scholarly journals Zinc isotopes as tracers of anthropogenic sources and biogeochemical processes in contaminated mangroves

2018 ◽  
Vol 95 ◽  
pp. 25-32 ◽  
Author(s):  
Daniel F. Araújo ◽  
Wilson Machado ◽  
Dominik Weiss ◽  
Daniel S. Mulholland ◽  
Jeremie Garnier ◽  
...  
Keyword(s):  
Anthropogenic Sources ◽  
Biogeochemical Processes ◽  
Zinc Isotopes

scholarly journals Use of Paleoflood Deposits to Determine the Contribution of Anthropogenic Trace Metals to Alluvial Sediments in the Hyperarid Rio Loa Basin, Chile

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 244 ◽  
Author(s):  
Jerry R. Miller ◽  
Danvey Walsh ◽  
Lionel F. Villarroel
Keyword(s):  
Trace Metals ◽  
Organic Matter Content ◽  
Enrichment Factors ◽  
Matter Content ◽  
Anthropogenic Sources ◽  
Biogeochemical Processes ◽  
Riverine Ecosystems ◽  
Local Background ◽  
Toxic Trace Metals ◽  
Source Materials

Toxic trace metals are a common and significant contaminant in riverine ecosystems, and are derived from both natural and anthropogenic sources. Determining the contributions of metals from these sources has proven difficult, in part, because physical and biogeochemical processes alter the nature (e.g., grain size, mineral composition, organic matter content) of the source materials as they are transported through the drainage network. This study examined the use of paleoflood deposits located along the hyperarid Rio Salado, a tributary to the Rio Loa of northern Chile, to construct local background functions and enrichment factors (LEFs) to differentiate between natural and anthropogenic metal sources. Significant variations in metal content occurred between river reaches and flood deposits of a given reach; these variations were primarily related to changes in sediment source that may reflect differences in El Niño and La Niña precipitation patterns. Three conservative elements (Al, Fe, Co) were examined to construct background functions for seven trace metals. Cobalt yielded the most effective background functions for As, Cd, Ni, Pb, and Zn; Fe was selected for Cr, and Al for Cu. The resulting LEFs approximated 1, illustrating that paleoflood deposits produced effective background functions, and could be applied to downstream sites contaminated by mining activity.

Bivalve-enhanced nitrogen removal from coastal estuaries

2012 ◽  
Vol 69 (7) ◽  
pp. 1131-1149 ◽  
Author(s):  
Ruth H. Carmichael ◽  
William Walton ◽  
Heidi Clark
Keyword(s):  
Crassostrea Virginica ◽  
Nitrogen Removal ◽  
Anthropogenic Sources ◽  
Data Sets ◽  
Particle Removal ◽  
Biogeochemical Processes ◽  
Empirical Examination ◽  
Trade Offs ◽  
N Removal ◽  
Anthropogenic Nitrogen

Interest in use of bivalves to remediate estuarine eutrophication has increased in recent years. High variation among data sets, substantial focus on particle removal, and insufficient links to anthropogenic nitrogen (N) sources encouraged this empirical examination of N removal by bivalves from estuaries receiving different N loads. We determined the capacity of the oyster Crassostrea virginica to remove N by comparing N assimilated into tissues with anthropogenic N from land or available in phytoplankton. Oyster growth yielded 0.2–0.4 g N in tissues and depended on estuary-specific conditions. δ15N values confirmed that N in oyster tissues derived from local anthropogenic sources. At representative restoration and aquaculture conditions (≤400 oysters·m–2 at 0.5%–1.0% of estuary area), estimated N removal was ≤15% of land-derived loads and <1% of phytoplankton N. N removal via biogeochemical processes was negligible during grow-out, but became important after oysters attained harvestable size. This study explicitly demonstrates that oysters assimilated land-derived N, but suggests that bivalve bioremediation consider trade-offs between intensity of planting, ecological effects, and available space.

