Blue carbon habitats like salt marshes and mangroves bury large amounts of carbon with limited area; however, they also are increasingly susceptible to current climate change. Combined effects of rising temperatures, decreasing freeze frequencies, and increasing sea-level rise rates are resulting in mangrove replacement of salt marshes along the southern United States. Studies on mangrove migration have revealed conflicting results regarding carbon burial, with some suggesting mangrove migration does not increase burial. Surface soils analyzed here from wetlands along northern Florida Atlantic and Gulf coasts showed higher apparent sedimentation rates in mangrove-dominated sites (1.5-3.2 mm yr-1) and where mangroves are migrating into the marsh (termed transition sites, 2.3-3.8 mm yr-1). Average carbon burial rates were higher in transition sites for both coasts (27-47 gC m-2 yr-1) compared to the respective mangrove (10-22 gC m-2 yr-1) and salt marsh (4-7 gC m-2 yr-1) sites. Lignin biomarker data (?-6, ?-8, C/V) indicated mangrove and transition sites had higher lignin inputs from woody vascular plants compared to salt marsh sites, which may slow decadal to centennial-scale decay. Higher amino acid concentrations in mangrove soils relative to mangrove biomass (1.8-2.3 mmol gC-1 vs. 0.2-0.9 mmol gC-1) and lower C/N indicated these mangrove sites receive higher algal inputs than the transition and salt marsh sites, attributed to greater tidal inundation in the mangrove sites given their position near the shoreline. Overall, increased accretion, carbon burial, and lignin in mangrove transition sites indicates this migration may increase carbon burial and increase the stability and residence time of buried soil carbon. Future studies on mangrove migration in northern Florida can verify this through replication and elevation analysis. Although carbon burial rates increased with mangrove expansion at the northern Florida sites, questions remained regarding future changes in these wetlands with a warming climate and sea-level rise. To better understand potential future responses of these wetlands, two studies were undertaken using longer sediment cores at the same northern Florida sites to examine the wetlands development over the mid- to late-Holocene. Carbon measurements within 1-3 meter length vibracores yielded total core stocks of 9.8 x 103 - 2.1 x 104 gC m-2 and 7.4 x 103 - 9.5 x 103 gC m-2 for the Atlantic and Gulf coast cores, respectively. Following recent IPCC guidelines, blue carbon stock estimates down to 1-meter were 6.8 x 103 gC m-2 - 7.3 x 103 gC m-2 and 5.8 x 103 gC m-2 - 8.6 x 103 gC m-2 for the Atlantic and Gulf cores, respectively. Changes in stable isotopic (?13C, C/N) and lignin biomarker (C/V) indices suggest both coastlines likely experienced salt marsh and mangrove transgressions into former non-blue carbon habitats during the mid- to late-Holocene following changes in relative sea-level rise and climate. This suggests that not all blue carbon was estimated in the Atlantic coast cores when restricting measurements to the 1-meter benchmark and some carbon deposited in a carbonate-dominant system was included in the 1-meter Gulf coast stocks. Constraining blue carbon measurements to include carbon within 1-meter thus may over- or under-estimate blue carbon stocks. If the natural carbon burying capabilities of these habitats are to be utilized in the future, preservation of regions upslope of wetlands is critical to allow for inland migration in response to ongoing sea-level rise.
Start date | End date |
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2017-04-11 | 2020-08-01 |
Rank name | Value |
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Species | Avicennia germinans |
Species | Sporobolus alterniflorus |
Species | Batis maritima |
Species | Rhizophora mangle |
Species | Juncus roemericanus |
attribute name | definition | format, unit or codes |
---|---|---|
study_id | Unique identifier for the study made up of the first author's family name, as well as the second author's or 'et al.' if more than three, then publication year spearated by underscores. See worksCited.bib for more detail. | |
coring_method | Code indicating what type of device was used to collect soil depth profiles. | vibracore = A technique involving collecting a core by sinking a continuous pipe into sediment attaching a source of vibration, then recovering using a winch and pulley |
roots_flag | Code indicating whether live roots were included or excluded from carbon assessments. | roots and rhizomes included = Roots and rhizomes were included in dry bulk density and or organic matter and carbon measurements |
sediment_sieved_flag | Code indicating whether or not sediment was sieved prior to carbon measurements. | sediment sieved = Sediment was sieved prior to analysis for organics |
compaction_flag | Code indicating how the authors qualified or quantified compaction of the core. | no obvious compaction = Authors observed no obvious compaction |
dry_bulk_density_sample_volume | Sample volume used for bulk density measurements, if held constant. | cubicCentimeter |
