scholarly journals Effects of anomalous high temperatures on carbon dioxide, methane, dissolved organic carbon and trace element concentrations in thaw lakes in Western Siberia in 2012

2013 ◽  
Vol 10 (4) ◽  
pp. 7257-7297 ◽  
Author(s):  
O. S. Pokrovsky ◽  
L. S. Shirokova ◽  
S. N. Kirpotin ◽  
S. P. Kulizhsky ◽  
S. N. Vorobiev

Abstract. During the anomalous hot summer in 2012, surface air temperatures in Western Siberia were 5 to 10 °C higher than those observed during the previous period of > 30 yr. This unusual climate phenomenon provided an opportunity to examine the effects of short-term natural heating of water in thermokarst ponds and lakes in discontinuous permafrost zones and compare these observations to previous field results obtained when the temperature was normal during the summer of 2010 in the same region. Thermokarst bodies of water shrank significantly, water levels dropped approximately 50 cm in large lakes and small (< 10–100 m2) ponds, and shallow soil depressions disappeared. Based on samples from ~ 40 bodies of water collected previously and in 2012, first-order features of changes in chemical composition in response to increased water temperatures (from 14.1 ± 2.2 to 23.8 ± 2.3 °C in 2010 and 2012, respectively) were established. In these thermokarst bodies of water that covered a full range of surface areas, the average conductivity and pH were almost unchanged, whereas dissolved organic carbon (DOC), Cl− and SO42− concentrations were higher by a factor of ~ 2 during summer 2012 compared to periods with normal temperatures. Similarly, most divalent metals and insoluble trivalent and tetravalent elements were more concentrated by a factor of 1.7–2.4 in the summer of 2012 than normal periods. The average concentrations of dissolved CO2 and CH4 during the hot summer of 2012 increased by factors of 1.4 and 4.9, respectively. For most of the trace elements bound to colloids, the degree of colloidal binding decreased by a factor of 1.44 ± 0.33 (for an average of 40 elements) during the hot summer of 2012 compared to normal periods. Increases in CO2 and CH4 concentrations with the decreasing size of the body of water were well-pronounced during the hot summer of 2012. The concentrations of CO2 and CH4 significantly increased by factors of 5 and 150, respectively, in small (≤ 102 m2) compared to large (≥ 104 m2) thermokarst (thaw) lakes. Taken together, these trends suggest that, for a conservative scenario of lake size distribution, lake water warming at high latitudes will produce (1) a significant increase in methane emission capacity from thaw lake surfaces; (2) decrease of molecular sizes of TE complexes and increase of potential bioavailability of metal micronutrients in water columns; and (3) relatively conservative responses by CO2, DOC and trace element concentrations.

2013 ◽  
Vol 10 (8) ◽  
pp. 5349-5365 ◽  
Author(s):  
O. S. Pokrovsky ◽  
L. S. Shirokova ◽  
S. N. Kirpotin ◽  
S. P. Kulizhsky ◽  
S. N. Vorobiev

Abstract. During the anomalously hot summer in 2012, surface air temperatures in Western Siberia were 5 to 15 °C higher than those observed during the previous period of > 30 yr. This unusual climate phenomenon provided an opportunity to examine the effects of short-term natural heating of water in thermokarst ponds and lakes in discontinuous permafrost zones and compare these observations to previous field results obtained when the temperature was normal during the summer of 2010 in the same region. In 2012, thermokarst bodies of water shrank significantly, water levels dropped approximately 50 cm in large lakes and small (< 10–100 m2) ponds, and shallow soil depressions disappeared. Based on samples from ~ 40 bodies of water collected previously and in 2012, first-order features of changes in chemical composition in response to increased water temperatures (from 14.1 ± 2.2 to 23.8 ± 2.3 °C in 2010 and 2012, respectively) were established. In these thermokarst bodies of water that covered a full range of surface areas, the average conductivity and pH were almost unchanged, whereas dissolved organic carbon (DOC), Cl- and SO42- concentrations were higher by a factor of ~ 2 during summer 2012 compared to periods with normal temperatures. Similarly, most divalent metals and insoluble trivalent and tetravalent elements were more concentrated by a factor of 1.7–2.4 in the summer of 2012 than normal periods. The average concentrations of dissolved CO2 and CH4 during the hot summer of 2012 increased by factors of 1.4 and 4.9, respectively. For most of the trace elements bound to colloids, the degree of colloidal binding decreased by a factor of 1.44 ± 0.33 (for an average of 40 elements) during the hot summer of 2012 compared to normal periods. Increases in CO2 and CH4 concentrations with the decreasing size of the body of water were well-pronounced during the hot summer of 2012. The concentrations of CO2 and CH4 rose by factors of 5 and 150, respectively, in small (≤ 102 m2) compared to large (≥ 104 m2) thermokarst (thaw) lakes. Taken together, these trends suggest that, for a conservative scenario of lake size distribution, lake water warming at high latitudes will produce (1) a significant increase in methane emission capacity from thaw lake surfaces; (2) decreased molecular sizes of trace element complexes and potential bioavailability of metal micronutrients in water columns; and (3) relatively conservative responses by CO2, DOC and trace element concentrations.


