1
00:00:03,500 --> 00:00:06,600
This is geology B with all of us
trampled. 

2
00:00:07,800 --> 00:00:11,100
The fossil record goes back 
through the phanerozoic. 

3
00:00:11,100 --> 00:00:16,000
Eon about, 540 million years, 
and even earlier into the 

4
00:00:16,000 --> 00:00:20,000
ediacaran period. 
But while the fossils, provide 

5
00:00:20,000 --> 00:00:23,800
incontrovertible evidence of 
ancient life, the fossils 

6
00:00:23,800 --> 00:00:27,800
themselves are certainly not 
alive in fossils. 

7
00:00:27,900 --> 00:00:31,100
The original organic matter 
belonging to the fossilized life

8
00:00:31,100 --> 00:00:33,700
form. 
Has been replaced by inorganic 

9
00:00:33,700 --> 00:00:37,500
materials cast into the shape 
formerly occupied by the life. 

10
00:00:37,600 --> 00:00:41,500
Form. 
However, in some situations the 

11
00:00:41,500 --> 00:00:43,900
original organic material does 
survive. 

12
00:00:44,400 --> 00:00:49,100
For example, original spores, as
old as 350 million years have 

13
00:00:49,100 --> 00:00:53,900
been identified using their 
original organic material and 

14
00:00:53,900 --> 00:00:56,800
DNA can survive for as much as a
million years. 

15
00:00:57,600 --> 00:01:01,000
But in 2019 bacteria that had 
been buried. 

16
00:01:01,000 --> 00:01:04,700
A hundred million years with 
barely any access to nutrients 

17
00:01:04,700 --> 00:01:09,600
were not only identified, but 
shown to be a I've had they been

18
00:01:09,600 --> 00:01:13,500
in suspended animation for all 
that time or where they managing

19
00:01:13,500 --> 00:01:17,200
to eke out a living using much 
less energy than was previously 

20
00:01:17,200 --> 00:01:21,700
thought to be necessary. 
Steve don't is a professor of 

21
00:01:21,700 --> 00:01:24,400
oceanography at the University 
of Rhode Island. 

22
00:01:25,100 --> 00:01:29,000
He studies life beneath the 
seafloor and was on the team 

23
00:01:29,000 --> 00:01:32,100
that discovered the bacterial 
cells living in a hundred 

24
00:01:32,100 --> 00:01:36,700
million year old sediment. 
Steve, don't welcome to geology 

25
00:01:36,700 --> 00:01:38,600
B. 
Thank you very much Oliver. 

26
00:01:38,600 --> 00:01:42,400
It's a pleasure to join you here
today where where the hundred 

27
00:01:42,400 --> 00:01:45,400
million year old sediments. 
Containing these ancient 

28
00:01:45,400 --> 00:01:48,600
bacteria? 
The sediment was in the middle 

29
00:01:48,600 --> 00:01:50,300
of the South Pacific. 
Civic gyre. 

30
00:01:50,300 --> 00:01:55,300
It's this extensive area of a 
Bissell clay that carpets the 

31
00:01:55,300 --> 00:01:56,900
middle of the South Pacific 
Ocean. 

32
00:01:57,000 --> 00:01:58,900
And why did you focus on that 
area? 

33
00:01:59,200 --> 00:02:01,900
We focused on that area because 
the sediment accumulates very 

34
00:02:01,900 --> 00:02:04,800
slowly. 
It accumulates as slowly in some

35
00:02:04,800 --> 00:02:07,600
places is a few centimeters per 
million years. 

36
00:02:08,000 --> 00:02:11,500
And why was it important to 
study an area? 

37
00:02:11,600 --> 00:02:14,200
That had? 
Such very low deposition rates 

38
00:02:15,000 --> 00:02:20,500
my colleagues and I wanted to 
study the microbes That had the 

39
00:02:20,500 --> 00:02:26,000
lowest access to energy anywhere
in the ocean and we wanted to do

40
00:02:26,000 --> 00:02:29,400
so in an environment where we 
could quarter them with 

41
00:02:29,400 --> 00:02:33,400
relatively little contamination.
So that meant relatively easily 

42
00:02:33,400 --> 00:02:37,800
penetrated sediment relatively, 
close to the sea floor and that 

43
00:02:37,800 --> 00:02:39,900
Clay is very low in organic 
matter. 

44
00:02:40,200 --> 00:02:43,200
It tiny amount of organic matter
and the amount of organic matter

45
00:02:43,200 --> 00:02:45,700
is relatively constant for tens 
of millions of years in the 

46
00:02:45,700 --> 00:02:47,500
sediment. 
So it's not eaten very quickly. 

47
00:02:48,100 --> 00:02:52,700
So these elements are below 
about 6 kilometers of water. 

48
00:02:53,400 --> 00:02:56,600
How does one go about recovering
sediments from that depth? 

49
00:02:57,400 --> 00:03:00,000
Well we're fortunate to have 
access to the Joy. 

50
00:03:00,000 --> 00:03:04,400
These resolution, which is a 
drill ship operated on behalf of

51
00:03:04,400 --> 00:03:07,100
the international ocean 
Discovery program, which is a 

52
00:03:07,108 --> 00:03:11,400
multinational collaboration to 
core of the sediment and rock of

53
00:03:11,400 --> 00:03:13,900
the world ocean. 
I'm fascinated about how you 

54
00:03:13,900 --> 00:03:17,000
actually go about doing that. 
Do you have a rigid drill that 

55
00:03:17,000 --> 00:03:18,800
goes down that enormous 
distance? 

56
00:03:19,700 --> 00:03:23,100
Is a rigid drill from your, in 
my perspective, it's drill pipe.

57
00:03:23,400 --> 00:03:26,200
And when we stand next to it, if
we lean on it, it's not going to

58
00:03:26,200 --> 00:03:28,700
bend. 
But when you have six kilometers

59
00:03:28,700 --> 00:03:32,100
of pipe out, it's a little bit 
more like, soft spaghetti. 

60
00:03:32,300 --> 00:03:36,000
I'm so it dangles from the ship 
and then when it hits the 

61
00:03:36,000 --> 00:03:40,100
bottom, it then starts spinning 
to drill a call it dangles from 

62
00:03:40,100 --> 00:03:44,400
the ship, there's a driller and 
the driller controls the rate of

63
00:03:44,400 --> 00:03:47,600
spin. 
So this drill ship is somewhat 

64
00:03:47,600 --> 00:03:49,400
like oil and gas drilling 
vessels. 

