Even though it is a desert, lakes are present. These are seasonal, the rainfall being a feast or famine phenomenon. In 2019 enough rain fell that flooding decimated a road and formed a new massive lake, at least new to local residents. Being a desert, and the area where the lake formed being a depression, it is likely that this is a wetland that is more often land than wet. Other wetlands form and dry up based on season and rainfall. Some of the water filling these bodies is from underground flow, which ebbs along with rainfall as well, but the rainfall might not be local
The soils in this desert contain salts, and the freshwater lakes that form are hyposaline or even mesosaline. Salinity is up to 134 gL but is usually lower since the rainfall is essentially zero ppt. Speaking of 134gL, this barely registers if you are familiar with ocean salinity. You would have a hard time reading it on your refractometer or hydrometer, the reading being 0.1346, whereas inshore seawater, at 32 ppt, reads 1.0245. However slight the salt content, it must influence the organisms. Salt and water balance are critical to the proper functioning of organisms: The adaptations to an abundance of water or salt, or lack thereof, are fascinating.
Migratory birds often use temporary wetlands. Other animals may also take advantage of the ephemeral waters; temporary wetlands typically have no fish to act as predators. If you’re an animal that lives here to take advantage of the lack of fishy predators, you still have to deal with the temporal nature of the wetland, the salinity, and the temperature.
During an expedition through the Lut desert in 2017, researchers collected a crustacean unknown to science. The animal was very similar to others in this genus but differed in the morphology of the brood pouch. And, of course, you also use molecular data these days to confirm a new species. The researchers used CO1 and rRNA sequences and compared them to available sequences from GenBank. The new crustacean is a fairy shrimp, Class Branchiopoda, and subsequently named Phallocryptus fahimii.
An aside: I have blogged about systematics and taxonomies using molecular data and the challenges presented; if not, I must soon. One problem… when molecular data started to be commonly used, it was regarded by many as a panacea that would clear up all questionable systematics. The reality is, it is just one more piece of evidence to evaluate, and one sequence may be more helpful in some taxonomic groups than others. CO1 is a case in point. CO1 stands for the Cytochrome c oxidase gene from the mitochondrial DNA and is the DNA segment first used for what is called DNA barcoding. Some animal groups have a wide variation in their mitochondrial DNA, even within a population (that is of the same species). So like, the presence and number of setae, the shape of the telson, or other anatomical features of crustaceans, the molecular data becomes one thing to compare.
Back to the more interesting stuff: How does this little crustacean survive the harsh desert? One way is that it lays hearty eggs. These eggs can hang out in the dry sand for years, waiting for the next rainfall. That is why the eggs of this group of organisms can be sold dry, and shipped from afar, for feeding other aquaria animals, and also sold sea monkeys. Who here bought sea monkeys?
Ending Note:
The genus name, Phallocryptus, described by Birabén in 1951, loosely means covered penis. I think the describer was the spider guy Max Birabén from Argentina, but I am not certain. This genus contains only five species. The new species is named after Hadi Fahimi, who took part in the expedition in 2017 but died in a plane crash in 2018 before the species was formally described, which occurred in 2020.
Second ending note:
My local brine shrimp guy Christopher Rogers is from the University of Kansas. I included one of his papers below. A super interesting guy, and like many high-volume researchers I meet, has waaaaaaaay more energy than I do. He and his colleague James Thorp edited the newest editing of the book that bears Thorp’s name on freshwater invertebrates, I listed this below as well. (I have two copies if you need to borrow one).
Sources and Further Readings:
Lyons BW, Welch SA, Gardner CB, Sharifi A, Agha Kouchak A, Mashkour M, Djamali M, Matinzadeh Z, Palacio S, and Akhani H. 2022). The hydrogeochemistry of shallow groundwater from Lut Desert, Iran: The hottest place on Earth. Journal of Arid Environments 178: 104143. doi: 10.1016/j.jaridenv.2020.104143
Rogers DC. 2006. A genus level revision of the Thamnocephalidae (Crustacea: Branchiopoda: Anostraca). Zootaxa 1260: 1–25.
Schwentner M, Alexander V. Rudov & Hossein Rajaei (2020): Some like it hot: Phallocryptus fahimii sp. n. (Crustacea: Anostraca: Thamnocephalidae) from the Lut desert, the hottest place on Earth, Zoology in the Middle East. DOI: 10.1080/09397140.2020.1805139
Shirsalimian MS, Mazidi SM, and Amoozegar MA. 2022. The Lut Desert and Its Microbial Diversity: Recent Studies and Future Research. Microbiology 91:3: 215-224.
Thorp and Covich's Freshwater Invertebrates: Ecology and General Biology. 2016. Netherlands: Elsevier Science. (edited by J.H. Thorp and D.C.Rogers)