This document discusses carbon fluxes along the land-water continuum from land to sea. It summarizes previous literature on carbon cycling in inland waters like lakes and rivers. Some key points made in the document include:
- Inland waters cover a small percentage of the Earth's surface but play an important role in the global carbon cycle as sinks and sources of carbon.
- Dissolved organic carbon imported from surrounding landscapes makes up a large portion of the carbon in many inland waters.
- Carbon is transformed in inland waters through processes like flocculation, microbial mineralization, and photochemical mineralization.
- Sediment burial is an important fate of carbon in inland waters, with flocculation of dissolved organic carbon accounting
A B S T R A C T
Urban stormwater lakes in cold regions are ice-covered for substantial parts of the winter. It has long been considered that the ice-covered period is the “dormant season,” during which ecological processes are inactive. However, little is known about this period due to the historical focus on the open-water season. Recent pioneering research on ice-covered natural lakes has suggested that some critical ecological processes play out on the ice. The objective of this study was to investigate the active processes in ice-covered stormwater lakes. Data collected during a two-year field measurement program at a stormwater lake located in Edmonton, Alberta, Canada were analyzed. The lake was covered by ice from November to mid-April of the following year. The mean value of chlorophyll-a during the ice-covered period was 22.09% of the mean value for the open-water season, suggesting that primary productivity under ice can be important. Nitrogen and phosphorus were remarkably higher during the ice-covered period, while dissolved organic carbon showed little seasonal variation. Under ice-covered conditions, the total phosphorus was the major nutrient controlling the ratio of total nitrogen to total phosphorus, and a significant positive correlation existed between total phosphorus and chlorophyll-a when the ratio was smaller than 10. The results provide preliminary evidence of the critical nutrient processes in the Stormwater Lake during the ice-covered period.
The year 2014 tied with 2010 as the warmest year on record for the last century. The melting of Greenland, mountain glaciers, and thermal expansion is raising sea levels four times faster than in 1900. Sea level rises of 2 to 6 feet are predicted by the end of the century. Flood highs from hurricanes Sandy and Katrina were ~ 10 feet.
The article “Treading Water” in the February 2015 "National Geographic" tells how Dutch Docklands LLC sees profit not loss from rising sea levels. They are building floating homes in Miami, FL. A floating classroom could assure ASPEC’s long-term future. It would provide a place to meet in the event of flooding by the 10-foot ocean surges that accompany hurricanes.
Dr. Carr describes how increasing greenhouse gases, mostly carbon dioxide from the burning of fossil fuels, trap the radiation that is warming our planet. Advances in non-carbon emitting energy sources can reduce global warming. Solar PV panels are now generating electricity at $0.07/kWhr, less than the national utility average of $0.12kWhr. Rising sea levels are a better measure of global warming than atmospheric temperature, as 90% of our planet’s heat content is in our oceans.
You can learn more at www.RiskyBusiness.org.
Raymond Desjardins - Impacto de la agricultura sobre el cambio climáticoFundación Ramón Areces
Los días 20 y 21 de mayo de 2014, la Fundación Ramón Areces organizó el Simposio Internacional 'Microorganismos beneficiosos para la agricultura y la protección de la biosfera' dentro de su programa de Ciencias de la Vida y de la Materia.
A B S T R A C T
Urban stormwater lakes in cold regions are ice-covered for substantial parts of the winter. It has long been considered that the ice-covered period is the “dormant season,” during which ecological processes are inactive. However, little is known about this period due to the historical focus on the open-water season. Recent pioneering research on ice-covered natural lakes has suggested that some critical ecological processes play out on the ice. The objective of this study was to investigate the active processes in ice-covered stormwater lakes. Data collected during a two-year field measurement program at a stormwater lake located in Edmonton, Alberta, Canada were analyzed. The lake was covered by ice from November to mid-April of the following year. The mean value of chlorophyll-a during the ice-covered period was 22.09% of the mean value for the open-water season, suggesting that primary productivity under ice can be important. Nitrogen and phosphorus were remarkably higher during the ice-covered period, while dissolved organic carbon showed little seasonal variation. Under ice-covered conditions, the total phosphorus was the major nutrient controlling the ratio of total nitrogen to total phosphorus, and a significant positive correlation existed between total phosphorus and chlorophyll-a when the ratio was smaller than 10. The results provide preliminary evidence of the critical nutrient processes in the Stormwater Lake during the ice-covered period.
