MSL - SAM and CHEMIN, Discussion of the science/results from these instruments |
MSL - SAM and CHEMIN, Discussion of the science/results from these instruments |
![]()
Post
#1
|
|
![]() Senior Member ![]() ![]() ![]() ![]() Group: Admin Posts: 3108 Joined: 21-December 05 From: Canberra, Australia Member No.: 615 ![]() |
ADMIN NOTE: Hi All, a new topic for the discussion of the science from the SAM and Chemin instruments.
There has been a very important amendment to Rule 1.3 which is explained here. Please remember Rule 1.3 at all times when discussing matters in this section. |
|
|
![]() |
![]()
Post
#2
|
|
![]() Senior Member ![]() ![]() ![]() ![]() Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 ![]() |
Ken Kremer from Spaceflight magazine asked about N and P:
QUOTE Kremer: I'm interested to know, maybe even from Paul Mahaffey, about the SAM run, did you see any nitrogen, or phosphorous or chlorobutanes, and can you talk about what was the weight percent level of the phyllosilicates? Mahaffey: I think the weigh percent of the phyllosilicates is best answered by CHEMIN, and you [looking at David Blake] gave a number for that... Blake: 20 to 30 weight percent. Mahaffey: ..and, did we see nitrogen compounds, we certainly are in our trace gases looking for those. It seems that we have some nitogen oxides coming up, we're looking at compounds like HCN and so on. Deconvoluting those spectra requires work and so we're working away on that, but it sure looks like we have nitrogen compounds there. In terms of phosphorous, we haven't seen any, but that really is an APXS result, they see phosphorous in their compounds. Very interestingly, we see a fair bit of hydrogen chloride coming up into our lines, and so the chlorine is not just producing these trace chloromethane compounds, but is also producing hydrochloric acid. Just before that, John Grotzinger said this about finding CO2 in the SAM gases: QUOTE Grotzinger: That's what we're real excited about there, because then that gives us our sort of desiderata of key elements that are the building blocks for life: hydrogen, oxygen, phosphorous, sulfur and then of course nitrogen and then also carbon. A mnemonic for that desiderata for life is sometimes given as CHNOPS (chi-nops). -------------------- |
|
|
![]()
Post
#3
|
|
Member ![]() ![]() ![]() Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 ![]() |
A mnemonic for that desiderata for life is sometimes given as CHNOPS (chi-nops). Hm, never heard that one before. Here on Earth 96%-98% of biomass is CHON. Phosphorus is the next most common, typically between 1% and 2%. Then calcium, with the exact figure a bit blurry depending on whether you count stuff like seashells as "biomass", but generally around 0.5%. (It's more like 1.5% for humans and other vertebrates, but that's because we concentrate calcium in our skeletons.) Then you have another group -- potassium, sulfur, chlorine, sodium and magnesium -- that are all between 0.5% and 0.05%; together these make up a bit less than 1% of all biomass. (They're all utterly essential, though. There's no life, not even weird extremophiles, that doesn't rely on these guys.) Sulfur is still below potassium and calcium, though. So maybe that mnemonic should be CHNOPKaCS? After that you have a steep dropoff to the next most common element, iron, which is typically less than 0.01% of biomass. AFAIK there's no life that doesn't use iron in its chemistry, but IANA biologist and I wouldn't be shocked to find some odd microbe getting along without it. It's involved in a number of important biological processes, but it doesn't seem to be mission-critical the way that the elements listed above are. So if we're looking at the elements needed for life, they're CHON, followed by P-Ca, followed by K-S-Cl-Na-Mg and maybe Fe. Doug M. |
|
|
![]()
Post
#4
|
|
![]() Member ![]() ![]() ![]() Group: Members Posts: 107 Joined: 29-January 09 Member No.: 4589 ![]() |
Phosphorous (in the form of phosphate) is required for nucleotide biosynthesis. Iron's pretty important for redox biochemistry too; it's essential for haem (think cytochromes) and FeS cluster assembly. I'm not aware of any organisms that don't utilise it.
-------------------- Protein structures and Mars fun - http://www.flickr.com/photos/nick960/
|
|
|
![]() ![]() |
![]() |
Lo-Fi Version | Time is now: 20th June 2024 - 08:16 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |
![]() |