These lines of evidence strongly suggest that conditions favor- able for B. braunii growth occur during moderate-to-strong El Nin?o events and thus that C34 botryococcene ?D records the hydrologic conditions of the lake during these events. In contrast, the avail- able evidence suggests that the dinoflagellate population persists throughout the varying hydrologic conditions experienced by El Junco Lake and thus that sedimentary dinosterol ?D records the long-term (decadal-to-centennial) mean lake conditions.
Trace GC with PTV inlet in splitless mode, 30m DB5 capillary column (J and W Scientific) with 0.25mm i.d. and 0.25 lm film, and was operated at a constant helium flow rate of 1 ml/min. The oven temperature pro gram differed for each lipid class. For hydrocarbons, the starting temperature was 90 �C, rising to 230 �C at 13 �C/min, then to 325 �C at 5.5 �C/min, followed by 13 min at 325 �C. Effluent from the GC entered the GCC III interface, a graphitelined ceramic tube at 1400 �C, where quantitative pyrolysis to graphite, hydrogen gas and carbon monoxide occurred (Bur goyne and Hayes, 1998). The hydrogen gas stream was introduced to the Finnigan Deltaplus XP mass spectrometer via an open split, where a flow of helium carried the H2 gas into the mass spectrometer.
; archiveType changed was originally Lake sediment (LS)
AA: This record is a duplicate of LS14ZHJU (and is a shorter version of the latter record). This study's unique record is dinosterol d2H, which LS14ATJU01A.
From this paper: "In particular, conditions favorable for B. braunii blooms are thought to occur during El Nin?o events in association with three distinct processes that promote olig- otrophic conditions and lake stratification. Firstly, the heavy rains associated with moderate-to-strong El Nin?o events are thought to dilute the nutrient pool and cause oligotrophic conditions. El Junco Lake is an endorheic lake (with the exception of occasional overflow conditions and possibly seepage) located within a caldera with a small catchment area consisting only of the narrow crater rim (Conroy et al., 2008). In such lakes the con- centration of nutrients tend to decrease as lake levels increase through dilution of the incoming nutrients (Smol et al., 2001; Magyari et al., 2009). Because monthly rainfall in this area can be an order of magnitude higher during strong El Nin?o events as com- pared to non-El Nin?o periods (cf., Fig. 4) and the lake has been re- ported to overflow during strong El Nin?o events, considerable dilu- tion and flushing of nutrients likely occur during these times. Sec- ondly, reduced nutrient input to the lake exacerbates oligotrophic conditions during strong El Nin?o events. A major source of nutri- ents to the lake is thought to be guano deposited directly into the lake by the large number of seabirds that frequent it (Colinvaux, 1968). Such a predominance of avian-derived nutrients has been documented in a number of lake systems (Manny et al., 1994; Marion et al., 1994). However, during strong El Nin?o events, this nutrient source is diminished as the Gala?pagos seabird population plummets in response to the massive fish die-offs associated with a deep thermocline and low ocean productivity in the EEP (Gibbs, 1987). Finally, El Nin?o events in the EEP are associated with con- ditions that increase water column stability and lake stratification, including warmer air temperatures, reduced cloud cover, and re- duced trade wind strength (Lewis Jr., 1983; O?Reilly et al., 2003; Ndebele-Murisa et al., 2010; Co?zar et al., 2012), conditions which have been shown to exacerbate nutrient depletion in the surface of oligotrophic lakes (O?Reilly et al., 2003). Increases in water column stability during El Nin?o events should further promote favorable conditions for the oil-rich, colony-forming B. braunii due to their buoyancy. In various lo- cations across the globe, B. braunii blooms have been strongly linked to increases in water column stability due to both their tolerance of oligotrophic conditions and their anti-sinking strategy (Kebede and Belay, 1994; Souza et al., 2008; Winder and Hunter, 2008). In particular, in a Columbian lake with conditions (including depth, pH, conductivity, and nutrient concentration) comparable to El Junco Lake, B. braunii blooms have been found to occur dur- ing the annual flood stage in association with nutrient flushing, oligotrophic conditions, and lake stratification (Pinilla, 2006), con- ditions that closely mimic moderate to strong El Nin?o events in El Junco Lake. These lines of evidence strongly suggest that conditions favor- able for B. braunii growth occur during moderate-to-strong El Nin?o events and thus that C34 botryococcene ?D records the hydrologic conditions of the lake during these events."
