GLG 466 SCC Microbial Life in Extreme Environments Atacama Desert Paper I have finished some work for this assignment, you need to first adjust my previous

GLG 466 SCC Microbial Life in Extreme Environments Atacama Desert Paper I have finished some work for this assignment, you need to first adjust my previous work based on the professor comment and then finish the rest of them. I upload one reference that you can use, you still need to find other 3 references like this one.You need to directly follow the instruction. Geomicrobiology
Term Paper
I) Topics
Microbial life in desert
II). Paper format:
Your term paper should be in a publishable format. Think of your paper as a review paper in
your field and you are submitting to an editor of a particular journal.
Necessary components include:
Sections of a scientific journal article (total length not counting the cover page is 5 pages
single-spaced, 12 pt font, times new roman, 2500 words at minimum):
1. Cover page with paper title and date, for anonymity purposes, do NOT include your name on this
page (1 page)
2. Abstract (0.5 page) – a summary of your main points
3. Introduction (~1 page) – discussion of the importance of the topic, existing (outstanding)
issues in this field, and the current controversy (if any).
4. Discussion of evidence/data & theories/models (minimum 3 pages including figures and
tables) – detailed presentation of evidence/data on which each of the competing
arguments/theories/models is based, including a critical assessment of each
6. Conclusions (~0.5 page) – a brief summary based on your critical assessment of the
evidence/data.
7. Reference list (only include sources cited in the paper, it doesn’t matter what format you use
but it has to be consistent)
Excellent (5 points)
Average (4 points)
Poor (3 point)
Quality of
Abstract
Abstract is a clear, concise
summary of the topic
including the relevant data
and models/theories and
conclusions; well written with
no typos; length requirement
met (= ½ page).
Quality of
Introduction
Clear explanation of the
importance of the topic from a
broad perspective, and the
current state of the topic (what
we know, current
controversies & unanswered
questions & future directions);
well written with no typos;
length requirement met (? 1
page).
Abstract is a clear, concise
summary of the topic but missing
mention of some key data and/or
some of the key models/theories
and/or conclusions; reasonably
well written with minimal typos;
length requirement met (=½
page).
Clear explanation of the
importance of the topic from a
broad perspective, but discussion
of the current state of the topic
and current controversies could
have been better developed;
reasonably well written with
minimal typos; length
requirement met (? 1 page).
Abstract is missing mention
of many of the key data,
models/theories, or
conclusions; or contains
significant typos and poorly
written text; or length
requirement (= ½ page) not
met.
Lacks a clear explanation of
the importance of the topic
from a broad perspective and
discussion of the current state
of the topic could have been
much better developed; or
contains significant typos and
poorly written text; or length
requirement (?1 page) not
met.
Quality of
Results &
Data
Clear and thorough
presentation of all of the key
data/evidence on which each
of the relevant theories/models
is based; incorporates results
from ? 4 journal articles; well
written with no typos.
Clear presentation of most of
the key data/evidence on which
each of the relevant
theories/models is based, but
could have been somewhat
more thorough; incorporates
results from ? 4 journal articles
reasonably well written with
minimal typos.
Presentation of the
data/evidence is lacking key
information and/or presented
in an unclear or incorrect
fashion, and/or does not
incorporate results from ? 4
journal articles; or contains
significant typos and poorly
written text.
No data or
results
presented
Quality of
Discussion
The discussion reflects clear,
scientifically sound & indepth interpretations of the
relevant data including critical
assessment of the
interpretations; well written
with no typos; length
requirement met (? 3 pages
including presentation of
data/results and discussion).
The discussion reflects clear and
scientifically sound
interpretations of the relevant
data, but lacks somewhat in
depth and critical assessment of
the interpretations; reasonably
well written with minimal typos;
length requirement met (? 3
pages including presentation of
data/results and discussion).
Discussion is unclear and/or
does not reflect scientifically
sound interpretations of the
data; or contains significant
typos and poorly written text;
or length requirement (? 3
pages including presentation
of data/results and discussion)
not met.
No
discussion
of the data
present
NonExistent
(0 pts)
No
abstract
present
No introduction
present
Quality of
Figures
Figures clearly present key
data/results that are useful for
illustrating the discussion
points; figures include useful
captions and source citations;
figures are numbered and
specifically referred to in the
discussion text; ? 3 figures are
present.
Quality of
Conclusions
Conclusions contain a brief
but thorough summary of the
state of the topic including
your critical assessment of the
evidence in support of each
theory/model, and future
questions/directions; well
written with no typos; length
requirement met (? ½ page).
Figures present key data/results
that are useful for illustrating
discussion points, but may not
all be the best figures for
illustrating the most important
concepts; figures include useful
captions and source citations;
figures are numbered and
specifically referred to in the
discussion text; ? 3 figures are
present.
