Difference between revisions of "Category:Lake Sediments Working Group"

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== Task 1: Depth ==
 
== Task 1: Depth ==
 
How should we report depth?
 
How should we report depth?
 +
 +
[[File:MetadataDefinitions.png | thumb | right | 400px | Definition of essential, recommended, and desired in regards to paleoclimate data standards]]
  
 
For this discussion we recommend:
 
For this discussion we recommend:
 
* structuring discussions around what scientific questions one would want to ask of the data
 
* structuring discussions around what scientific questions one would want to ask of the data
−
* listing essential, recommended, and optional information for:
+
* listing essential, recommended, and desired information for:
 
** the measurements themselves
 
** the measurements themselves
 
** any inference made from the measurements (e.g. calibration to temperature)
 
** any inference made from the measurements (e.g. calibration to temperature)
Line 24: Line 26:
  
 
=== Sample Depth ===
 
=== Sample Depth ===
 +
 +
'''Note''': Do not edit the polls (even for typos) once voting has started as it will reset the vote counts to zero. If a change needs to be made, make an annotation above the old poll (i.e., above the poll tags) and place the new poll below the first one.
  
 
In all cases, most simply, we want to report the geometry of a sample from a core. This requires two pieces of information, typically this is either the mid-point depth and thickness, or top and bottom depth. Each has its advantages:
 
In all cases, most simply, we want to report the geometry of a sample from a core. This requires two pieces of information, typically this is either the mid-point depth and thickness, or top and bottom depth. Each has its advantages:
  
 
*Top and bottom depth is more explicit and self explanatory, but typically requires an additional step to use for analysis
 
*Top and bottom depth is more explicit and self explanatory, but typically requires an additional step to use for analysis
−
*Mid-point depth is more typically reported, and is what is needed for most age models, but can be ambiguous
+
*Mid-point depth is more typically reported, and is what is needed for most age models, but can be ambiguous<br />
 +
 
 +
 
 +
In the case of tilted or deformed sedimentary units (for instance due to coring operations), core depths should be read at the center of the core, and information regarding the width of the subsample should be reported.
 +
 
  
 
[[File:LakeSediment Depth TwitterPoll.png|thumb|right|Results from Twitter Poll (3/14/17 to 3/21/17)]]
 
[[File:LakeSediment Depth TwitterPoll.png|thumb|right|Results from Twitter Poll (3/14/17 to 3/21/17)]]
Line 42: Line 50:
  
 
=== Dealing with multiple cores ===
 
=== Dealing with multiple cores ===
−
* We need to distinguish between measured depth and modeled depth, in the cases where a composite depth scale is used.
+
Commonly, multiple cores are used in a study that each have their own depth scale ("Core Depth") and using various methods, those depths are converted to "Composite Depth", which is used for most of the scientific inference. This is important additional information. We want:
−
* We need to ensure a common reference. I suggest that depth always refers to depth below lake floor.
+
 
 +
#Mid-point depth (Core Depth)
 +
#Mid-point depth (Composite Depth)
 +
#thickness
 +
 
 +
and ideally, we want to store the necessary information that describes the relationship between core depth and composite depth.
 +
 
 +
LacCore (and others) use splice and affine tables to accomplish that.
 +
 
 +
Add a description and discussion of splice and affine tables for discussion here.
 +
 
 +
===Depth Datum===
 +
For both core depth and composite depth, we need a datum for depth.  Most typically, this is the top of the sediment in each core, for core depth (where depth=0), and is the sediment surface for composite depths. Sometimes, depth from the lake (water) surface is used.  
 +
 
 +
We need to either
 +
 
 +
*Describe what datum is being used for each depth measurement
 +
OR
 +
*choose a universal datum and force datasets to adhere
 +
 
 +
Or we could do both.
  
 
== Sensors ==
 
== Sensors ==
Line 49: Line 77:
 
Sensors in lakes fall into several different categories
 
Sensors in lakes fall into several different categories
  
−
=== Sediment ===
+
=== Physical properties of sediment ===
 
Several observations can be made on sedimentary sensors including:
 
Several observations can be made on sedimentary sensors including:
−
*grain size
+
*Density
 +
{| class="wikitable"
 +
|-
 +
|+Table : Essential/Recommended/Desired Metadata for density properties of sediment
 +
|-
 +
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| Density || E || e.g., Wet Bulk Density, Dry Bulk Density, gamma attenuation derived density, X-radiographic derived density, CT-scan derived || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Water content / Porosity || R || Often measured along with density, in % mass (for WC) & % volume (for porosity) || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Native data (for inferred density) || D || measured data used to infer density || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Units || E || for all variables. e.g., mass per volume, preferably g cm-3 || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Density Type || R || e.g., inferred or measured density|| [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Method || R || e.g, direct sampling, gamma attenuation, X-ray, CT || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Interpretation|| R|| Is the density sensitive to organic content, glacier extent, temperature, geomorphology? || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|}
 +
 
