the saturated zone will give better chances for the aquifer to dolomitize the carbonate rocks.
The study area is located about 15 miles southeast of Alamogordo. To get there, drive to Alamogordo taking highway 54 from El Paso, or highway 70 from Las Cruces. From Alamogordo continue north on HW-54 towards Tularosa, and then turn right on HW-80 towards Cloudcroft. Once you are at the entrance of Cloudcroft, turn right on paved rural road to Sunspot National Solar Observatory. Keep driving for more than 12 miles until you hit the improved dirt road that leads you to the Sacramento Lake and further down to Timberon. See figure 1 for location map. In less than half of a mile you will see the two water wells that supply the observatory.
The specific area its within the Lincoln National Forest, between latitudes 32°45’N to 32°47’15"N, and longitudes 105°46’ W to 105°49’ W. The highest point close to the area is 9,665 ft. To the east of the Sacramento River, but is not accessible by car. Although the Sunspot National Solar Observatory, is to the west of the river, with an amazing outlook to the west of the Tularosa Basin below. See figure 2 for map.
The Sacramento Mountains are part of the Rio Grande Rift. They are part of the uplifted faulted blocks, trending NW, and which are now pulling apart from east to west. Their location makes it be part of the Basin and Range physiographic province. The downthrow is to the west, with a maximum displacement along the Sacramento River fault area of about 1000 ft. (Darton, 1928). Permian limestone, gypsum, mudstone, and some red beds are also folded exposing several synclines and anticlines all over the area. The Sacramento River, which is primarily the area of study, is enveloped by the Sacramento and McAfee anticlines, which trend NS to the east and to the west of the river respectively. The Sacramento syncline runs through the faulted area, which is also the current channel of the Sacramento River. Refer to cross-section on figure 3.
At the surface, the San Andres Limestone is mostly exposed with a variable thickness between, 450 and 700 ft. The formation is mainly light to dark gray colored, and is in part dolomitic (Mourant, 1957). Underlain the San Andres Limestone, is the Hondo member, which also belongs to the San Andres Limestone, this member is exposed in some parts of the improved road that runs along the river. It is about 150 ft thick (Pray, 1954). Below is the Yeso formation, also Permian in age. This formation is characterized by its thickness of 1,200 to 1,800 ft and silty sandstone, limestone, siltstone, shale and gypsum. (Pray, 1954).
The Sacramento Mountains, is one of the few ranges with mean annual precipitation values, up to 30 in/yr., this can happen, thanks to considerable snowfalls during the winter, and several rainfalls in the summer. The area had developed a three-way drainage pattern, where the Sacramento River is taking the least advantage of all, between the Sacramento River to the southeast, the Peñasco River to the east, and the Tularosa Basin to the west. In 1961, Robert L. Bates defined the present drainage, as a structure-controlled pattern. Bates considered that the streams are on a very young stage. Moreover the river alluvial fan from the Sacramento River, reflected changing hydrological conditions since the Pleistocene. In some cross sections there is evidence that flows have diminished with time, resulting in modern channels. (Wilkins, 1995). In 1957, Mourant mention that on the last 10 years from then, the flow of several springs has diminished or ceased. On February 1999, the river flow was not as expected, but I did not have a point of comparison from previous times. Not too many snowfalls hit the ground in the area, and the soil was not very humid either.
Ground water occurrence is believed to exist under unconfined, or water table conditions, (Mourant, 1957). Water wells, #1 and #2, which are now alternating supplying the Sunspot national Solar Observatory; pump their water from the upper part of the Yeso formation. These two pumps were drilled in 1951, and since then, they had been used for public supply for the Sunspot observatory. Both were originally built with a wall diameter of 8 in. Currently well #2, is pumping at a rate of 70 gpm. Which is very likely that this extraction had contributed to the low flow of the river and its springs, since their installation.
SAMPLING AND ANALYZING METHODS
As mentioned before, this study pretend to characterized the biological activity in the complete system. That includes the recharge and discharge areas, some locations in between at the surface, and one location at the subsurface. Six different samples were taken from the study area (see map on figure 2.) To do this, a new pair of sterile gloves were used every time, as well as pre-prepared sampling bottles.
Several different types of analysis were performed according to each sample. In general terms, the field parameters were, temperature, acidity, dissolved oxygen, electrical conductivity, and turbidity. They were mostly measured at the time of sampling. PLFA analysis samples were collected on bottles with formaldehyde as preservative. Samples collected for DNA analysis had no preservative. Water and snow samples collected for anion analysis, total organic carbon and dissolved gases were filled into sampling bottles which contained a chemical-specific preservative. Water collected for cation analysis was sampled in sterile sampling bottles and was acidified less than 12 hours after sampling.