All botryococcene dD values were highly correlated with water dD values (R2>0.99). And, Zhang and Sachs 2007, Organic Geochemistry, 38: 582-608.
changes in rainfall amount are imprinted in the isotopic composition of botryococcenes, with negative (posi- tive) ?D values co-occurring with wetter (drier) periods.
Semipreparative HPLCMS to isolate dinosterol, which was then acetylated and injected on a GC, Delta V IRMS system. From Supplemental Methods: "Hydrogen isotope measurements of dinosterol were performed on a Finnigan Delta V Plus Isotope Ratio Mass Spectrometer (IRMS) coupled to a Thermo Trace GC Ultra with a Varian VF17ms FactorFour capillary column (60 m x 0.32 mm x 0.25 ?m) and a pyrolysis reactor according to the methods described in Atwood and Sachs (2012). Samples were injected into a split/splitless inlet in splitless mode at 310 �C. The oven temperature was ramped from 100 �C to 220 �C at a rate of 20 �C/min, then at 2 �C /min up to 325 �C where it was held for 17 min. The carrier gas, He, was held constant at 2.6 mL/min. The pyroloysis reactor was maintained at 1400 �C. Isotope values, expressed as ?D values, were calculated in Isodat software relative to VSMOW using a coinjection standard containing nC32, nC40, and nC44 of known ?D values (obtained from A. Schimmelmann, Indiana University, Bloomington, IN, USA). The measured isotope values of dinosterol were corrected for the addition of hydrogen atoms (of known ?D value) that occurred during acetylation. Triplicate analyses were typically performed on each sample and mean values and standard deviations reported. Instrument performance was evaluated using H2 reference gas and a prepared standard of nalkanes of known ?D values."
In closed (endorheic) lakes, lake water dD is driven by the ratio of precipitation to evaporation and the isotopic value of the precipitation which, in the tropics, is strongly negatively correlated with the amount of precipitation on monthly and longer timescales. The combination of these processes amplifies the response of lake water dD to changes in rainfall with lower (higher) dD values occurring during periods of wetter (drier) conditions. Changes in rainfall patterns can therefore be reconstructed from dD values of sedimentary algal lipids, due to the near perfect correlation between water dD and algal lipid dD values.
"In closed (endorheic) lakes, lake water dD is driven by the ratio of precipitation to evaporation and the isotopic value of the precipitation which, in the tropics, is strongly negatively correlated with the amount of precipitation on monthly and longer timescales. The combination of these processes amplifies the response of lake water dD to changes in rainfall with lower (higher) dD values occurring during periods of wetter (drier) conditions. Changes in rainfall patterns can therefore be reconstructed from dD values of sedimentary algal lipids, due to the near perfect correlation between water dD and algal lipid dD values."
fraction of modern 14C activity uncertainty
210Pb, 239+240Pu or 137Cs activity uncertainty
Y if supported 210Pb activity, N if unsupported 210Pb activity
model used to convert 210Pb activity to age (e.g., constant rate of supply)
years before 1950 (calibrated age, or ages that dont need calibration)
was this date used in the age modelpermil
d2H (LS14ATJU01A): paleoData_isPrimary: '' has been replaced by 'FALSE'
d2H (LS14ATJU01A): paleoData_primaryAgeColumn: '' has been replaced by 'FALSE'
d2H (LS14ATJU01B): paleoData_isPrimary: '' has been replaced by 'FALSE'
d2H (LS14ATJU01B): paleoData_primaryAgeColumn: '' has been replaced by 'FALSE'
depth (MAT6c43cd5d85): paleoData_isPrimary: '' has been replaced by 'FALSE'
depth (MAT6c43cd5d85): paleoData_primaryAgeColumn: '' has been replaced by 'FALSE'
year (MAT795501f3aa): paleoData_isPrimary: '' has been replaced by 'TRUE'
year (MAT795501f3aa): paleoData_primaryAgeColumn: '' has been replaced by 'TRUE'
d2H (LS14ATJU01A): interpretation1_basis: 'In closed (endorheic) lakes, lake water dD is driven by the ratio of precipitation to evaporation and the isotopic value of the precipitation which, in the tropics, is strongly negatively correlated with the amount of precipitation on monthly and longer timescales. The combination of these processes amplifies the response of lake water dD to changes in rainfall with lower (higher) dD values occurring during periods of wetter (drier) conditions. Changes in rainfall patterns can therefore be reconstructed from dD values of sedimentary algal lipids, due to the near perfect correlation between water dD and algal lipid dD values.' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_direction: 'negative' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_rank: '1' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_scope: 'isotope' has been replaced by 'climate'