 +
<poll>
 +
For density measurements in lake sediment cores, should the density name (e.g. wet bulk density, X-radiographic derived density,...) be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For density measurements in lake sediment cores, should the water content/porosity be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For inferred density in lake sediment cores, should the native data be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For density measurements in lake sediment cores, should the units be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For density measurements in lake sediment cores, should the density type (inferred or measured) be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For density measurements in lake sediment cores, should the method (e.g., direct sampling, gamma attenuation...) be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For density measurements in lake sediment cores, should the interpretation be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
*particle size
 +
{| class="wikitable"
 +
|-
 +
|+Table : Essential/Recommended/Desired Metadata for particle size properties of sediment
 +
|-
 +
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| % volume or mass (depending on method), by grain size class/interval || E || Should usually sum to 100% across all classes || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Units || E || for all variables. e.g., usually percent by mass or volume || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Native data (full range of measured grain sizes) || R || if above is presented at coarser grain size than measured|| [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Summary statistics used to characterize distribution || R || typically median, mode, skewness, kurtosis, sorting statistics, other quantiles || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Particle size type || R || e.g., inferred or measured particle size|| [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Pretreatment Method || R || methods for removing organic, carbonate and biogenic silica components of sediment, as well as defloculation || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Analytical Method || R || e.g, laser diffraction, sieving, pipette settling, sedigraph, counter, hydrometer, image analysis|| [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Analytical Instrument || R || e.g, Coulter LS 230|| [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Interpretation|| R|| Is the percent abundance grain size class interpreted to reflect environmental variability (e.g., lake level, flooding, dust deposition, glacial activity, etc)? || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|}
 +
 
 +
<poll>
 +
For particle size measurements, should the %volume or mass by grain size class/interval be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the units be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the native data (full range of measured grainsizes) be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the summary statistics used to characterize distribution be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the partical size type (measured vs inferred) be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the pretreatment methods (e.g. organics removal, defloculation) be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the analytical method be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the instrument be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For particle size measurements, should the interpretation be considered:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 
*mineralogy
 
*mineralogy
−
*geochemistry
+
{| class="wikitable"
−
**bulk organic carbon concentrations
+
|-
−
**bulk inorganic carbon concentrations
+
|+Table : Essential/Recommended/Desired Metadata for sediment mineralogy
−
**bulk nitrogen concentrations
+
|-
−
**C:N
+
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| relative abundance, by mineral || E || Often relative to the total mass, reference minerals, or ratios between minerals || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Units || E || for all variables. e.g., usually percent or unitless || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Native data || R || full XRD or other (Raman, electromagnetic) spectrum, counts or images from thin sections || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| mineralogy type || R || e.g., inferred or measured mineralogy|| [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Pretreatment Method || R || methods for XRD pretreatment (essential for XRD), thin section preparation, removing organic components of sediment, fraction analyzed, etc. || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Analytical Method || R || e.g, XRD, microscopy, Raman spectroscopy, other spectral inference || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Analytical Instrument || R || Instrument used || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Interpretation|| R|| Is the mineral abundance interpreted to reflect environmental variability (e.g., provenance, weathering, lake level, dust deposition, Redox, water geochemistry, glacial activity, etc)? || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|}
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, the relative abundance, by mineral, should be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the units be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the native data be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the mineralogy type be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the pretreatment method be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the analytical method be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the analytical instrument be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For mineralogy measurements made on lake sediment cores, should the interpretation be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
*imagery data
 +
{| class="wikitable"
 +
|-
 +
|+Table : Essential/Recommended/Desired Metadata for sediment imagery data
 +
|-
 +
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| reflectance or transmittance, by wavelength || E || detected or normalized intensity of reflected or transmitted electromagnetic radiation || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Units || E || for all variables. usually unitless || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Native data || R || unnormalized electromagnetic spectrum || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Post acquisition processing methods || R || methods describing how the imagery was processed || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Data reduction methods  || R || peak or trough area methods, etc. || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Pretreatment Method || D || methods core or thin section pretreatment || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Analytical Method || R || e.g, grayscale, RGB linescan, hyperspectral imagery || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Analytical Instrument || R || Instrument used || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Interpretation|| R|| Is the imagery interpreted to reflect environmental variability (e.g., chlorohphyll abundance, provenance, weathering, lake level, dust deposition, Redox, water geochemistry, glacial activity, etc)? || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|}
 +
 