The year 2014 tied with 2010 as the warmest year on record for the last century. The melting of Greenland, mountain glaciers, and thermal expansion is raising sea levels four times faster than in 1900. Sea level rises of 2 to 6 feet are predicted by the end of the century. Flood highs from hurricanes Sandy and Katrina were ~ 10 feet.
The article “Treading Water” in the February 2015 "National Geographic" tells how Dutch Docklands LLC sees profit not loss from rising sea levels. They are building floating homes in Miami, FL. A floating classroom could assure ASPEC’s long-term future. It would provide a place to meet in the event of flooding by the 10-foot ocean surges that accompany hurricanes.
Dr. Carr describes how increasing greenhouse gases, mostly carbon dioxide from the burning of fossil fuels, trap the radiation that is warming our planet. Advances in non-carbon emitting energy sources can reduce global warming. Solar PV panels are now generating electricity at $0.07/kWhr, less than the national utility average of $0.12kWhr. Rising sea levels are a better measure of global warming than atmospheric temperature, as 90% of our planet’s heat content is in our oceans.
You can learn more at www.RiskyBusiness.org.
Raymond Desjardins - Impacto de la agricultura sobre el cambio climáticoFundación Ramón Areces
Los días 20 y 21 de mayo de 2014, la Fundación Ramón Areces organizó el Simposio Internacional 'Microorganismos beneficiosos para la agricultura y la protección de la biosfera' dentro de su programa de Ciencias de la Vida y de la Materia.
The EXPLODING POPULATION OF 7 B IS INFLUENCING OUR CLIMATE BY BURNING FOSSIL FUELS THAT EMIT CARBON DIOXIDE, CO2.
1. THE HUMAN INFLUENCE ON WARMING
Emissions of the greenhouse gas CO2 are increasing at a rate of 2.5 ppm per year.
2. CONTRAST THIS WITH SLOWER NATURAL PROCESSES
18K – 10K years ago, C02 increased at a rate 1/300th slower.
3. THE IMPACT OF CONTINUING CLIMATE CHANGE
Melting of the Arctic is increasing our winter climate extremes.
This presentation focuses, how carbon dioxide plays dirty role in Ocean Acidification and Global Warming. I have analyzed data and presented it with some real samples collected from Visakhapatnam, India. Thank you!
The IMF warns that human fortunes will “evaporate like water under a relentless sun” if climate change is not checked. “It’s nice for people to talk about two degrees,” says Bill Gates, a philanthropist and investor. “But we don’t even have the commitments that are going to keep us below four degrees of warming.”
Alarmist?
On the contrary - my review has changed my world view and it's not a comfortable feeling.
But you know what's funny ? I mean odd not humourous - this site only allows me to file this paper under 'science'!
The money view - between “5 and 20 per cent of global GDP every year now and forever"
The EXPLODING POPULATION OF 7 B IS INFLUENCING OUR CLIMATE BY BURNING FOSSIL FUELS THAT EMIT CARBON DIOXIDE, CO2.
1. THE HUMAN INFLUENCE ON WARMING
Emissions of the greenhouse gas CO2 are increasing at a rate of 2.5 ppm per year.
2. CONTRAST THIS WITH SLOWER NATURAL PROCESSES
18K – 10K years ago, C02 increased at a rate 1/300th slower.
3. THE IMPACT OF CONTINUING CLIMATE CHANGE
Melting of the Arctic is increasing our winter climate extremes.
This presentation focuses, how carbon dioxide plays dirty role in Ocean Acidification and Global Warming. I have analyzed data and presented it with some real samples collected from Visakhapatnam, India. Thank you!
The IMF warns that human fortunes will “evaporate like water under a relentless sun” if climate change is not checked. “It’s nice for people to talk about two degrees,” says Bill Gates, a philanthropist and investor. “But we don’t even have the commitments that are going to keep us below four degrees of warming.”
Alarmist?