65
00:03:49,600 --> 00:03:53,300
But the rig is set up very 
differently with an oil or a gas

66
00:03:53,300 --> 00:03:56,300
vessel. 
They have a really wide outer 

67
00:03:56,300 --> 00:04:00,500
pipe to prevent blowouts, so we 
don't use that outer pipe. 

68
00:04:00,500 --> 00:04:03,600
We use an inner pipe and we make
sure that we drill where there's

69
00:04:03,600 --> 00:04:07,300
no chance of oil or gas. 
And that allows us to work in 

70
00:04:07,300 --> 00:04:09,900
much deeper water because we 
don't have the way to that big 

71
00:04:09,900 --> 00:04:12,500
outer pipe and how far below the
surface. 

72
00:04:12,500 --> 00:04:15,800
Did you have to go to get these 
bacteria that we're talking 

73
00:04:15,800 --> 00:04:18,899
about here? 
This sediment is really thin out

74
00:04:18,899 --> 00:04:21,300
there because this Sedimentation
rate is really slow. 

75
00:04:21,700 --> 00:04:26,000
So even where the basement is 
100 million years old, we might 

76
00:04:26,000 --> 00:04:30,000
have only 70 meters of sediment.
This is a really different 

77
00:04:30,000 --> 00:04:32,200
situation than people usually 
think of when they think of 

78
00:04:32,200 --> 00:04:35,200
drilling the deep sea other 
Expeditions have gone out and 

79
00:04:35,200 --> 00:04:37,700
drill as much as two and a half 
kilometres beneath the seafloor.

80
00:04:37,900 --> 00:04:40,700
But our Target wasn't depth, our
Target was age. 

81
00:04:41,000 --> 00:04:44,400
So we chose this region where we
knew the sediment accumulates, 

82
00:04:44,400 --> 00:04:47,700
very, very slowly and we could 
get hundred million year old 

83
00:04:47,700 --> 00:04:50,700
sediment roughly. 
Eeyore 70 meters, beneath the 

84
00:04:50,700 --> 00:04:51,700
seafloor. 
Wow! 

85
00:04:51,800 --> 00:04:54,100
So you only have to drill a few 
tens of meters. 

86
00:04:54,100 --> 00:04:56,600
Really not very much at all. 
Exactly. 

87
00:04:57,000 --> 00:05:00,900
So when you got down to those 
bacteria, to the 100 million 

88
00:05:00,900 --> 00:05:05,700
year old age, how many bacteria 
were actually present in the 

89
00:05:05,700 --> 00:05:07,800
core samples? 
And how does that compare 

90
00:05:08,200 --> 00:05:10,400
roughly to the bacterial 
population? 

91
00:05:10,400 --> 00:05:16,300
On the sea floor surface. 
So we have roughly 1,000 cells 

92
00:05:16,300 --> 00:05:19,400
per cubic, centimeter of 
sediment in the old sediment. 

93
00:05:19,600 --> 00:05:23,400
At the sea floor in that region,
we might have more like a 

94
00:05:23,400 --> 00:05:26,600
million cells per cubic 
centimeter or 10 million cells 

95
00:05:26,600 --> 00:05:30,100
per cubic centimeter. 
And in environments on 

96
00:05:30,100 --> 00:05:33,300
Continental shelves we might 
have like a billion cells or 10 

97
00:05:33,300 --> 00:05:34,900
billion cells per cubic 
centimeter. 

98
00:05:35,500 --> 00:05:39,400
So at some level of thousand 
individuals is a lot, right? 

99
00:05:39,400 --> 00:05:42,700
You give you can imagine a room 
full of a thousand people but 

100
00:05:42,700 --> 00:05:46,300
compared to what you would have 
living at the seafloor, even at 

101
00:05:46,300 --> 00:05:49,800
the same site, almost all the 
cells that were and at the 

102
00:05:49,808 --> 00:05:53,200
seafloor are gone. 
So this is a pretty unlikely 

103
00:05:53,200 --> 00:05:56,000
environment to see something 
that could survive for this 

104
00:05:56,000 --> 00:06:00,100
length of time, but I'd like to 
understand why it was unlikely 

105
00:06:00,100 --> 00:06:02,300
in by altering. 
That question would be good if 

106
00:06:02,300 --> 00:06:04,500
you could explain what it is. 
That a bacterium? 

107
00:06:04,800 --> 00:06:09,700
Normally needs in order to be 
alive and well, well, bacteria 

108
00:06:09,700 --> 00:06:14,100
and need nutrients, and they 
need energy microbiologist who 

109
00:06:14,100 --> 00:06:17,400
work in Labs often think about 
nutrients, but when they discuss

110
00:06:17,400 --> 00:06:19,900
that they're often lumping in 
the sources of energy, G. 

111
00:06:20,000 --> 00:06:23,900
And in my mind, I separate these
things because I think a little 

112
00:06:23,900 --> 00:06:26,600
bit more like an oceanographer 
and so classical oceanographic 

113
00:06:26,600 --> 00:06:29,200
nutrients. 
Are elements like phosphorus and

114
00:06:29,200 --> 00:06:33,100
nitrogen, and sulfur and iron. 
And then we need a source of 

115
00:06:33,100 --> 00:06:35,000
energy. 
When normally, when people think

116
00:06:35,000 --> 00:06:39,000
about bacteria, they think of 
bacteria eating organic matter, 

117
00:06:39,200 --> 00:06:42,200
whether they're attacking our 
bodies or whether they're 

118
00:06:42,600 --> 00:06:44,600
attacking something in the world
around us. 

119
00:06:45,200 --> 00:06:48,000
And in that case, they're 
getting their nutrients in their

120
00:06:48,000 --> 00:06:50,500
energy from the same. 
Place in a way that getting the 

121
00:06:50,500 --> 00:06:53,100
nutrients from the organic 
matter that they eat and they're

122
00:06:53,100 --> 00:06:56,200
getting energy from oxidizing, 
the organic matter just like we 

123
00:06:56,200 --> 00:07:00,600
do just like we do and if you 
think about that for a second 

124
00:07:00,600 --> 00:07:03,000
you realize is that the energy 
really doesn't come from the 

125
00:07:03,000 --> 00:07:05,500
food. 
It comes from the oxidation of 

126
00:07:05,500 --> 00:07:08,900
the food so it comes from the 
combination of the oxidant in 

127
00:07:08,900 --> 00:07:12,700
the food source and in the 
broader world of bacteria, there

128
00:07:12,700 --> 00:07:16,600
are many, many categories of 
bacteria that use oxidants in 

129
00:07:16,600 --> 00:07:19,400
the world around them, Like 
Oxygen or nitrate or sulfate. 