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the reflectance or transmittance (by wavelength) be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the units be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the native data be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the post acquisition processing methods be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the data reduction methods be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the pretreatment method be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the analytical method be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the analytical instrument be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For imagery data used for studies on lake sediment cores, should the instrument be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
*Accumulation rate (varves & more)
 +
{| class="wikitable"
 +
|-
 +
|+Table : Essential/Recommended/Desired Metadata for sedimentary accumulation rate
 +
|-
 +
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| accumulation rate || E || the rate of sedimentary accumulation, either as vertical change per year, or as mass per area change per year  || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| thickness || R || the vertical thickness of the sedimentary unit  || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| density || R || necessary for mass flux accumulation rates, see standards above || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Units || E || length per time for vertical change, mass per area per time for mass flux || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| chronological constraint || E || is the accumulation rate based on varve counts, other markers of known age, a chronological model, etc || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| accumulation rate type || R || e.g., inferred or measured || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Method || R || e.g, thin section, core surface, software, image analysis, etc. || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Pretreatment Method || D || methods for core or thin section pretreatment || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|-
 +
| Interpretation|| R|| Is the accumulation sensitive to climate, glacier extent, discharge, geomorphology, anthropogenic activities, etc? || [[nick mckay]], [[Darrell]] 15 September 2017
 +
|}
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the accumulation rate be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the thickness be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the density be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the units be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the chronological constraints be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the accumulation rate type be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the method be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the pretreatment method be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
<poll>
 +
For accumulation rate studies on lake sediment cores, should the interpretation be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 
 +
=== Geochemical properties of sediment ===
 +
*bulk organic carbon concentrations
 +
*bulk inorganic carbon concentrations
 +
*bulk nitrogen concentrations
 +
*C:N
 
*isotope geochemistry
 
*isotope geochemistry
 
**bulk organic carbon isotopic composition
 
**bulk organic carbon isotopic composition
 
**bulk inorganic carbon isotopic composition
 
**bulk inorganic carbon isotopic composition
 
**bulk nitrogen isotopic composition
 
**bulk nitrogen isotopic composition
 +
**Compound Specific Isotopic Analysis (CSIA)
 +
{| class="wikitable"
 +
|-
 +
|+Table 4: Essential/Recommended/Desired Metadata for Compound Specific Isotopes
 +
|-
 +
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| [[:Category:  Location_(L)]] (Lat, Lon) || E || Location is a must || [[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| | [[:Property:Wgs84:Alt (L)]] (Depth) || E || Water depth can be useful to get an idea of diagenesis in the core. Especially for deep-sea drilling sediments, water depths can be important to assess various biogeochemical properties || [[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| Sample Depth || E || Positional information needed to relate the samples back to the archive || [[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| ChonDataTable || E for new datasets/ R for legacy datasets || The raw radiocarbon, tie points, 210Pb measurements should be made available so that age models can be updated in light of new calibration curves or new age modeling techniques ||[[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| Compound(s) analyzed || E || e.g., n-alkanes, FAMEs, alkenones, dinosterol || [[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| Source of compound in sediments || R || Is this compound marine/aquatic or terrestrial in origin? || [[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| Isotope measured || E || e.g., ∂2H, ∂13C, ∂15N ||[[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
| Environmental Parameter CSIA is sensitive to || R|| Is the CSIA sensitive to salinity, precipitation, E-P, productivity, temperature? ||[[User:Jrichey|Jrichey]] ([[User talk:Jrichey|talk]]) 07:40, 24 April 2017 (PDT)
 +
|-
 +
|}
 +
 +
'''Note''': Do not edit the polls (even for typos) once voting has started as it will reset the vote counts to zero. If a change needs to be made, make an annotation above the old poll (i.e., above the poll tags) and place the new poll below the first one.
 +
 +
<poll>
 +
For compound specific isotopes in lake sediments, should the compound analyzed be:
 +
Essential Metadata
 +
Recommended Metadata
 +
Desired Metadata
 +
</poll>
 +
 +
[[File:TwitterPoll LakeSediments CompoundIsotope Source.png | thumb | right | 400px | Results of the poll placed on Twitter from May 12th to 19th 2017]]
 +
 +
<poll>
 +
For compound specific isotopes in lake sediments, should the source of the compound (terrestrial vs aquatic) be:
 +
Essential Metadata
 +
Recommended Metadata
 +
Desired Metadata
 +
</poll>
 +
 +
[[File:TwitterPoll LakeSediments CompoundIsotope Interpretation.png | thumb | right | 400px | Results of the poll placed on Twitter from May 12th to 19th 2017]]
 +
 +
<poll>
 +
For compound specific isotopes in lake sediments, should the interpretation (e.g., temperature, salinity, precipitation) be:
 +
Essential Metadata
 +
Recommended Metadata
 +
Desired Metadata
 +
</poll>
  
 
=== Aquatic organisms ===
 
=== Aquatic organisms ===
Line 95: Line 591:
 
