ALBERT

Beschreibung: This data set is predominantly sourced from the National Water Quality Monitoring Council (https://www.waterqualitydata.us/portal) and contains water quality data for the United States as well as climate and other ancillary data. This data was used to develop a model to explain groundwater dissolved organic carbon concentrations in the manuscript "Changes in global groundwater organic carbon driven by climate change and urbanization". Units for variables are included in the file "Units for Variables". --- National Water Quality Monitoring Council water chemistry data (https://www.waterqualitydata.us/portal) was obtained from: Chapelle, F. H., Bradley, P. M., Journey, C. A., & McMahon, P. B. (2013). Assessing the Relative Bioavailability of DOC in Regional Groundwater Systems. Ground water 51(3), doi:10.1111/j.1745-6584.2012.00987.x. --- Water table depth data obtained from: Fan, Y., Li, H., & Miguez-Macho, G. (2013). Global patterns of groundwater table depth. Science, 339, 940–943, doi:10.1126/science.1229881. --- Climatic data obtained from www.worldclim.org: Hijmans, R. J., Cameron, S. E., Parra, J. L., Jones, P. G., & Jarvis, A. (2005). Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology, 25, 1965-1978, doi:10.1002/joc.1276. --- Land use data obtained from: Channan, S., Collins, K., & Emanuel, W. R. (2014). Global mosaics of the standard MODIS land cover type data. University of Maryland and the Pacific Northwest National Laboratory, College Park, Maryland, USA. Retrieved from University of Maryland and the Pacific Northwest National Laboratory. - Friedl, M. A., Sulla-Menasche, D., Tan, B., Schneider, A., Ramankutty, N., Sibley, A., & Huang, X. (n.d.). MODIS Collection 5 global land cover: Algorithm refinements and characterization of new datasets, 2001-2012. Collection 5.1 IGBP Land Cover. Boston University, Boston, MA, USA.

Beschreibung: Ocean acidification (OA) is expected to drive the transition of coral reef ecosystems from net calcium carbonate (CaCO3) precipitating to net dissolving within the next century. Although permeable sediments represent the largest reservoir of CaCO3 in coral reefs, the dissolution of shallow CaCO3 sands under future pCO2 levels has not been measured under natural conditions. In situ, advective chamber incubations under elevated pCO2 (~800 µatm) shifted the sediments from net precipitating to net dissolving. Pore water advection more than doubled dissolution rates (1.10 g CaCO3/m**2/day) when compared to diffusive conditions (0.42 g CaCO3/m**2 /day). Sediment dissolution could reduce net ecosystem calcification rates of the Heron Island lagoon by 8% within the next century, which is equivalent to a 25% reduction in the global average calcification rate of coral lagoons. The dissolution of CaCO3 sediments needs to be taken into account in order to address how OA will impact the net accretion of coral reefs under future predicted increases in CO2.

Beschreibung: Some predictions of how ocean acidification (OA) will affect coral reefs assume a linear functional relationship between the ambient seawater aragonite saturation state (Omega a) and net ecosystem calcification (NEC). We quantified NEC in a healthy coral reef lagoon in the Great Barrier Reef during different times of the day. Our observations revealed a diel hysteresis pattern in the NEC versus Omega a relationship, with peak NEC rates occurring before the Omega a peak and relatively steady nighttime NEC in spite of variable Omega a. Net ecosystem production had stronger correlations with NEC than light, temperature, nutrients, pH, and Omega a. The observed hysteresis may represent an overlooked challenge for predicting the effects of OA on coral reefs. If widespread, the hysteresis could prevent the use of a linear extrapolation to determine critical Omega a threshold levels required to shift coral reefs from a net calcifying to a net dissolving state.