130
00:07:19,600 --> 00:07:23,200
And then use reduced compounds 
in the world around them like 

131
00:07:23,200 --> 00:07:28,000
methane or hydrogen or organic 
matter and they get their energy

132
00:07:28,000 --> 00:07:32,800
from combining those two things.
So you need both things, you 

133
00:07:32,800 --> 00:07:36,000
need the nutrients, which would 
be the reduced matter and you 

134
00:07:36,000 --> 00:07:41,600
need the oxygen to supply, but 
you need to have the energy 

135
00:07:41,600 --> 00:07:46,200
generating reaction that then 
keeps the organism alive, right?

136
00:07:46,200 --> 00:07:49,100
For the energy. 
You need something reduced and 

137
00:07:49,100 --> 00:07:51,800
you need. 
Something oxidized and for you 

138
00:07:51,800 --> 00:07:55,500
and me and our listeners, the 
thing that we use to oxidize is 

139
00:07:55,500 --> 00:07:59,500
oxygen itself and the reduced 
matter that we eat is our food, 

140
00:08:00,000 --> 00:08:03,200
okay? 
So what was extremely scarce 

141
00:08:03,200 --> 00:08:05,500
than in this environment for 
these bacteria? 

142
00:08:06,000 --> 00:08:09,600
So it's extremely scarce. 
In this environment is food, one

143
00:08:09,600 --> 00:08:13,000
of the things we discovered on 
this Expedition is that. 

144
00:08:13,300 --> 00:08:16,900
So little organic matter is 
consumed in the sediment that 

145
00:08:16,900 --> 00:08:19,500
oxygen is present all the way 
from the sea. 

146
00:08:19,700 --> 00:08:23,900
E floor down to, and into the 
basement below. 

147
00:08:24,900 --> 00:08:28,300
So even where the sediment is 
100 meters thick, there's oxygen

148
00:08:28,300 --> 00:08:30,000
in the sediment all the way 
down. 

149
00:08:30,600 --> 00:08:34,200
How does it get that it diffuses
in from the ocean above? 

150
00:08:34,299 --> 00:08:38,400
It takes a long time for oxygen 
to make it 100 meters into 

151
00:08:38,400 --> 00:08:40,500
sediment is probably a few 
hundred thousand years. 

152
00:08:41,500 --> 00:08:46,900
So the process of Organic 
oxidation in this sediment is 

153
00:08:46,900 --> 00:08:51,100
incredibly slow, very little 
organic matter is eaten, in any 

154
00:08:51,100 --> 00:08:55,600
cubic centimeter or even any 
vertical, 70 meters of sediment.

155
00:08:56,100 --> 00:08:59,700
But nonetheless, they did have 
oxygen, but they had virtually 

156
00:08:59,700 --> 00:09:04,000
no nutrients. 
So, what was previously known 

157
00:09:04,000 --> 00:09:07,800
about the ability of bacteria to
survive under these sorts of 

158
00:09:07,800 --> 00:09:11,700
conditions? 
People have found bacteria in 

159
00:09:11,700 --> 00:09:16,200
sediment in Marine sediment up 
to around 35 million years and 

160
00:09:16,200 --> 00:09:19,500
it should mention that people 
have pulled bacteria out of gold

161
00:09:19,500 --> 00:09:23,600
mines in Canada and in South 
Africa where the rock is more 

162
00:09:23,600 --> 00:09:26,900
than a billion years old. 
And so those bacteria and those 

163
00:09:26,900 --> 00:09:31,200
gold mines are living in the 
water in the fractures of The 

164
00:09:31,200 --> 00:09:33,300
Rock. 
And they've been isolated from 

165
00:09:33,300 --> 00:09:36,800
the surface world for probably 
most of that billion years. 

166
00:09:37,300 --> 00:09:40,700
But it's not a very analogous. 
Situation to the sediment that 

167
00:09:40,700 --> 00:09:43,800
we're talking about because the 
bacteria can move around in the 

168
00:09:43,800 --> 00:09:49,000
fractures and their oxidants and
their reductants can move 

169
00:09:49,000 --> 00:09:50,600
through the water of the 
fractures. 

170
00:09:51,400 --> 00:09:54,600
We've previously found microbes 
living in sediment from the 

171
00:09:54,600 --> 00:09:59,800
eocene little over thirty four 
million years ago and we were 

172
00:10:00,000 --> 00:10:03,200
trying to push back deeper into 
time here, but they're thing 

173
00:10:03,200 --> 00:10:06,900
were really interested in wasn't
finding the oldest living back 

174
00:10:06,900 --> 00:10:09,300
heel communities. 
It was Finding bacterial. 

175
00:10:09,500 --> 00:10:13,300
These were challenged by so 
little access to energy in until

176
00:10:13,300 --> 00:10:17,900
this Expedition people really 
had not looked at bacteria from 

177
00:10:17,900 --> 00:10:20,400
environments that have been 
exposed to oxygen for tens of 

178
00:10:20,400 --> 00:10:22,900
millions of years where there 
was too little organic matter 

179
00:10:22,900 --> 00:10:24,800
around for them to use up all 
the oxygen. 

180
00:10:25,500 --> 00:10:29,000
So let's get back to the 
experiment that you did what was

181
00:10:29,000 --> 00:10:32,700
done to the sediments that were 
taken out of the coal. 

182
00:10:32,800 --> 00:10:34,500
Once you got them back into the 
lab. 

183
00:10:35,000 --> 00:10:39,000
So with the experiment that you 
and I are talking about today, 

184
00:10:39,400 --> 00:10:43,000
our colleague Yuki Morano took 
little pieces of the sediment 

185
00:10:43,000 --> 00:10:46,300
using sterile, sampling. 
And he'd set one piece of side. 

186
00:10:46,300 --> 00:10:49,900
So we could use DNA sequencing 
to determine what was in it and 

187
00:10:49,900 --> 00:10:53,100
then splits of that same little 
piece he would put in different 

188
00:10:53,100 --> 00:10:58,100
vowels with different food 
sources and in some he would put

189
00:10:58,200 --> 00:11:03,200
amino acid mixture in others, he
would put ammonium as a reduced 

190
00:11:03,200 --> 00:11:07,700
molecule, he put carbon dioxide 
and some, which could be a 

191
00:11:07,708 --> 00:11:09,300
source of carbon but not a 
source. 

192
00:11:09,500 --> 00:11:13,400
Produced material and he put 
lactate in some. 