dry_bulk_density_flag | Any notable codes regarding how the authors quantified dry bulk density. | freeze dried = Bulk density was measured on freeze dried samples |
carbonates_removed | Whether or not carbonates were removed prior to calculating fraction organic carbon. | TRUE = Carbonates were removed before measuring organic carbon. |
carbonate_removal_method | The method used to remove carbonates prior to measuring fraction carbon. | acid fumigation = Carbonates were removed by fumigating with concentrated acid |
carbon_measured_or_modeled | Code indicating whether fraction carbon was measured or estimated as a function of organic matter. | measured = Fraction carbon was measured as opposed to modeled |
fraction_carbon_method | Code indicating the method for which fraction carbon was measured or modeled (Note: regression based models are permitted, but the use of the Bemmelen factor [0.58 gOC gOM-1] is discouraged). | EA = Each sample presented was measured using Elemental Analysis |
fraction_carbon_type | Code indicating whether fraction_carbon refers to organic or total carbon. | organic carbon = Author specified that fraction carbon measurements were of organic carbon |
cs137_counting_method | Code indicating the method used for determining radiocesium activity. | gamma = Gamma counting method used. |
pb210_counting_method | Code indicating the method used for determining lead 210 activity. | gamma = Gamma counting method used. |
ra226_assumption | Code indicating the assumption used to estimate the core's background 226Ra levels. | each sample = 226Ra was measured for each sample |
age_depth_model_reference | Code indicating the reference or 0 year of the age depth model. | CE = Year zero is set according to Common Era and Before Common Era standards |
c14_counting_method | Code indicating the method used for determining radiocarbon activity. | AMS = Accelerator mass spectroscopy used |
attribute name | definition | format, unit or codes |
---|---|---|
study_id | Unique identifier for the study made up of the first author's family name, as well as the second author's or 'et al.' if more than three, then publication year spearated by underscores. See worksCited.bib for more detail. | |
site_id | Site identification code unique to each study. | |
core_id | Core identification code unique to each site. | |
core_date | Date of core collection. | YYYY-MM-DD |
core_latitude | Positional latitude of the core in decimal degree WGS84. | degree |
core_longitude | Positional longitude of the core in decimal degree WGS84. | degree |
core_position_method | Code indicating how latitude and longitude were determined. | handheld = Conventional Commercially available hand-held GPS |
core_position_notes | Any relevant submitter generated notes on how latitude and longitude were determined. | |
salinity_class | Code based on submitter field observation or measurement indicating average annual salinity (Note: Palustrine and freshwater should only include tidal wetlands, or wetlands that are potentially/formerly tidal but artificially freshened due to artificial tidal restrictions). | estuarine = 0.5-35 ppt according to most definitions |
salinity_method | Indicate whether salinity_class was determined using a field observation or a measurement | field observation = Salinity inferred by field observation such as vegetation |
vegetation_class | Code based on submitter field observations or measurement indicating dominant wetland vegetation type. | emergent = Describes wetlands dominated by persistent emergent vascular plants scrub shrub = Describes wetlands dominated by woody vegetation < or equal to 5 meters in height |
vegetation_method | Indicate whether vegetation_class was determined using a field observation or a measurement | measurement = Vegetation measured by counts or plots. |
inundation_class | Code based on submitter field observation or measurement indicating how often the coring location is inundated. | high = Study-specific definition of an elevation relatively high in the tidal frame, typically defined by vegetation type mid = Study-specific definition of an elevation in the relative middle of the tidal frame, typically defined by vegetation type |
inundation_method | Indicate whether inundation_class was determined using a field observation or a measurement | field observation = Inundation inferred by field observation such as vegetation |
attribute name | definition | format, unit or codes |
---|---|---|
study_id | Unique identifier for the study made up of the first author's family name, as well as the second author's or 'et al.' if more than three, then publication year spearated by underscores. See worksCited.bib for more detail. | |
site_id | Site identification code unique to each study. | |
core_id | Core identification code unique to each site. | |
depth_min | Minimum depth of a sampling increment. | centimeter |
depth_max | Maximum depth of a sampling increment. | centimeter |
sample_id | Sample identification unique to the core. This should be used in the case that there are relevant lab specific sample codes, or in the case that there are multiple replicate samples. | |
dry_bulk_density | Dry mass per unit volume of a soil sample. This does not include ash free bulk density. | gramsPerCubicCentimeter |
