Data from: Microplastic and organic carbon storage in sediments of intertidal and subtidal seagrass meadows

This datasets support the scientific article (submitted) " Microplastic and organic carbon storage in sediments of intertidal and subtidal seagrass meadows." It contains detailed data on sedimentary organic carbon content and the abundance of microplastics in both intertidal and subtidal seagrass meadows within the Ria Formosa lagoon (Southern Portugal). The datasets are accompanied by analysis code, available at GitHub repository, allowing for reproducibility and further exploration of the data.

The data is composed by 4 datasets with the following variables:

data_cores.csv. Contains properties related to the sampling of the sediment cores.

core_id [character] - unique core identification code used in the field.

core_id_new [character] - unique core identification code used in the article.

species [character] - species of the seagrass meadow.

replicate [character] - replicate number of the core in each seagrass meadow.

core_depth [numeric] - depth sampled with the core (in centimeters).

sample_length [numeric] - length of the sampled core measured in the laboratory (in centimeters).

compaction_factor [numeric] - fraction of the sample depth interval reduced due to compaction. It is calculated by dividing the core length by the core depth.

compaction_perc [numeric] - core compaction in percentage (%). It is calculated as 100*(1 - compaction_factor).

data_samples.csv. Contains properties of the sediment samples.

core_id [character] - unique core identification code used in the field.

sample_id [character] - unique sample identification code (obtained by concatenating the core id and the minimum non-corrected depth of the sample).

depth_middle [numeric] - middle depth of a sampling increment, calculating as the average of depth_min and depth_max (in centimeters).

depth_min [numeric] - minimum depth of a sampling increment, corrected for compaction (in centimeters).

depth_max [numeric] - maximum depth of a sampling increment, corrected for compaction (in centimeters).

sample_volume [numeric] - volume of the sediment sample, corrected for compaction (in cubic centimeters).

sample_dw [numeric] - dry mass of the sample (in grams of dry weight).

percentage_organic_matter [numeric] - mass of organic matter relative to sample dry mass, obtained by loss-on-ignition (in percentage of dry weight).

percentage_organic_carbon [numeric] - mass of organic carbon relative to sample dry mass, obtained by a local organic carbon to organic carbon ratio (as a percentage of dry weight).

bag_id [character] - identification code for the aluminium envelope containing the sample.

weight_sample_mp [numeric] - dry mass of the sample used for the microplastic extraction (in grams of dry weight).

dry_bulk_density [numeric] - dry mass per unit volume of the sample. This is calculated as the sample_dw divided by the sample_dw (in grams of dry weight per cubic centimeter). 

data_particles_visual.csv. Contains properties of the suspected microplastic particles found in the sediment samples and the negative controls, based on visual inspection.

core_id [character] - unique core identification code used in the field.

core_id_new [character] - unique core identification code used in the article.

species [character] - species of the seagrass meadow.

habitat_label [character] - text for labelling purposes regarding the habitat.

type [factor] - whether the particle comes from a sediment sample ("sediment") or a control sample ("control"). 

cycle [character] - cycle in which samples were analysed.

sample_id [character] - unique sample identification code (obtained by concatenating the core id and the minimum non-corrected depth of the sample).

bag_id [character] - identification code for the aluminium envelope containing the sample.

filter_id [character] - identification code of the filter used for the particle extraction.

filter_area [numeric] - area of the filter that was screened for microplastics (in fraction of total).

visual_id [character] - unique particle identification code based on visual identification.

colour [factor] - particle colour category: black_grey, blue_green, brown_tan, opaque, orange_pink_red, transparent, white_cream, yellow.

shape [factor] - particle shape category: film, foam, fragment, line, pellet.

major [numeric] - longest dimension of the particle, analysed in ImageJ (in micrometers).

minor [numeric] - Longest dimension perpendicular to major, analysed in ImageJ (in micrometers).

data_particles_ftir.csv. Contains properties of the suspected microplastic particles found in the sediment samples and the negative controls, based on the FTIR analysis.

species [character] - species of the seagrass meadow.

habitat_label [character] - text for labelling purposes regarding the habitat.

core_id [character] - unique core identification code used in the field.

core_id_new [character] - unique core identification code used in the article.

filter_id [character] - identification code of the filter used for the particle extraction.

filter_area [numeric] - area of the filter that was screened for microplastics (in fraction of total).

cycle [character] - cycle in which samples were analysed.

type [factor] - whether the particle comes from a sediment sample ("sediment") or a control sample ("control"). 

sample_id [character] - unique sample identification code (obtained by concatenating the core id and the minimum non-corrected depth of the sample).

num_ftir [numeric] - numerical order in which particles were identified within a filter.

colour [factor] - particle colour category: black_grey, blue_green, brown_tan, opaque, orange_pink_red, transparent, white_cream, yellow.

shape [factor] - particle shape category: film, foam, fragment, line, pellet.

ref_analysis [boolean] - whether the reflection analysis was preformed or not.

atr_analysis [boolean] - whether the ATR analysis was preformed or not.

ftir_match_ref [character] - name of the polymer with the highest match found using µFTIR for reflection analysis.

match_ref [numeric] - percentage of match corresponding to highest match for reflection analysis.

ftir_match_atr [character] - name of the polymer with the highest match found using µFTIR for ATR analysis.

match_atr [numeric] - percentage of match corresponding to highest match for ATR analysis.

plastic_ref [boolean] - whether the particle is classified as having a plastic composition or not, based on the reflection analysis.

polymer_group_ref [factor] - polymer group based on the reflection analysis: Non-plastic, Nylon-polyamides, Poluacrylamides, Polyacrylates, Polyesters, Polyethylene, Polyglycols, Polyhaloolefins, Polymethylmethacrylate, Polypropylene, Polystyrene, Polyurethane, Polyvinylalcohol, Silicones, Others.

plastic_atr [boolean] - whether the particle is classified as having a plastic composition or not, based on the ATR analysis.

polymer_group_atr [factor] - polymer group based on the ATR analysis: Non-plastic, Nylon-polyamides, Poluacrylamides, Polyacrylates, Polyesters, Polyethylene, Polyglycols, Polyhaloolefins, Polymethylmethacrylate, Polypropylene, Polystyrene, Polyurethane, Polyvinylalcohol, Silicones, Others.

ftir_match_final [character] - final decision on the polymer composition, including the option "unclear".

plastic_final [factor] - whether the particle is classified as having a plastic composition or not, based on final decision "ftir_match_final", includes categories: yes, no, unclear.

final_analysis [character] - the analysis performed and used for the final decision, includes categories: ref (reflection analysis), atr (ATR analysis), both-but-atr-more-conclusive, both-but-ref-more-conclusive, both-unclear.

polymer_group_final [character] - polymer group based final decision: Non-plastic, Nylon-polyamides, Poluacrylamides, Polyacrylates, Polyesters, Polyethylene, Polyglycols, Polyhaloolefins, Polymethylmethacrylate, Polypropylene, Polystyrene, Polyurethane, Polyvinylalcohol, Silicones, Others.