193
00:11:13,400 --> 00:11:16,600
So, a variety of very simple, 
organic molecules carbon bearing

194
00:11:16,600 --> 00:11:21,000
molecules and nitrogen bearing 
molecules and then he waited to 

195
00:11:21,000 --> 00:11:24,300
see what would grow. 
And what he found was that, 

196
00:11:24,300 --> 00:11:28,500
after a few weeks, he had growth
in all of the vials where there 

197
00:11:28,500 --> 00:11:32,600
was reduced, material, added 
where there was a monia added or

198
00:11:32,600 --> 00:11:36,500
acetate or amino acids. 
And the growth can be measured 

199
00:11:36,500 --> 00:11:39,300
in terms of the number of cells 
per cubic centimeter. 

200
00:11:39,400 --> 00:11:42,300
Liter of fluid in the vial. 
He went from 1,000 cells per 

201
00:11:42,300 --> 00:11:45,500
cubic centimeter in the sediment
to having something like 100,000

202
00:11:45,500 --> 00:11:47,900
cells per cubic centimeter of 
culture. 

203
00:11:48,000 --> 00:11:51,400
So after a few weeks essentially
these organisms that have been 

204
00:11:51,400 --> 00:11:54,400
trapped or this community that 
have been trapped for 100 

205
00:11:54,400 --> 00:11:57,300
million years, they woke up and 
they said, wow, food. 

206
00:11:57,300 --> 00:12:00,600
And then they reproduced. 
And that didn't happen to the 

207
00:12:00,600 --> 00:12:02,600
samples. 
Why he just added oxygen. 

208
00:12:02,900 --> 00:12:06,500
It didn't happen to the samples 
where he just added CO2 and it 

209
00:12:06,500 --> 00:12:11,300
didn't happen to the samples 
where He did not add any Oxygen,

210
00:12:11,300 --> 00:12:14,700
he did some control samples 
without oxygen to see what would

211
00:12:14,700 --> 00:12:16,500
happen and they didn't have 
growth. 

212
00:12:16,900 --> 00:12:20,900
So, this confirms that it was 
the nutrients they were really 

213
00:12:20,900 --> 00:12:24,000
lacking, not the oxygen in a 
sense, it's the food. 

214
00:12:24,000 --> 00:12:25,200
That was really lacking. 
Yes. 

215
00:12:25,900 --> 00:12:30,800
So from this result, we can say 
that some bacteria from the 

216
00:12:30,800 --> 00:12:34,900
sample had survived a hundred 
million years of food starvation

217
00:12:35,600 --> 00:12:39,000
and they started to behave like 
normal bacteria. 

218
00:12:39,600 --> 00:12:43,900
Does this mean, they were alive,
IE dividing or repairing? 

219
00:12:43,900 --> 00:12:48,400
Or be it at an extremely slow 
rate all along or where they 

220
00:12:48,400 --> 00:12:52,500
essentially Frozen or 
hibernating, and just started 

221
00:12:52,500 --> 00:12:55,400
Living again, when they had 
access to a supply of food? 

222
00:12:55,700 --> 00:12:58,900
This is a really good question 
because we're faced with a 

223
00:12:58,900 --> 00:13:03,200
conundrum here. 
These microbes on average had so

224
00:13:03,200 --> 00:13:07,500
little access to energy that 
they really had barely enough 

225
00:13:07,500 --> 00:13:11,200
energy to keep repairing. 
Molecules as they broke just 

226
00:13:11,200 --> 00:13:14,700
like you or I might get a muscle
tear if we strain ourselves. 

227
00:13:14,700 --> 00:13:17,100
So they had enough energy to 
repair their equivalent of a 

228
00:13:17,108 --> 00:13:20,100
muscle tear but they didn't have
enough energy formally to 

229
00:13:20,100 --> 00:13:24,900
reproduce as we know it if they 
weren't reproducing though this 

230
00:13:24,900 --> 00:13:27,300
meant that the individual cells 
and survive something like 100 

231
00:13:27,300 --> 00:13:29,600
million years. 
So we're left with two 

232
00:13:29,600 --> 00:13:33,000
ridiculous Alternatives, one 
that individual cells have lived

233
00:13:33,000 --> 00:13:37,500
for 100 million years or to 
population has turned over over 

234
00:13:37,500 --> 00:13:38,800
the course of that hundred 
million years. 

235
00:13:38,800 --> 00:13:43,700
But Much much, much slower rates
on much less energy than our 

236
00:13:43,700 --> 00:13:47,000
current understanding allows. 
And I think that the answer 

237
00:13:47,000 --> 00:13:49,800
probably lies somewhere in 
between that these cells 

238
00:13:49,800 --> 00:13:52,500
probably are living much longer 
than the bacteria in the world 

239
00:13:52,500 --> 00:13:55,000
around us. 
But they're probably reproducing

240
00:13:55,000 --> 00:13:56,300
over those hundred million 
years. 

241
00:13:56,800 --> 00:14:00,600
There have actually been some 
recent Studies by a group at the

242
00:14:00,600 --> 00:14:04,100
Technical University of Munich. 
Looking at microbes from parts 

243
00:14:04,100 --> 00:14:08,300
of the North Atlantic. 
They've shown that at least some

244
00:14:08,300 --> 00:14:11,200
bacteria. 
Multiply over the first few 

245
00:14:11,200 --> 00:14:13,900
million years of burial. 
So that's not quite the same 

246
00:14:13,900 --> 00:14:16,100
thing as showing that 
something's been multiplying 

247
00:14:16,100 --> 00:14:18,800
over a full hundred million 
years and it's not the same 

248
00:14:18,800 --> 00:14:21,400
thing as showing that every 
lineage that survives is 

249
00:14:21,400 --> 00:14:23,400
multiplying. 
But they've been able to show 

250
00:14:23,400 --> 00:14:25,000
that at least a couple of 
lineages. 

251
00:14:25,000 --> 00:14:27,800
Do multiply it in the subsea 
floor environment so that 

252
00:14:27,800 --> 00:14:30,900
provides I think reasonable 
evident that at least some of 

253
00:14:30,900 --> 00:14:34,800
them can reproduce on much less 
energy than we've previously 

254
00:14:34,800 --> 00:14:39,300
believed realistic. 
So you said that, there was an 

255
00:14:39,500 --> 00:14:43,200
Impulsivity of nutrients, which 
was what the limiting factor was

256
00:14:43,200 --> 00:14:47,200
down there in those sediments, 
but if they were at least eking 

257
00:14:47,200 --> 00:14:51,500
out a very sparse living but 
nonetheless dividing does that 

258
00:14:51,500 --> 00:14:55,500
mean they had access to a key, 
some form of nutrients of some 

259
00:14:55,500 --> 00:14:59,300
reducing agent that could just 
keep the processes ticking over.

