Dataset title: Organic and inorganic data for soil cores from Brazil and Florida Bay seagrasses to support Howard et al 2018, CO2 released by carbonate sediment production in some coastal areas may offset the benefits of seagrass “Blue Carbon” storage, Limnology and Oceanography, DOI: 10.1002/lno.10621 Dataset ID: doi:10.6073/pasta/45cfe2505580cedf88a82f8911bdd741 Dataset Creator Name: Jason Howard Organization: FIU Email: Jhowa003@fiu.edu Name: James Fourqurean Organization: FIU Email: jim.fourqurean@fiu.edu Dataset Abstract Using piston corers, soils from Florida Bay and Brazilian seagrass meadows were collected to complete organic and inorganic carbon inventories for the top 1 m of soil. Instrumental analyses and loss on ignition at 500C were used to measure C content of downcore slices. Geographic Coverage Bounding Coordinates Geographic description: Urca West bounding coordinate: -43.163558 East bounding coordinate: -43.163558 North bounding coordinate: -22.947603 South bounding coordinate: -22.947603 Geographic description: Arraial do Cabo West bounding coordinate: -42.020278 East bounding coordinate: -42.020278 North bounding coordinate: -22.973434 South bounding coordinate: -22.973434 Geographic description: Ilha do Japones - site 1 West bounding coordinate: -42.002751 East bounding coordinate: -42.002751 North bounding coordinate: -22.881841 South bounding coordinate: -22.881841 Geographic description: Ilha do Japones - site 2 West bounding coordinate: -42.003653 East bounding coordinate: -42.003653 North bounding coordinate: -22.878932 South bounding coordinate: -22.878932 Geographic description: Praia dos Ossos West bounding coordinate: -41.88145 East bounding coordinate: -41.88145 North bounding coordinate: -22.745867 South bounding coordinate: -22.745867 Geographic description: Praia da Ferradura West bounding coordinate: -41.888983 East bounding coordinate: -41.888983 North bounding coordinate: -22.772383 South bounding coordinate: -22.772383 Geographic description: Manguinhos West bounding coordinate: -41.912172 East bounding coordinate: -41.912172 North bounding coordinate: -22.769126 South bounding coordinate: -22.769126 Geographic description: Ilha Grande - site 1 West bounding coordinate: -44.213233 East bounding coordinate: -44.213233 North bounding coordinate: -23.104933 South bounding coordinate: -23.104933 Geographic description: Ilha Grande - site 2 West bounding coordinate: -44.151083 East bounding coordinate: -44.151083 North bounding coordinate: -23.133783 South bounding coordinate: -23.133783 Geographic description: Bracui - site 1 West bounding coordinate: -44.384567 East bounding coordinate: -44.384567 North bounding coordinate: -22.9571 South bounding coordinate: -22.9571 Geographic description: Bracui - site 2 West bounding coordinate: -44.381133 East bounding coordinate: -44.381133 North bounding coordinate: -22.957267 South bounding coordinate: -22.957267 Geographic description: Santa Cruz West bounding coordinate: -40.152067 East bounding coordinate: -40.152067 North bounding coordinate: -19.95365 South bounding coordinate: -19.95365 Geographic description: Vitoria West bounding coordinate: -40.285967 East bounding coordinate: -40.285967 North bounding coordinate: -20.301767 South bounding coordinate: -20.301767 Geographic description: Vila Velha West bounding coordinate: -40.271533 East bounding coordinate: -40.271533 North bounding coordinate: -20.325117 South bounding coordinate: -20.325117 Geographic description: Bob Allen Key West bounding coordinate: -80.681 East bounding coordinate: -80.681 North bounding coordinate: 25.0248 South bounding coordinate: 25.0248 Geographic description: rb West bounding coordinate: -80.6397 East bounding coordinate: -80.6397 North bounding coordinate: 25.0343 South bounding coordinate: 25.0343 Geographic description: nm West bounding coordinate: -80.8642 East bounding coordinate: -80.8642 North bounding coordinate: 24.9412 South bounding coordinate: 24.9412 Geographic description: tc West bounding coordinate: -80.5404 East bounding coordinate: -80.5404 North bounding coordinate: 25.2148 South bounding coordinate: 25.2148 Temporal Coverage Start Date: 2015-06-01 End Date: 2015-08-31 Data Table Entity Name: brazil_cores.csv Entity Description: brazil_cores.csv Object Name: brazil_cores.csv Data Format Number of Header Lines: 1 Attribute Orientation: column Field Delimiter: , Number of Records: Attributes Attribute Name: Site Attribute Label: Attribute Definition: Site Name Storage Type: string Measurement Scale: Site Name Missing Value Code: Attribute Name: Latitude Attribute Label: Attribute Definition: Latitude Storage Type: float Measurement Scale: Units: degree Number Type: real Missing Value Code: Attribute Name: Longitude Attribute Label: Attribute Definition: Longitude Storage Type: float Measurement Scale: Units: degree Number Type: real Missing Value Code: Attribute Name: Rep Attribute Label: Attribute Definition: Core Replicate Storage Type: string Measurement Scale: Core Replicate Missing Value Code: Attribute Name: depth Attribute Label: Attribute Definition: