The Skin of the Earth - Where Life Meets Rocks
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| Anzahl der Teile | 3 | |
| Autor | 0000-0002-2964-717X (ORCID) | |
| Lizenz | CC-Namensnennung 4.0 International: Sie dürfen das Werk bzw. den Inhalt zu jedem legalen Zweck nutzen, verändern und in unveränderter oder veränderter Form vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen. | |
| Identifikatoren | 10.2312/GFZ.3.3.2019.002 (DOI) | |
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Inhaltliche Metadaten
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| Abstract |
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| Schlagwörter |
00:31
Besprechung/Interview
00:58
Besprechung/Interview
04:39
Besprechung/Interview
05:10
Besprechung/Interview
06:42
Pflanze
07:08
Besprechung/Interview
07:34
Besprechung/Interview
09:35
Säugetier
10:00
Vorlesung/Konferenz
10:59
Vorlesung/KonferenzBesprechung/Interview
11:26
Vorlesung/KonferenzBesprechung/Interview
11:54
Vorlesung/KonferenzBesprechung/InterviewComputeranimation
12:21
Besprechung/Interview
12:52
Besprechung/Interview
13:32
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14:11
Besprechung/Interview
14:36
Besprechung/Interview
15:02
Besprechung/Interview
15:35
ComputeranimationBesprechung/Interview
16:34
Pflanze
17:27
Pflanze
17:55
Pflanze
18:40
Pflanze
19:39
Besprechung/Interview
20:31
Besprechung/InterviewComputeranimation
21:04
Besprechung/Interview
21:31
Besprechung/Interview
25:47
Besprechung/Interview
26:32
Besprechung/Interview
26:59
Besprechung/Interview
27:57
Besprechung/InterviewComputeranimation
28:36
Besprechung/Interview
29:06
Besprechung/Interview
29:32
Besprechung/Interview
30:00
Besprechung/Interview
Transkript: Englisch(automatisch erzeugt)
00:29
this is wonderful yeah but the ocean is next to the desert and there's some cacti over here and just no vegetation at all there and then the ocean next
00:40
to it I wonder how that could be
01:05
Wow look at the landscape it's so pretty and so much broader and then you have only rocks about and lots of vegetation at the bottom yeah and a lot of vegetation because it's raining here also yeah does it rain more yeah I
01:21
wonder if the soils are different here because of the vegetation
01:48
the surface of the earth is constantly in motion this happens very slowly we can only see snapshots in time the two most important processes of the earth's surface work against each other on one hand soil formation is driven from below
02:06
when rocks are lifted upwards by forces inside the earth and then when close to the surface broken down into soil by weathering on the other hand soil is removed from Earth's surface from above by erosion erosion occurs
02:22
through flowing water through wind or through glaciers and simply because of gravity erosion is heavily influenced by the climate form of plants animals and microorganisms a green skin on Earth's surface how does this biologic
02:42
skin of the earth change the effect of the two opposing processes is it even the most important factor these questions require a completely new way of thinking does the bio world form the geo world or is the geo world the
03:03
basis for the bio world alternatively are the geo world the rocks and soils and the bio world the plants animals and microbes interdependent we already know a lot about processes acting at the earth's surface but most studies fall within the traditional boundaries of
03:22
individual scientific disciplines soil science deals with soil formation and the plant roots that grow in it geochemistry is concerned with chemical conversions at the earth's surface microbiology investigates the
03:44
microbial communities under the earth's surface plant ecology investigates the relationships between climate and plant diversity geomorphology
04:04
investigates how landscapes form and erode three scientists provide different perspectives I am a geochemist I deal with the chemistry
04:23
of the earth and this is the earth's surface at the earth's surface rock is converted into weathered rock this from soil it's done with rain that contains acids it's an abiogenic process purely chemical
04:48
I am Michaela default soil ecologist from Gottingen University my main interest is to understand how the biota drives the element cycles in ecosystems there are two main interaction zones between the biota and
05:04
the soil the litter layer where the elements from the plants enter the soil and the rice is fear the tiny little so around the roots through which all nutrients plants need for growth need to be acquired
05:35
I'm a geologist I investigate the equations for how processes deep within
05:41
the earth build mountains and how climate through erosion shapes the topography we see today exploring the skin of the earth presents a big challenge the process is active on the earth's surface take place over completely different periods of time in science these are called time scales
06:02
hours for microbial proliferation by cell division days over which plants and animals sleep and wake a few decades for tree growth tens of thousands of years for natural climate fluctuations hundreds of thousands of years for
06:25
transforming rock into soil many millions of years for the movement of the earth's plates but what we see at the earth's surface also depends on how long we look if you let a plant grow visible changes can be seen after
06:48
only a few days biological research tends to think about the time scales plants grow over on the other hand landforms like mountains and valleys always seem to look the same geological research therefore thinks in