260
00:14:59,700 --> 00:15:02,300
That's another really good 
question and they really have 

261
00:15:02,300 --> 00:15:05,400
accesses to two sources of 
energy if you will. 

262
00:15:05,600 --> 00:15:09,300
The First Source is that the 
organic matter is being a 

263
00:15:09,400 --> 00:15:13,800
Oxidized at very low rates, we 
can tell that because as we go 

264
00:15:13,800 --> 00:15:16,600
down in the sediment we find 
slightly higher nitrate 

265
00:15:16,600 --> 00:15:19,900
concentrations as we go and 
slightly lower oxygen 

266
00:15:19,900 --> 00:15:23,200
concentrations as we go. 
And we can tell from the ratio 

267
00:15:23,200 --> 00:15:27,000
of those things that oxygen is 
being used to oxidize Marine 

268
00:15:27,000 --> 00:15:31,200
organic matter, it very very 
slow rates, the other source of 

269
00:15:31,200 --> 00:15:35,000
energy in there in the form of 
reduced compounds and oxidized 

270
00:15:35,000 --> 00:15:38,400
compounds is natural radioactive
splitting of water. 

271
00:15:38,700 --> 00:15:44,400
So In all natural environments, 
there is some concentration of 

272
00:15:44,400 --> 00:15:48,000
naturally, radioactive material.
So even in our bodies, we have 

273
00:15:48,000 --> 00:15:51,000
radioactive potassium, 
radioactive carbon, for example,

274
00:15:51,200 --> 00:15:55,400
and deep sea sediment, has 
radioactive uranium radioactive,

275
00:15:55,400 --> 00:15:57,800
thorium radioactive potassium in
it. 

276
00:15:57,900 --> 00:16:02,500
And as those radioactive 
elements, in the minerals Decay,

277
00:16:03,000 --> 00:16:04,900
they release radiation that 
strikes. 

278
00:16:04,900 --> 00:16:08,900
The water around them in the 
sediment and striking that water

279
00:16:08,900 --> 00:16:11,200
breaks. 
It up and then it can recombine 

280
00:16:11,200 --> 00:16:16,300
into hydrogen and various 
oxidized chemicals. 

281
00:16:16,300 --> 00:16:19,600
So hydrogen peroxide is one. 
But if you've got reduced metal 

282
00:16:19,600 --> 00:16:23,800
around the oxidized products of 
the radioactive breakage will 

283
00:16:23,800 --> 00:16:26,400
oxidize the metal and then they 
can use that as an oxidant. 

284
00:16:26,400 --> 00:16:30,200
We've done some basic 
calculations that suggest in 

285
00:16:30,200 --> 00:16:34,000
this settlement where organic 
matter is so scarce there may be

286
00:16:34,000 --> 00:16:37,600
70 times as much energy 
available from radioactive 

287
00:16:37,600 --> 00:16:40,500
splitting of water as from the 
Mission of organic matter. 

288
00:16:41,200 --> 00:16:44,500
Wow, that's amazing. 
But if that is the primary 

289
00:16:44,500 --> 00:16:47,600
source of the nutrients and that
presumably is pervasive 

290
00:16:47,600 --> 00:16:51,200
throughout the crust and the 
mantle, in fact, so with this 

291
00:16:51,200 --> 00:16:56,600
kind of survival mechanism be 
viable at arbitrary depth this 

292
00:16:56,600 --> 00:17:00,700
kind of survival mechanism 
should work in any mineral 

293
00:17:00,700 --> 00:17:04,800
environment where there's water.
So it's the survival mechanism 

294
00:17:04,800 --> 00:17:07,700
that the people who study the 
gold mines believe supports the 

295
00:17:07,700 --> 00:17:11,099
microbes in their fractures It's
the mechanism that we believe 

296
00:17:11,099 --> 00:17:15,800
supports life in deep sediment 
and as you can surmise, it's a 

297
00:17:15,800 --> 00:17:19,400
mechanism that might support 
life on mars or Europa or 

298
00:17:19,400 --> 00:17:25,700
extrasolar planets. 
All the bacteria that survived 

299
00:17:25,700 --> 00:17:30,100
those thousand per cubic 
centimeter versus the million or

300
00:17:30,100 --> 00:17:31,800
10 million that you would get on
the sea floor. 

301
00:17:31,800 --> 00:17:35,700
Surface, are they a special 
subset of the population? 

302
00:17:35,700 --> 00:17:38,400
A kind of extremophiles 
specially adapted to living 

303
00:17:38,400 --> 00:17:41,100
under such energy. 
Poor conditions, their 

304
00:17:41,100 --> 00:17:44,800
extremophiles in the sense that 
they've survived the burial for 

305
00:17:44,800 --> 00:17:48,400
100 million years but they're 
not typically thought of as 

306
00:17:48,400 --> 00:17:51,500
extremophiles because they're 
part of the standard. 

307
00:17:51,700 --> 00:17:54,700
Immunity at the seafloor. 
And so, this leads us to this 

308
00:17:55,200 --> 00:17:58,200
curious thought that, although 
they dominate subsea floor 

309
00:17:58,200 --> 00:18:00,500
sediment. 
They may not be very happy. 

310
00:18:00,500 --> 00:18:03,900
There, there are a normal part 
of the seafloor Community, but 

311
00:18:03,900 --> 00:18:06,600
unlike most of the seafloor 
Community, they can survive 

312
00:18:06,600 --> 00:18:09,300
burial for up to 100 million 
years or more. 

313
00:18:09,500 --> 00:18:13,000
So, we would not normally think 
of them as extremophiles. 

314
00:18:13,000 --> 00:18:15,800
If we weren't collecting them 
from the sediment beneath the 

315
00:18:15,800 --> 00:18:18,800
seafloor, we would think of them
as just part of a normal Marine 

316
00:18:18,800 --> 00:18:22,900
community. 
Wow, so the same bacteria that 

317
00:18:22,900 --> 00:18:25,500
manages to survive under these 
extreme conditions are also 

318
00:18:25,500 --> 00:18:27,600
viable like in normal 
conditions. 

319
00:18:27,600 --> 00:18:32,300
Yeah. 
But if this ancient population 

320
00:18:32,600 --> 00:18:35,500
represented the bacterial 
population of 100 million years 

321
00:18:35,500 --> 00:18:39,400
ago, when we expect it to be 
different from a modern-day 

322
00:18:39,400 --> 00:18:43,400
population that has been 
evolving at a normal Pace. 

