Professor Isaac R Santos

The dataset includes empirical observations in global fjords of geochemical characteristics and processes (NAR_data.csv), microbial nitrogen cycling rates (N2_data.csv), as well as sediment nitrogen cycling rate measurements in seasonal hypoxic fjord - Gullmar Fjord, Sweden (gullmar_data.csv). Units and remarks of each dataset are found in the corresponding *_metadata.csv files. These dataset were used to generate figures in the article and to perform all statistical analyses.

This dataset contains activity levels of 223Ra (short-lived radium isotope) in groundwater, surface water and river samples collected along the Baltic Sea coastline. This data was used in radium mass balance models that were applied along 17 beach transects in the Baltic Sea. Activity levels were measured using a Delayed Coincedence Counter (RaDeCC). 
Details of column names in the file are as follows:
Sample_ID : ID of the sample
Sample_Type : Source of the sample denoted by SW, GW, and RIV. SW refers to surface water sample, GW and RIV are used to denote groundwater and river samples, respectively.
Latitude : Latitudinal coordinate of the location (DD)
Longitude : Longitudinal coordinate of the location (DD)
Ra223_dpm/100L : Activity level of 223-radium in units of dpm/100L
Ra223_unc_dpm/100L : Associated uncertainty in the measurement of 223-radium activity levels, expressed as dpm/100L

The global dataset includes time series observations from 23 mangrove tidal channels (Figure 1a). Two sites were located in North America (Reithmaier et al., 2020), five in Latin America (Cabral et al., 2024a; Cabral et al., 2024b; Call et al., 2019b; Ray et al., 2020), two in Africa (Bouillon et al., 2007), six in Asia (Borges et al., 2003; Call et al., 2019a; Linto et al., 2014; Reithmaier et al., 2023; Tomer et al., 2025), and eight in Australia (Cotovicz Jr et al., 2024; Santos et al., 2019; Sippo et al., 2016; Tomer et al., 2025). For inclusion in the analysis, we required temperature, salinity, dissolved oxygen (DO), and the partial pressure of carbon dioxide (pCO2), sampled at one-hour intervals (or more frequent) over at least 24 hours (Table S2). Loggers were deployed in tidal channels adjacent to mangrove forests. Instrument details and analytical accuracy are available in the original studies.Borges, A., et al. (2003), Atmospheric CO2 flux from mangrove surrounding waters, Geophysical Research Letters, 30(11). doi:10.1029/2003GL017143Bouillon, S., et al. (2007), Importance of intertidal sediment processes and porewater exchange on the water column biogeochemistry in a pristine mangrove creek (Ras Dege, Tanzania), Biogeosciences, 4(3), 311-322. doi:10.5194/bg-4-311-2007Cabral, A., et al. (2024a), Tidally driven porewater exchange and diel cycles control CO2 fluxes in mangroves on local and global scales, Geochimica et Cosmochimica Acta, 374, 121-135. doi:10.1016/j.gca.2024.04.020Cabral, A., et al. (2024b), Large porewater‐derived carbon outwelling across mangrove seascapes revealed by radium isotopes, Journal of Geophysical Research: Oceans, 129(9), e2024JC021319. doi:10.1029/2024JC021319Call, M., C. J. Sanders, P. A. Macklin, I. R. Santos, &D. T. Maher (2019a), Carbon outwelling and emissions from two contrasting mangrove creeks during the monsoon storm season in Palau, Micronesia, Estuarine, Coastal and Shelf Science, 218, 340-348. doi:10.1016/j.ecss.2019.01.002Call, M., et al. (2019b), High pore-water derived CO2 and CH4 emissions from a macro-tidal mangrove creek in the Amazon region, Geochimica et Cosmochimica Acta, 247, 106-120. doi:10.1016/j.gca.2018.12.029Cotovicz Jr, L. C., et al. (2024), Methane oxidation minimizes emissions and offsets to carbon burial in mangroves, Nature Climate Change, 14(3), 275-281. doi:10.1038/s41558-024-01927-1Linto, N., et al. (2014), Carbon dioxide and methane emissions from mangrove-associated waters of the Andaman Islands, Bay of Bengal, Estuaries and Coasts, 37(2), 381-398. doi:10.1007/s12237-013-9674-4Ray, R., et al. (2020), Mangrove‐derived organic and inorganic carbon exchanges between the Sinnamary estuarine system (French Guiana, South America) and the Atlantic Ocean, Journal of Geophysical Research: Biogeosciences, 125, e2020JG005739. doi:10.1029/2020JG005739Reithmaier, G. M. S., D. T. Ho, S. Johnston, &D. T. Maher (2020), Mangroves as a source of greenhouse gases to the atmosphere and alkalinity and dissolved carbon to the coastal ocean: A case study from the Everglades National Park, Florida, Journal of Geophysical Research: Biogeosciences, 125, e2020JG005812. doi:10.1029/2020JG005812Reithmaier, G. M. S., et al. (2022), Inorganic carbon outwelling from mangroves and saltmarshes drives coastal acidification, PANGAEA. doi:10.1594/PANGAEA.949660Santos, I. R., D. T. Maher, R. Larkin, J. R. Webb, &C. J. Sanders (2019), Carbon outwelling and outgassing vs. burial in an estuarine tidal creek surrounded by mangrove and saltmarsh wetlands, Limnology and Oceanography, 64(3), 996-1013. doi:10.1002/lno.11090Sippo, J. Z., D. T. Maher, D. R. Tait, C. Holloway, &I. R. Santos (2016), Are mangroves drivers or buffers of coastal acidification? Insights from alkalinity and dissolved inorganic carbon export estimates across a latitudinal transect, Global Biogeochemical Cycles, 30(5), 753-766. doi:10.1002/2015gb005324Tomer, A. S., et al. (2024), Global data for SGD and CO2, NIAID Data Ecosystem. doi:10.5281/zenodo.10491454