07:05
much longer periods of time than biological research these different time scales are a major hurdle for interdisciplinary research the research project earthshape wants to overcome this obstacle with joint geo and bio research earthshape investigates the influence of biological processes on
07:25
the earth's surface it is a large international project led in Germany and located in the Chilean coastal mountains in earthshape German and Chilean universities and research institutes work together the scientists investigate
07:41
how the activity of living organisms affects the earth's surface and how conversely the composition of the subsoil influences the life sitting on it what I wonder is when this is not the common landscape there are no trees here so how how works that if there would be trees or grassland or shrubs I think what we'd have to do is have a series of control experiments with
08:02
different amounts of vegetation and climate which we can do here in Chile to figure out the influence of climates on plants and microorganisms for locations in Chile with very different climates are compared with each other the most obvious impact of climate can be seen in the vegetation density the
08:26
northernmost location the pandazooka National Park is located in the driest desert on earth the Atacama Desert here scientists can explore a surface with virtually no plants the Santa Gracia reserve is a semi arid area
08:52
with only a few cacti and shrubs but no trees the more southern la campana
09:04
National Park has a Mediterranean climate with palm trees and considerable rainfall and dense vegetation the southernmost location now well Buddha National Park is a rainforest with a lot of rainfall a rock area an
09:25
impressive tree that dates back to the Jurassic period can be found here in the earth shape project samples and fields data are collected during field
09:41
work in the Chilean coastal mountains the construction of weather stations the installation of cameras for the permanent observation of soil change by
10:02
digging animals the measurement of rock strength the construction of rain out shelters to simulate the effect of climate on plants the determination
10:28
of minerals in rocks recording soil properties in soil profiles the
10:46
investigation of the underlying rocks with geological drilling in March 2019 the kickoff event of the second phase of the earth shape project took place in all more in the Chilean coastal mountains the project runs until 2022
11:03
and is coordinated by Todd a loss University of tubing and and free term from Blankenbork geoforcial center on Potsdam staff from the Chilean national parks conif were warmly welcomed first the 80 scientists that
11:22
conducted research in the first phase of earth shape exchanged their results among other things topics include the geology of Chile soil formation plant species distribution and nutrient uptake in plants how erosion works
11:46
simulation of the vegetation and climate with numeric models the scientists then develop strategies for the future course of the project in discussions the doctoral students presented their research project an
12:11
important goal of the project is to stimulate discussion beyond discipline boundaries here the soil ecologist discusses with the geochemist from
12:23
blank so during weathering solids are released from minerals they are present in solution and poor solutions and plants can access them but plants can also really efficiently recycle nutrients from the vegetation to the soil and back into the vegetation okay but isn't that soil layer
12:43
continuously eroded and also dissolved by water so nutrients are being lost yes but this is exactly the proportion of nutrients which needs to get reacquired from the depth the soil ecologist Michaela default also finds common ground with the geologist Todd illness I was thinking about this and we have models climate models and tectonic models and we can combine
13:04
these and we can understand how erosion occurs at the earth's surface but how do plants fit into that plant plant have a massive effect on erosion and weathering so what we could do is have coupled models of the biosphere atmosphere and geosphere and look at how these processes interact to
13:23
form the earth's surface the spectacular views of their study site are particularly inspiring for discussion in order to model these types of things we need a way of knowing the how you convert bedrock into loose material that you can move down slope are there ways of doing this so
13:41
yes we have geochemical methods with which we measure exactly the rate at which the rock is converted into soil that then is available for transport with water but in a landscape like this we don't have any vegetation does what if we're in a vegetated landscape does this work also there so this would be a key experiment that one could do in this landscape is
14:04
actually the rate at which this happens geochemically different from the one in the landscape that is totally covered with trees 30 doctoral students from all disciplines are working in Chile to establish new knowledge some of the questions are where do plants take up nutrients from withered rock hi I'm
14:28
PhD student in isotope geochemistry and I assemble rock regular and plants and use isotopes to decipher states of weathering and ecosystem nutrition back in Germany there are many steps to be taken first Ralph weighs the samples
14:44
collected in Chile in an ultra clean laboratory their isotope composition is measured using an isotope mass spectrometer the isotope ratios are
15:04