323
00:18:43,400 --> 00:18:47,600
Continuously, since that time, I
think it's reasonable to expect 

324
00:18:47,600 --> 00:18:51,600
that, you'll have some mutation 
that would Operate say this 

325
00:18:51,600 --> 00:18:54,400
individual cell from that 
individual cell over a hundred 

326
00:18:54,400 --> 00:18:57,300
million years. 
The subsea floor populations are

327
00:18:57,300 --> 00:19:01,900
probably not accumulating 
mutations very fast and the 

328
00:19:01,900 --> 00:19:03,600
populations in the surface 
world. 

329
00:19:03,600 --> 00:19:07,200
Like at the sea floor they've 
got a lot of mutations, I'll say

330
00:19:07,300 --> 00:19:10,400
two things with regard to this. 
The first is that there's 

331
00:19:10,400 --> 00:19:14,200
undoubtedly been some mutation 
in both the surface World. 

332
00:19:14,200 --> 00:19:17,200
A lot of mutation in the surface
world and perhaps some mutation 

333
00:19:17,200 --> 00:19:20,000
in the subsurface world since 
they've been separated. 

334
00:19:20,200 --> 00:19:25,500
But the richness of mutations if
you will in the surface World, 

335
00:19:25,500 --> 00:19:29,200
populations is already so great.
It wouldn't be very easy to pick

336
00:19:29,200 --> 00:19:32,200
out the differences. 
We do know that the mutation 

337
00:19:32,200 --> 00:19:36,000
rates are low enough that we can
still assign these microbes to 

338
00:19:36,000 --> 00:19:40,300
the same categories of bacteria.
So we know which family in which

339
00:19:40,300 --> 00:19:44,000
genus they belong to. 
And if we wandered around the 

340
00:19:44,000 --> 00:19:48,500
world exhaustively sequencing 
everything, we'd probably find 

341
00:19:48,500 --> 00:19:52,300
lineages that we would Call the 
same species in fact, in other 

342
00:19:52,300 --> 00:19:54,200
studies in my lab is done in a 
shorter time. 

343
00:19:54,200 --> 00:19:57,600
Scales looking at things over a 
few million years, we actually 

344
00:19:57,600 --> 00:20:00,300
find that to a first 
approximation. 

345
00:20:00,300 --> 00:20:04,400
What we see in the subsea floor 
is not just a subset of a 

346
00:20:04,400 --> 00:20:07,300
seafloor Community, but a subset
of the local sea floor 

347
00:20:07,300 --> 00:20:10,100
community. 
And what I mean by that is that 

348
00:20:10,100 --> 00:20:13,800
if we see something that we 
might call a separate species, 

349
00:20:13,800 --> 00:20:16,500
in the subsea floor, at some 
site in million-year-old 

350
00:20:16,500 --> 00:20:19,400
sediment or three million year 
old settlement, we typically 

351
00:20:19,400 --> 00:20:22,700
have the same Species at the sea
floor, but it's important to 

352
00:20:22,708 --> 00:20:26,900
bear in mind that definitions of
things like species and genus 

353
00:20:26,900 --> 00:20:30,900
for bacteria and archaea, which 
are other very simple one-celled

354
00:20:30,900 --> 00:20:34,500
organisms are numerical. 
So in the world around us, we 

355
00:20:34,500 --> 00:20:38,500
think, oh, horses and zebras are
different species because they 

356
00:20:38,500 --> 00:20:42,800
can't have fertile offspring but
bacteria don't reproduce by 

357
00:20:42,800 --> 00:20:46,000
having sex with each other. 
They just divide so our sexual 

358
00:20:46,000 --> 00:20:48,500
definition of a species, doesn't
apply to bacteria. 

359
00:20:49,100 --> 00:20:53,100
And what my Microbiologists do 
instead is they say, oh if it's 

360
00:20:53,100 --> 00:20:58,300
97 percent similar or more 
similar to some other thing in 

361
00:20:58,300 --> 00:21:03,300
its gene content, we're going to
call it the same species and 

362
00:21:03,300 --> 00:21:07,000
what that basically means then 
is that for the genes that are 

363
00:21:07,000 --> 00:21:10,100
used for identification. 
It's for like a barcode. 

364
00:21:10,100 --> 00:21:13,200
We take a chunk of the genome. 
We always take the same chunk of

365
00:21:13,208 --> 00:21:16,300
the genome over and over again. 
If that chunk of the genome is, 

366
00:21:16,300 --> 00:21:20,700
like 400 bases long, then 
they've got to be more Than 12 

367
00:21:20,700 --> 00:21:23,800
mutations, separating it from 
another one for us to call them 

368
00:21:23,800 --> 00:21:26,800
different species, because we 
have that three percent we can 

369
00:21:26,800 --> 00:21:29,100
play with. 
So, I've wandered a little bit 

370
00:21:29,100 --> 00:21:31,500
on this explanation, but the 
basic point is, you can 

371
00:21:31,500 --> 00:21:34,600
accommodate mutation, and still 
call it the same thing, and 

372
00:21:34,600 --> 00:21:37,100
that's what we basically do. 
We see that as we go deeper and 

373
00:21:37,100 --> 00:21:39,700
deeper in the sediment, we're 
still calling them the same 

374
00:21:39,700 --> 00:21:43,100
thing, but they can be separated
by some number of mutations over

375
00:21:43,100 --> 00:21:46,400
time. 
But just from a naive point of 

376
00:21:46,400 --> 00:21:50,200
view, it seems a bit surprising 
that over 100 million years of 

377
00:21:50,200 --> 00:21:52,600
the population. 
That's been subject to this very

378
00:21:52,600 --> 00:21:56,500
extreme selection pressure. 
If you like to survive with 

379
00:21:56,500 --> 00:22:01,100
virtually, no food should still 
be represented in the 

380
00:22:01,100 --> 00:22:04,200
population. 
That's on the seafloor surface, 

381
00:22:04,200 --> 00:22:06,700
which is had none of that 
pressure and could have evolved 

382
00:22:06,700 --> 00:22:08,500
quite happily in other 
directions. 

383
00:22:08,700 --> 00:22:11,800
You know, one of the curious 
things about selection is it 

384
00:22:11,800 --> 00:22:15,400
applies differently to different
Gene's ultimately what you 

385
00:22:15,400 --> 00:22:17,500
select against is the organism, 
right? 