Conclusions contain a brief
summary of the state of the topic,
but are somewhat lacking in
thoroughness, critical assessment
of the evidence in support of
each theory/model, and/or the
future questions/directions; well
written with no typos; length
requirement met (? ½ page).
Figures are present, but are not
relevant or useful for
illustrating discussion points;
or figures are lacking captions
and/or source citations; or
figures are not specifically
referred to in the discussion
text; or fewer than 3 figures
are present.
No figures
are present
Conclusions do not clearly
summarize the state of the
topic or provide any
assessment of the
theories/models or the future
questions/directions; or
contains significant typos and
poorly written text; or length
requirement length
requirement (? ½ page) not
met.
Conclusion
section not
present
Available online at www.sciencedirect.com
ScienceDirect
Endolithic microbial habitats as refuges
for life in polyextreme environment
of the Atacama Desert
Jacek Wierzchos1, M Cristina Casero1, Octavio Artieda2 and
Carmen Ascaso1
The extremely harsh conditions of hyperarid deserts are a true
challenge for microbial life. Microorganisms thriving in such
polyextreme environments are fascinating as they can tell us
more about life, its strategies and its boundaries than other
groups of organisms. The Atacama Desert (North Chile) holds
two world records of extreme environmental characteristics:
the lowest rainfall and greatest surface ultraviolet radiation and
total solar irradiance ever measured on Earth. Despite these
limiting conditions for life, we recently identified several
remarkable examples of endolithic habitats colonized by
phototrophic and heterotrophic microorganisms in the
hyperarid core of the Atacama Desert.
Addresses
1
Department Biogeoqu??mica y Ecolog??a Microbiana Museo Nacional de
Ciencias Naturales, CSIC c/ Serrano 115 dpdo, 28006 Madrid, Spain
2
Dpto. Biolog??a Vegetal, Ecolog??a y Ciencias de la Tierra, Universidad de
Extremadura Avda, Virgen del Puerto, 2, 10600 Plasencia, Spain
Corresponding author: Wierzchos, Jacek (j.wierzchos@mncn.csic.es)
Current Opinion in Microbiology 2018, 43:124–131
This review comes from a themed issue on Environmental
microbiology
Edited by Alberto Scoma and Julia Vorholt
For a complete overview see the Issue and the Editorial
Available online 4th February 2018
https://doi.org/10.1016/j.mib.2018.01.003
1369-5274/ã 2018 Elsevier Ltd. All rights reserved.
Introduction
The combined extreme environmental conditions of the
hyperarid desert give rise to perhaps the harshest setting
faced by microbial life. As such, desert microbial ecosystems are excellent models to address the environmental
selection of a terrestrial biome and the limits of life on our
planet. The aridity of the desert environment implies a
scarcity of water. Water is the single most important
requirement for life on Earth, and theoretically, there
is a threshold in the natural environment — the dry
limit — where liquid water is too scarce for the full range
of necessary functions required to sustain viable populations of organisms. Thus, some known environments
Current Opinion in Microbiology 2018, 43:124–131
exist with multiple and/or simultaneous forms of stress
that will determine the limits of life. These environments
can be considered as polyextreme as they could be
inhabited by polyextremophilic and/or polyextremotolerant (sensu McElroy [1]) microorganisms. Polyextreme
environments could thus be optimal models for the study
of the multiple biochemical survival mechanisms and
resistance strategies of their inhabitants.
This report reviews the endolithic microbial communities
discovered in the past decade within the hyperarid core of
the Atacama Desert. We excluded the microbial communities of the Pacific Coastal Cordillera, as this zone
receives significant fog and humid air, along with the soil
biome, because of its abiotic nature [2–4]. After an initial
description of the polyextreme environment of this desert, we focus on its endolithic microbial habitats and the
structure, diversity and adaptation strategies of their
colonizing endoliths.
The Atacama Desert as Earth’s most
polyextreme environment
Among others deserts, the Atacama Desert (North Chile) is
perhaps the most challenging polyextreme environment on
Earth and the most barren region imaginable. Until 2006 it
was thought that the hyperarid core of this desert was
devoid of photosynthetic life [5]. This hyperarid core lies
between 20 S and 24 S, between the Pacific Coastal Range
and the Andean Altiplano, and is known as the driest places
on our planet [6], its rainfall being 3–27 mm y 1 [7,8].
