Land–sea dataset linking sediment composition, organic matter sources, land use, and urban contaminants in the Tamandaré reef complex (Brazil)
Data files
Jun 10, 2026 version files 60.96 KB
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Database_Thales_Vidal.xlsx
50.68 KB
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README.md
10.28 KB
Abstract
This dataset compiles a multi-proxy environmental monitoring record from the Tamandaré Reef Complex, a shallow coastal reef system in northeastern Brazil. The database integrates information on sedimentation dynamics, sediment composition, land-use and land-cover change, stable isotope signatures (δ¹³C and δ¹⁵N), carbon-to-nitrogen ratios (C), sewage tracers (linear alkylbenzenes, LABs), and Bayesian isotope mixing model outputs. Data were collected across multiple years and spatial scales, including long-term sedimentation records (2005–2008 and 2022–2023), fine-scale reef monitoring at three sampling sites, and watershed-scale land-use assessments.
The dataset is organized into seven tables containing: (i) temporal sedimentation and environmental variables, including rainfall, wave energy, carbonate and non-carbonate fractions; (ii) fine-scale sedimentological and organic matter characteristics; (iii) stable isotope measurements and C ratios of sediment samples; (iv) isotopic source end-members used in mixing models; (v) Bayesian mixing model estimates of organic matter contributions; (vi) concentrations and diagnostic ratios of linear alkylbenzenes (LABs); and (vii) historical land-use and land-cover data for the adjacent watershed.
The database provides a valuable resource for investigating land–sea interactions, sediment transport processes, wastewater contamination, organic matter sources, and cumulative anthropogenic pressures on tropical coastal ecosystems. It can support comparative studies, environmental monitoring programs, ecosystem management, and the development of conservation and restoration strategies for coral reefs and other coastal habitats. The dataset contains no personal or sensitive information and can be reused without ethical restrictions, subject to the terms of the repository license.
Dataset DOI: 10.5061/dryad.tmpg4f5bc
Description of the data and file structure
This dataset was generated as part of a multidisciplinary effort to assess how land-based activities and oceanographic conditions influence sedimentation patterns, organic matter composition, and contamination in the Tamandaré reef complex (northeastern Brazil). Data collection included remote sensing of land use and land cover across coastal watersheds (1985–2023), wave height and precipitation monitoring, and in situ sediment sampling near the reef during two periods (2005–2008 and 2022–2023). Sediment samples collected in 2022–2023 were analyzed for grain size distribution, organic and inorganic composition, stable isotopes (δ¹³C and δ¹⁵N), and hydrocarbon contaminants (LABs) for three sites. Bayesian isotope mixing models were applied to estimate the relative contributions of terrestrial, marine, and sewage sources to sedimentary organic matter. This dataset supports research on land–sea connectivity, anthropogenic impacts on coral reef ecosystems, and long-term coastal environmental change.
Files and variables
File: Database_Thales_Vidal.xlsx
All data are included in a single Excel workbook file (Database_Thales_Vidal.xlsx), organized into seven separate sheets (tabs). Each sheet corresponds to a specific data component described in the manuscript. Below is a detailed description of each sheet and its variables:
1. Sheet: isotopic_ratios_site_season
Description: This table contains stable isotope and elemental composition data of sediment organic matter collected at different reef sites and seasons. Measurements include δ¹³C and δ¹⁵N values, carbon and nitrogen concentrations, and molar C:N ratios. These variables are widely used to distinguish among marine, terrestrial, and sewage-derived organic matter sources, evaluate seasonal changes in organic matter inputs, and support isotopic mixing model analyses.
Variables:
- Site: Sampling site identifier.
- Season: Sampling season and tourism period associated with each estimate.
- d13C: Stable carbon isotope ratio of sediment organic matter (‰).
- d15N: Stable nitrogen isotope ratio of sediment organic matter (‰).
- CN: Molar carbon-to-nitrogen (unitless).
2. Sheet: sources_grouped
Description: Grouped isotopic source signatures used as end-members in Bayesian stable isotope mixing models. The table contains representative carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values for the major organic matter source groups considered in the analysis, including marine, terrestrial, and sewage-derived materials.
Variables:
- Source: Organic matter source group identifier (Marine, Continental, Sewage).
- d13C: Stable carbon isotope ratio of the source group (‰).
- d15N: Stable nitrogen isotope ratio of the source group (‰)
3. Sheet: Bayesian_isotope_mixing_models
Description: Results of Bayesian stable isotope mixing models estimating the proportional contribution of different organic matter sources to reef sediment organic matter across sampling sites and seasons.
Variables:
- Source: Organic matter source category used in the mixing model (marine, continental, sewage).
- Season: Sampling season and tourism period associated with each estimate.
- P1: Estimated source contribution for Site P1 (%; mean ± SD and credibility interval).
- P2: Estimated source contribution for Site P2 (%; mean ± SD and credibility interval).
- P3: Estimated source contribution for Site P3 (%; mean ± SD and credibility interval).
4. Sheet: LABs_and_IE_ratio
Description: This table contains concentrations of linear alkylbenzenes (LABs) and corresponding internal-to-external isomer ratios (I/E) measured in reef sediment samples. LABs are anthropogenic organic compounds commonly used as molecular tracers of domestic wastewater contamination in aquatic environments. The I/E ratio provides information on the extent of biodegradation and environmental processing of sewage-derived organic matter, allowing the assessment of contamination sources and wastewater treatment influence across sites and sampling periods.