Several sensors in the air above and around lakes may leave microfossils in lake sediments, these include
 
Several sensors in the air above and around lakes may leave microfossils in lake sediments, these include
 
* chironimid tests, these are organic microfossils
 
* chironimid tests, these are organic microfossils
 +
 +
== Magnetic data ==
 +
 +
From Steve Lund
 +
 +
{| class="wikitable"
 +
|-
 +
|+Essential/Recommended/Desired Metadata for Magnetic Data
 +
|-
 +
! Metadata || Essential (E)/ Recommended (R) / Desired (D) || Reason || Added by (optional)
 +
|-
 +
| [[:Category:  Location_(L)]] (Lat, Lon) || E || Location is a must || [[User:Khider|Deborah Khider]] ([[User talk:Khider|talk]]) 12:05, 14 September 2017 (PDT)
 +
|-
 +
| [[:Property:Wgs84:Alt (L)]] (Depth) || E ||  ||[[User:Khider|Deborah Khider]] ([[User talk:Khider|talk]]) 12:05, 14 September 2017 (PDT)
 +
|-
 +
| Position within the lake basin ||E|| Need to know the distance from land || [[User:Khider|Deborah Khider]] ([[User talk:Khider|talk]]) 12:05, 14 September 2017 (PDT)
 +
|-
 +
| Ancillary data about the archive (carbonate and organic content) || R ||  || [[User:Khider|Deborah Khider]] ([[User talk:Khider|talk]]) 12:05, 14 September 2017 (PDT)
 +
|-
 +
| Flag that the signal recorded hasn't been altered by geochemistry || D || || [[User:Khider|Deborah Khider]] ([[User talk:Khider|talk]]) 12:05, 14 September 2017 (PDT)
 +
|}
 +
 +
<poll>
 +
For magnetic measurements made on lake sediments, should the position of the core within the lake basin be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 +
<poll>
 +
For magnetic measurements made on lake sediments, should ancillary data about the archive (carbonate and orgnaic content) be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
 +
 +
<poll>
 +
For magnetic measurements made on lake sediments, should a flag that the signal recorded hasn't been alterd by geochemistry be:
 +
Essential
 +
Recommended
 +
Desired
 +
</poll>
  
 
== Polls ==
 
== Polls ==

Latest revision as of 18:20, 18 September 2017


Overview

In the Linked Earth context, a working group (WG) is a self-organized coalition of knowledgeable experts, whose activities are governed herewith. This page is dedicated to the discussion of data and metadata standards for lake sediments (see this page for a definition of the lake sediment archive), and aims to formulate a set of recommendations for such a standard. Note that chronological aspects should be discussed within the Chronologies WG.

Specific tasks

Thinking about data standards for lakes is a challenging task because of the incredible diversity of observations made on this archive. To start this process, the working group will focus on developing standards for the one variable in lake sediments that all scientists rely on: depth.

After we've done this process for depth, I suggest we reach out and broaden this group to include broad expertise of different sensor and observations types. A preliminary list is presented below.

Task 1: Depth

How should we report depth?

Definition of essential, recommended, and desired in regards to paleoclimate data standards

For this discussion we recommend:

  • structuring discussions around what scientific questions one would want to ask of the data
  • listing essential, recommended, and desired information for:
    • the measurements themselves
    • any inference made from the measurements (e.g. calibration to temperature)
    • the underlying uncertainties, and what those numbers correspond to (e.g. 1-sigma or 2-sigma?)
  • provide an ideal data table for each type of observation, so the community knows what to report and how to report it.
  • provide separate recommendations for new and legacy datasets

Sample Depth

Note: Do not edit the polls (even for typos) once voting has started as it will reset the vote counts to zero. If a change needs to be made, make an annotation above the old poll (i.e., above the poll tags) and place the new poll below the first one.

In all cases, most simply, we want to report the geometry of a sample from a core. This requires two pieces of information, typically this is either the mid-point depth and thickness, or top and bottom depth. Each has its advantages:

  • Top and bottom depth is more explicit and self explanatory, but typically requires an additional step to use for analysis
  • Mid-point depth is more typically reported, and is what is needed for most age models, but can be ambiguous


In the case of tilted or deformed sedimentary units (for instance due to coring operations), core depths should be read at the center of the core, and information regarding the width of the subsample should be reported.


Results from Twitter Poll (3/14/17 to 3/21/17)
What should be the primary way of reporting depth of samples taken from lake sediments:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 10 votes since the poll was created on 19:18, 21 September 2016.
poll-id BE3AECAB02A5C21AD92F447B763D2C96

The wiki and twitter polls indicate a slight preference for mid-point and thickness

Dealing with multiple cores

Commonly, multiple cores are used in a study that each have their own depth scale ("Core Depth") and using various methods, those depths are converted to "Composite Depth", which is used for most of the scientific inference. This is important additional information. We want:

  1. Mid-point depth (Core Depth)
  2. Mid-point depth (Composite Depth)
  3. thickness

and ideally, we want to store the necessary information that describes the relationship between core depth and composite depth.

