We measured rates of sediment, C, N, and P accumulation at four floodplain sites spanning the nontidal through oligohaline Choptank and Pocomoke Rivers, Maryland, USA. Ceramic tiles were used to collect sediment for a year and sediment cores were collected to derive decadal sedimentation rates using 137Cs. The results showed highest rates of short- and long-term sediment, C, N, and P accumulation occurred in tidal freshwater forests at the head of tide on the Choptank and the oligohaline marsh of the Pocomoke River, and lowest rates occurred in the downstream tidal freshwater forests in both rivers. Presumably, watershed material was mostly trapped at the head of tide, and estuarine material was trapped in oligohaline marshes. This hydrologic transport bottleneck at the head of tide stores most available watershed sediment, C, N, and P creating a sediment shadow in lower tidal freshwater forests potentially limiting their resilience to sea level rise.
| Start date | End date |
|---|---|
| 2012 | 2012 |
| Rank name | Value |
|---|
| 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. | piston corer = A device that extrudes core into tube upward with a plunger |
| 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 not sieved = Sediment was not sieved prior to analysis for organics. |
| compaction_flag | Code indicating how the authors qualified or quantified compaction of the core. | compaction quantified = Compaction was quantified and corrected for in core based measurements |
| dry_bulk_density_temperature | Temperature at which samples were dried to measure dry bulk density. This can include either samples that were freeze dried or oven dried. | celsius |
| 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. | air dried to constant mass = Methodology specified that samples were air dried to a constant mass to constant mass = Bulk density methodology did not specify drying temperature or length, only that samples were dried to a constant mass |
| loss_on_ignition_temperature | Temperature at which samples were combusted to estimate fraction organic matter. | celsius |
| loss_on_ignition_time | Time over which samples were combusted to estimate fraction organic matter. | hour |
| 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 |
| carbonates_removed | Whether or not carbonates were removed prior to calculating fraction organic carbon. | FALSE = Carbonates were not removed before measuring organic carbon |
| 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. | total carbon = Author specified that fraction carbon measurements were of total carbon. |
| cs137_counting_method | Code indicating the method used for determining radiocesium activity. | gamma = Gamma counting method 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_year | Year of core collection | nominalYear |
| core_notes | Any other relevant submitter generated notes on how cores were collected. | |
| 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 |
| 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). | fresh = <0.5 ppt oligohaline = 0.5-5 ppt. |
| salinity_method | Indicate whether salinity_class was determined using a field observation or a measurement | measurement = Salinity observed from local instrument. |
| vegetation_class | Code based on submitter field observations or measurement indicating dominant wetland vegetation type. | emergent = Describes wetlands dominated by persistent emergent vascular plants forested = Describes wetlands dominated by woody vegetation > 5 meters in height |
| vegetation_method | Indicate whether vegetation_class was determined using a field observation or a measurement | field observation = Vegetation inferred by field observation |
| 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 | measurement = Inundation class assessed from elevation and nearby tide gauge or other similar method. |
| 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 |
| 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 |
| compaction_notes | Any submitter generated notes on compaction. | |
| cs137_activity | Radioactivity counts per unit dry weight for radiocesium (137Cs). | becquerelsPerKilogram |
| unit name | parent SI unit | unit type | description |
|---|---|---|---|
| becquerelsPerKilogram | radionucleotideActivityPerMass | becquerels per kilogram | |
| cubicCentimeter | cubicMeter | volume | cubic centimeter |
This dataset is listed under a Creative Commons BY 4.0 and can be used with attribution. https://creativecommons.org/licenses/by/4.0/