Variables:
- Site: Sampling site identifier.
- Total_LABs: Total concentration of linear alkylbenzenes in sediment samples (ng g⁻¹ dry sediment).
- IE_ratio: Internal-to-external LAB isomer ratio (unitless), used as an indicator of sewage degradation and wastewater treatment efficiency.
- Sample_date: Date of sample collection (YYYY-MM-DD).
5. Sheet: Temporal_sedimentar_data
Description: Time-series dataset (2005–2008 and 2022–2023) of sedimentation rates and CaCO₃ content collected exclusively at Site P2 in the Tamandaré Reef Complex. The table contains long-term records used to assess temporal variability in sediment deposition, sediment composition, and environmental drivers, including rainfall and wave high.
Variables:
- Year
- Sampling month
- Sedimentation rate (g m⁻² day⁻¹).
- CaCO3: dry weight (g) and content (%)
- Non carbonate fraction (g)
- Waves high (m)
- Rainfall (mm)
- Standard deviation (SD)
- Season: Sampling season (dry or rainy)
6. Sheet: Fine_scale_sedimentar_data
Description: Fine-scale sedimentological and organic matter data collected across reef sampling sites (p1, P2 and P3) and seasons in the Tamandaré Reef Complex. This table contains measurements of total organic matter characteristics, CaCO3 content and grain size fractions used to assess spatial and seasonal variability in sediment dynamics during the 2022–2023 period.
Variables:
- Site: P1, P2 and P3
- Season: Sampling season
- Month/years (ex: sep/22)
- Gravel_fraction: % (>2 mm)
- Sand_fraction: % (63 µm – 2 mm)
- Mud_fraction: % (<63 µm)
- CaCO3: dry weight (g) and content (%)
- TOM: Total organic matter dry weight (g) and content (%)
- Other components (%)
- Sedimentation rate (g m⁻² day⁻¹).
- Standard deviation (SD)
7. Sheet: Land_use_and_cover
Description: Historical land-use and land-cover data for the set of municipalities surrounding the Tamandaré reef complex from 1985 to 2023. This table contains the spatial extent and proportional coverage of different land-use classes across multiple time periods, providing information on landscape changes and potential sources of terrestrial and anthropogenic inputs to the reef ecosystem.
Variables:
- Year: Year of land-use and land-cover assessment.
- Urban_area: ha and %
- Agricultural_area: ha and %
- Forest_area: ha and %
- Water_area: ha and %
- Total_area: ha and %
- Progression of the temporal development of each class (%)
Missing Values
Missing data are indicated using "ND".
Code/software
The data can be explored and analyzed using R (R Core Team), a free and open-source statistical computing software. All statistical analyses were performed in R version 4.3.1, including:
- Analysis of Variance (ANOVA)
- Bayesian Isotope Mixing Models using the MixSIAR package (Stock et al., 2018)
- Generalized Additive Models (GAMs) using the mgcv package (Hastie, 2017)
The typical workflow involved:
- Data cleaning and preprocessing (tidyverse)
- Descriptive and inferential statistics
- Isotope mixing models with MixSIAR
- Ecological modeling using mgcv for GAMs
Key R packages used:
- tidyverse (for data manipulation and visualization)
- MixSIAR (for stable isotope mixing models)
- mgcv (for fitting GAMs)
- car (for ANOVA post hoc tests)
If included in the submission, R scripts are provided with clear comments and organized sections for:
- Data import and preparation
- Statistical tests and models
- Graph generation
Each script can be run independently in R 4.3.1 or higher.
No proprietary software is required to access or analyze the data.
Access information
- Rainfall Data: Daily precipitation data were obtained from the Pernambuco Water and Climate Agency (Agência Pernambucana de Águas e Clima – APAC), available at: http://www.apac.pe.gov.br.\
• Data are publicly available but subject to APAC’s terms of use. - Wave Height Data: Modeled wave data for the Tamandaré coast were obtained from the Surfguru platform (https://www.surfguru.com.br), using outputs from the WAVEWATCH III model (Tolman, 2009).
• Data are publicly accessible for non-commercial use. Refer to Surfguru’s website for terms and conditions. - Historical Sediment Data (2005–2008): Sedimentation rates and calcium carbonate content for site P2 were derived from data published by Macêdo (2009), which used the same sampling method (PVC sediment traps) and analytical protocols as in the present study.
• Reference: Macêdo, E. C. (2009). Um ensaio sobre a sedimentação e suas implicações ecológicas nos recifes costeiros da baía de Tamandaré/PE (Master's thesis, Universidade Federal de Pernambuco). - Historical land-use and land-cover data (1985 to 2023): Land use and land cover data was sourced for a set of municipalities which encompass the main hydrographic basins of the region (Tamandaré, Rio Formoso, Sirinhaém, Barreiros, and São José da Coroa Grande), from the MAPBiomas website (MapBiomas, 2025: https://plataforma.brasil.mapbiomas.org) based on Landsat images with 30-meter resolution. This data provided the area (ha) occupied by urban developments, forest formation (forest and mangrove), agriculture (pasture and sugar cane), and water bodies in the municipalities between 1985 and 2023, encompassing approximately 111,000 hectares surrounding the Tamandaré Reef Complex.
All derived data were properly cited and harmonized with the original datasets for consistency in methodology and units.