One of the recharge sources in the area, is snow. So a sample was taken from a layer of snow, about one of the highest point of the system. Snow was collected and then, field parameters were measured from the sampling bottles, about four hours later at the laboratory. These parameters are shown on table 1. Other tests were performed from the molten snow. These include anion, total organic carbon, PLFA, and DNA analysis. To acquire the sample, a thin layer of snow (1 in.) was removed from the surface, after that sample was collected. While sampling the snow, this looked very clean, but when it melts, it really change its appearance from clear to light dusty colors, or at least not clears. May be the blown material from the surroundings was all over the snow.
In order to know the existence of organisms and chemical compounds in the soil. Two samples were taken, one from soil at the surface, close to the snow sample, and other one 20cm deep, about 20 meters across the road. The analysis performed on the soil at the surface were PLFA and DNA analysis. For the soil 20cm deep, anion and total organic carbon analysis were performed. The surface soil, which was below the snow layer of about 30cm thick, has a frozen consistency. The sample was taken with an isopropyl alcohol sterilized auger, and then deposited in the previously prepared plastic containers.
Three different water sample locations were chosen on this experiment. One of the locations is the main reservoir of the system. This reservoir is mentioned before as the aquifer located at the upper part of the Yeso Formation, which is pumped by water well #2, also mentioned above. Other one is the Sacramento Lake at the southern end of the study area, and finally a spring at pond, which is located about 0.5 miles south from well #2.
Water well #2 has a shaft and fishing spear starting at 268 ft, with the pipe at 230 ft. It is currently monitored and complying with the EPA regulations for drinking water. For taking the sample from this well, the pump was working for 15min. Diverting the pumped water into the river channel, which was very unclear at that particular site.
At the spring at pond sampling location, (see figure 4). The river channel opens about 3 meters, and extends for about 7 meters. A lot of life was seen at this point, grass was green and some plants inside the pond were also in there. Water had a greenish color thanks to the plants around it, but it has no visible organisms. Water samples were taken from the clearest area of the pond. Field parameters were measured at this time.
The Sacramento Lake was mostly frozen with an icy layer of less than 2cm. Samples were collected from an area close to the road, to the east side of the lake. The lake was full of dry plants and grass.
For all three, water samples, field parameters were measured at the site, after bottles were filled out. Anion and total organic carbon analysis was performed for well #2 and pond only. Cation analysis was performed on the three water samples and finally, the PLFA analysis was performed to the water sample from well #2 and spring at pond.
Phospholipid Fatic Acids (PLFA) are an important component in the metabolism of the cell. They provide quantitative means to measure viable microbial biomass, community composition, and nutritional status (White, et al., 1998), the PFLA analysis represents an enormous amount information for this experiment. Tables and figures are presented in this report to have a graphical understanding of these results.
In order to characterize microbial populations at the species level, a DNA analysis, denaturing gradient gel electrophoresis (DGGE,) is needed. The intensity and banding patterns of the analysis provide information about the changes in the community. The amplification of 16S rDNA fragments determines the species composition. High-resolution sequence analysis of a particular band is used to infer the identity of the source organisms based upon database searchers and phylogenetic methods (Ward, and others, 1992).
Temperature for the different water samples were a little bit cold, temperature at well #2 and spring at pond were very similar, 7.7 and 7.2 °C respectively, this can suggests a physical connection of the aquifer and the spring, even when the topography is not quite related. Temperature for snow is assumed to be below 0°C. But at the Sacramento Lake, which was partially frozen a temperature of 3.7 °C, was registered. This suggests to me a minimum interconnection of the aquifer. The pH value for the 3 water samples was about to normal with readings between 7.5 and 7.9, snow sample presented a pH value of 8.5. High amounts of dissolved oxygen were present on samples, in decreasing order snow, well #2, lake and spring at pond, range from 12.3 to 8.9. Quite low readings for electrical conductivity were seen at all locations. See figure 5 and table1.
Carbon dioxide concentrations for well #2 and spring at pond were about normal and predictable, spring at pond was 33ppm while water well was 24.81ppm. It was expected to have a higher value for the pond, which was seen to have much more microbial activity. See figure 6.
The 20cm deep soil sample brought a particular attention because of its high nutrients concentrations. Values of 5.0 mg/kg for nitrogen/nitrates, 990 mg/kg phosphates, 310,000 mg/kg carbonates, and 32,000-mg/kg total organic carbon. Even when the soil is very rich, there are no big signs of agricultural activity in the area. See table 2.
The cation results for pond and lake were very similar (see table 3.) Findings were about 100 ppm of calcium, 10 ppm for magnesium, and 4.0 ppm for potassium and sodium. With these results can be inferred that the water flourishing from the spring is the main source of water going into the lake. In the other hand chemical elements found in well #2 are approximately five times higher than in the lake and pond, fact that can be attributed to the San Andres Limestone and the Yeso formation. See figure 7.