Further, this desert holds another world record: the highest
surface UV (UV Index up to 43.3), photosynthetic active
radiation (PAR up to 2700 mmol m 2 s 1) and annual mean
surface solar radiation (up to 312 W m 2); Figure 1b in
graphical abstract adapted from [9–11]. Yet another constraint for life in this desert are the extremely high temperatures of rock surfaces of up to 68 C (JW unpublished
results). All together, the hyperaridity, solar irradiance, high
day/night temperature fluctuations (up to 60 C; JW unpublished results), oligotrophy and in some cases high salinity,
make the Atacama Desert an exceptional polyextreme
environment.
Against all odds, microbial life in this inhospitable environment supported by primary producers has sought out
refuges in endolithic (inside rocks) habitats. These habitats comprise a network of pores and fissures connected to
www.sciencedirect.com
Endoliths from the polyextreme Atacama Desert Wierzchos et al. 125
Figure 1
ENDOLITHIC MICROBIAL HABITATS
CRYPTOENDOLITHIC
CHASMOENDOLITHIC
Rock
HYPOENDOLITHIC
Soil
Current Opinion in Microbiology
Endolithic habitats found within rocks in the hyperarid core of the Atacama Desert (figure in part adapted from Golubic et al. [49]). Cryptoendoliths
inhabit rock pores; chasmoendoliths inhabit cracks and fissures; hypoendoliths [19] inhabit the undermost layer of the rock. The translucence of
the rocks allows light to penetrate into the endolithic habitat allowing phototrophic life of primary producers.
the surface within semi-translucent rock. Endolithic colonization can be viewed as a stress avoidance strategy
whereby the overlying mineral substrate provides certain
protection from incident lethal UV and PAR radiation,
physical stability and enhanced moisture availability
[12,13]. Several forms of highly selective and endolithic
microbial colonization have been detected within the
rocks such as: halites [14–17], Ca-sulfate crusts [18,19],
ignimbrites [20] and calcites and rhyolites [21]. Most of
the elsewhere cited microbial communities has belonged
to prokaryotes. However, eukaryotic microbial diversity
have also been reported in the hyperarid zone of the
Atacama Desert — notably, the non-lichenized [22,23]
and lichenized fungi [19] and algae [8].
genomics microbial species spatial patterns and the key
nutrient sources for cryptoendolithic microbial communities in halites of Salar Llamara along a fog gradient.
Their conclusion was that moisture level, controlled by
coastal fog intensity, was the strongest driver of community membership. This finding is in agreement with the
results of similar studies by Robinson et al. [14], who
compared the structure and diversity of halite cryptoendoliths from Yungay and Salar Grande. We should mention that moisture content in Salar Grande and Salar de
Llamara is due to temporal fog events and high relative
humidity (RH) not comparable to the continuous exposure of Coastal Cordillera to the influence of fog coming
from the Stratocumulus clouds [28].
Endolithic habitats in the hyperarid zone
At three other locations of the hyperarid core of the Atacama
Desert, endolithic microbial colonization was found within
translucent soil gypsum crusts, gypsum deposits covering
volcanic rocks and gypcrete — massive deposits of gypsum
(all formation composed mostly of CaSO42H2O). High
biodiverse communities were reported by Dong et al. [18]
and Wierzchos et al. [19] attributed to frequent fog and a
high air RH in this zone leading to the frequent deposition
of liquid water in gypsum crust.
The first evidence of an endolithic microbial community
in the hyperarid core of the Atacama Desert was the
discovery of exceptional cryptoendolithic colonization
within the halite (NaCl) rocks of the Yungay area [16],
considered one of the most hyperarid zones of this desert.
This colonization takes place just a few millimeters
beneath the rock surface, occupying spaces among salt
crystals (Figure 2a–c). Liquid water, in the form of NaCl
saturated brine appears within these rocks due to deliquescence phenomena taking place in the halite
[16,24,25] and water vapor capillary condensation within
nanoporous spaces among halite nanocrystals [26]. Multivariate statistical analyses also revealed that halite community distribution patterns correlated with atmospheric
moisture. Cryptoendoliths from halites exposed to coastal
fogs were more diverse including the presence of a novel
microalga, which was not detected in the Yungay halites
[14]. Recently, Finstad et al. [27] examined through
www.sciencedirect.com
Cryptoendolithic microbial communities comprised
mainly of eukaryotic microorganisms, such as melanized
fungi and microalgae, have been found in soil gypsum
crusts in Salar de Navidad [29]. Melanin pigments present
in this fungus, belonging to the genus Neocatenulostroma
[30] were examined by Raman microspectroscopy. It was
suggested that melanized black fungi may play a role in
hydration or protection of photobionts by dissipating
excessive sunlight [31].