386
00:22:17,600 --> 00:22:21,600
The actual living thing, not the
individual Gene, but this is 

387
00:22:21,600 --> 00:22:23,000
something again, that oversees 
lab in. 

388
00:22:23,000 --> 00:22:27,400
Munich is looked at recently, 
and what Bill finds is that 

389
00:22:27,400 --> 00:22:31,000
again over just a few million 
years which is what the depth of

390
00:22:31,000 --> 00:22:34,300
sediment that he's looked at in 
the North Atlantic that you can 

391
00:22:34,300 --> 00:22:38,500
see mutations accumulate in the 
genomes of the organisms that 

392
00:22:38,500 --> 00:22:42,800
live beneath the seafloor, but 
the mutation is preferentially 

393
00:22:42,800 --> 00:22:46,100
accumulating in Is associated 
with functions that the bacteria

394
00:22:46,100 --> 00:22:49,100
probably aren't using. 
So the genes for motility for 

395
00:22:49,100 --> 00:22:53,900
examples for swimming are 
accumulating mutation and the 

396
00:22:53,900 --> 00:22:58,100
genes for reproduction or not 
the remaining more stable. 

397
00:22:58,600 --> 00:23:02,400
One Thing Worth bearing in mind 
is that something like only one 

398
00:23:02,400 --> 00:23:06,200
in five thousand mutations are 
so, as positive right most 

399
00:23:06,200 --> 00:23:07,800
mutations are negative or 
neutral? 

400
00:23:08,100 --> 00:23:12,200
And so, essentially what bill is
seeing, accumulate are mutations

401
00:23:12,200 --> 00:23:14,900
that are basically neutral 
because these things aren't 

402
00:23:14,900 --> 00:23:17,700
swimming anymore. 
If you had a mutation in those 

403
00:23:18,300 --> 00:23:21,700
Gene sequences that are used for
reproduction, almost all of the 

404
00:23:21,700 --> 00:23:24,600
time that would be negative and 
The Offspring just wouldn't 

405
00:23:24,600 --> 00:23:26,900
survive. 
So there's a lot of positive 

406
00:23:26,900 --> 00:23:30,800
pressure to keep their core 
genes from not changing very 

407
00:23:30,800 --> 00:23:33,000
much. 
And then, once that pressure is 

408
00:23:33,000 --> 00:23:36,000
released from genes that are 
used for functions that the 

409
00:23:36,000 --> 00:23:38,500
microbe no longer uses, then we 
start to see the mutations 

410
00:23:38,500 --> 00:23:42,100
accumulate, it would be fun to 
look at evolution in the context

411
00:23:42,100 --> 00:23:43,800
of a hundred million year old 
community. 

412
00:23:44,300 --> 00:23:48,100
And see if what Bill sees over a
few million years just carries 

413
00:23:48,100 --> 00:23:50,600
on. 
We haven't really tested the 

414
00:23:50,600 --> 00:23:53,200
cells that you keep brought back
to life to see if they can swim.

415
00:23:53,200 --> 00:23:57,600
For example, all that any 
special constraints than on the 

416
00:23:57,600 --> 00:24:01,300
nature of the geological 
environment that enables such 

417
00:24:01,300 --> 00:24:04,700
extremely long-lived, bacterial 
colonies to survive. 

418
00:24:05,200 --> 00:24:07,900
I mean, obviously, they won't 
survive passing into a 

419
00:24:07,900 --> 00:24:11,400
subduction zone. 
For example, one can imagine a 

420
00:24:11,400 --> 00:24:14,900
number of constraints, the usual
constraints that People talk 

421
00:24:14,900 --> 00:24:17,400
about when they think about 
these natural environments, 

422
00:24:17,500 --> 00:24:21,400
revolve around temperature if 
it's too hot, everything dies. 

423
00:24:21,500 --> 00:24:24,900
And so, when people talk about 
extremophiles, there's a lot of 

424
00:24:24,900 --> 00:24:28,600
focus on temperature. 
One, could imagine more subtle 

425
00:24:28,600 --> 00:24:32,200
constraints. 
For example, the sediment that 

426
00:24:32,200 --> 00:24:35,500
these microbes are removed from 
has been continually exposed to 

427
00:24:35,500 --> 00:24:37,700
oxygen for 100 million years or 
more. 

428
00:24:38,000 --> 00:24:41,300
It's conceivable that anaerobic 
bacteria. 

429
00:24:41,600 --> 00:24:45,700
So bacteria that can't live In 
the presence of oxygen are 

430
00:24:45,700 --> 00:24:49,200
driven to Extinction in 
environments like that and in 

431
00:24:49,200 --> 00:24:53,000
fact, Yuki's control experiments
suggest that, that's the case. 

432
00:24:53,000 --> 00:24:56,400
He wasn't able to grow anything 
in the vials without oxygen. 

433
00:24:56,700 --> 00:24:59,700
And in the case of subduction, 
which you mentioned, it's an 

434
00:24:59,700 --> 00:25:02,700
enticing thought that the 
combination of temperature and 

435
00:25:02,700 --> 00:25:05,700
pressure and subduction zones is
extraordinary from a surface 

436
00:25:05,700 --> 00:25:08,000
World perspective. 
And if you think about the 

437
00:25:08,000 --> 00:25:11,500
temperature, you can also get 
deviations from a long-term 

438
00:25:11,500 --> 00:25:13,900
equilibrium like the core of the
subducting slab. 

439
00:25:14,100 --> 00:25:17,700
Be cooler than the edges as it 
penetrates into the mantle. 

440
00:25:17,800 --> 00:25:21,100
So you could imagine a temporary
refugium of even a few million 

441
00:25:21,100 --> 00:25:23,100
years in the core of the sinking
slab. 

442
00:25:23,100 --> 00:25:26,200
That's what amazing thought, 
tens of kilometers down in the 

443
00:25:26,200 --> 00:25:28,800
middle of a slab, it just 
depends on when you break 

444
00:25:28,800 --> 00:25:31,700
through the temperature 
threshold, the known temperature

445
00:25:31,700 --> 00:25:34,600
limit to life. 
Right now is about 120 degrees 

446
00:25:34,600 --> 00:25:38,600
Celsius under normal 
circumstances for the average or

447
00:25:38,600 --> 00:25:42,200
that will take you down, you 
know, about 20 degrees per 

448
00:25:42,200 --> 00:25:43,900
kilometer. 
So that's six kilometers. 

