Biogeochemical characterization of carbon sources in the Strickland and Fly rivers, Papua New Guinea

The highstanding islands of Oceania are recognized as a source of significant particulate organic carbon delivered to nearshore marine environments. The existing data on carbon export in Oceania are largely derived from small mountainous watersheds (<10,000 km2) with little or no sediment storage capacity and located in subtropical to temperate regions. The Fly-Strickland fluvial dispersal system is the largest in tropical Oceania and has high sediment yields, aged organic matter in its suspended-sediment load, and lowland sediment storage capacity. The Fly River system also has very high soil organic carbon content and conditions favorable to perennially high production, oxidation, and discharge within the watershed. We used stable and radiogenic isotopes (δ13C, Δ14C, and δ15N), lignin phenols, and X-ray photoelectron spectroscopy to examine the organic and inorganic composition of particulate and dissolved carbon at several lowland sites in the Fly and Strickland rivers and on the Strickland River floodplain. Isotopic, elemental, and biomarker results suggest that organic carbon in the Strickland River was more degraded than in the Fly River, with a greater input of ancient organics from upland sources, and that aquatic production constituted a larger source in the Fly River. Radiocarbon results indicate that all carbon fractions were older in the Strickland than in the Fly and that Strickland floodplain sediments were also depleted in radiocarbon. Collectively, these results suggest that rivers of New Guinea export a comparable amount of particulate organic carbon to the Amazon, with a significant contribution from radiocarbon-depleted sources

Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere

Author Posting. © Ecological Society of America, 2011. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Frontiers in Ecology and the Environment 9 (2011): 53–60, doi:10.1890/100014.Streams, rivers, lakes, and other inland waters are important agents in the coupling of biogeochemical cycles between continents, atmosphere, and oceans. The depiction of these roles in global-scale assessments of carbon (C) and other bioactive elements remains limited, yet recent findings suggest that C discharged to the oceans is only a fraction of that entering rivers from terrestrial ecosystems via soil respiration, leaching, chemical weathering, and physical erosion. Most of this C influx is returned to the atmosphere from inland waters as carbon dioxide (CO2) or buried in sedimentary deposits within impoundments, lakes, floodplains, and other wetlands. Carbon and mineral cycles are coupled by both erosion–deposition processes and chemical weathering, with the latter producing dissolved inorganic C and carbonate buffering capacity that strongly modulate downstream pH, biological production of calcium-carbonate shells, and CO2 outgassing in rivers, estuaries, and coastal zones. Human activities substantially affect all of these processes.The US National Science Foundation (NSF) and the National Oceanographic and Atmospheric Administration (NOAA) provided funding for this work

Interpretation and design of ocean acidification experiments in upwelling systems in the context of carbonate chemistry co-variation with temperature and oxygen

AbstractCoastal upwelling regimes are some of the most productive ecosystems in the ocean but are also among the most vulnerable to ocean acidification (OA) due to naturally high background concentrations of CO2. Yet our ability to predict how these ecosystems will respond to additional CO2 resulting from anthropogenic emissions is poor. To help address this uncertainty, researchers perform manipulative experiments where biological responses are evaluated across different CO2 partial pressure (pCO2) levels. In upwelling systems, however, contemporary carbonate chemistry variability remains only partly characterized and patterns of co-variation with other biologically important variables such as temperature and oxygen are just beginning to be explored in the context of OA experimental design. If co-variation among variables is prevalent, researchers risk performing OA experiments with control conditions that are not experienced by the focal species, potentially diminishing the ecological relevance of the experiment. Here, we synthesized a large carbonate chemistry dataset that consists of carbonate chemistry, temperature, and oxygen measurements from multiple moorings and ship-based sampling campaigns from the California Current Ecosystem (CCE), and includes fjord and tidal estuaries and open coastal waters. We evaluated patterns of pCO2 variability and highlight important co-variation between pCO2, temperature, and oxygen. We subsequently compared environmental pCO2–temperature measurements with conditions maintained in OA experiments that used organisms from the CCE. By drawing such comparisons, researchers can gain insight into the ecological relevance of previously published OA experiments, but also identify species or life history stages that may already be influenced by contemporary carbonate chemistry conditions. We illustrate the implications co-variation among environmental variables can have for the interpretation of OA experimental results and suggest an approach for designing experiments with pCO2 levels that better reflect OA hypotheses while simultaneously recognizing natural co-variation with other biologically relevant variables