LacCore (and others) use splice and affine tables to accomplish that.

Add a description and discussion of splice and affine tables for discussion here.

Depth Datum

For both core depth and composite depth, we need a datum for depth. Most typically, this is the top of the sediment in each core, for core depth (where depth=0), and is the sediment surface for composite depths. Sometimes, depth from the lake (water) surface is used.

We need to either

  • Describe what datum is being used for each depth measurement

OR

  • choose a universal datum and force datasets to adhere

Or we could do both.

Sensors

Sensors in lakes fall into several different categories

Physical properties of sediment

Several observations can be made on sedimentary sensors including:

  • Density
Table : Essential/Recommended/Desired Metadata for density properties of sediment
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
Density E e.g., Wet Bulk Density, Dry Bulk Density, gamma attenuation derived density, X-radiographic derived density, CT-scan derived nick mckay, Darrell 15 September 2017
Water content / Porosity R Often measured along with density, in % mass (for WC) & % volume (for porosity) nick mckay, Darrell 15 September 2017
Native data (for inferred density) D measured data used to infer density nick mckay, Darrell 15 September 2017
Units E for all variables. e.g., mass per volume, preferably g cm-3 nick mckay, Darrell 15 September 2017
Density Type R e.g., inferred or measured density nick mckay, Darrell 15 September 2017
Method R e.g, direct sampling, gamma attenuation, X-ray, CT nick mckay, Darrell 15 September 2017
Interpretation R Is the density sensitive to organic content, glacier extent, temperature, geomorphology? nick mckay, Darrell 15 September 2017
For density measurements in lake sediment cores, should the density name (e.g. wet bulk density, X-radiographic derived density,...) be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 16:59, 17 September 2017.
poll-id 3CD81E7613CAA9DF2835DFE255414F5F

For density measurements in lake sediment cores, should the water content/porosity be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 16:56, 17 September 2017.
poll-id 055EBEF6694713778F557A5B8D06393E

For inferred density in lake sediment cores, should the native data be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 16:58, 17 September 2017.
poll-id 33D778CEFC0A64125339F0CF8D9073B3

For density measurements in lake sediment cores, should the units be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 16:58, 17 September 2017.
poll-id FE664291523FDE9078E5ADB497E2B896

For density measurements in lake sediment cores, should the density type (inferred or measured) be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 16:59, 17 September 2017.
poll-id 014DA8043C68D03C26381296A9FD6365

For density measurements in lake sediment cores, should the method (e.g., direct sampling, gamma attenuation...) be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:00, 17 September 2017.
poll-id 9C089E66554F9D70A8F28F362B7025CD

For density measurements in lake sediment cores, should the interpretation be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:00, 17 September 2017.
poll-id B2D591EBC3D062FD0A35018A5C0A5B7E

  • particle size
Table : Essential/Recommended/Desired Metadata for particle size properties of sediment
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
 % volume or mass (depending on method), by grain size class/interval E Should usually sum to 100% across all classes nick mckay, Darrell 15 September 2017
Units E for all variables. e.g., usually percent by mass or volume nick mckay, Darrell 15 September 2017
Native data (full range of measured grain sizes) R if above is presented at coarser grain size than measured nick mckay, Darrell 15 September 2017
Summary statistics used to characterize distribution R typically median, mode, skewness, kurtosis, sorting statistics, other quantiles nick mckay, Darrell 15 September 2017
Particle size type R e.g., inferred or measured particle size nick mckay, Darrell 15 September 2017
Pretreatment Method R methods for removing organic, carbonate and biogenic silica components of sediment, as well as defloculation nick mckay, Darrell 15 September 2017
Analytical Method R e.g, laser diffraction, sieving, pipette settling, sedigraph, counter, hydrometer, image analysis nick mckay, Darrell 15 September 2017
Analytical Instrument R e.g, Coulter LS 230 nick mckay, Darrell 15 September 2017
Interpretation R Is the percent abundance grain size class interpreted to reflect environmental variability (e.g., lake level, flooding, dust deposition, glacial activity, etc)? nick mckay, Darrell 15 September 2017
For particle size measurements, should the %volume or mass by grain size class/interval be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:14, 17 September 2017.
poll-id 5928045E7443BED15E0A8C02E541C31C

For particle size measurements, should the units be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:14, 17 September 2017.
poll-id DDD52E4C421F14DCDCA1FE1F0CE5CE61

For particle size measurements, should the native data (full range of measured grainsizes) be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:14, 17 September 2017.
poll-id E8A1590AD5DEA31D0F7B6C029ABCA9C3