Beschreibung: Greenhouse gas emission studies from Coral Reef settings remain sparce compared to open ocean, rivers, and estuaries. Here we sampled the greenhouse gases of carbon dioxide (CO2) with isotopic fractions (δ13C-CO2), methane (CH4) with isotopic fractions (δ13C-CH4), and nitrous oxide (N2O) in high resolution (905 individual georeferenced 5 minute averaged samples) from ship based cruises throughout the southern half of the Great Barrier Reef Australia. Time and location matched high-resolution physio-chemical data (salinity, temperature, dissolved oxygen, turbidity and chlorophyll a) were also measured to determine driving factors of greenhouse gases in the lagoon. Overall, the lagoon was oversaturated in CO2 which is consistent with previous coral reef area studies. CH4 was also oversaturated despite highly oxygenated waters that are normally unconducive for CH4 production. N2O was undersaturated and up-taking N2O from the atmosphere which contrasts with the few coral reef and continental shelf area studies. Dissolved greenhouse gases were measured with a Picarro G2201-i Cavity Ring Down Spectrometer for CO2 (200 ppb ±0.05%) and CH4 (5 ppb ± 0.05%) with respective δ12C and δ13C stable isotope fractions and a Picarro G2308 Cavity Ring Down Spectrometer for N2O concentrations (〈3.5 ppb ± 0.008%). Both Cavity Ring Down Spectrometer instruments were connected in a closed loop with twin showerhead exchangers and a gas drying agent (Drierite). The showerhead exchangers received seawater from the vessel cold water intake. Both instruments averaged 300 measurements over a five-minute cycle for each greenhouse gas sample. Salinity, temperature, and turbidity were also recorded at the inlet of the seawater system with a Seabird SBE 21 (salinity ± 0.005 psu, temperature ± 0.002 °C, turbidity ± 0.04% NTU). Dissolved oxygen, pH, and Chlorophyll were recorded using respective Hydrolab MS5 multi-parameter sonde (dissolved oxygen 0.1 ± 0.02 mg L-1), SAMI-pH (〈0.001 ± 0.003 pH units) and ECO 3-Triplet fluorometer (Chl-a 0.016 ± 0.025 μg L-1) instruments fitted with inline flow cells.

Beschreibung: Estimates of coral reef ecosystem calcification (Gnet) and productivity (Pnet) provide insight into coral community health and functionality in response to short- and long-term stressors such as ocean warming and acidification. Here, we investigate spatial variability in calcification and organic production at One Tree Island (OTI) and compare our new observations to sporadic metabolic rates reported over the previous 50 years on the same reef flat. Gnet and Pnet estimates at the nearshore site were 50% and 166% lower than an offshore site with a shift in organic production from net productive to net respiratory. Contrary to expectations, calcification rates in 2017 (145.7 +- 20.2 mmol/m**2/d) were comparable to the 1970s estimate (125.0 +- 12.5 mmol/m**2/d) and 400% greater than similar observations in 2014. Our results indicate only weak associations between Gnet and aragonite (Omega ar). A local increase in coral cover from 18% in 2014 to 31% in 2017 was the likely driver of increased calcification. A steeper TA–DIC slope in 2017 demonstrates a greater control of calcification on seawater carbonate chemistry than prior years. Overall, these results highlight the importance of site selection and replication when comparing metabolic datasets, and demonstrate major short-term variability in metabolic rates. The predictive capabilities of ecosystem metabolism studies may be constrained by using the available short-term datasets to represent long-term calcification trends.

Beschreibung: This dataset provides discrete nutrient, dissolved and greenhouse gas samples collected during ship-based cruises in the southern Great Barrier Reef lagoon, Australia. Here we sampled the greenhouse gases of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) with time matched (georeferenced samples) discrete nutrient measurements (dissolved organic carbon, ammonium, nitrate, dissolved inorganic nitrogen, total nitrogen and phosphate) collected from the lagoon. Nutrient concentrations remained low overall, while the lagoon was oversaturated in CO2 and CH4 despite highly oxygenated waters that are normally unconducive for CH4 production. N2O was also undersaturated in the oligotrophic conditions. Dissolved greenhouse gases were measured with a Picarro G2201-i Cavity Ring Down Spectrometer for CO2 (200 ppb ±0.05%) and CH4 (5 ppb ± 0.05%) and a Picarro G2308 Cavity Ring Down Spectrometer for N2O concentrations (〈3.5 ppb ± 0.008%). Both Cavity Ring Down Spectrometer instruments were connected in a closed loop with twin showerhead exchangers and a gas drying agent (Drierite). The showerhead exchangers received seawater from the vessel cold water intake. Both instruments averaged 300 measurements over a five-minute cycle for each greenhouse gas sample. Salinity and temperature were recorded at the inlet of the seawater intake system with a Seabird SBE 21 (salinity ± 0.005 psu, temperature ± 0.002 °C). Dissolved oxygen was also recorded using a Hydrolab MS5 (dissolved oxygen 0.1 ± 0.02 mg L-1) fitted with an inline flow cell. Discrete nutrient and dissolved organic carbon (DOC) water samples were collected along survey transects using Niskin bottles from a depth of ⁓3 m. Dissolved nutrient samples were collected by filtering sample water through cellulose acetate syringe filters (0.45 µm) into sample rinsed 12 mL polypropylene vials before immediate freezing until laboratory analysis. Nutrient concentrations were determined using a Lachat QuickChem 8500 Flow Injection Analyser [Detection limits were 0.07 μmol ± 0.3% for nitrate (NOx-) and 0.35 μmol ± 5% for ammonium (NH4+)]. DOC samples were collected by filtering sample water through Whatman G/FF syringe filters (0.7 μm) into 40 ml pre-treated (100 μL mercuric chloride) VOC vials before immediate refrigeration until laboratory analysis. DOC concentrations were determined with OI Aurora 1030 W TOC Analyzer.

