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[Music]

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hi I'm Miriam and I'm here to talk about

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the salt of the earth and how they could

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help when looking for life in the solar

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system

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Earth can provide us with analogs that

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can

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mimic extra planetary environments and

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one of the most ones most often used for

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Mars is the Atacama Desert I'm really

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proud of this graphic

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so in the Atacama life has been shown to

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live off the deli questions of salts but

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uh can the salts that I studied

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deliquest in Autumn conditions so for my

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project I tried to answer two scientific

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questions could nitrate salts or their

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salt mixtures uptake water or release

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water

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autocom environmental conditions and

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could the temperature and relative

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humidity values lead to nitrate salt

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deloquiescence

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so to answer this we used a Ramen

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microscope attached to an environmental

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cell in which the temperature and

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relative humidity could be controlled

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and we used this to study the phase

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transitions of our salts of Interest

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so we can answer our first question

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could nitrate salts or salt mixtures

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take up water under autocommer

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conditions well yes and thank you for

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coming to my talk

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um so

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but let me tell you why and so the first

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thing that we're going to do is look at

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the spectral series of the pure

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magnesium nitrate

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um so if we look at the crystalline

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nitrate which is going to be shown by

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the black Spectra at the bottom it

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starts off at a higher wave number of

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1062 and as we increase the as we

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decrease the relative sorry increase the

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decrease the temperature and increase

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the relative humidity it's going to stay

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there until it reaches the deli

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questions relative humidity of 63

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percent

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um at which point it shifts the lower

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wave number of 1052 so it's going to

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stay here

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and this is really cool it's going to

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stay here and as we increase the

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temperature and decrease the relative

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humidity it stays at that lower wave

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number until the efflorescence relative

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humidity of 23 and that means that

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magnesium nitrate the pure one can

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maintain a metal stable brine for over a

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um so we repeated these experiments

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multiple times over different

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temperatures and we made this lovely

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phase diagram

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uh and it's as temperature versus

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relative humidity so for the pure

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magnesium nitrate has a hydrate the Dell

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questions is going to be shown by the

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blue dots and the efflorescence is shown

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by the orange squares and it was a

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relatively temperature independent and

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occurred around 25 RH

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so magnesium nitrate exhibited a very

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large hysteresis which you can tell by

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the gap between the Dell questions and

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the fluorescence relative humidity and

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this is going to be our meta-stable

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brine region but I also mentioned salt

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regions so what about them so we

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did the exact same experiment but we

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used

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um different salts so we have magnesium

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nitrate so this is a one-to-one mixture

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and we have magnesium nitrate on the

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left and magnesium per chlorate on the

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right and we see that same shift in the

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nitrate Peak which we use to determine

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when dull questions would occur

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and so

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we took different ratios of chlorate and

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nitrate and we looked at how the pcori

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can influence the water uptake of the

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nitrate salts in the soil

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and so the blue dots once again are

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going to be the Dell questions and the

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orange triangles are the efflorescence

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um and then the lines in between is the

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average of the experiment so what we can

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see is that for chlorate seem to be

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helping or assisting with the magnesium

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nitrate water uptake or deloquiescence

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and so if we look at our overall picture

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so this is pure magnesium nitrate and

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its Dell questions is at 60 RH

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however if we look at our pechlorate

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mixtures we can see that the water

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uptake seems to be assisted by that and

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we see this with the downward facing

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Trend

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um so we also wanted to look at what

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affects a less hygroscopic or

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deliquisite salt would have on that and

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so we did a one-to-one mixture with

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sulfate nitrates and we saw that this

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did not inhibit the water uptake of

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nitrate because it's still below the

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deloquiescence relative humidity of

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magnesium nitrate so finally we can

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answer our last question

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which is could the temperature and

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relative humidity values lead to nitrate

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salt deloquistence in the soil

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um so we took our phase diagram and we

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took relative humidity and temperature

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datus from these two sites in the

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Atacama Desert and both of these sites

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contain nitrates perchlorates in the

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soil composition and also sulfates so

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site a which you see above was

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relatively close to the ocean and was

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therefore warmer and more humid this was

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likely a contributor to why the nitrate

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cells in the soil could maintain a

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stable liquid brine which is shown by

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the dark blue highlights and a

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metastable line which is the light blue

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highlights throughout most of the year

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then if we look at site B this was more

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Inland and therefore significantly drier

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and colder but despite this we do have

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points throughout the year in which the

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salts could uptake and deliquest and

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maintain a medicinal place so of course

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this is very highly variable and that

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could be due to the different

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environmental conditions as well as the

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different soil compositions and would

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need to be further studied

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so

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um if you have any questions comments

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concerns or a job please stop by my

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poster

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um which is number 23 so thank you

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[Applause]

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[Music]

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[Applause]