For particle size measurements, should the summary statistics used to characterize distribution be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:15, 17 September 2017.
poll-id 99FF59233413E4F99BF2CF54330A5CF6

For particle size measurements, should the partical size type (measured vs inferred) be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:15, 17 September 2017.
poll-id 00A94DD9AFDA110F9586402CA7D31C79

For particle size measurements, should the pretreatment methods (e.g. organics removal, defloculation) be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:16, 17 September 2017.
poll-id DA358DEF757B8B0B631CB50E96C08769

For particle size measurements, should the analytical method be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:16, 17 September 2017.
poll-id 128D7324CFE8319587517A394AD99074

For particle size measurements, should the instrument be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:16, 17 September 2017.
poll-id BF2FA1AEA2CE0457B9746635313C7E5F

For particle size measurements, should the interpretation be considered:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:17, 17 September 2017.
poll-id 74C2BCF571306B62C7468B4AD7E99F51

  • mineralogy
Table : Essential/Recommended/Desired Metadata for sediment mineralogy
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
relative abundance, by mineral E Often relative to the total mass, reference minerals, or ratios between minerals nick mckay, Darrell 15 September 2017
Units E for all variables. e.g., usually percent or unitless nick mckay, Darrell 15 September 2017
Native data R full XRD or other (Raman, electromagnetic) spectrum, counts or images from thin sections nick mckay, Darrell 15 September 2017
mineralogy type R e.g., inferred or measured mineralogy nick mckay, Darrell 15 September 2017
Pretreatment Method R methods for XRD pretreatment (essential for XRD), thin section preparation, removing organic components of sediment, fraction analyzed, etc. nick mckay, Darrell 15 September 2017
Analytical Method R e.g, XRD, microscopy, Raman spectroscopy, other spectral inference nick mckay, Darrell 15 September 2017
Analytical Instrument R Instrument used nick mckay, Darrell 15 September 2017
Interpretation R Is the mineral abundance interpreted to reflect environmental variability (e.g., provenance, weathering, lake level, dust deposition, Redox, water geochemistry, glacial activity, etc)? nick mckay, Darrell 15 September 2017
For mineralogy measurements made on lake sediment cores, the relative abundance, by mineral, should be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:43, 18 September 2017.
poll-id F44AB406DD9E43CB192E0BC34C658507

For mineralogy measurements made on lake sediment cores, should the units be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:43, 18 September 2017.
poll-id 4DD4F337F381BA7E0FF7957649FAB569

For mineralogy measurements made on lake sediment cores, should the native data be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:43, 18 September 2017.
poll-id B0DAB0CE26B473F9738E9322B8E5EDA9

For mineralogy measurements made on lake sediment cores, should the mineralogy type be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:43, 18 September 2017.
poll-id 9B732356E35F33DFD9236F0A7A16C827

For mineralogy measurements made on lake sediment cores, should the pretreatment method be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:44, 18 September 2017.
poll-id ACFE0552CFED314130ADE96A29309814

For mineralogy measurements made on lake sediment cores, should the analytical method be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:44, 18 September 2017.
poll-id 96755DE3AD281D32FB3A40A2F0B1A34F

For mineralogy measurements made on lake sediment cores, should the analytical instrument be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:44, 18 September 2017.
poll-id 886755F38024755049A05894D5F598A7

For mineralogy measurements made on lake sediment cores, should the interpretation be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 17:44, 18 September 2017.
poll-id A95456AF3EE28D747341DCCCA877348B

  • imagery data
Table : Essential/Recommended/Desired Metadata for sediment imagery data
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
reflectance or transmittance, by wavelength E detected or normalized intensity of reflected or transmitted electromagnetic radiation nick mckay, Darrell 15 September 2017
Units E for all variables. usually unitless nick mckay, Darrell 15 September 2017
Native data R unnormalized electromagnetic spectrum nick mckay, Darrell 15 September 2017
Post acquisition processing methods R methods describing how the imagery was processed nick mckay, Darrell 15 September 2017
Data reduction methods R peak or trough area methods, etc. nick mckay, Darrell 15 September 2017
Pretreatment Method D methods core or thin section pretreatment nick mckay, Darrell 15 September 2017
Analytical Method R e.g, grayscale, RGB linescan, hyperspectral imagery nick mckay, Darrell 15 September 2017
Analytical Instrument R Instrument used nick mckay, Darrell 15 September 2017
Interpretation R Is the imagery interpreted to reflect environmental variability (e.g., chlorohphyll abundance, provenance, weathering, lake level, dust deposition, Redox, water geochemistry, glacial activity, etc)? nick mckay, Darrell 15 September 2017


For imagery data used for studies on lake sediment cores, should the reflectance or transmittance (by wavelength) be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:49, 18 September 2017.
poll-id 8D181A49BD57CC25DB2A94BCE6EFA5E4