d2H (LS14ATJU01A): interpretation1_seasonality: 'Annual' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_seasonalityOriginal: 'Annual' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_variable: 'effectivePrecipitation' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_variableGroup: 'EffectiveMoisture' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_variableGroupDirection: 'negative' has been replaced by ''
d2H (LS14ATJU01A): interpretation1_variableGroupOriginal: 'P_E' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_basis: '"In closed (endorheic) lakes, lake water dD is driven by the ratio of precipitation to evaporation and the isotopic value of the precipitation which, in the tropics, is strongly negatively correlated with the amount of precipitation on monthly and longer timescales. The combination of these processes amplifies the response of lake water dD to changes in rainfall with lower (higher) dD values occurring during periods of wetter (drier) conditions. Changes in rainfall patterns can therefore be reconstructed from dD values of sedimentary algal lipids, due to the near perfect correlation between water dD and algal lipid dD values."' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_direction: 'positive' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_rank: '2' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_scope: 'isotope' has been replaced by 'climate'
d2H (LS14ATJU01A): interpretation2_seasonality: 'Annual' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_seasonalityOriginal: 'Annual' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_variable: 'precipitationIsotope' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_variableGroup: 'P_isotope' has been replaced by ''
d2H (LS14ATJU01A): interpretation2_variableGroupDirection: 'positive' has been replaced by ''
d2H (LS14ATJU01A): interpretation3_scope: '' has been replaced by 'climate'
d2H (LS14ATJU01A): interpretation4_basis: '' has been replaced by 'In closed (endorheic) lakes, lake water dD is driven by the ratio of precipitation to evaporation and the isotopic value of the precipitation which, in the tropics, is strongly negatively correlated with the amount of precipitation on monthly and longer timescales. The combination of these processes amplifies the response of lake water dD to changes in rainfall with lower (higher) dD values occurring during periods of wetter (drier) conditions. Changes in rainfall patterns can therefore be reconstructed from dD values of sedimentary algal lipids, due to the near perfect correlation between water dD and algal lipid dD values.'
d2H (LS14ATJU01A): interpretation4_direction: '' has been replaced by 'negative'
d2H (LS14ATJU01A): interpretation4_rank: '' has been replaced by '1'
d2H (LS14ATJU01A): interpretation4_scope: '' has been replaced by 'isotope'
d2H (LS14ATJU01A): interpretation4_seasonality: '' has been replaced by 'Annual'
d2H (LS14ATJU01A): interpretation4_seasonalityOriginal: '' has been replaced by 'Annual'
d2H (LS14ATJU01A): interpretation4_variable: '' has been replaced by 'effectivePrecipitation'
d2H (LS14ATJU01A): interpretation4_variableGroup: '' has been replaced by 'EffectiveMoisture'
d2H (LS14ATJU01A): interpretation4_variableGroupDirection: '' has been replaced by 'negative'
d2H (LS14ATJU01A): interpretation4_variableGroupOriginal: '' has been replaced by 'P_E'
d2H (LS14ATJU01A): interpretation5_basis: '' has been replaced by '"In closed (endorheic) lakes, lake water dD is driven by the ratio of precipitation to evaporation and the isotopic value of the precipitation which, in the tropics, is strongly negatively correlated with the amount of precipitation on monthly and longer timescales. The combination of these processes amplifies the response of lake water dD to changes in rainfall with lower (higher) dD values occurring during periods of wetter (drier) conditions. Changes in rainfall patterns can therefore be reconstructed from dD values of sedimentary algal lipids, due to the near perfect correlation between water dD and algal lipid dD values."'