then evaluated as fingerprints of the origin of nutrients another question is how exactly do nutrients get from the soil into the plants I'm a doctorate student in soil ecology here I'm studying roots and their associated
15:24
mycorrhizal fungi which supports the plant in the uptake of nutrients in the laboratory he looks at the samples from Chile under the microscope he simulates carbon uptake to follow the path of carbon in the plant and in
15:49
the soil and he evaluates the different forms of carbon of the soil on a gas chromatograph how exactly does the nutrient uptake from soil and
16:10
rock work in different climate zones a landscape with heavily weathered soils and hardly any pristine rock remaining is covered by a dense forest there is
16:22
heavy rainfall so soil moisture symbolized by the blue dots is high but where do the trees get their nutrients from when there are hardly any of the original rocks left a fascinating cycle begins phosphorus in red is an important mineral nutrient found in rock and soil phosphorus is
16:44
largely absorbed by fungal hyphae these fine white fungal tissues are connected with the roots of many trees fungal hyphae help phosphorus get into the roots from where it migrates to the tree trunk and then to the leaves
17:00
but this process costs energy the leaves absorb carbon through photosynthesis some of which is delivered back to the roots there it is partly transferred to the fungal hyphae which draw energy from it additional carbon is also released into the soil where it accumulates over many years
17:21
and turns the soil dark brown the organic carbon accumulates in the soil in autumn the leaves fall and decompose into soil organic matter this makes the soil even darker in addition the phosphorus contained in the leaves can be reabsorbed incredibly efficiently by the dense network of
17:40
fungal hyphae and recycled again through the tree released as leaf litter and taken up again and again this is a recycling ecosystem it draws much more mineral nutrients from the leaf litter than it does from the rock in a dry area with little soil moisture this is quite different the only vegetation
18:01
is shrubs and cacti that grows slowly and not very densely nevertheless these plants also absorb their nutrients with roots and fungal hyphae but since little litter is produced each year not much organic soil material is formed which would supply fungal hyphae and vegetation with nutrients this
18:20
means the fungal hyphae have to find the nutrients deep in the rock since there is less vegetation less carbon is also transferred to roots and fungal hyphae the entire nutrient cycle is slower and nutrient fluxes are lower this ecosystem is acquiring because it draws its mineral nutrients mainly
18:46
from the rock in the humid area here on the left there are not enough nutrients
19:05
in the soil the fast-growing ecosystem is sustained mainly by recycling in the dry area here on the right side with sparse and slowly growing vegetation the nutrients are mainly supplied by uptake from the rock this is the fundamental difference between element cycles in ecosystems of
19:24
different climate zones another question how does the climate and vegetation in the different regions affect how landscapes look like and how
19:42
fast they erode hi I'm a doctorate student at the German Research Center of geosciences in Potsdam I just measured channel grain sizes and took a river sediment sample to estimate erosion rates using magnets she removes the magnetic minerals from the sand samples in the laboratory so that only
20:01
the mineral quartz remains she dissolves the sample in the laboratory with
20:22
hydrofluoric acid an acid strong enough that it can dissolve even the resistant mineral quartz she measures so-called cosmogenic nuclides held within the dissolved quartz these reveal the erosion rates of the river basin with the erosion rates she can explain the influence of vegetation on
20:41
landscape development these relationships can be evaluated mathematically with the help of a digital landscape model how does climate affect plants diversity
21:04
and the decomposition of their leaves I'm a plant ecologist and I'm studying litter decomposition which is the decomposition of leaves Lisbeth van den Brink weighs the samples from the leaf litter to
21:23
determine how quickly the leaves decompose over time in this way she can see how nutrients such as phosphorus from plants could be reabsorbed from the leaf litter she then uses statistical methods to determine the influence of climate on plant cycles so how do we combine all
21:48
the findings of the landscapes with data of their vegetation one possibility is by using computer simulations tectonic forces push up the surface
22:01
and lift it to higher and higher elevations Earth's surface represents a delicate balance between tectonic and climatic forces which through erosion removes material and lowers the surface these models are based on what we think are the best mathematical relationships to explain how different
22:23
processes work on this landscape for example hill slope processes convert bedrock into soil which then moves downslope to rivers rivers take this
22:42
sediment from the hill slopes and flush them downstream if there is enough water one of the biggest questions facing geoscientists today is how different with this landscape look if vegetation were on it in this computer model we can see how the addition of dense vegetation to the
23:02
Earth's surface would influence the landscape development to grow dense vegetation we need large amounts of rainfall plants influence how the rivers erode into the landscape and how sediment makes it to the rivers they