Terrigenous organic matter in sediments from the Fly River delta-clinoform system (Papua New Guinea)

Although an inordinate fraction of the global sediment flux to the ocean occurs in tropical mountainous river margins, little is known regarding the sources and fate of organic matter in these systems. To address these knowledge gaps, the distribution and composition of organic matter in sediments from the Fly River delta-clinoform were examined in the context of the source-to-sink study of the Papuan Continuum. The significant contrasts in the texture of seabed sediments measured across the study area coincided with stark contrasts in concentration and composition of the sedimentary organic matter. Coarser sediments displayed significantly lower organic carbon and nitrogen contents, more enriched stable carbon and nitrogen compositions, lower lignin product yields, and distinctly different lignin and nonlignin product compositions than their fine-textured counterparts. Compositional differences were also measured between high- and low-density fractions of selected sediment samples. Subsurface sediments showed marked compositional variations that were predominantly associated with changes in the texture of the deposits. Most sediments were characterized by moderate carbon loadings (0.5–1.0 mg C m–2), although several samples from the outer topset region, an area of sediment bypass, were characterized by lower carbon loadings indicative of enhanced carbon losses. Overall, the organic matter in both surface and subsurface sediments appeared to have predominantly a terrigenous origin, with no evidence for dilution and/or replacement by marine carbon. The measured compositions were consistent with contributions from modern vascular plant detritus, aged soil organic matter, and very old or fossil organic matter devoid of recognizable biochemicals

Marine CO2 Patterns in the Northern Salish Sea

Marine carbon dioxide (CO2) system data has been collected from December 2014 to June 2018 in the Northern Salish Sea (NSS; British Columbia, Canada) and consisted of continuous measurements at two sites as well as spatially- and seasonally distributed discrete seawater samples. The array of CO2 observing activities included high-resolution CO2 partial pressure (pCO2) and pHT (total scale) measurements made at the Hakai Institute’s Quadra Island Field Station (QIFS) and from an Environment Canada weather buoy, respectively, as well as discrete seawater measurements of pCO2 and total dissolved inorganic carbon (TCO2) obtained during a number of field campaigns. A relationship between NSS alkalinity and salinity was developed with the discrete datasets and used with the continuous measurements to highly resolve the marine CO2 system. Collectively, these datasets provided insights into the seasonality in this historically under-sampled region and detail the area’s tendency for aragonite saturation state (Ωarag) to be at non-corrosive levels (i.e., Ωarag &gt; 1) only in the upper water column during spring and summer months. This depth zone and time period of reprieve can be periodically interrupted by strong northwesterly winds that drive short-lived (∼1 week) episodes of high-pCO2, low-pH, and low-Ωarag conditions throughout the region. Interannual variability in summertime conditions was evident and linked to reduced northwesterly winds and increased stratification. Anthropogenic CO2 in NSS surface water was estimated using data from 2017 combined with the global atmospheric CO2 forcing for the period 1765 to 2100, and projected a mean value of 49 ± 5 μmol kg-1 for 2018. The estimated trend in anthropogenic CO2 was further used to assess the evolution of Ωarag and pHT levels in NSS surface water, and revealed that wintertime corrosive Ωarag conditions were likely absent pre-1900. The percent of the year spent above Ωarag = 1 has dropped from ∼98% in 1900 to ∼60% by 2018. Over the coming decades, winter pHT and spring and summer Ωarag are projected to decline to conditions below identified biological thresholds for select vulnerable species

Experiments with Seasonal Forecasts of ocean conditions for the Northern region of the California Current upwelling system

Resource managers at the state, federal, and tribal levels make decisions on a weekly to quarterly basis, and fishers operate on a similar timeframe. To determine the potential of a support tool for these efforts, a seasonal forecast system is experimented with here. JISAO’s Seasonal Coastal Ocean Prediction of the Ecosystem (J-SCOPE) features dynamical downscaling of regional ocean conditions in Washington and Oregon waters using a combination of a high-resolution regional model with biogeochemistry and forecasts from NOAA’s Climate Forecast System (CFS). Model performance and predictability were examined for sea surface temperature (SST), bottom temperature, bottom oxygen, pH, and aragonite saturation state through model hindcasts, reforecast, and forecast comparisons with observations. Results indicate J-SCOPE forecasts have measurable skill on seasonal timescales. Experiments suggest that seasonal forecasting of ocean conditions important for fisheries is possible with the right combination of components. Those components include regional predictability on seasonal timescales of the physical environment from a large-scale model, a high-resolution regional model with biogeochemistry that simulates seasonal conditions in hindcasts, a relationship with local stakeholders, and a real-time observational network. Multiple efforts and approaches in different regions would advance knowledge to provide additional tools to fishers and other stakeholders.NOAA data is available from CDIAC (http://cdiac.ornl.gov). Data from Newport is available upon request by emailing Bill Peterson ([email protected]), and for the NH10 temperature moored time series, that is available upon request by emailing Mike Kosro ([email protected]). Data from the OCNMS is available on their website http://olympiccoast.noaa.gov/science/oceanography/oceanographic_moorings/oceanographic_moorings_data.html). This is PMEL contribution number 4395 and JISAO contribution number 2709

