Water is a deceptively simple molecule, consisting of two hydrogen atoms attached to an oxygen atom, yet its properties are complex and ideally suited for carbon-based life. Organisms are composed mostly of liquid water, which performs many functions and should not be considered merely an inert diluent. Despite much research, some of the properties of water remain puzzling. However, it is widely acknowledged that life depends on the properties of water.

For example, the high water content in organisms and the high specific heat of water contribute to a life forms ability to thermoregulate and prevent local temperature fluctuations with in the life form. The high latent heat of evaporation provides resistance to dehydration and considerable evaporative cooling.

Water is an excellent solvent due to its polarity, high dielectric constant, and small size, particularly for polar and ionic compounds and salts. Water ionizes and allows for easy proton exchange between molecules, contributing to the richness of the ionic interactions in biology. The structuring of water around molecules allows them to sense and be sensed at a distance. The unique hydration properties of water towards biological macromolecules, particularly proteins and nucleic acids, largely determine their three-dimensional structures and hence their functions in solution.

Water is not simply a passive participant in biochemical reactions; it actively influences the structure and behavior of macromolecules and can even impact other processes across long distances.

Therefore, we must recognize the vital role that water plays in biological systems and prioritize its study and inclusion in education. It is crucial that we remain mindful of the fundamental importance of water in the complex web of biological processes.

Water should not be underestimated as merely an inert diluent in biochemical processes. It plays a vital role in determining the structure and reactions of macromolecules, and its own structuring can influence other processes over significant distances. Therefore, water should be given greater prominence in both research and teaching, as it has a central role in the rich diversity of biological processes. Although water is often seen as a mundane substance, it is, in fact, a most remarkable material. It is essential for life, and life as we know it could not have evolved without water. And, life on Earth cannot be sustained without water.

Precipitation

Keeping weather records in Tucson started in 1895, with 8.06 inches of rainfall. In 2020, Tucson had a dry “non-soon,” with less than two inches of rain. The well-below-normal rainfall and record-high temperatures fueled Arizona’s  most significant wildfire season in a decade. The Bighorn Fire decimated over 60% of the forest in the Catalina Mountains north of Tucson. However, 2021 was the third wettest monsoon ever in Tucson, with 12.8 inches of rain.

The precipitation database for the Santa Rita Experimental Range (SRER) spans a century. The SRER started collecting rainfall data in 1922, including monthly measurements at 75 rain gauges.

The elevation of the SRER increases from about (2950 to 4593 ft), and the average annual precipitation increases along this gradient. The precipitation data shows a distinct summer-winter pattern, with more precipitation in the summer than in the winter. Twenty-four gauges on the SRER, show that 2021 was the wettest July-September period, with an average of 15.08 inches. A close second was 1931 with 15.01 inches and 1990 was the third wettest at 13.87 inches. The driest year was 2020, which averaged 2.1 inches followed by 1973, 1956, 1989, and 1924.

Water running west off the Santa Rita crest drains into the Santa Cruz watershed and feeds washes running through the Santa Rita Experimental Range and into the community of Corona de Tucson. Papago Canyon connects to Davidson Canyon on the east side of the range, a critical wildlife corridor for species moving between the Santa Rita Mountains, Cienega Creek, and the Rincon and Catalina Mountains. The eastern edge of the Santa Rita management area borders the Sonoita Valley’s grassland. Water run-off from the eastern versant of the Santa Rita’s feeds into Cienega Creek as it runs through Las Cienegas National Conservation Area. The eastern and southern flanks of the mountains feed Sonoita Creek. The Patagonia-Sonoita Creek Preserve also encompasses riparian habitat fed in part by runoff from the Santa Rita’s. The Nature Conservancy owns the Patagonia-Sonoita Creek Preserve, and the preserve is home to three species of rare fish, threatened leopard frogs, many interesting plants, and over 200 species of birds.

Deserts are defined by the precipitation received – less than eight inches per/annum, and hyper-arid environments receive less than one-inch per/annum. The result is plants are widely scattered between patches of bare substrate. Water scarcity means photosynthesis (=plant food production) is low, and the secondary biomass is also low. Subsequently, life forms in deserts are scattered and tend to be rare.

Four topographic situations produce deserts (1) a rain shadow created by high mountains, (2) the desert is at a great distance from water bodies that generate moist air, (3) the desert is near cold ocean currents, or (4) soil conditions are such that make water unavailable to plants.