Carbon Reservoir Effects in Eastern Oyster from Apalachicola Bay, USA

Radiocarbon ◽  
2017 ◽  
Vol 59 (5) ◽  
pp. 1497-1506 ◽  
Author(s):  
Carla S Hadden ◽  
Alexander Cherkinsky
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Eastern Oyster ◽  
Spatiotemporal Variability ◽  
Multiple Points ◽  
Study Region ◽  
Apalachicola Bay ◽  
Apalachicola River ◽  
Carbon Reservoir ◽  
River Dynamic ◽  
Eastern Edge

AbstractEastern oyster (Crassostrea virginica) is an ubiquitous estuarine shellfish taxon in eastern North America and one of the most abundant materials available for radiocarbon (14C) dating. We examine spatiotemporal variability in carbon reservoir effects among pre-bomb oysters from Apalachicola Bay, USA, a river-influenced estuary on the northern Gulf of Mexico. Shells were sampled at multiple points along the valve to produce time-series records of 14C variation during the lives of the mollusks. Conventional ages within shells differed by as little as 36 14C yr to as much as 295 14C yr. Reservoir offsets varied sub-regionally within the estuary, increasing from 92±37 yr in the eastern edge of study region to 227±110 yr in the west, reflecting the influence of 14C-depleted dissolved inorganic carbon from the Apalachicola River. Dynamic carbon reservoirs can pose problems for the estimation of ΔR and for building coastal chronologies. Estimating sub-regional ΔR values can be useful for assessing the range of variability in reservoir offsets within an estuary, and for correcting sample ages if the shell origin is known. Greater variability and/or uncertainty in ΔR lead to greater uncertainty in the calibrated age.

Radiocarbon in Marsh Periwinkle (Littorina Irrorata) Conchiolin: Applications for Archaeology

Radiocarbon ◽  
2019 ◽  
Vol 61 (5) ◽  
pp. 1489-1500
Author(s):  
Carla S Hadden ◽  
Kathy M Loftis ◽  
Alexander Cherkinsky ◽  
Brandon T Ritchison ◽  
Isabelle H Lulewicz ◽  
...  
Keyword(s):  
Dissolved Inorganic Carbon ◽  
The United States ◽  
Chemical Oxidation ◽  
Shell Weight ◽  
Apalachicola Bay ◽  
Shell Matrix ◽  
Novel Approach ◽  
Littorina Irrorata ◽  
Carbon Reservoir ◽  
Shell Carbonate

ABSTRACTIn coastal and island archaeology, carbonate mollusk shells are often among the most abundant materials available for radiocarbon (14C) dating. The marsh periwinkle (Littorina irrorata) is one of these such species, ubiquitously found along the Atlantic and Gulf coasts of the United States in both modern and archaeological contexts. This paper presents a novel approach to dating estuarine mollusks where rather than attempting to characterize the size and variability of reservoir effects to “correct” shell carbonate dates, we describe a compound-specific approach that isolates conchiolin, the organic matter bound with the shell matrix of the L. irrorata. Conchiolin typically constitutes <5% of shell weight. In L. irrorata, it is derived from the snail’s terrestrial diet and is thus not strongly influenced by marine, hardwater, or other carbon reservoir effects. We compare the carbon isotopes (δ13C and Δ14C) of L. irrorata shell carbonate, conchiolin, and bulk soft tissue from six modern, live-collected specimens from Apalachicola Bay, Florida, with samples that represent possible sources of carbon within their environment including surface sediments, marsh plant tissues, and dissolved inorganic carbon (DIC) in water. Ultimately, this paper demonstrates that samples obtained from wet chemical oxidation of L. irrorata conchiolin produces accurate 14C dates.

scholarly journals Assessment of Precipitation Variability and Trends Based on Satellite Estimations for a Heterogeneous Colombian Region

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 128
Author(s):  
Enrique Morales-Acuña ◽  
Jean R. Linero-Cueto ◽  
Fausto A. Canales
Keyword(s):  
Sierra Nevada ◽  
Rainfall Variability ◽  
Spatiotemporal Variability ◽  
Monthly Precipitation ◽  
Study Region ◽  
Resources Management ◽  
Heterogeneous Region ◽  
Average Monthly Precipitation

Adequate water resources management includes understanding patterns and spatiotemporal variability of precipitation, as this variable is determinant for ecosystems’ stability, food security, and most human activities. Based on satellite estimations validated through ground measurements from 59 meteorological stations, the objective of this study is to evaluate the long-term spatiotemporal variability and trends of the average monthly precipitation in the Magdalena Department, Colombia, for the 1981–2018 period. This heterogeneous region comprises many different ecoregions in its 23,188 km2 area. The analysis of spatial variability allowed for the determination of four different subregions based on the differences in the average values of precipitation and the degree of rainfall variability. The trend analysis indicates that the current rainfall patterns contradict previous estimates of a progressive decrease in annual averages due to climate change in the study region, as most of the department does not exhibit statistically significant trends, except for the Sierra Nevada de Santa Marta area, where this study found reductions between 10 mm yr−1 and 30 mm yr−1. The findings of this study also suggest the existence of some links between precipitation patterns with regional phenomena of climate variability and solar activity.