A multi-decade record of high quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)

The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) “living data” publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID

Interpretation and design of ocean acidification experiments in upwelling systems in the context of carbonate chemistry co-variation with temperature and oxygen

Coastal upwelling regimes are some of the most productive ecosystems in the ocean but are also among the most vulnerable to ocean acidification (OA) due to naturally high background concentrations of CO₂. Yet our ability to predict how these ecosystems will respond to additional CO₂ resulting from anthropogenic emissions is poor. To help address this uncertainty, researchers perform manipulative experiments where biological responses are evaluated across different CO₂ partial pressure (pCO₂) levels. In upwelling systems, however, contemporary carbonate chemistry variability remains only partly characterized and patterns of co-variation with other biologically important variables such as temperature and oxygen are just beginning to be explored in the context of OA experimental design. If co-variation among variables is prevalent, researchers risk performing OA experiments with control conditions that are not experienced by the focal species, potentially diminishing the ecological relevance of the experiment. Here, we synthesized a large carbonate chemistry dataset that consists of carbonate chemistry, temperature, and oxygen measurements from multiple moorings and ship-based sampling campaigns from the California Current Ecosystem (CCE), and includes fjord and tidal estuaries and open coastal waters. We evaluated patterns of pCO₂ variability and highlight important co-variation between pCO₂, temperature, and oxygen. We subsequently compared environmental pCO₂–temperature measurements with conditions maintained in OA experiments that used organisms from the CCE. By drawing such comparisons, researchers can gain insight into the ecological relevance of previously published OA experiments, but also identify species or life history stages that may already be influenced by contemporary carbonate chemistry conditions. We illustrate the implications co-variation among environmental variables can have for the interpretation of OA experimental results and suggest an approach for designing experiments with pCO₂ levels that better reflect OA hypotheses while simultaneously recognizing natural co-variation with other biologically relevant variables.Keywords: hypoxia, multistressor experiment, California Current, pH, climate chang

State of the Carbon Cycle - Consequences of Rising Atmospheric CO2

The rise of atmospheric CO2, largely attributable to human activity through fossil fuel emissions and land-use change, has been dampened by carbon uptake by the ocean and terrestrial biosphere. We outline the consequences of this carbon uptake as direct and indirect effects on terrestrial and oceanic systems and processes for different regions of North America and the globe. We assess the capacity of these systems to continue to act as carbon sinks. Rising CO2 has decreased seawater pH; this process of ocean acidification has impacted some marine species and altered fundamental ecosystem processes with further effects likely. In terrestrial ecosystems, increased atmospheric CO2 causes enhanced photosynthesis, net primary production, and increased water-use efficiency. Rising CO2 may change vegetation composition and carbon storage, and widespread increases in water use efficiency likely influence terrestrial hydrology and biogeochemical cycling. Consequences for human populations include changes to ecosystem services including cultural activities surrounding land use, agricultural or harvesting practices. Commercial fish stocks have been impacted and crop production yields have been changed as a result of rising CO2. Ocean and terrestrial effects are contingent on, and feedback to, global climate change. Warming and modified precipitation regimes impact a variety of ecosystem processes, and the combination of climate change and rising CO2 contributes considerable uncertainty to forecasting carbon sink capacity in the ocean and on land. Disturbance regime (fire and insects) are modified with increased temperatures. Fire frequency and intensity increase, and insect lifecycles are disrupted as temperatures move out of historical norms. Changes in disturbance patterns modulate the effects of rising CO2 depending on ecosystem type, disturbance frequency, and magnitude of events. We discuss management strategies designed to limit the rise of atmospheric CO2 and reduce uncertainty in forecasts of decadal and centennial feedbacks of rising atmospheric CO2 on carbon storage