On the contrary - my review has changed my world view and it's not a comfortable feeling.
But you know what's funny ? I mean odd not humourous - this site only allows me to file this paper under 'science'!
The money view - between “5 and 20 per cent of global GDP every year now and forever"
Ocean Acidification: Cause, Impact and mitigationIIT Kanpur
Ocean Acidification and the battle for Carbonate.
In this presentation the points covered are detailed briefing of ocean acidification, its causes, its impact on marine ecosystems and measures to mitigate this.
Climate change discussion and various scientific viewpoints weave a matrix of knowledge in an incredibly complex global environment. Carbon dioxide sequestration is part of the matrix of environmental solutions that will accelerate our ability to develop and deploy green renewable energy.
58 S C I E N T I F I C A M E R I C A N M A R C H 2 0 0 6.docxtroutmanboris
58 S C I E N T I F I C A M E R I C A N M A R C H 2 0 0 6
I
n 1956 Roger Revelle and Hans Suess, geochemists at
the Scripps Institution of Oceanography in California,
pointed out the need to measure carbon dioxide in the
air and ocean so as to obtain “a clearer understanding
of the probable climatic effects of the predicted great indus-
trial production of carbon-dioxide over the next 50 years.”
In other words, they wanted to fi gure out how dire the situ-
ation would be today. That they had to argue the importance
of such observations now seems astonishing, but at the time
scientists did not know for certain whether the carbon diox-
ide spewing out of tailpipes and smokestacks would indeed
accumulate in the atmosphere. Some believed that it would
all be absorbed benignly by the sea or be happily taken up by
growing plants on land.
Revelle and the young researcher he hired for this project,
the late Charles David Keeling, realized that they had to set
up equipment at remote locations, far from local sources and
sinks of carbon dioxide, which would cause the measure-
ments to vary erratically. One spot they chose was about as
far from industrial activity and vegetation as anyone could
get: the South Pole. Another was at a newly established
weather station atop Mauna Loa in Hawaii.
The Mauna Loa monitoring has continued (with just one
brief interruption) from 1958 to this day. Being not so remote
as Antarctica, Hawaii sees carbon dioxide levels rise and fall
sharply in step with the Northern Hemisphere’s growing sea-
son, but at the end of each and every year, the concentration
of this heat-trapping gas always ends up higher than it was 12
Much of the carbon dioxide given off from the burning of fossil fuels goes into the ocean, where it changes the
acid balance of seawater. The r eper cussions for marine lif e may be enor mous B Y S C O T T C . D O N E Y
The Dangers of
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COP YRIGHT 2006 SCIENTIFIC A MERIC A N, INC.
w w w . s c i a m . c o m S C I E N T I F I C A M E R I C A N 59
months before. So it did not take long for the scientifi c com-
munity to realize that Revelle was right—much of the carbon
dioxide released into the atmosphere was destined to remain
there. But his calculations were also correct in showing that
a substantial fraction would end up in the sea. And it was clear
to Revelle long ago that the part that went into the ocean would
fundamentally alter the chemistry of seawater. Unlike some
aspects of climate change, the reality of this effect— essentially
the acidifi cation of the ocean—is not much debated, although
its full implications are just now being revealed.
How Unnatural?
t h e h a l f - c e n t u r y r e c o r d that Keeling produced is
extremely valuable, but it is too short to place the current
situation in context. Scientists have, however, been able to
obtain a longer-term perspe.