This dataset presents seawater carbonate chemistry measurements and ancillary hydrographical data collected on the southeast Iceland shelf between June 26th and July 1st 2023 onboard R/V Skagerak, and from freshwater endmembers on shore. The dataset contains information on the measured contents of dissolved inorganic carbon, total alkalinity, and stable isotope composition of dissolved inorganic carbon from water samples, as well as the calculated values of the saturation state of aragonite, partial pressure of carbon dioxide and the air-sea flux of carbon dioxide.
The dataset contains four files:
iceland_metadata.xlsx: Metadata of all datafiles. Contains column-headers, units and parameter description.
iceland_discrete.csv: Discrete and continous measured and calculated marine carbonate system variables.
iceland_underway.csv: Hydrographical sensor data from the ships Ferrybox system.
iceland_ctd.csv: Hydrographical sensor data from the ships CTD.
 

This dataset comprises raw data obtained from measurements conducted within a temperate coastal lagoon, Nissum Fjord, located at the west coast of Denmark. The dataset originates from continuous timeseries observations over four days in March 2025. It includes measurements of carbon dioxide partial pressure within the water column and the additional parameters water depth, temperature, salinity, dissolved oxygen, pH, wind speed, and radon decay. The timestamps correspond to the Central European Time zone (CET). This dataset was used to resolve tidal and gate opening dynamics of carbon dioxide water-air fluxes and related submarine groundwater discharge dynamics. 
Dataset is found in csv.file "Data". 
Units, parameter and instrument description are found in csv.file "Metadata". 

This repository contains the compiled dataset of new and referenced observations of fjord nitrogen loss processes, and the R Markdown files required to conduct spatial weighted bootstrap analyses.
The dataset (in data_file) includes empirical observations in global fjords of geochemical characteristics and processes (NAR_data.csv), microbial nitrogen cycling rates (N2_data.csv), as well as sediment nitrogen cycling rate measurements in seasonal hypoxic fjord - Gullmar Fjord, Sweden (gullmar_data.csv). Units and remarks of each dataset are found in the corresponding *_metadata.csv files. These dataset were used to generate figures in the article and to perform all statistical analyses.
Shapefiles (in shp_file) are used to generate base map and highlight major fjord regions in plots.
The R code used to perform spatial weighted bootstrap analyses (in spatial_weighted_bootstrap) is available in R Markdown format and rendered as HTML and PDF files. Data and shape files that required to perform the analyses and the visualization can be found in data_file and shp_file.

This dataset is the foundation for Scott-Askin, S., Santos, I. R., Albert, G., Asplund, M. E., Deyanova, D., Forsberg, S. C., Ricart, A. M., Gullström, M., Björk, M., Reithmaier, G. M. S. (In Review). In-situ measurements reveal alkalinity release from cold-temperate seagrass meadows.An in-situ chamber experiment was conducted from the 5th to the 9th of September 2024. At two sites, 24-hour time series were performed using six chambers to resolve diel changes in DIC and TA fluxes. Water samples were collected at seven time points during incubations: 11:00, 13:00, 16:00, 19:00, 23:00, 6:00 and 11:00. Loggers were deployed adjacent to each chamber to develop consecutive time series of physiochemical parameters at each site. Light intensity was measured by Odyssey PAR loggers, indicating that the chosen sampling intervals captured key light transitions. Dissolved oxygen (DO) was measured with HOBO Dissolved Oxygen Data Loggers. Temperature, salinity and water depth were measured with YSI EXO 2 sondes. Sediment porewater samples were taken next to the chambers at the start and end of both time series.

