Tag: Earth Sciences

A study led by Prof. Noa Shenkar and graduate student Gal Navon, from the Tel Aviv University (TAU) School of Zoology and the Steinhardt Museum of Natural History, has found significant concentrations of residual pharmaceuticals at 11 sampled sites along the Israeli coastline. These substances have been found in ascidians – marine, filter-feeding, sessile invertebrates. This study was conducted with the participation of the Hydrochemistry Lab of the Water Research Center of the Porter School of the Environment and Earth Sciences, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, headed by Prof. Dror Avisar. The study was published in the journal “Marine Pollution Bulletin”, in August 2020. The study involved sampling of ascidians from 9 different sites along the Mediterranean coastline (Achziv, Acre, Haifa Marina, Sdot Yam, Hadera power station, Acadia beach in Herzliya, HaSela beach in Bat-Yam, Ashdod Marina and Ashkelon Marina) and 2 different Red Sea sites (Eilat Marina and Dolphin Reef). Ascidians are marine invertebrates, few centimetres in size that attach to hard surfaces – such as rocks, peers or breakwaters. Since ascidians feed on small particles found in the water, large quantities of particles from the marine environment accumulate in their bodies over time – including different pollutants. The researchers have performed chemical analysis of the collected ascidians, searching for active compounds of three frequently used pharmaceuticals: Bezafibrate, which reduces blood lipids content; Carbamazepine, an antiepileptic, and mood stabilizer; and Diclofenac, an anti-inflammatory agent present in the well-known medicine Voltaren. These three substances are extremely durable, are hardly degraded by sewage treatment facilities, and last long in the marine environment. The findings are extremely worrisome: in 10 out of 11 sampled sites significant concentrations of the tested pharmaceuticals have been found.

• All three substances have been detected at 4 of the tested sites (Ashdod, Ashkelon, Sdot Yam and Haifa).
• Residuals of two of the pharmaceuticals have been detected at 5 of the tested sites (Achziv, Acre, Herzliya, Bat-Yam and the Eilat Marina).
• One site – Eilat Dolphin Reef, has shown signs of one pharmaceutical only – Diclofenac, though at a concerning concentration
• Ascidians collected from deep water at the Hadera power station were the only ones to show no traces of pharmaceuticals.
• Especially high concentrations of Diclofenac and Bezafibrate were found in Acre, Ashdod and Ashkelon.

  ^{Did they take their medicine today? Ascidians} Prof. Shenkar and the researcher Gal Navon explain that various pharmaceuticals consumed by humans are not fully metabolized in the body, and high percentage of their active compounds are later excreted in their original form. In addition, lack of public awareness often results in the disposal of unused drugs in toilets or home garbage bins. Currently existing sewage treatment facilities are not suitable for the treatment of medication residuals, and, unlike other pollutants, their final concentrations at the endpoint of sewage treatment are not monitored. Eventually, a substantial amount of pharmaceuticals is discharged into the sea by sewage water. According to the research team, a variety of pharmaceutical residuals can be found in marine ecosystems worldwide – antibiotics, anti-inflammatory drugs, analgesics, anti-depressants and many more. “Many of these compounds are very stable”, the researchers say, “These take a long time to degrade in the marine environment, and the damage they cause to marine life could be extremely excessive, since these pharmaceuticals are designed to affect biological systems (the human body). For example, various studies performed in different sites around the world have shown that Estrogen, present in birth control pills, leads to the development of female features in male fish in certain species, thus damaging their fertility; Prozac triggers increased aggressiveness and risk-taking in crustaceans; anti-depressants impair memory and learning in cuttlefish, and more”. Prof. Avisar: “We have been studying the chemo-physical fate of drug residuals in groundwater and surface water for the past 15 years, and their detection in marine ecosystems has been surprising. The results indicate a chronic large-scale pharmaceutical residuals contamination, as well as the absorption of micro- and nano-pollutants, measured at very low concentrations in marine organisms”. “Our study shows that Israel is no stranger to the global serious issue of seawater pharmaceutical contamination.”, Prof. Shenkar concludes. “The medications we use end up in the sea, mainly through sewage discharge, and cause great damage to the marine environment, indirectly affecting humans, who feed on sea foods that are exposed to such contamination. There are different ways to tackle this problem: on the individual level, we recommend that the population as a whole takes personal responsibility, disposing of unused pharmaceuticals into designated containers – which can be found at pharmacies and health maintenance organizations’ facilities. In addition, we are working to expand research on monitoring pharmaceutical contamination along the Israeli coastline, using advanced analysis of a greater variety of widely used medication, while examining the changes exerted upon the various organisms exposed to the environmental concentrations of those pharmaceuticals”.

For the first time in history, researchers at Tel Aviv University tracked fruit bats from birth to maturity, in an attempt to understand how they navigate when flying long distances. The surprising results: Fruit bats, just like humans, build a visual cognitive map of the space around them, making use of conspicuous landmarks. In this case, bat pups from Tel Aviv University came to know the city by looking for large unique structures such as the Azrieli Towers, the Dizengoff Center etc. The groundbreaking study was conducted by Prof. Yossi Yovel, together with students Amitai Katz, Lee Harten, Aya Goldstein and Michal Handel from the Sensory Perception and Cognition Laboratory at the Department of Zoology. The paper was published in July 2020 as the cover story of the prestigious Science Magazine. “How animals are able to navigate over long distances is an ancient riddle,” explains Prof. Yovel. “Bats are considered world champions of navigation: they fly dozens of kilometers in just a few hours, and then come back to the starting point. For this study we used tiny GPS devices – the smallest in the world, developed by our team, in an experiment never attempted before: tracking bat pups from the moment they spread their wings until they reach maturity, in order to understand how their navigation capabilities develop. No such study has ever been conducted on any living creature, and the findings are very interesting.” The researchers monitored 22 fruit bat pups born in a colony raised at TAU – from infancy to maturity, tracking them as they scoured the city for food. The results show that Tel Aviv bats navigate the space around them in much the same way as the city’s human inhabitants. “Bats use their sonar to navigate over short distances – near a tree, for example,” says Prof. Yovel. “The sonar doesn’t work for greater distances. For this, fruit-bats use their vision. Altogether we mapped about 2000 bat flight-nights in Tel Aviv. We found that bats construct a mental map: They learn to identify and use salient visual landmarks such as the Azrieli Towers, the Reading Power Station and other distinct features that serve as visual indicators. The most distinct proof of this map lies in their ability to perform shortcuts. Like humans, bats at some stage get from one point to another via direct new routes not previously taken. Since we knew the flight history of each bat since infancy, we could always tell when a specific bat took a certain shortcut for the first time. We discovered that when taking new, unknown routes the bats flew above the buildings. Sending up drones to the altitude and location where a bat had been observed, we found that the city’s towers were clearly visible from this high angle. Here is another amazing example of how animals make use of manmade features.”