The Ozone Layer: Formation and DepletionKamran Ansari
This presentation explains the Earth's atmosphere and its composition and variation of temperature and pressure in different layers of the atmosphere. It contains atmospheric circulation in troposphere and stratosphere. It explains the process of ozone formation and how its stability affects by the other chemical components which lead to the ozone depletion and ozone hole. It also contains the cosmic ray theory of ozone hole.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptxRASHMI M G
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...Wasswaderrick3
In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Lateral Ventricles.pdf very easy good diagrams comprehensive
Tranvik, Lars: The carbon fluxes at the land-ocean-atmosphere continuum
1. Lars J. Tranvik
Limnology, Department of Ecology and Genetics,
Uppsala University, Sweden
The carbon fluxes along the land aquatic continuum
from land to sea
2. Lars J. Tranvik
Work presented here primarily by:
Katrin Attermeyer
Núria Catalán
Anne Kellerman
Birgit Koehler
Dolly Kothawala
Alina Mostovaya
Jeff Hawkes
Thorsten Dittmar
Limnology, Department of Ecology and Genetics,
Uppsala University, Sweden
The carbon fluxes along the land aquatic continuum
from land to sea
3. Earth has 117 million lakes > 0.002 km2 (a little less than half a soccer
field) , covering 4% of the continents
Verpoorter et al. 2014. Geophysical Research Letters
4. Swedish lakes
95700 lakes larger than 1 ha comprising
9% of the total land area
Swedish lakes : SMHI
Inland waters – perfusing the landscape
10. Recent
publications
Older
publications
The lake as a
microcosm
with a “closed”
C cycle
The inland water
C cycle is heavily
influenced by
import
Thienemann 1925
Forbes 1887
Naumann 1932
Salonen et al. 1983
Tranvik 1988
del Giorgio and Peters 1993
11. Recent
publications
Older
publications
The lake as a
microcosm
with a “closed”
C cycle
The inland water
C cycle is heavily
influenced by
import
Thienemann 1925
Forbes 1887
Naumann 1932
Inland waters
are landscape
sinks and
sources of C
Salonen et al. 1983
Tranvik 1988
del Giorgio and Peters 1993
Cole et al. 1994
Kling et al. 1991
12. Recent
publications
Older
publications
The lake as a
microcosm
with a “closed”
C cycle
The inland water
C cycle is heavily
influenced by
import
Thienemann 1925
Forbes 1887
Naumann 1932
Inland waters
are landscape
sinks and
sources of C
Salonen et al. 1983
Tranvik 1988
del Giorgio and Peters 1993
Cole et al. 1994
Richey et al. 2002
Algesten et al. 2003
Dillon and Molot 1997
Duarte and Prairie 2005
Kling et al. 1991
13. Recent
publications
Older
publications
The lake as a
microcosm
with a “closed”
C cycle
The inland water
C cycle is heavily
influenced by
import
Thienemann 1925
Forbes 1887
Naumann 1932
Inland waters
are substantial
sinks and
sources of C at
global scale
Inland waters
are landscape
sinks and
sources of C
Salonen et al. 1983
Tranvik 1988
del Giorgio and Peters 1993
Cole et al. 1994
Richey et al. 2002
Algesten et al. 2003
Einsele et al. 2001
Dean and Gorham 1998Dillon and Molot 1997
Duarte and Prairie 2005
Kling et al. 1991
14. Recent
publications
Older
publications
Raymond et al. 2013
The lake as a
microcosm
with a “closed”
C cycle
The inland water
C cycle is heavily
influenced by
import
Thienemann 1925
Forbes 1887
Naumann 1932
Inland waters
are substantial
sinks and
sources of C at
global scale
Inland waters
are landscape
sinks and
sources of C
Salonen et al. 1983
Tranvik 1988
del Giorgio and Peters 1993
Cole et al. 1994
Richey et al. 2002
Algesten et al. 2003
Cole et al. 2007
Einsele et al. 2001
Dean and Gorham 1998Dillon and Molot 1997
Duarte and Prairie 2005
Kling et al. 1991
Tranvik, Cole, Prairie, LO Letters 2018
24. OceanLand Inland waters
Things that transform the organic matter
Flocculation/Sedimentation
Microbial mineralization
Photochemical mineralization
25. bacterial enzymes
photons and photochemically
produced reactive
oxygen species
OH
OH
OH
OH
HOOC
HOOC
OHO
OH
O
COOH
N
OH
NH
O O
-
O O
OH
O
OHOH
OH
C H3
O
OH
OH
OH
OH
NH
NH2
NH
NH
O
O
NH
COOH
COOH
NH C H2
O
C H2 NH2
CH3
H
Fe
2+
O
O
O
C H3O
O
O
-
OO
-
NH2
O
CH 2OH
O
NH2
O
NH2
CH 2OH
O O
NH2
OH
OO
C H3
O
N
C H2
H
NH C H2 NH
C H2
OH
NO 2
O
NH
C H2
NH
O
C H2
COOH
O
NH
OH
OH
O
O
O
-
O
OH
OCH 3OH
OH
C H2C H2OC
O
NHC
C H2O
-
O
O
H
O H
O N
O
H
O
O
NH C H C H2
COOH
O
C H2 C H2
NNH
O
H3CO
O O
O
H3CO
H
O
H CH 2OH
O C H3
COOH
H
K
+
Si
OH
OH
O H
O H
Fe
2+
Fe
2+
Fe
O
O
H
H
O
-
O
NH2
H O
H
Al
+
OH
OH
O
O
Al
Si
O
H
O
O
O
O
Si
O
O OH
Fe
2+O
H
H
.