d2H (LS14ATJU01A): interpretation5_direction: '' has been replaced by 'positive'
d2H (LS14ATJU01A): interpretation5_rank: '' has been replaced by '2'
d2H (LS14ATJU01A): interpretation5_scope: '' has been replaced by 'isotope'
d2H (LS14ATJU01A): interpretation5_seasonality: '' has been replaced by 'Annual'
d2H (LS14ATJU01A): interpretation5_seasonalityOriginal: '' has been replaced by 'Annual'
d2H (LS14ATJU01A): interpretation5_variable: '' has been replaced by 'precipitationIsotope'
d2H (LS14ATJU01A): interpretation5_variableGroup: '' has been replaced by 'P_isotope'
d2H (LS14ATJU01A): interpretation5_variableGroupDirection: '' has been replaced by 'positive'
d2H (LS14ATJU01A): interpretation6_scope: '' has been replaced by 'isotope'
d2H (LS14ATJU01B): interpretation2_basis: 'All botryococcene dD values were highly correlated with water dD values (R2>0.99). And, Zhang and Sachs 2007, Organic Geochemistry, 38: 582-608.' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_direction: 'positive' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_inferredMaterial: 'lake water' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_integrationTime: '1 to 10' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_integrationTimeBasis: 'These lines of evidence strongly suggest that conditions favor- able for B. braunii growth occur during moderate-to-strong El Nin?o events and thus that C34 botryococcene ?D records the hydrologic conditions of the lake during these events. In contrast, the avail- able evidence suggests that the dinoflagellate population persists throughout the varying hydrologic conditions experienced by El Junco Lake and thus that sedimentary dinosterol ?D records the long-term (decadal-to-centennial) mean lake conditions.' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_integrationTimeUnits: 'years' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_mathematicalRelation: 'linear' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_scope: 'isotope' has been replaced by 'climate'
d2H (LS14ATJU01B): interpretation2_seasonality: 'Annual' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_seasonalityOriginal: 'Annual' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_variable: 'precipitationIsotope' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_variableGroup: 'P_isotope' has been replaced by ''
d2H (LS14ATJU01B): interpretation2_variableGroupDirection: 'positive' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_basis: 'changes in rainfall amount are imprinted in the isotopic composition of botryococcenes, with negative (posi- tive) ?D values co-occurring with wetter (drier) periods.' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_direction: 'negative' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_inferredMaterial: 'lake water' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_integrationTime: '1 to 10' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_integrationTimeBasis: 'These lines of evidence strongly suggest that conditions favor- able for B. braunii growth occur during moderate-to-strong El Nin?o events and thus that C34 botryococcene ?D records the hydrologic conditions of the lake during these events. In contrast, the avail- able evidence suggests that the dinoflagellate population persists throughout the varying hydrologic conditions experienced by El Junco Lake and thus that sedimentary dinosterol ?D records the long-term (decadal-to-centennial) mean lake conditions.' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_integrationTimeUnits: 'years' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_mathematicalRelation: 'linear' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_scope: 'isotope' has been replaced by 'climate'
d2H (LS14ATJU01B): interpretation3_seasonality: 'Annual' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_seasonalityOriginal: 'Annual' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_variable: 'effectivePrecipitation' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_variableGroup: 'EffectiveMoisture' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_variableGroupDirection: 'negative' has been replaced by ''
d2H (LS14ATJU01B): interpretation3_variableGroupOriginal: 'P_E' has been replaced by ''
d2H (LS14ATJU01B): interpretation4_basis: '' has been replaced by 'All botryococcene dD values were highly correlated with water dD values (R2>0.99). And, Zhang and Sachs 2007, Organic Geochemistry, 38: 582-608.'
d2H (LS14ATJU01B): interpretation4_direction: '' has been replaced by 'positive'
d2H (LS14ATJU01B): interpretation4_inferredMaterial: '' has been replaced by 'lake water'
d2H (LS14ATJU01B): interpretation4_integrationTime: '' has been replaced by '1 to 10'
d2H (LS14ATJU01B): interpretation4_integrationTimeBasis: '' has been replaced by 'These lines of evidence strongly suggest that conditions favor- able for B. braunii growth occur during moderate-to-strong El Nin?o events and thus that C34 botryococcene ?D records the hydrologic conditions of the lake during these events. In contrast, the avail- able evidence suggests that the dinoflagellate population persists throughout the varying hydrologic conditions experienced by El Junco Lake and thus that sedimentary dinosterol ?D records the long-term (decadal-to-centennial) mean lake conditions.'
d2H (LS14ATJU01B): interpretation4_integrationTimeUnits: '' has been replaced by 'years'
d2H (LS14ATJU01B): interpretation4_mathematicalRelation: '' has been replaced by 'linear'
d2H (LS14ATJU01B): interpretation4_scope: '' has been replaced by 'isotope'
d2H (LS14ATJU01B): interpretation4_seasonality: '' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation4_seasonalityOriginal: '' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation4_variable: '' has been replaced by 'precipitationIsotope'
d2H (LS14ATJU01B): interpretation4_variableGroup: '' has been replaced by 'P_isotope'
d2H (LS14ATJU01B): interpretation4_variableGroupDirection: '' has been replaced by 'positive'
d2H (LS14ATJU01B): interpretation5_basis: '' has been replaced by 'changes in rainfall amount are imprinted in the isotopic composition of botryococcenes, with negative (posi- tive) ?D values co-occurring with wetter (drier) periods.'