Marine Reservoir Effects in Eastern Oyster (Crassostrea Virginica) from Southwestern Florida, USA

Radiocarbon ◽  
2019 ◽  
Vol 61 (5) ◽  
pp. 1501-1510 ◽  
Author(s):  
Carla S Hadden ◽  
Margo Schwadron
Keyword(s):  
Crassostrea Virginica ◽  
National Park ◽  
Archaeological Site ◽  
Eastern Oyster ◽  
Everglades National Park ◽  
Future Research ◽  
Southwest Florida ◽  
Functional Relationships ◽  
Best Estimate ◽  
Carbon Reservoir

ABSTRACTIn southwestern Florida, USA, terraformed landscapes built almost entirely of oyster shells (Crassostrea virginica) reflect a unique pre-Columbian tradition of shell-built architecture. The ability to reliably date oyster shells is essential to identifying spatial, temporal, and functional relationships among shellworks sites, yet to date there has been no systematic attempt to quantify or correct for carbon reservoir effects in this region. Here we present 14 radiocarbon (14C) ages for 5 known-age, pre-bomb oyster shells collected between AD 1932–1948, as well as 6 14C ages for archaeological oyster/charcoal pairs from the Turner River Mound Complex, Everglades National Park. We report our current best estimate of ΔR = 92 ± 74 yr for Greater Southwest Florida, and ΔR = –15 ± 42 yr for the Turner River archaeological site. Future research should focus on paired archaeological specimens to obtain spatially and temporally relevant estimates of ΔR.

Transformation of dissolved inorganic carbon (DIC) into particulate organic carbon (POC) in the lower Xijiang River, SE China: an isotopic approach

2011 ◽  
Vol 8 (5) ◽  
pp. 9471-9501 ◽  
Author(s):  
H. G. Sun ◽  
J. T. Han ◽  
S. R. Zhang ◽  
X. X. Lu
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Rainy Season ◽  
Chemical Weathering ◽  
Dissolved Inorganic Carbon ◽  
Dry Season ◽  
Study Region ◽  
Carbon Isotopic ◽  
Xijiang River ◽  
Extreme Flood

Abstract. The sources and dynamics of riverine carbon have been discussed extensively, but knowledge about the transformation from DIC into organic carbon (OC) is still poorly understood. In this study, we conducted a comprehensive investigation on the riverine carbon, stable carbon isotopic components and C/N ratios for different seasons, including an extreme flood event, in the lower Xijiang and its three tributaries. Detailed analyses are also performed for soil samples across the study region. Downstream increase in δ13CDIC and downstream decrease in both δ13CPOC and C/N have been observed for all the tributaries. Meanwhile, positive shift of δ13CDIC and negative shift of δ13CPOC are also observed from summer to winter. These observations likely indicate that the isotopic compositions of both DIC and POC are significantly affected by in-river primary production that converts DIC into organic matter through photosynthesis. It is estimated that the percentage contribution of the riverine aquatic primary production to the riverine POC in the Xijiang and three tributaries of Guijiang, Hejiang and Luoding is respectively 7.1%, 43.2%, 36.4% and 9.9% in rainy season, and 35.6%, 47.3%, 50.3% and 40.1% in dry season. Based on the stoichiometry involved in chemical weathering of the bedrocks, the transformation of the carbonate-sourced DIC to POC is further quantified to be 3.4–20.5% in rainy season, and 12.3–22.1% in dry season. This may suggest an important sink of atmospheric CO2 in river systems that was largely ignored previously.

Environmental and seasonal controls on riverine dissolved uranium in the Hudson, James, and Ungava bays region, Canada

2012 ◽  
Vol 49 (6) ◽  
pp. 758-771 ◽  
Author(s):  
Eric Rosa ◽  
Claude Hillaire-Marcel ◽  
Bassam Ghaleb ◽  
Terry A. Dick
Keyword(s):  
Flow Control ◽  
Activity Ratio ◽  
Uranium Concentration ◽  
Monitoring Program ◽  
Weighted Average ◽  
Spatiotemporal Variability ◽  
Seasonal Fluctuations ◽  
Study Region ◽  
Field Surveys ◽  
Control Structures