.
.
OH
OH
O
O
O
O
NHCH3
OH
O
-
OH
O OH
OH
OH
NO2
OH
OH
O
NH2
O
OH
O
O
N
OH
O
C H2C H2
O
NH
OH
NH2
O
O
-
H
H
H
OH
OH
O O
H3CO
OH
O
CH 2OH
CH 2OH
O O
O
O
C H2
O
OO
CH 2OH
OO
C H2
O
CH 2OH
O
O
H
HOH
C H3
OH
H
H
H
OH
OH
O
-
O
LMW labile
organic C
CO2
27. “UV has the potential to account for most of the DOC losses …
and thus may play a significant role in regulating DOC
concentrations in lakes”
28. Photochemical mineralization of organic matter
It is an easy an safe experiment to put some water in a thin quartz
vessel under the sun or under some lamp
Many nice experiments,
especially in surface water on
sunny days – but does it
matter at larger scales?
31. Absorbance and attenuation spectra
Ø DOC absorbance spectra of 1086 lakes across Sweden,
Riksinventering 2009
Ø Assuming that attenuation only due to
absorption from dissolved organic
matter and water
32. Irradiance spectra, at each time point, at each lake
Atmospheric radiative transfer model libRadTran
Ø Absorption and scattering by atmospheric constituents
Ø Using actual ozone and cloud profiles from 2009 for each
spatial point
Ø Hourly time scale
Fichot and Miller 2010; Mayer et al. 2011
33. Irradiance spectra, at each time point, at each lake
Atmospheric radiative transfer model libRadTran
Ø Absorption and scattering by atmospheric constituents
Ø Using actual ozone and cloud profiles from 2009 for each
spatial point
Ø Hourly time scale
Fichot and Miller 2010; Mayer et al. 2011
34. Upscaling of photomineralization to the scale of
Sweden
• integration of photochemically
active radiation over time
Koehler et al. 2014
35. Upscaling of photomineralization to the scale of
Sweden
• integration of photochemically
active radiation over time
• wavelength dependent
depth attenuation of the
photochemically active
radiation
Koehler et al. 2014
36. Upscaling of photomineralization to the scale of
Sweden
• integration of photochemically
active radiation over time
• wavelength dependent
depth attenuation of the
photochemically active
radiation
• wavelength dependent
photochemical
reactivity of DOC
Koehler et al. 2014
38. Depth profiles of DIC photoproduction
example from two lakes, one day
Brownwater vs. Clearwater lake
~10-fold difference in a350:
6.7 vs. 60.5 m-1
Similar DIC photoproduction:
26.9 vs. 25.5 mg C m-2 day-1
Photomineralization is photon-limited
39. Annual course of DIC photoproduction,
example from one lake, one year
Clear-sky irradiances
40. Annual course of DIC photoproduction,
example from one lake, one year
Clear-sky irradiances
Cloud-corrected
irradiances
41. Annual total Swedish CO2-C emissions
Photomineralization (this study):
0.1-0.3 Mtons C yr-1, i. e. 6-18% of total emissions*
Hence, photochemistry is significant, but not the
main driver of lake CO2 emissions
*Algesten et al. 2003
Koehler et al. 2014
42. OceanLand Inland waters
Things that transform the organic matter
Flocculation/Sedimentation
Microbial mineralization
Photochemical mineralization
44. The OC collected in sediment traps is to a large extent of
terrestrial origin
von Wachenfeldt and Tranvik Ecosystems 2008
Allochthony calculated
from 13C
45. CO2
DOC
Plankton
CO2
CO2
Light
100%
C
C
~ 50 %
DOCPOC
The OC settling onto the sediment can only to a
minor extent be explained by particles imported
from land
Flocculation of DOC accounts for most of the OC
found in sediments of boreal lakes
von Wachenfeldt and Tranvik Ecosystems 2008, L&O 2008, 2009
47. OceanLand Inland waters
Whatever the things are that make the organic carbon
dissappear – how fast do they act?
