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TODAY'S FACT IS

Did you know that the Banded Dye-Murex (Hexaplex trunculus) is a species of rock snail found around the Mediterranean and eastern Atlantic coasts? People have been using a mucus from this snail as an indigo dye since at least the time of the Canaanites.

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This humble sea snail, Hexaplex trunculus, has played an oversized role in Jewish history.  After literally centuries of searching, it is believed to be the source of the “biblical blue” dye, or tekhelet, that the Jews were commanded to use on their ritual garments, most conspicuously the tallit; in turn, those blue stripes of dye influenced the tallit-based design of the flag of Israel. 

Despite the importance of using tekhelet dye, the precise identity of the species from which it is extracted had been lost in antiquity.  You can get purple or violet dyes from several local marine snails, but the scribes insisted that the dye had to be blue, not purple, and all known candidate species either produced the wrong shade or made a blue that was only short-lived, fading into uselessness that disqualified them.  Only three ancient artifacts using tekhelet dye are known to still exist, which didn’t make things easier.

I encourage you to read the full story of how the right snail species and method for creating “biblical blue” was at last recovered. 

And yes, of COURSE various Jewish scholars were arguing for different candidates! 

OCEAN ACIDIFICATION CAN HINDER  REPRODUCTIVE HABITS

Ocean acidification is predicted to have detrimental effects on many marine organisms and ecological processes. Despite growing evidence for direct impacts on specific species, few studies have simultaneously considered the effects of ocean acidification on individuals (e.g. consequences for energy budgets and resource partitioning) and population level demographic processes.

A new study claims that the acidification of the ocean could be negatively altering the population dynamics of marine species and preventing them from being able to adapt to future climate change. In particular, the study examines the gastropod banded dye-murex (Hexaplex trunculus), a widespread Mediterranean mollusc.  and its response to ocean acidification over numerous generations, and found that they trade-off the maintenance of their shells in order to compensate for the living conditions of acidified oceans, which poses a higher cost of living.

UK researchers  discovered that that these changes to the energy budget may not be the same for males and females, and at a population-level, those individuals contributing to reproduction change year-on-year, resulting in a genetic drift that could hinder the potential for genetic adaptation to ocean acidification

Acclimatization can buffer populations against the immediate impacts of ocean acidification, and even provide time for adaptation (...) However, it can also result in stress-induced energetic trade-offs, and unless organisms can compensate for the extra costs caused by ocean acidification, then they may suffer negative consequences in the form of reduced growth, development and reproduction. said Samuel Rastrick, who participated in the research.

Even against a background of high gene flow, ocean acidification is driving individual- and population-level changes that will impact eco-evolutionary trajectories.

Photo:  Samples of H. trunculus living at the Low pH site (a) showing shell dissolution and reduced shell size when compared to individuals from the Control (b), and Reference site (c). The individuals displayed are representative for both the mean shell length.

From Wikipedia, the free encyclopedia Hexaplex trunculus Hexaplex trunculus Hexaplex trunculus Scientific classification Kingdom: Animalia Phylum: Mollusca Class: Gastropoda (unranked): clade Caenogastropoda clade Hypsogastropoda clade Neogastropoda Superfamily: Muricoidea Family: Muricidae Genus: Hexaplex Subgenus: Trunculariopsis[1] Species: H. trunculus