Data products are organized into the following files:
Ferrybox surface water survey (1-minute resolution): 1_Cruise_Ferrybox_1min.csv
Meteorological survey (2-minute resolution): 2_Cruise_meteo_2min.csv
HydroFIA pH survey with matched and down-sampled Ferrybox data (10-minute resolution): 3_Cruise_HydroFIA_pH_10min.csv
222Rn surface water survey with matched and down-sampled Ferrybox and meteorological data (30-minute resolution): 4_Cruise_RAD7_30min.csv
Processed CTD profiles: 5_Cruise_CTD.csv
Cruise campaign discrete sample data: 6_Land_discrete.csv
Land campaign discrete sample data: 7_Land_discrete.csv
Additional description of the files, variables, and metadata can be found in the file "Baltic_data_metadata.txt".

Sampling was conducted in two mangrove seascapes in Brazil covering the intertidal porewater-mangrove creek-coastal bay-shelf continuum. The first site is situated in a tropical mesotidal region (23°18'06.2S 44°38'53.6W) near Paraty city (Rio de Janeiro). The mangrove catchment area (260,112 m2) is centered in a pristine setting connected to the southeast Brazil shelf through the oligotrophic and shallow (~5m) Mamanguá bay. The second seascape is in a subtropical microtidal region (27°38'55.6S 48°33'11.2W), located in Florianópolis city in the State of Santa Catarina. The mangrove creek (146,065 m2) is surrounded by urban areas and potentially impacted by sewage and agricultural runoff discharging in the Santa Catarina Island Bay. Mangroves at both sites have a mixed semidiurnal tidal pattern.A small vessel was moored in the mouth of the mangrove creeks for time series sampling at neap and spring tides to serve as a temporary sampling station. Surface water samples (0.5 m depth) were collected each hour for 30 hours using a peristaltic pump (Solinst, Model 410). Samples for carbon and alkalinity were collected using sample-rinsed 60 ml polypropylene syringes and pre-combusted (450°C 4h) 0.7 µm Whatman GF/F filters.Water samples for dissolved inorganic carbon (DIC) and its stable isotope composition (δ13C – DIC) were stored in gas-tight 12 ml evacuated exetainer with rubber septum (Labco UK), poisoned with 20 µL of a saturated solution of HgCl2 and stored at 4°C in the dark. DIC samples were analyzed using a AS-C5 (multi-port version, Apollo SciTech, LLC) with an infrared CO2 detector (LI-850, LI-COR, USA). δ13C – DIC samples were analyzed by EA-IRMS, an elemental analyzer (Carlo Erba 1110, CE Instruments, Italy) coupled to a Thermo Scientific Delta V Advantage isotope-ratio mass spectrometer. δ13C – DIC measurements were calibrated with certified reference materials LSVEC and NBS-19.Total alkalinity (TA) samples were stored in 50 ml Falcon tubes at 4°C in the dark until analysis using potentiometric Gran titration with 0.01 M HCl in an 888 Titrando (Tiamo software, Metrohm AG). DIC and TA samples were calibrated using measurements of certified reference material (CRM) Batch #197 from the Scripps Institution of Oceanography (UCSD) provided by Andrew Dickson.DOC samples were collected in 60 ml Thermo Scientific Nalgene HDPE bottles acidified with 600 µL of concentrated H3PO4 and stored at 4°C in the dark. DOC was analyzed using a Shimadzu 5000. Particulate material was collected by filtering 0.1 – 1L of seawater through pre-combusted (450°C 4h) 0.7 µm Whatman GF/F filters and stored at -20°C until analysis. Inorganic carbon was removed by exposing the filters to concentrated HCl fume for 24 h. POC was determined using a FLASH 2000 elemental analyzer (Thermo Scientific). The analytical control was performed by sampling replicates (Coefficient of Variation < 10%) and certified standards (Elemental Microanalysis Protein Standard).Water samples for short-lived radium isotopes were collected with submergible bilge pump into 2-80L barrels and filtered through 25g of Mn fibers at < 1 L min-1. The fibers were rinsed with radium-free water, partially dried and placed in Radium Delayed Coincidence Counters (RaDeCC) to measure 224Ra and 223Ra. Radium samples were first analyzed between 1-3 days after sampling and again after one month to account for 224Ra from 228Th decay.Salinity and temperature (Solinst Levelogger 5), dissolved oxygen (DO, PME miniDOT) and pH (Onset HOBO pH logger) probes were attached to the vessel at 0.5 m depth to record every minute. The probe data were smoothed to 1 hour time steps to enable comparisons with discrete water samples.Porewater samples were collected using a peristaltic pump during ebb tide in both mangroves towards the end of neap (N = 12) and spring (N = 12) tides. In the mesotidal mangrove, porewater was sampled from seeping water from crab burrows, which integrates the creek intertidal sediment signature. In the microtidal mangrove, bores were dug in the mud up to 50 cm depth and purged for several minutes before sampling after porewater recharging at least three times. Transects extending from the mangroves into the bays and across the continental shelves were conducted to measure the aforementioned variables in surface waters.