This study documents the spatiotemporal variability of riverine uranium contents and fluxes in rivers discharging into the Hudson, James, and Ungava bays (HJUB). Samples retrieved during a monitoring program of the Koksoak, Great Whale, La Grande, and Nelson rivers were analyzed for dissolved uranium concentration [U] and activity ratio (234U/238U). Field surveys conducted during baseflow and snowmelt in six other rivers of the HJUB basin provided complementary data. It is estimated that altogether, the studied rivers export 3.4 × 105 mol/year of U towards the HJUB, with a discharge weighted average (234U/238U) of 1.27. Two main factors appear to control seasonal fluctuations in dissolved U exports from HJUB rivers: snowmelt and anthropogenic flow control. Under natural hydrological regimes, the dilution of U caused by snowmelt does not compensate for the associated increase in discharge, and riverine U fluxes are intensified during springtime. Contrastingly, the timing of riverine U exports is decoupled from hydroclimatic conditions in rivers affected by flow-control structures. Despite the seasonal variations in riverine U contents, the sampling profiles carried along two of the monitored rivers reveal that within the study region, sample locality is at least as important as sampling time for evaluating riverine U fluxes. In addition, a compilation of data from North American rivers reveals that spatial variations in riverine U contents seem to respond to a prominent lithological control, as rivers draining sedimentary rocks (with abundant carbonates) tend to present overall higher U contents and lower (234U/238U) variability than the rivers of the Canadian Shield.

scholarly journals Enhance Ocean Carbon Observations: Successful Implementation of a Novel Autonomous Total Alkalinity Analyzer on a Ship of Opportunity

2020 ◽  
Vol 7 ◽  
Author(s):  
Katharina Seelmann ◽  
Tobias Steinhoff ◽  
Steffen Aßmann ◽  
Arne Körtzinger
Keyword(s):  
Large Volume ◽  
Polyvinylidene Fluoride ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Spatiotemporal Variability ◽  
Global Ocean ◽  
Observation System ◽  
Successful Implementation ◽  
Ocean Carbon

Over recent decades, observations based on merchant vessels (Ships of Opportunity—SOOP) equipped with sensors measuring the CO2 partial pressure (pCO2) in the surface seawater formed the backbone of the global ocean carbon observation system. However, the restriction to pCO2 measurements alone is one severe shortcoming of the current SOOP observatory. Full insight into the marine inorganic carbon system requires the measurement of at least two of the four measurable variables which are pCO2, total alkalinity (TA), dissolved inorganic carbon (DIC), and pH. One workaround is to estimate TA values based on established temperature-salinity parameterizations, but this leads to higher uncertainties and the possibility of regional and/or seasonal biases. Therefore, autonomous SOOP-based TA measurements are of great interest. Our study describes the implementation of a novel autonomous analyzer for seawater TA, the CONTROS HydroFIAⓇ TA system (-4H-JENA engineering GmbH, Germany) for unattended routine TA measurements on a SOOP line operating in the North Atlantic. We present the installation in detail and address major issues encountered with autonomous measurements using this analyzer, e.g., automated cleaning and stabilization routines, and waste handling. Another issue during long-term deployments is the provision of reference seawater in large-volume containers for quality assurance measurements and drift correction. Hence, a stable large-volume seawater storage had to be found. We tested several container types with respect to their suitability to store seawater over a time period of 30 days without significant changes in TA. Only one gas sampling bag made of polyvinylidene fluoride (PVDF) satisfied the high stability requirement. In order to prove the performance of the entire setup, we compared the autonomous TA measurements with TA from discrete samples taken during the first two trans-Atlantic crossings. Although the measurement accuracy in unattended mode (about ± 5 μmol kg^-1) slightly deteriorated compared to our previous system characterization, its overall uncertainty fulfilled requirements for autonomous TA measurements on SOOP lines. A comparison with predicted TA values based on an established and often used parameterization pointed at regional and seasonal limitations of such TA predictions. Consequently, TA observations with better coverage of spatiotemporal variability are needed, which is now possible with the method described here.

scholarly journals The Effects of Climate Change on Variability of the Growing Seasons in the Elbe River Lowland, Czech Republic

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Vera Potopová ◽  
Pavel Zahradníček ◽  
Luboš Türkott ◽  
Petr Štěpánek ◽  
Josef Soukup
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Growing Season ◽  
Spatiotemporal Variability ◽  
Elbe River ◽  
Study Region ◽  
The Elbe River ◽  
Projected Changes

This research aimed to identify an approach for adaptation of agriculture to increased climate variability and projected changes, taking into account regional specificity of climate change. Changes in the timing of growing season (GS) parameters for both observation and models data were computed using daily mean temperatures for three thresholds that correspond to the physiological requirements of the vegetable types. This research included a new assessment of the potential impacts of climate change on the GS of vegetables grown in the Elbe River lowland, one of the largest farmed vegetable regions in Central Europe. To accomplish this, a comprehensive analysis was conducted of the spatiotemporal variability of the date of the beginning of the growing season (BGS), the date of the end of the growing season (EGS), and the length of the growing season (GSL) for the period 1961–2011. In addition, an assessment was made of the potential changes in the dates of the BGS, EGS, and GSL for the Elbe River lowland, simulated using the regional climate models. Prospective areas for growing thermophilic vegetables in the study region were also determined.