Depth in Soil Profile Storage Type: float Measurement Scale: Units: centimeter Number Type: integer Missing Value Code: Attribute Name: loi Attribute Label: Attribute Definition: Loss on ignition at 500 C (percent of dry weight of sample) Storage Type: float Measurement Scale: Units: dimensionless Number Type: real Missing Value Code: Attribute Name: Cinorg Attribute Label: Attribute Definition: Inorganic Carbon Content (percent of dry weight of sample) Storage Type: float Measurement Scale: Units: dimensionless Number Type: real Missing Value Code: Attribute Name: Corg Attribute Label: Attribute Definition: Organic Carbon Content (percent of dry weight of sample) Storage Type: float Measurement Scale: Units: dimensionless Number Type: real Missing Value Code: Attribute Name: dbd Attribute Label: Attribute Definition: Dry Bulk Density (grams dry weight per centimeter cubed) Storage Type: float Measurement Scale: Units: gramPerCentimeterCubed Number Type: real Missing Value Code: Data Table Entity Name: Fl_bay_cores.csv Entity Description: Fl_bay_cores.csv Object Name: Fl_bay_cores.csv Data Format Number of Header Lines: 1 Attribute Orientation: column Field Delimiter: , Number of Records: Attributes Attribute Name: Site Attribute Label: Attribute Definition: Site Name Storage Type: string Measurement Scale: Site Name Missing Value Code: Attribute Name: Lat Attribute Label: Attribute Definition: Latitude Storage Type: float Measurement Scale: Units: degree Number Type: real Missing Value Code: Attribute Name: Long Attribute Label: Attribute Definition: Longitude Storage Type: float Measurement Scale: Units: degree Number Type: real Missing Value Code: Attribute Name: Rep Attribute Label: Attribute Definition: Core Replicate Storage Type: string Measurement Scale: Core Replicate Missing Value Code: Attribute Name: depth Attribute Label: Attribute Definition: Depth in Soil Profile Storage Type: float Measurement Scale: Units: centimeter Number Type: integer Missing Value Code: Attribute Name: loi Attribute Label: Attribute Definition: Loss on ignition at 500 C (percent of dry weight of sample) Storage Type: float Measurement Scale: Units: dimensionless Number Type: real Missing Value Code: Attribute Name: Cinorg Attribute Label: Attribute Definition: Inorganic Carbon Content (percent of dry weight of sample) Storage Type: float Measurement Scale: Units: dimensionless Number Type: real Missing Value Code: Attribute Name: Corg Attribute Label: Attribute Definition: Organic Carbon Content (percent of dry weight of sample) Storage Type: float Measurement Scale: Units: dimensionless Number Type: real Missing Value Code: Attribute Name: dbd Attribute Label: Attribute Definition: Dry Bulk Density (grams dry weight per centimeter cubed) Storage Type: float Measurement Scale: Units: gramPerCentimeterCubed Number Type: real Missing Value Code: Methods Method Step Description For seagrass characteristics, 15cm diameter cores were collected at randomly chosen locations during low tide within each sampling site in triplicate. Seagrass biomass was separated from sediment using a coarse mesh bag. Seagrasses were separated by species and shoots were counted. Leaves were counted on each shoot, measured and scraped of any epiphytes. Aboveground and belowground components were separated and dried at 50C until a constant weight was achieved. Dry weight of above- and belowground components were recorded. The dried leaf samples were homogenized and ground to a fine powder using a motorized mortar and pestle. Powdered samples were analyzed for total carbon (C) and nitrogen (N) content using a CHN analyzer (Thermo Flash EA, 1112 series). Total phosphorus content was determined by a dry-oxidation, acid hydrolysis extraction followed by a colorimetric analysis of phosphate concentration of the extract. Homogenized leaf samples were additionally analyzed for δ13C using EA-IRMS techniques; high temperature catalytic combustion was used to combust the organic carbon to CO2, which was then measured on a Finnigan MAT Delta C IRMS in a continuous flow mode. Isotopic ratios (R) were reported in the standard delta notation (‰ ): δ (‰) = [(Rsample/Rstandard)-1]×1000. These results are presented with respect to the international standard Vienna Pee Dee Belemnite (V-PDB). Analytical reproducibility of the reported values, based on sample replicates, was better than ±0.08‰. Soil cores were collected at randomly selected locations within each site in duplicate by driving a manually operated piston core (6cm diameter) into the soil until 1m depth or the depth at which the piston core could no longer be inserted. A depth of one meter was chosen for straightforward comparison to existing soil carbon inventories and is not associated with a known period of accumulation. This method yielded samples of ~9 cm3 along the depth profile, while minimizing compaction. Sediment samples of a known wet volume were dried and weighed to calculate dry bulk density (g dry soil mL wet soil-1). Soil samples were homogenized using a motorized mortar and pestle then analyzed for Corg and Cinorg Dataset Contact