23:21
intercept rainfall which limits the water's ability to erode Earth's surface and because of their protective effect on the mountain slopes the plants concentrate water runoff and erosion into large deep valleys however as uplift continues the mountains between the valleys rise
23:44
higher and higher if we zoom into one catchment we see that vegetation
24:03
obstructs the flow of water and focuses it in channels we can also see the deep weathering of rock by water and plant roots this landscape is
24:22
very similar to what we see in Parque Nacional Nuevo in south central Chile this next computer model shows how different the land surface looks with very little precipitation and thus little vegetation on top of it the
24:44
sparse vegetation is unable to protect the surface from erosion so even though there is less rainfall it is easier for it to erode the hill slopes because of the low water flow only small river valleys form the eroded
25:08
sediment is transported into a dense drainage network of many small rivers due to a lack of water a lot of sediment remains in the valleys drought and reduced plant cover also lead to less weathering and thinner soils this
25:34
example of an arid landscape with very little vegetation is similar to what we see in northern Chile in the Parque Nacional Pandasucar have the
25:47
earth-shaped scientists now taken a step forward in exploring the interdependencies between the geo world and the bio world let's once again ask Friedhelm von Blankenborg the geochemist Michaela Dipolt the soil
26:00
ecologist and Todd Ehlers the geologist so after sampling plant material rock material soils and measuring geochemical fluxes and isotopic ratios we cannot say whether plants get their mineral nutrients from rock and from what depth or whether they are released by processes where
26:24
plants have no involvement and this is a big step forward in the question whether the biology or the geology drives the earth's surface we can quantify enzyme activity and root exudation in the rhizosphere the
26:42
small zone around the root where the bio and the geosphere interact with this we can quantify the energy investment of the vegetation actively shaping the earth's surface from our coupled models of the biosphere geosphere
27:02
and atmosphere what we've learned is that the type of plants that are present and the number of plants can make a big difference for the topography that we see today however this isn't always the case and there are situations when geologic processes or atmospheric processes can be more important and that's what we're working on understanding more of now
27:25
are we at the end of our story do we now know what happens when life meets rocks not quite yet what our experts say is that although they can quantify dependencies these dependencies always run in both directions from life
27:42
to rocks and from rocks to life it is based on a fundamental property of coupled natural systems feedback so under equilibrium conditions we have
28:00
here an ecosystem now let's assume we have a uplift here we uplift this rock and as a result we have lots of erosion they discuss how short biological and long geological processes intertwine the interaction results in a classic negative feedback two parts of a system are in a state of equilibrium with each other an outside disturbance of the upper partner
28:24
throws the entire system out of balance the lower partner acts against this perturbation and the system returns to its original state we can imagine this as a dance we see the rock world in gray and living world in
28:41
green both dance harmoniously in a stable balance a disturbance brings the
29:05
two out of beautiful harmony only slowly does green life bring the gray
29:24
rocky world and its landscape back into their original balance all of a
29:42
sudden another disturbance occurs much bigger than the previous this time the rock world pulls the living world into balance but the balance is a different one the state of the system has changed this is how feedback works in natural systems the earth system constantly stabilizes itself through
30:14
numerous such feedbacks one such feedback is rock weathering in which biology plays a role by using carbonic acid rock weathering constantly consumes
30:25
co2 from the atmosphere albeit very slowly thus rock weathering balances the release of new co2 from volcanoes since co2 warms the earth's atmosphere this feedback has stabilized Earth's climate for many
30:41
millions of years another feedback comes from the plants of the earth that stabilize the co2 of the atmosphere and thus the Earth's climate much faster if the co2 concentration in the atmosphere increases more plants grow through faster photosynthesis the co2 in the atmosphere falls again but
31:03
today humans are adding large amounts of additional co2 to the atmosphere it throws the system out of balance and neither the vegetation nor the rock weathering of the earth can retain balance again quickly enough the result is global warming with major consequences for the planet's surface
31:22
and humankind with their research on the coupled processes within this fragile zone where life meets rock the members of the earth shape project aim at evaluating the sensitivity of this system to perturbations in doing so they allow mankind to assess the impact of the climate change induced
31:44
today and what should be done to preferably prevent this major perturbation which will affect our livelihood in ways that are hard to imagine