For imagery data used for studies on lake sediment cores, should the units be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:50, 18 September 2017.
poll-id E1AE0C1751EC1295E03DD0293F31959F

For imagery data used for studies on lake sediment cores, should the native data be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:50, 18 September 2017.
poll-id 4F24D8E2234AEC49FBF251355ACC87FB

For imagery data used for studies on lake sediment cores, should the post acquisition processing methods be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:50, 18 September 2017.
poll-id 728C1B30EA37886333F574EB2335859F

For imagery data used for studies on lake sediment cores, should the data reduction methods be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:50, 18 September 2017.
poll-id 799283454436A81119839093117A99C0

For imagery data used for studies on lake sediment cores, should the pretreatment method be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:51, 18 September 2017.
poll-id A857E23AE966139030C2DA6E06CA68AC

For imagery data used for studies on lake sediment cores, should the analytical method be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:51, 18 September 2017.
poll-id EFF55697EF59824F1A733433343702C0

For imagery data used for studies on lake sediment cores, should the analytical instrument be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:49, 18 September 2017.
poll-id 65E8C58733863530E84F7F3DABC61616

For imagery data used for studies on lake sediment cores, should the instrument be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:51, 18 September 2017.
poll-id 1C4056290933B7CD472D0960881DC772

  • Accumulation rate (varves & more)
Table : Essential/Recommended/Desired Metadata for sedimentary accumulation rate
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
accumulation rate E the rate of sedimentary accumulation, either as vertical change per year, or as mass per area change per year nick mckay, Darrell 15 September 2017
thickness R the vertical thickness of the sedimentary unit nick mckay, Darrell 15 September 2017
density R necessary for mass flux accumulation rates, see standards above nick mckay, Darrell 15 September 2017
Units E length per time for vertical change, mass per area per time for mass flux nick mckay, Darrell 15 September 2017
chronological constraint E is the accumulation rate based on varve counts, other markers of known age, a chronological model, etc nick mckay, Darrell 15 September 2017
accumulation rate type R e.g., inferred or measured nick mckay, Darrell 15 September 2017
Method R e.g, thin section, core surface, software, image analysis, etc. nick mckay, Darrell 15 September 2017
Pretreatment Method D methods for core or thin section pretreatment nick mckay, Darrell 15 September 2017
Interpretation R Is the accumulation sensitive to climate, glacier extent, discharge, geomorphology, anthropogenic activities, etc? nick mckay, Darrell 15 September 2017
For accumulation rate studies on lake sediment cores, should the accumulation rate be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:52, 18 September 2017.
poll-id 7DD8ACCD0B16D63A5A3C99B7138F55F9

For accumulation rate studies on lake sediment cores, should the thickness be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:52, 18 September 2017.
poll-id BD0216E86D8154A970CBA68A197EB564

For accumulation rate studies on lake sediment cores, should the density be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:52, 18 September 2017.
poll-id 377E4E9CEC5BEF673D7A5EE243E7FC8C

For accumulation rate studies on lake sediment cores, should the units be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:52, 18 September 2017.
poll-id A0EBEE1349784A2DA41A829A33C679CE

For accumulation rate studies on lake sediment cores, should the chronological constraints be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:53, 18 September 2017.
poll-id 72177F73FC5261D2697B540F8CED5F2D

For accumulation rate studies on lake sediment cores, should the accumulation rate type be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:53, 18 September 2017.
poll-id 9B2A6B43FBB676DC12B7836D937A4CB9

For accumulation rate studies on lake sediment cores, should the method be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:53, 18 September 2017.
poll-id 7C772E9352CA369F0A9BC89F178470D5

For accumulation rate studies on lake sediment cores, should the pretreatment method be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:53, 18 September 2017.
poll-id 72914682E3AB3446EDB1060D6C38A991

For accumulation rate studies on lake sediment cores, should the interpretation be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 14:54, 18 September 2017.
poll-id 9CA3AF34DD416A056823DF1F21CA408F