Beschreibung: These data were compiled from original and published datasets of coastal groundwater / subterranean estuary research efforts along global coastline (sites within 1km of shoreline). The dataset includes sampling site names, locations, original sample information, sample depth, temperature, salinity, dissolved nitrogen concentrations, and dissolved phosphorus concentrations. The data source or curator is also included in the dataset.

Beschreibung: Concentrations of alkalinity (TA) and dissolved inorganic carbon (DIC) in porewater as well as in surface water measured during timeseries (fixed location) and spatial surveys (fixed time period) were compiled from 38 mangrove- and 8 saltmarsh-dominated creeks and estuaries. We used data from creeks that were predominantly surrounded by mangrove or saltmarsh vegetation and with minimal confounding factors such as mixed vegetation or large catchments. These creeks were located in either pristine or anthropologically impacted estuaries or coastal areas. Anthropologically impacted areas were defined as areas that were affected by nearby urban or agricultural activities, potentially delivering pollutants, e.g., sewage or fertilizers, to creeks. We also included pristine mangrove- and saltmarsh dominated estuaries. When available, environmental parameters were also recorded, i.e., season, salinity, temperature, pH, dissolved oxygen (DO), water level, porewater tracer radon (222Rn), partial pressure of carbon dioxide (pCO2), dissolved organic carbon (DOC), particulate organic carbon (POC), nitrate and nitrite (NOx), ammonium (NH4), total nitrogen (TN), phosphate (PO4), and total phosphorus (TP). Methods used to determine parameters are explained in each corresponding reference.

Beschreibung: Estuaries play a key role in controlling the land-ocean fluxes of dissolved organic matter (DOM), nutrients and trace metals. Here, we study how mangrove-fringed areas affect the molecular DOM and trace metal composition in a subtropical estuary. We combined molecular analysis of solid-phase extractable (SPE) DOM using ultrahigh-resolution mass spectrometry with organic and inorganic bulk parameter analyses in surface and porewater along the estuarine gradient of a mangrove-fringed estuary in Australia (Coffs Creek). Statistical analysis and mixing models demonstrate that the fluvial and mangrove-porewater derived DOM and inorganic chemical species were altered and/or removed by the estuarine filter before reaching the coastal ocean. The mangrove-fringed central estuary was a net source for dissolved Mn and Ba as well as total dissolved nitrogen (TDN) and dissolved organic carbon (DOC) to the tidal creek, likely due to the exchange of mangrove-porewater strongly enriched in these constituents. Dissolved Fe was removed from the water column, probably during the tidally driven circulation of creek water through the sulfidic mangrove sediments. In the mangrove-porewater dominated tidal creek, sulfur- and nitrogen-containing as well as aromatic DOM compounds were relatively enriched, whereas phosphorous-containing DOM was relatively depleted compared to non-mangrove fringed areas. In areas with intense mixing of estuarine and marine water masses we observed a strong decrease of these DOM compounds relative to values expected from conservative mixing, suggesting their removal by photodegradation and co-precipitation with particles such as Mn(hydr)oxides and/or as organometallic complexes, leading to more aliphatic DOM signatures at the creek-mouth. Tidally driven porewater exchange and surface water runoff from the mangroves had a stronger effect on the biogeochemical cycling in the estuary than the fluvial input during a dry compared to a wet season. Our study confirms that mangroves can significantly contribute to biogeochemical budgets of (sub)tropical estuaries.