Implications of radiocarbon ages of organic and inorganic carbon in coastal lakes in Florida for establishing a reliable chronology for sediment-based paleoclimate reconstruction

2018 ◽  
Vol 91 (2) ◽  
pp. 638-649
Author(s):  
Yang Wang ◽  
Oindrila Das ◽  
Xiaomei Xu ◽  
Jin Liu ◽  
Shakura Jahan ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Sediment Cores ◽  
Bulk Sediment ◽  
Storm Events ◽  
Coastal Lake ◽  
Paleoclimate Reconstruction ◽  
Small Reservoir ◽  
Coastal Lakes ◽  
Close Proximity ◽  
Organic And Inorganic Carbon

AbstractCoastal lake sediments are valuable paleoclimate archives provided that they can be accurately dated. Here, we report radiocarbon ages of bulk sediment organic matter (OM), plants, shells, particulate OM, and dissolved OM from coastal lakes in Florida. Bulk sediment OM yielded ages that are consistently older than contemporaneous plants and shells, indicating significant radiocarbon deficiencies in sedimentary OM in these lakes. The data show that the OM radiocarbon deficiency varies over time and with location, making it impossible to determine a proper correction factor for radiocarbon ages of bulk sediments from these lakes. As a result, we consider ages obtained from bulk sediment OM from these lakes unreliable. The age reversals in bulk sediment OM observed in the sediment cores are likely caused by rapid increases in erosion and sedimentation resulting from large storm events. The data also show that sedimentation rate can vary considerably within a given lake, implying that an age-depth model established for one core cannot be directly applied to other cores despite their close proximity. Analyses of shells from one of the lakes suggest that fresh/brackish-water shells may serve as a good substrate for radiocarbon dating owing to a small reservoir effect on inorganic carbon.

Impact of Catchment Urbanisation on Lake Macquarie (Australia)

1989 ◽  
Vol 21 (2) ◽  
pp. 205-210 ◽  
Author(s):  
B. L. Simmons ◽  
S. L. Trengove
Keyword(s):  
Nutrient Enrichment ◽  
Benthic Algae ◽  
Water Clarity ◽  
Nutrient Concentrations ◽  
Lake Area ◽  
Seagrass Beds ◽  
Coastal Lake ◽  
Aesthetic Quality ◽  
Wastewater Disposal ◽  
Coastal Lakes

Increasing urbanisation of coastal areas is leading to impacts on coastal lakes which decrease their amenity for recreation and tourism. Runoff and wastewater discharge cause siltation, impact seagrass beds and change the characteristics of open waters, affecting boating, swimming, fishing and the aesthetic quality of the locale. Management of urban development and wastewater disposal is required to minimise sedimentation and nutrient enrichment. This could include development restrictions, runoff controls and a strategy for wastewater treatment and discharge. The catchment of Lake Macquarie, a marine coastal lake, has been progressively urbanised since 1945. Urbanisation, through increased stormwater runoff and point source discharges, has caused a major impact on the lake in terms of sedimentation and nutrient enrichment. Losses of lake area and navigable waters have occurred. Accompanying problems include changes in the distribution of seagrass beds and nuisance growths of benthic algae. Since the 1950's, dry weather nutrient concentrations have increased and mean water clarity has decreased. Severe problems, as observed in other New South Wales coastal lakes, for example benthic algae in Lake Illawarra and Tuggerah Lakes, have not yet developed. Because of the lead time taken to implement policies and controls, trends should be identified and policies developed now so as to avoid nutrient buildup and development of sustained problems.

scholarly journals Solute transport dynamics in small, shallow groundwater-dominated agricultural catchments: insights from a high-frequency, multisolute 10 yr-long monitoring study

2013 ◽  
Vol 17 (4) ◽  
pp. 1379-1391 ◽  
Author(s):  
A. H. Aubert ◽  
C. Gascuel-Odoux ◽  
G. Gruau ◽  
N. Akkal ◽  
M. Faucheux ◽  
...  
Keyword(s):  
High Frequency ◽  
Inorganic Carbon ◽  
Shallow Groundwater ◽  
Data Series ◽  
Wet Season ◽  
Transport Dynamics ◽  
Agricultural Catchments ◽  
Organic And Inorganic Carbon ◽  
The Impact