scholarly journals Spatiotemporal variability and drivers of <i>p</i>CO<sub>2</sub> and air–sea CO<sub>2</sub> fluxes in the California Current System: an eddy-resolving modeling study

2014 ◽  
Vol 11 (3) ◽  
pp. 671-690 ◽  
Author(s):  
G. Turi ◽  
Z. Lachkar ◽  
N. Gruber
Keyword(s):  
Surface Temperature ◽  
Dissolved Inorganic Carbon ◽  
Current System ◽  
California Current ◽  
Spatiotemporal Variability ◽  
Co2 Fluxes ◽  
Biological Reduction ◽  
California Current System ◽  
Surface Ocean ◽  
Source Sink

Abstract. We quantify the CO2 source/sink nature of the California Current System (CalCS) and determine the drivers and processes behind the mean and spatiotemporal variability of the partial pressure of CO2 (pCO2) in the surface ocean. To this end, we analyze eddy-resolving, climatological simulations of a coupled physical–biogeochemical oceanic model on the basis of the Regional Oceanic Modeling System (ROMS). In the annual mean, the entire CalCS within 800 km of the coast and from ∼33° N to 46° N is essentially neutral with regard to atmospheric CO2: the model simulates an integrated uptake flux of −0.9 ± 3.6 Tg C yr−1, corresponding to an average flux density of −0.05 ± 0.20 mol C m−2 yr−1. This near zero flux is a consequence of an almost complete regional compensation between (i) strong outgassing in the nearshore region (first 100 km) that brings waters with high concentrations of dissolved inorganic carbon (DIC) to the surface and (ii) and a weaker, but more widespread uptake flux in the offshore region due to an intense biological reduction of this DIC, driven by the nutrients that are upwelled together with the DIC. The air–sea CO2 fluxes vary substantially in time, both on seasonal and sub-seasonal timescales, largely driven by variations in surface ocean pCO2. Most of the variability in pCO2 is associated with the seasonal cycle, with the exception of the nearshore region, where sub-seasonal variations driven by mesoscale processes dominate. In the regions offshore of 100 km, changes in surface temperature are the main driver, while in the nearshore region, changes in surface temperature, as well as anomalies in DIC and alkalinity (Alk) owing to changes in circulation, biological productivity and air–sea CO2 fluxes dominate. The prevalence of eddy-driven variability in the nearshore 100 km leads to a complex spatiotemporal mosaic of surface ocean pCO2 and air–sea CO2 fluxes that require a substantial observational effort to determine the source/sink nature of this region reliably.

scholarly journals Spatiotemporal Variability of Longshore Sediment Transport on the Brazilian Coast

2020 ◽  
Author(s):  
Thaisa Beloti Trombetta ◽  
Wiliam Correa Marques
Keyword(s):  
Sediment Transport ◽  
Southern Region ◽  
Spatiotemporal Variability ◽  
Environmental Damage ◽  
Brazilian Coast ◽  
Study Region ◽  
Longshore Sediment Transport ◽  
Annual Means ◽  
Source Of Information

Abstract The lack of planning and management regarding the transport of sediments along the coast can alter the existing equilibrium in coastal regions, causing or accelerating erosive processes and resulting in economic and environmental damage. Thus, it is important that the characteristics of the coastal drift be investigated, serving as source of information for future projects involving the coastal environment management. Within this context, the present work aims to identify the annual sediment transport averages along the Brazilian coast, the dominant direction of the coastal drift and its spatial variability. For this, a wind-generated wave modeling was considered, with 37 years of data (1979 to 2015), as well as four sediment transport formulations. For the spatiotemporal variability, the analysis of wavelets was applied, relating the effect of cycles of variability over the behavior of longshore sediment transport. The results showed that the largest annual volumes of sediment transport occurred in the northeastern Region of Brazil, reaching approximately 850000 m3/year-1. On the other hand, the smallest transport averages occurred in the southern region, in the state of Santa Catarina, reaching the value of 13497 m3/year-1. In the northeast region, annual and interannual cycles were more frequent and more energetic than in the southern Region, where short cycles presented similar importance to longer cycles, during 37 years of the study. However, in the overall context of the analysis, the long period cycles are more significant for longshore sediment transport, since this is a long term process. In this way, the present article contributes with information on longshore sediment transport, highlighting the annual means and the dominant drift, and deals with important questions about the influence of cycles of variability in the study region, emphasizing the importance of longer period events for the control of sedimentary transport in the Brazilian coast.

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