Habitat fragmentation causes collapse of kelp recruitment

2020 ◽  
Vol 648 ◽  
pp. 111-123
Author(s):  
C Layton ◽  
MJ Cameron ◽  
M Tatsumi ◽  
V Shelamoff ◽  
JT Wright ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Patch Size ◽  
Life Stage ◽  
Extended Period ◽  
Anthropogenic Disturbances ◽  
Anthropogenic Sources ◽  
Kelp Forests ◽  
Natural Disturbances ◽  
Short Term ◽  
Turf Algae

Kelp forests in many regions are experiencing disturbance from anthropogenic sources such as ocean warming, pollution, and overgrazing. Unlike natural disturbances such as storms, anthropogenic disturbances often manifest as press perturbations that cause persistent alterations to the environment. One consequence is that some kelp forests are becoming increasingly sparse and fragmented. We manipulated patch size of the kelp Ecklonia radiata over 24 mo to simulate persistent habitat fragmentation and assessed how this influenced the demography of macro- and microscopic juvenile kelp within the patches. At the beginning of the experiment, patch formation resulted in short-term increases in E. radiata recruitment in patches <1 m2. However, recruitment collapsed in those same patches over the extended period, with no recruits observed after 15 mo. Experimental transplants of microscopic and macroscopic juvenile sporophytes into the patches failed to identify the life stage impacted by the reductions in patch size, indicating that the effects may be subtle and require extended periods to manifest, and/or that another life stage is responsible. Abiotic measurements within the patches indicated that kelp were less able to engineer the sub-canopy environment in smaller patches. In particular, reduced shading of the sub-canopy in smaller patches was associated with proliferation of sediments and turf algae, which potentially contributed to the collapse of recruitment. We demonstrate the consequences of short- and longer-term degradation of E. radiata habitats and conclude that habitat fragmentation can lead to severe disruptions to kelp demography.

Interannual variability in oceanic biogeochemical processes inferred by inversion of atmospheric O2/N2and CO2data

Tellus B ◽  
2008 ◽  
Vol 60 (5) ◽  
Author(s):  
C. Rödenbeck ◽  
C. Le Quéré ◽  
M. Heimann ◽  
R. F. Keeling
Keyword(s):  
Interannual Variability ◽  
Biogeochemical Processes

VALORIZATION OF THE URBAN ENVIRONMENT OF SOUTH SERBIA FROM THE AIR QUALITY ASPECT

2018 ◽  
Vol 28 (4) ◽  
pp. 1329-1333
Author(s):  
Miodrag Šmelcerović
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Urban Environment ◽  
Pollution Sources ◽  
Anthropogenic Sources ◽  
Anthropogenic Factors ◽  
Limit Values ◽  
Cause And Effect ◽  
Sources Of Pollution

The protection of the environment and people’s health from negative influences of the pollution of air as a medium of the environment requires constant observing of the air quality in accordance with international standards, the analysis of emission and imission of polluting matters in the air, and their connection with the sources of pollution. Having in mind the series of laws and delegated legislations which define the field of air pollution, it is necessary to closely observe these long-term processes, discovering cause-and-effect relationships between the activities of anthropogenic sources of emission of polluting matters and the level of air degradation. The relevant evaluation of the air quality of a certain area can be conducted if the level of concentration of polluting matters characteristic for the pollution sources of this area is observed in a longer period of time. The data obtained by the observation of the air pollution are the basis for creation of the recovery program of a certain area. Vranje is a town in South Serbia where there is a bigger number of anthropogenic pollution sources that can significantly diminish the air quality. The cause-and-effect relationship of the anthropogenic sources of pollution is conducted related to the analysis of systematized data which are in the relevant data base of the authorized institution The Institute of Public Health Vranje, for the time period between the year of 2012. and 2017. By the analysis of data of imission concentrations of typical polluting matters, the dominant polluting matters were determined on the territory of the town of Vranje, the ones that are the causers of the biggest air pollution and the risk for people’s health. Analysis of the concentration of soot, sulfur dioxide and nitrogen oxides indicates their presence in the air of Vranje town area in concentrations that do not exceed the permitted limit values annually. The greatest pollution is caused by the soot content in the air, especially in the winter period when the highest number of days with the values above the limit was registered. By perceiving the influence of natural and anthropogenic factors, it is clear that the concentration of polluting matters can be decreased only by establishing control over anthropogenic sources of pollution, and thus it can be contributed to the improvement of the air quality of this urban environment.

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