Abstract. High-frequency, long-term and multisolute measurements are required to assess the impact of human pressures on water quality due to (i) the high temporal and spatial variability of climate and human activity and (ii) the fact that chemical solutes combine short- and long-term dynamics. Such data series are scarce. This study, based on an original and unpublished time series from the Kervidy-Naizin headwater catchment (Brittany, France), aims to determine solute transfer processes and dynamics that characterise this strongly human-impacted catchment. The Kervidy-Naizin catchment is a temperate, intensive agricultural catchment, hydrologically controlled by shallow groundwater. Over 10 yr, five solutes (nitrate, sulphate, chloride, and dissolved organic and inorganic carbon) were monitored daily at the catchment outlet and roughly every four months in the shallow groundwater. The concentrations of all five solutes showed seasonal variations but the patterns of the variations differed from one solute to another. Nitrate and chloride exhibit rather smooth variations. In contrast, sulphate as well as organic and inorganic carbon is dominated by flood flushes. The observed nitrate and chloride patterns are typical of an intensive agricultural catchment hydrologically controlled by shallow groundwater. Nitrate and chloride originating mainly from organic fertilisers accumulated over several years in the shallow groundwater. They are seasonally exported when upland groundwater connects with the stream during the wet season. Conversely, sulphate as well as organic and inorganic carbon patterns are not specific to agricultural catchments. These solutes do not come from fertilisers and do not accumulate in soil or shallow groundwater; instead, they are biogeochemically produced in the catchment. The results allowed development of a generic classification system based on the specific temporal patterns and source locations of each solute. It also considers the stocking period and the dominant process that limits transport to the stream, i.e. the connectivity of the stocking compartment. This mechanistic classification can be applied to any chemical solute to help assess its origin, storage or production location and transfer mechanism in similar catchments.

scholarly journals The chemical signature of a livestock farming catchment: synthesis from a high-frequency multi-element long term monitoring

2012 ◽  
Vol 9 (8) ◽  
pp. 9715-9741 ◽  
Author(s):  
A. H. Aubert ◽  
C. Gascuel-Odoux ◽  
G. Gruau ◽  
J. Molénat ◽  
M. Faucheux ◽  
...  
Keyword(s):  
High Frequency ◽  
Inorganic Carbon ◽  
Shallow Groundwater ◽  
Wet Season ◽  
Livestock Farming ◽  
Agricultural Catchments ◽  
Organic And Inorganic Carbon ◽  
Five Elements ◽  
The Impact

Abstract. Assessing the impact of human pressures on water quality is difficult. First, there is a high temporal and spatial variability of climate and human activity. Second, chemical elements have their own characteristics mixing short and long term dynamics. High frequency, long-term and multi-element measurements are required. But, such data series are scarce. This paper aims at determining what the hydro-chemical particularities of a livestock farming catchment are in a temperate climatic context. It is based on an original and never published time series, from Kervidy-Naizin headwater catchment. Stream chemistry was monitored daily and shallow groundwater roughly every four month, for 10 yr and five elements (nitrate, sulphate, chloride, and dissolved organic and inorganic carbon). The five elements present strong but different seasonal patterns. Nitrate and chloride present a seasonal flush, all along or at the beginning of the wet season, respectively. Sulphate, organic and inorganic carbon present storm flushes, with constant or decreasing peaks throughout the wet season. These depicted nitrate and chloride patterns are typical of a livestock farming catchment. There, nitrate and chloride coming from organic fertilisation have been accumulating over years in the shallow groundwater. They are seasonally flushed when the groundwater connects to the stream. Sulphate, organic and inorganic carbon patterns do not seem specific to agricultural catchments. These elements are produced each year and flushed by storms. Finally, a generic classification of temporal patterns and elements is established for agricultural catchments. It is based on the distance of the source component to the stream and the dominant controlling process (accumulation versus production). This classification could be applied to any chemical element and help assessing the level of water disturbances.

scholarly journals Planting trees and amending with waste increases the capacity of mine tailings soils to retain Ni, Pb and Zn

2014 ◽  
Vol 4 ◽  
Author(s):  
Verónica Asensio Fandiño ◽  
Flora A. Vega ◽  
Rubén Forján ◽  
Emma F. Covelo
Keyword(s):  
Sorption Capacity ◽  
Soil Ph ◽  
Mine Tailings ◽  
Cation Exchange Capacity ◽  
Inorganic Carbon ◽  
Exchange Capacity ◽  
Tree Planting ◽  
Batch Adsorption ◽  
Organic And Inorganic Carbon ◽  
High Concentrations

The sorption capacity for Ni, Pb and Zn of mine tailings soil with and without reclamation treatment (tree planting and waste amendment) was evaluated using the batch adsorption technique. It is important to determine the capacity of waste-amended soils to retain Ni, Pb and Zn, as the sludges used usually have high concentrations of these metals. The results obtained in the present study showed that the untreated mine tailings soil had a low capacity for Ni, Pb and Zn retention. The sorption capacity for Pb increased significantly in all of the treated soils, without any significant differences between them. The treatment that most increased the sorption capacity for Ni and Zn was planting with trees and amending with waste simultaneously, as this increased the concentration of both organic and inorganic carbon, exchangeable calcium, soil pH and effective cation exchange capacity

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