fraction_carbon | Mass of carbon relative to sample dry mass. | dimensionless |
cs137_activity | Radioactivity counts per unit dry weight for radiocesium (137Cs). | disintegrationPerMinutePerGram |
cs137_activity_sd | 1 standard deviation of uncertainty associated with cs137_activity. | disintegrationPerMinutePerGram |
total_pb210_activity | Total radioactivity counts per unit dry weight for excess lead 210 (210Pb). | disintegrationPerMinutePerGram |
total_pb210_activity_sd | 1 standard deviation of uncertainty associated with total_pb210_activity. | disintegrationPerMinutePerGram |
ra226_activity | Total radioactivity counts per unit dry weight for Radium 226 (226Ra) if measured as part of the 210Pb dating process. | disintegrationPerMinutePerGram |
ra226_activity_sd | 1 standard deviation of uncertainty associated with ra226_activity. | disintegrationPerMinutePerGram |
excess_pb210_activity | Excess radioactivity counts per unit dry weight for excess lead 210 (210Pb). | disintegrationPerMinutePerGram |
excess_pb210_activity_sd | 1 standard deviation of uncertainty associated with excess_pb210_activity. | disintegrationPerMinutePerGram |
c14_age | Radiocarbon age as estimated from AMS measurements. | radiocarbonYear |
c14_age_sd | Estimated uncertainty in c14_age. | radiocarbonYear |
c14_material | Description of the material selected for radiocarbon (14C) dating. | |
c14_notes | Any relevant submitter generated notes on 14C dating process. | |
delta_c13 | The isotopic signature of 13C. This is oftentimes measured along with c14_age and can be useful for analyzing carbon lability and provenance. | dimensionless |
CRS_model_age | Age of soil at depth as determined by excess Pb-210 activity using the constant rate of supply (CRS) model | nominalYear |
CRS_age_se | Standard error of age estimation of soil at depth as determined by excess Pb-210 activity using the constant rate of supply (CRS) model | nominalYear |
carbon_nitrogen_ratio | Molar ratio of total organic carbon to total nitrogen | dimensionless |
BACON_model_age | Mean calibrated radiocarbon date using the age-depth BACON (Bayesian accumulation histories for deposits) calibration model | nominalYear |
BACON_model_age_min | Minimum calibrated radiocarbon date using the age-depth BACON (Bayesian accumulation histories for deposits) calibration model | nominalYear |
BACON_model_age_max | Maximum calibrated radiocarbon date using the age-depth BACON (Bayesian accumulation histories for deposits) calibration model | nominalYear |
total_lignin_l8 | summation of vanillyl (V), syringyl (S), and cinnamyl (C) lignin phenols normalized to 100 mg of OC | milligramsPerOneHundredMilligramsOrganicCarbon |
lignin_l6 | summation of V and S phenols normalized to 100 mg OC | milligramsPerOneHundredMilligramsOrganicCarbon |
CV_phenols_ratio | ratio of C phenols to V phenols, used to estimate non-woody vs. woody vascular plant inputs | dimensionless |
SV_phenols_ratio | ratio of S phenols to V phenols, used to estimate angiosperm vs. gymnosperm vascular plant inputs | dimensionless |
ad_al_vanillyls_ratio | acid-to-aldehyde ratios of the vanillyl lignin phenol group, used as a degradation indicator | dimensionless |
ad_al_syringyls_ratio | acid-to-aldehyde ratios of the syringyl lignin phenol group, used as a degradation indicator | dimensionless |
total_amino_acids | summation of 19 amino acids that were detected and quantified, normalized to OC | millimolesPerGramOrganicCarbon |
fraction_amino_acids_nitrogen | Fraction of which the 19 amino acids made of the total nitrogen pool | dimensionless |
degradation_index | Amino acid degradation index generated from mole percentages of each amino acid in a principal component analysis | dimensionless |
DAPA_concentration | Carbon-normalized concentration of the individual amino acid Diaminopimelic acid (DAPA) | micromolesPerGramOrganicCarbon |
GABA_concentration | Carbon-normalized concentration of the individual amino acid gamma-aminobutyric acid (GABA) | micromolesPerGramOrganicCarbon |
Hyp_concentration | Carbon-normalized concentration of the individual amino acid hydroxyproline (Hyp) | micromolesPerGramOrganicCarbon |
MurA_concentration | Carbon-normalized concentration of the individual amino acid muramic acid (MurA) | micromolesPerGramOrganicCarbon |
unit name | parent SI unit | unit type | description |
---|---|---|---|
disintegrationPerMinutePerGram | radionucleotideActivityPerMass | disintegrations per minute per gram is a measure of the activity of the source of radioactivity | |
cubicCentimeter | cubicMeter | volume | cubic centimeter |
milligramsPerOneHundredMilligramsOrganicCarbon | ligninSummationNormalizedToOrganicCarbon | summation of measured object normalized to 100 mg organic carbon | |
millimolesPerGramOrganicCarbon | amountOfSubstanceConcentration | Concentration normalized to 1 g organic carbon | |
micromolesPerGramOrganicCarbon | amountOfSubstanceConcentration | Concentration normalized to 1 g organic carbon | |
radiocarbonYear | time | Age based on decay of 14C |
This dataset is listed under a Creative Commons BY 4.0 and can be used with attribution. https://creativecommons.org/licenses/by/4.0/