A strong relation exists between the biomass content of the soil at surface and the nutrient-rich 20cm deep soil samples. Thanks to the great amount of nutrients in the soil is easy to believe the enormous possibility for organisms to live. Well, this is not an exception, a total of 115,765 picomoles PLFA/g dry wt. were found on this sample, with a prokaryote/eukaryote ratio of 5:1 (see table 4). The next in line is the molten snow with 206 picomoles PLFA/ml filtered and a ratio of 1:1, and followed by the spring at pond with 80 picomoles prokaryote PLFA, and 39 picomoles eukaryote PLFA, giving a total of 119. May be the reason for the snow to have a higher content of biomass, is the wind factor. Probably the blown soil from the surroundings had transported the organisms into both environments, but the eukaryotes had not been able to live in the pond environment, while they had in the snow. Moreover well #2 contained only trace amounts of eukaryotic life, so it is possible that these organisms prefer a dry environment. See figure 8.
Community structure results (figure 9 and table 5) are based on six major structure groups that are explained on table 6. Molten snow shows a high proportion of eukaryotes mainly due to high concentrations of fungi, but also found in algae, protozoa and higher plants.
The surface soil has the most diverse PLFA profile, with a major participation of the Monoeonic group; other four groups are roughly evenly distributed between 12 and 19% of the total PLFA, and finally the Branched Monoeonics with 6.8%. The water well #2, which had only prokaryotic organisms, is evenly distributed with 50 and 50% of the Normal Saturates and Terminally Branch Saturates who may be found in Gram Positive bacteria, and many sulfate reducing bacteria.
Three main groups: Monoeonics, Normal Saturates, and Eukaryotes, with about 30% each build most of the spring at pond water PLFA total content. The other three groups contain the rest of the total community.
On table 7 and figure 10, specific biomakers were identified for molten snow, surface soil and spring at pond. Representative amounts of their total population, Fungi was present at molten snow and surface soil. In smaller relative amounts was found in the pond. Algae and higher plants were another important biomaker for molten snow and pond, with 7.2 and 11.8% respectively. The spring at pond contained 6.6% of Diatoms, and about 1% of protozoa as well as the surface soil. Organisms at the water well #2 were not detected with this technique, and the reason for that, according to the DNA analysis is that there is no close relatives in the available databases.
Another indicator of the PLFA analysis is the metabolic status of the organisms. Ratio calculations of communities can detect the phase of growth of certain community. Results shows that the Gram negative communities in the spring at pond water sample, was in the log phase of growth, while the community in the surface soil sample, was in the stationary phase of growth.
DGGE analysis results shown in figure 11, shows the DNA profile for molten snow, surface soil, water well #2, and spring at pond water samples using eubacterial and archaea primer sets. DNA profile for molten snow produced 7 bands with distinguishable sequences (see table 8a). Band 1 has some relation with a novel strain of Cyanobacterium and Chloroplast phylum, band 7 was closely related to a bacteria found within the Rhodobacter subgroup in the alpha subdivision of purple bacteria. Bands 5 and 6 appeared to be two different strains of bacteria closely related to species Friedmanniella antartica found within the propionibacterium subgroup in the Gram-positive phylum.
The surface soil sample only contained two bands with distinguishable sequences from the eubacterial DNA. Both bands lie within the High G+C subdivision of the Gram positive phylum. Band 16 is closely related to the genus Frankia and band 17 closely related to the genus Microlunatus.
On water well #2 sample, the DGGE analysis produced three distinct bands on the eubacterial domain that appeared to be three different strains of bacteria closely related to the genus Methylbacillus within the Methophilus subgroup in the beta subdivision of purple bacteria. The archaea DNA profile contained four bands where three of these produced distinguishable sequences that represented Novel sequences with no close relatives in the available database.
Finally the eubacterial DNA profile of the spring at pond water sample, produced four bands with only two distinguishable sequences, band 12 was closely affiliated with the genus Navicula. Band 11was closely related to the genus Flavobacterium in the cytophaga. The archaea DNA profile contained one dominant band that was closely related to endosymbiont of Metopus paaeformis. One faint band was also sequenced and was closely affiliated with the genus Methanosarvina.
Even when the area receives high precipitation, most of it is drained towards the west. There, the Sacramento escarpment gives a better outflow through its steep canyons, that finishes into the Tularosa basin, east of Alamogordo. A detailed analysis of the recharge and discharge results, from C. Nagel in 1985, in conjunction with the geology of the area, can be of tremendous importance to define the shape and boundaries of this karst aquifer.
The water quality from well #2 is in compliance with the EPA standards. Although PLFA analysis showed presence of prokaryotic organisms, with specific biomakers representative of Gram positive bacteria, or some type of sulfate reducing bacteria. Moreover the archaea DNA profile contained three distinguishable sequences that represented Novel sequences with no close relatives in the available database. Further investigation is recommended in this particular field, at least to recognize these three organisms and update the database.
For molten snow, surface soil, and spring at pond samples, the PLFA analysis showed that fungi is present in important amounts. Algae and higher plants are also significant part of the specific biomakers.
The soil besides the Sacramento River, and close to the Sunspot observatory seems to be very nutrient rich. Contents of nitrate, phosphate, carbonate, and total organic carbon, are representatives of a good fertile soil.
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