Geochemical properties of sediment

  • bulk organic carbon concentrations
  • bulk inorganic carbon concentrations
  • bulk nitrogen concentrations
  • C:N
  • isotope geochemistry
    • bulk organic carbon isotopic composition
    • bulk inorganic carbon isotopic composition
    • bulk nitrogen isotopic composition
    • Compound Specific Isotopic Analysis (CSIA)
Table 4: Essential/Recommended/Desired Metadata for Compound Specific Isotopes
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
Category: Location_(L) (Lat, Lon) E Location is a must Jrichey (talk) 07:40, 24 April 2017 (PDT)
Property:Wgs84:Alt (L) (Depth) E Water depth can be useful to get an idea of diagenesis in the core. Especially for deep-sea drilling sediments, water depths can be important to assess various biogeochemical properties Jrichey (talk) 07:40, 24 April 2017 (PDT)
Sample Depth E Positional information needed to relate the samples back to the archive Jrichey (talk) 07:40, 24 April 2017 (PDT)
ChonDataTable E for new datasets/ R for legacy datasets The raw radiocarbon, tie points, 210Pb measurements should be made available so that age models can be updated in light of new calibration curves or new age modeling techniques Jrichey (talk) 07:40, 24 April 2017 (PDT)
Compound(s) analyzed E e.g., n-alkanes, FAMEs, alkenones, dinosterol Jrichey (talk) 07:40, 24 April 2017 (PDT)
Source of compound in sediments R Is this compound marine/aquatic or terrestrial in origin? Jrichey (talk) 07:40, 24 April 2017 (PDT)
Isotope measured E e.g., ∂2H, ∂13C, ∂15N Jrichey (talk) 07:40, 24 April 2017 (PDT)
Environmental Parameter CSIA is sensitive to R Is the CSIA sensitive to salinity, precipitation, E-P, productivity, temperature? Jrichey (talk) 07:40, 24 April 2017 (PDT)

Note: Do not edit the polls (even for typos) once voting has started as it will reset the vote counts to zero. If a change needs to be made, make an annotation above the old poll (i.e., above the poll tags) and place the new poll below the first one.

For compound specific isotopes in lake sediments, should the compound analyzed be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There was one vote since the poll was created on 17:31, 9 May 2017.
poll-id 4A67470058F7ECF24C434F9791E66635

Results of the poll placed on Twitter from May 12th to 19th 2017
For compound specific isotopes in lake sediments, should the source of the compound (terrestrial vs aquatic) be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There was one vote since the poll was created on 17:31, 9 May 2017.
poll-id 160E02C446E0079473B68B9F692FF32E

Results of the poll placed on Twitter from May 12th to 19th 2017
For compound specific isotopes in lake sediments, should the interpretation (e.g., temperature, salinity, precipitation) be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There was one vote since the poll was created on 17:32, 9 May 2017.
poll-id E885F833CA0177DD9EA2200E40145179

Aquatic organisms

Several sensors may be found in lakes including

  • Diatoms
    • may contribute silicic microfossils and biomarkers
  • Ostracods
    • may contribute carbonate microfossils
  • Algae
    • may contribute biomarkers, including alkenones
  • Archaea
    • may contribute biomarkers, including GDGTs
  • Bacteria
    • may contribute biomarkers, including GDGTs
  • Fish
    • may contribute macrofossils, including otoliths

Terrestrial plants

Plants growing around the lake and in the catchment of the lake may contribute macro and microfossils as well as biomarkers to the sediments. Plants are the sensors of the environment and the observations include:

  • Organic geochemical biomarkers:
    • plant wax n-alkanes
    • plant wax n-alkanoic acids
    • plant wax n-alkanols acids
    • plant wax terpenoids
    • lignin
  • Macro/microfossils
    • pollen
    • leaf
    • wood
    • charcoal

Insects

Several sensors in the air above and around lakes may leave microfossils in lake sediments, these include

  • chironimid tests, these are organic microfossils

Magnetic data

From Steve Lund

Essential/Recommended/Desired Metadata for Magnetic Data
Metadata Essential (E)/ Recommended (R) / Desired (D) Reason Added by (optional)
Category: Location_(L) (Lat, Lon) E Location is a must Deborah Khider (talk) 12:05, 14 September 2017 (PDT)
Property:Wgs84:Alt (L) (Depth) E Deborah Khider (talk) 12:05, 14 September 2017 (PDT)
Position within the lake basin E Need to know the distance from land Deborah Khider (talk) 12:05, 14 September 2017 (PDT)
Ancillary data about the archive (carbonate and organic content) R Deborah Khider (talk) 12:05, 14 September 2017 (PDT)
Flag that the signal recorded hasn't been altered by geochemistry D Deborah Khider (talk) 12:05, 14 September 2017 (PDT)
For magnetic measurements made on lake sediments, should the position of the core within the lake basin be:
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There were 0 votes since the poll was created on 18:19, 18 September 2017.
poll-id 1674EFCEAA2D055F97CC7584F39C9F81

For magnetic measurements made on lake sediments, should ancillary data about the archive (carbonate and orgnaic content) be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 18:20, 18 September 2017.
poll-id 20C82FB21B38AF8C93469B949EC45D7F

For magnetic measurements made on lake sediments, should a flag that the signal recorded hasn't been alterd by geochemistry be:
You are not entitled to vote.
You are not entitled to view results of this poll.
There were 0 votes since the poll was created on 18:20, 18 September 2017.
poll-id 52717B670C3D4704B480AA6E291B663A

Polls

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References

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