d2H (LS14ATJU01B): interpretation5_direction: '' has been replaced by 'negative'
d2H (LS14ATJU01B): interpretation5_inferredMaterial: '' has been replaced by 'lake water'
d2H (LS14ATJU01B): interpretation5_integrationTime: '' has been replaced by '1 to 10'
d2H (LS14ATJU01B): interpretation5_integrationTimeBasis: '' has been replaced by 'These lines of evidence strongly suggest that conditions favor- able for B. braunii growth occur during moderate-to-strong El Nin?o events and thus that C34 botryococcene ?D records the hydrologic conditions of the lake during these events. In contrast, the avail- able evidence suggests that the dinoflagellate population persists throughout the varying hydrologic conditions experienced by El Junco Lake and thus that sedimentary dinosterol ?D records the long-term (decadal-to-centennial) mean lake conditions.'
d2H (LS14ATJU01B): interpretation5_integrationTimeUnits: '' has been replaced by 'years'
d2H (LS14ATJU01B): interpretation5_mathematicalRelation: '' has been replaced by 'linear'
d2H (LS14ATJU01B): interpretation5_scope: '' has been replaced by 'isotope'
d2H (LS14ATJU01B): interpretation5_seasonality: '' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation5_seasonalityOriginal: '' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation5_variable: '' has been replaced by 'effectivePrecipitation'
d2H (LS14ATJU01B): interpretation5_variableGroup: '' has been replaced by 'EffectiveMoisture'
d2H (LS14ATJU01B): interpretation5_variableGroupDirection: '' has been replaced by 'negative'
d2H (LS14ATJU01B): interpretation5_variableGroupOriginal: '' has been replaced by 'P_E'
d2H (LS14ATJU01B): interpretation6_scope: '' has been replaced by 'isotope'
depth (MAT6c43cd5d85): interpretation1_scope: '' has been replaced by 'climate'
depth (MAT6c43cd5d85): interpretation2_scope: '' has been replaced by 'climate'
year (MAT795501f3aa): interpretation1_scope: '' has been replaced by 'climate'
year (MAT795501f3aa): interpretation2_scope: '' has been replaced by 'climate'
Updated lipdverse database entry with a changed file.
d2H (LS14ATJU01A): interpretation1_seasonality: 'annual' has been replaced by 'Annual'
d2H (LS14ATJU01A): interpretation1_variable: 'P_E' has been replaced by 'effectivePrecipitation'
d2H (LS14ATJU01A): interpretation2_seasonality: 'annual' has been replaced by 'Annual'
d2H (LS14ATJU01A): interpretation2_variable: 'P_isotope' has been replaced by 'precipitationIsotope'
d2H (LS14ATJU01B): interpretation1_seasonality: 'annual' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation1_variable: 'El Nino related rainfall' has been replaced by 'precipitation'
d2H (LS14ATJU01B): interpretation2_seasonality: 'annual' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation2_variable: 'P_isotope' has been replaced by 'precipitationIsotope'
d2H (LS14ATJU01B): interpretation3_seasonality: 'annual' has been replaced by 'Annual'
d2H (LS14ATJU01B): interpretation3_variable: 'P_E' has been replaced by 'effectivePrecipitation'
Changes made as part of LiPDverse vocabulary standardization process
d2H (LS14ATJU01A): paleoData_longName: '' has been replaced by 'AD'
d2H (LS14ATJU01B): paleoData_longName: '' has been replaced by 'AD'
depth (MAT6c43cd5d85): paleoData_longName: '' has been replaced by 'AD'
year (MAT795501f3aa): paleoData_units: 'AD' has been replaced by 'yr AD'
year (MAT795501f3aa): paleoData_longName: '' has been replaced by 'AD'
Atwood, A. R. and Sachs, J. P.: Separating ITCZ- and ENSO-related rainfall changes in the Galapagos over the last 3 kyr using D/H ratios of multiple lipid biomarkers, Earth and Planetary Science Letters, 404, 408–419, doi:10.1016/j.epsl.2014.07.038, 2014.
Separating ITCZ and ENSOrelated rainfall changes in the Gal�pagos over the last 3 kyr using D/H ratios of multiple lipid biomarkers