Current Opinion in Microbiology 2018, 43:124–131
126 Environmental microbiology
Figure 2
(a)
(b)
(c)
10 ?m
5 mm
(d)
(f)
20 ?m
(g)
(h)
Gy
Sp
20 ?m
A
5 mm
(e)
10 ?m
10 ?m
(j)
(i)
(k)
10 mm
(l)
3 mm
20 ?m
5 mm
(m)
(n)
Gl
5 mm
10 ?m
10 mm
Current Opinion in Microbiology
Cross sections of lithic substrates and endolithic microbial communities with these habitats from the hyperarid core of the Atacama Desert: halite
(a–c); gypcrete (d–h); calcite (i–k) and ignimbrite (l–n). (a) A cross-section of halite (from the Yungay area) reveals a distinct gray layer
representing the zone colonized by cryptoendoliths a few millimeters beneath the surface; the dark color is due to scytonemin, a UV protecting
pigment produced by cyanobacteria. (b) and (c) CLSM images of cryptoendoliths in halites from Yungay and Salar Grande respectively;
cyanobacterial aggregates (red autofluorescence signal), associated heterotrophic bacteria and archaea (SYBR Green stained DNA structures –
green signal) and scytonemin pigment (blue reflection laser light signal). (d) SM view of the orange-to-green cryptoendolithic colonization layer
comprised of algae close to the gypcrete surface. (e) SEM-BSE image of alga (A) and detailed view of bacteria (arrow). (f) SEM-BSE image of
cryptoendolithic cyanobacteria in gypcrete surrounding gypsum crystals (Gy) and adhered to sepiolite (Sp). (g) SM view of a hypoendolithic habitat
in gypcrete colonized by cyanobacteria (arrow) and shown in detail by CLSM in the image in (h). (i) SM view of the fissure wall of calcite colonized
by chasmoendoliths (green color); other potentially colonized fissures are indicated by arrowheads. White arrow points to the calcite surface
showing microrill weathering features. (j) HD-CIM view of calcite microrills produced by dewfall at a depth of 1 mm; deep coded image provides
surface metrology details. (k) FM image of chasmoendolithic microorganisms within calcite rock showing undisturbed aggregates of viable and
damaged cyanobacteria (red and green-blue autofluorescence respectively); extra polymeric substance sheaths surrounding cyanobacterial
Current Opinion in Microbiology 2018, 43:124–131
www.sciencedirect.com
Endoliths from the polyextreme Atacama Desert Wierzchos et al. 127
Another example of distinct endolithic colonization was
found a few millimeters beneath the translucent gypcrete
surface in Cordo?n de Lila where the transmitted PAR
value was 0.1–1% that of the incident PAR light. No UVA
or UVB radiation was detected within colonization zone
[8]. These cryptoendoliths showed an exceptional succession of organized horizons of orange and green microalgae and cyanobacteria (Figure 2d–f) [8]. Intense PAR
induced the synthesis and accumulation of carotenoids in
the upper layer of orange-colored microalgae. This layer
has a shielding effect that prevents photoinhibition and
lethal photooxidative damage due to the green microalgae
and cyanobacteria colonizing a slightly deeper layer. The
architectural features of this translucent gypcrete deposits
with sepiolite inclusions (Figure 2f) provide the cryptoendolithic microbial communities with increased water availability and attenuate harmful UV and PAR radiation.
DiRuggiero et al. [21] described for the first time chasmoendolithic colonization of fissures of rhyolite-gypsum
(Lomas de Tilocalar) and calcite rocks (Valle de la Luna)
(Figure 2i–k) in the hyperarid core of the Atacama visible
as a narrow 0.2–1 mm thin, pale green layer. Microclimate
data and geomorphic analysis of the mineral substrates
suggested greater water availability in the calcite rocks
and the increased occurrence of liquid water on this rock
surface due to dewfall, which forms the weathering
feature microrills (Figures 2i and j).
Porous ignimbrite rocks formed by pyroclastic flow deposition are common volcanic materials in the hyperarid
core of the Atacama. Ignimbrite rocks in Cordo?n de Lila
showed cryptoendolithic colonization, which was visible
as a narrow 1–2 mm green layer beneath the rock surface
running parallel to the ignimbrite surface despite its
surface roughness (Figure 2l) [20]. The porosity of ignimbrite (Figure 2n) can help retain moisture after scarce
rainfall events (27 mm y 1) thus extending the period of
potential metabolic activity.
Diversity and functioning of endolithic
microbial communities
Different endolithic associations in the hyperarid core of
the Atacama Desert have been reported from several
substrates where distinct communities occur. Halite
nodules in details described by Artieda et al. [32] harbor
a unique community that reflects the adaptation of its
members to high-salt conditions. Metagenomic analysis
revealed the composition of this association: archaea
(80%), bacteria (20%) and eukarya (1%) barely
represented in Salar Grande [14,33], Salar de Llamara
[27], Salar S…
Purchase answer to see full
attachment