449
00:25:44,100 --> 00:25:48,600
Down but where the geothermal is
cooler, it can be deeper as for 

450
00:25:48,600 --> 00:25:53,200
example in a subduction zone. 
So if bacteria can survive for 

451
00:25:53,200 --> 00:25:57,300
100 million years is there 
really any upper limit as to how

452
00:25:57,300 --> 00:26:00,600
long they might live from a 
practical perspective. 

453
00:26:00,600 --> 00:26:05,000
I really don't think so. 
The bacteria in our digestive 

454
00:26:05,000 --> 00:26:09,600
systems are living a few hours 
before they divided the bacteria

455
00:26:09,600 --> 00:26:12,600
in this sediment have been 
living in isolation for 100 

456
00:26:12,600 --> 00:26:14,800
million years and so Over 
slowly. 

457
00:26:14,800 --> 00:26:19,000
They're dividing their dividing 
a lot more slowly than the 

458
00:26:19,000 --> 00:26:22,500
bacteria in our digestive 
systems orders of magnitude more

459
00:26:22,500 --> 00:26:25,500
slowly. 
And the community has survived a

460
00:26:25,500 --> 00:26:28,700
hundred million years as, you 
know, so to survive a billion 

461
00:26:28,700 --> 00:26:32,700
years on mars or even a billion 
years on Earth, that's only one 

462
00:26:32,700 --> 00:26:35,700
more order of magnitude. 
We took an extreme example and 

463
00:26:35,700 --> 00:26:38,600
thought of the community, in our
digestive systems, is surviving 

464
00:26:38,600 --> 00:26:41,900
the durations of our lifetimes. 
If each of us lives 100 years, 

465
00:26:41,900 --> 00:26:45,300
this is the tiniest fraction of 
that. 100 million, right? 

466
00:26:45,300 --> 00:26:47,600
The ones in the settlement of 
the communities and settlement 

467
00:26:47,600 --> 00:26:49,500
of lived, a million times 
longer. 

468
00:26:49,500 --> 00:26:52,800
And so to pick up one more order
of magnitude doesn't seem so 

469
00:26:52,800 --> 00:26:55,000
striking gosh. 
So you can really imagine 

470
00:26:55,100 --> 00:26:59,000
communities living for of the 
order of the age of the planet 

471
00:26:59,000 --> 00:27:02,400
or even the age of the universe.
If you're up to about what 13 

472
00:27:02,400 --> 00:27:05,900
and a half billion, if you could
retain the environment for that 

473
00:27:05,900 --> 00:27:08,600
long, you could in principle 
retain the community. 

474
00:27:08,800 --> 00:27:11,400
What we see on Earth of course, 
is that stuff that approaches 

475
00:27:11,400 --> 00:27:13,900
four billion years old has been 
massively heated. 

476
00:27:14,100 --> 00:27:17,400
Impressed and probably lost its 
bacteria long time ago. 

477
00:27:17,700 --> 00:27:20,600
But if you could somehow take a 
piece of ancient Greenland when 

478
00:27:20,600 --> 00:27:24,000
it was young and hold it, aside 
from the rock cycle, the 

479
00:27:24,000 --> 00:27:25,600
community, and it might reside 
there. 

480
00:27:25,600 --> 00:27:30,100
For four billion years, you 
touched on the space aspect. 

481
00:27:30,100 --> 00:27:32,500
When you mention the possibility
of such communities, perhaps, 

482
00:27:32,500 --> 00:27:34,000
living below the surface of 
Mars. 

483
00:27:34,000 --> 00:27:37,200
And in fact, we had a podcast on
the perseverance for over and by

484
00:27:37,200 --> 00:27:41,300
looking just for that right now,
but what about the implications 

485
00:27:41,400 --> 00:27:46,100
for life and perhaps that? 
Bacteria, traveling from one 

486
00:27:46,100 --> 00:27:50,300
planet to another, there are 
experiments, and a lot of 

487
00:27:50,300 --> 00:27:55,900
calculations that show that 
bacteria can survive relatively 

488
00:27:55,900 --> 00:27:59,400
small body impacts, right? 
So, if you have a chunk of Mars 

489
00:27:59,400 --> 00:28:04,000
that gets knocked out into space
by a big impact, you probably 

490
00:28:04,000 --> 00:28:07,200
know that when you get a really 
big impact, the center of the 

491
00:28:07,200 --> 00:28:09,900
target is vaporized. 
And then, as you move farther 

492
00:28:09,900 --> 00:28:12,500
from the center, it liquefies, 
and as you move farther from the

493
00:28:12,500 --> 00:28:15,900
center, it's just mechanically 
Erupted and that mechanically 

494
00:28:15,900 --> 00:28:19,400
disrupted stuff flies out of the
crater area during the rebound. 

495
00:28:20,000 --> 00:28:23,200
So stuff that's mechanically 
disrupted, never reaches the 

496
00:28:23,200 --> 00:28:26,800
temperatures necessary to kill 
wife and people have shown with 

497
00:28:26,800 --> 00:28:28,400
vertical gun experiments at 
Nasa. 

498
00:28:28,400 --> 00:28:32,200
That you can essentially take 
the bacterium impregnated piece 

499
00:28:32,200 --> 00:28:36,100
of sandstone and fire it at a 
Target and it will survive. 

500
00:28:36,900 --> 00:28:39,500
So you certainly have the 
possibility for moving life 

501
00:28:39,500 --> 00:28:43,400
around on these timescales. 
So perhaps a potential support 

502
00:28:43,400 --> 00:28:45,500
for the pants. 
Bye, Mia, hypothesis for the 

503
00:28:45,500 --> 00:28:48,100
origin of life. 
It is potential support person. 

504
00:28:48,100 --> 00:28:51,100
I find panspermia hypotheses 
interesting because from my 

505
00:28:51,100 --> 00:28:54,000
perspective, the simplest 
explanation for the origin of 

506
00:28:54,008 --> 00:28:56,000
life on Earth. 
Is that it originated here? 

507
00:28:56,200 --> 00:28:58,800
Most of the people who talk 
about panspermia and the Earth. 

508
00:28:58,800 --> 00:29:02,600
Mars context, talk about it. 
Coming here from Mars, I think 

509
00:29:02,600 --> 00:29:06,100
it may be likelier that it's 
gone to Mars from here, Steve 

510
00:29:06,100 --> 00:29:09,400
don't thank you very much. 
Thank you very much Oliver. 

511
00:29:09,400 --> 00:29:13,100
It's been a pleasure to speak 
with you today. for more about 

512
00:29:13,100 --> 00:29:17,500
geology b, as well as pictures 
and illustrations, that support 

513
00:29:17,500 --> 00:29:21,300
this podcast, you can go to 
geology B.com