Flocculation/Sedimentation
Microbial mineralization
Photochemical mineralization
50. Degradability of organic carbon decreases over time, due to gradual
loss of the more labile compounds, and
Reactivity continuum
Boudreau and Rudick, 1991; Koehler et al. 2012
Apparent initial age of DOC (a)
Distribution of the intrinsic reactive types (ν)
Decayconstant,k
Time, t
51. Data from 208 bioassays
and 107 field studies
Longer retention time -> slower decay
52. Data in previous slide vs marine sediments
The same general pattern of slower decay extends
over 10 orders of magnitude
Open symbols: Marine
sediment OC decay
(Middelburg 1989)
Catalán et al. 2016
54. DOC input/output budgets of 82 water bodies,
mostly from Europe and North America
Evans et al. 2017, Nature Geoscience
55. Loss of DOC overestimated at long WRT, and
underestimated at short WRT*
PredictedremainingDOC
*if an average decay rate is used
Evans et al. 2017, Nature Geoscience
56. Loss of DOC overestimated at long WRT, and
underestimated at short WRT*
PredictedremainingDOC
*if an average decay rate is used
Loss is faster in the
beginning, before labile
compounds are exhausted
Evans et al. 2017, Nature Geoscience
57. Loss of DOC overestimated at long WRT, and
underestimated at short WRT*
PredictedremainingDOC
*if an average decay rate is used
Loss is faster in the
beginning, before labile
compounds are exhausted
Loss is slower in the
end, when
predominantly
recalcitrant
compounds remain
Evans et al. 2017, Nature Geoscience
58. Loss of DOC overestimated at long WRT, and
underestimated at short WRT*
PredictedremainingDOC
*if an average decay rate is used
Loss is faster in the
beginning, before labile
compounds are exhausted
Loss is slower in the
end, when
predominantly
recalcitrant
compounds remain
…and when loss is
increasingly
counteracted by
new primary
production
Evans et al. 2017, Nature Geoscience
59. OceanLand Inland waters
Different molecular properties are lost at different rates
Will this result in emergent patterns across aquatic
environments?
Flocculation/Sedimentation
Microbial mineralization
Photochemical mineralization
60. Köhler et al. PloSONE 2013
Increasing water retention time
Basin A: 0.07 years; Basin F: 2.8 years
61. DOC half-life: 6.1 years
Color (abs420) half life: 1.7 years
Fe half-life: 0.6 years
The DOC becomes “fresher”
62. Köhler et al. PloSONE 2013
Increasing water retention time
Basin A: 0.07 years; Basin F: 2.8 years
Loss rate: DOC < Color < Fe
Colored DOC lost by co-precipitation with Fe, and with photodecay
64. Ultra high resolution mass spectrometry
Kellerman et al. Nature Communications 2014
1000s of formula plotted in space of elemental ratios,
H/C and O/C
67. OceanLand Inland waters
Yes, there is some apparent selective loss of compounds resulting in
emergent patterns across the inland water continuum
Flocculation/Sedimentation
Microbial mineralization
Photochemical mineralization
69. • DOC in inland waters is a major agent in
continental carbon budgets
Take home message
70. • DOC in inland waters is a major agent in
continental carbon budgets
Take home message
• Transformations of DOC results in
substantial emissions to the
atmosphere and a significant sediment
C sink
71. • DOC in inland waters is a major agent in
continental carbon budgets
Take home message
• The composition of organic
matter is shaped by selective
biogeochemical processes
• Transformations of DOC results in
substantial emissions to the
atmosphere and a significant sediment
C sink