Author(s):  
Diana Flood

Migratory fish-eating birds occupy the highest trophic positions of aquatic ecosystems and as such serve as invaluable end-point indicators of the presence and bioaccumulation of anthropogenic contaminants. The birds’ main route of contaminant exposure is through food consumption. Migration can complicate this pathway by introducing numerous feeding habitats and thus, potential sources of contamination. Birds possess a number of depuration mechanisms that permit them to reduce their contaminant burden, namely the elimination of metals and mercury (Hg) through their feathers, feces and eggs. Trace element concentrations found in the feathers reflect the contaminants circulating in the body at the time of feather growth, representing local exposure and potential mobilization from internal tissues. Molt schedules and patterns are important considerations when selecting feathers to link feeding ecology with contaminants, as migratory birds’ feathers grow on and represent different sites. Stable nitrogen (δ15N) and carbon (δ13C) and hydrogen isotopes (δD) can reveal feeding ecology and habitat use during their annual cycle. Consequently, anthropogenic and natural sources of metal accumulation can be linked to those ecological variables. This study will examine the assimilation of trace element in male Caspian Tern (Sterna caspia) and Double-crested Cormorant (Phalacrocorax auritus) breast feathers grown on wintering sites and stable isotope signatures will be used to determine origin of contaminants. The aims for this study are to determine (i) whether isotopic signatures of feathers grown on wintering sites can explain variations in feather trace element concentrations, (ii) whether isotopes can determine the source of contamination, and (iii) whether differences in trace elements between individuals are determined by location of wintering ground or species.


2021 ◽  
Author(s):  
◽  
Monique Francis Holmes

<p>Heavy metals in the marine environment are a worldwide issue due to their toxicity, non-biodegradability and their ability to accumulate and magnify in organisms. Increased human activity has caused higher inputs of heavy metals, resulting in escalated pressures on delicate coastal ecosystems. A means of assessing the natural environment and how it is changing in response to pollution and other environmental degradation is through the use of biological indicator or biomonitor species. These organisms provide information on the bioavailability of metals present in the environment. In recent years amphipods, a diverse order of small crustaceans, have been increasingly used as bioindicators of disturbed aquatic communities. They are widespread and important components of many food webs, and likely to be frequently exposed to metal contamination through both sediment and seawater. The aim of this research was two-fold: 1) to use amphipods to examine variation across sites and species in concentration of 20+ trace elements and 2) to examine whether the uptake of two metals, copper (Cu) and neodymium (Nd), is mediated by the presence of the other metal or an elevated seawater temperature.  To investigate variation of trace element concentrations across sites, the amphipod Eusiroides monoculoides was collected from three sites in the Wellington region, approximately 5 km apart: Oriental Bay, Evans Bay and Point Halswell. To investigate differences amongst species comparisons were made between Eusiroides monoculoides, Apohyale papanuiensis and Sunamphitoe mixtura when they occurred at the same site. Analysing the trace element concentrations of 36 metals was done using an Inductively Coupled Mass Spectrometer (ICPMS). Overall, although these sites were not greatly distant from each other, there were differences among sites. Evans Bay in general had the highest concentration of trace elements. Further, there were also species-specific differences and S. mixtura was the species with the highest concentration of trace elements. There was also a size effect, where the average dry weight of S. mixtura was negatively related to the concentration of trace elements in the body.  To assess the effects of heavy metals Cu and Nd in both an ambient (14 °C) and elevated (20 °C) temperature, an experiment was run at Victoria University’s Coastal Ecology Lab (VUCEL). Sand hoppers, Bellorchestia quoyana, were collected from a single site in Wellington (Scorching Bay) and assigned to eight treatments: ambient and warm controls in raw seawater and ambient and warm seawater doped with Cu, Nd and Cu and Nd together. Amphipods from treatments with Cu and Nd added had significantly higher concentrations of these metals from the controls, however temperature had no effect, and neither was there an interaction between the metals. Similar to S. mixtura from the field study, dry weight of B. quoyana was negatively related to the concentration of trace elements in the body.  Results from this work demonstrate that when using amphipods as bioindicator species it is important to consider species and size specific effects. This thesis also provides baseline data for 20+ elements from three Wellington sites and demonstrates that there can be unexpected variation across relatively small spatial scales. The laboratory experiment did not yield results that coincided with the consensus of the literature. The experiment showed that at least in this case, temperature did not mediate the uptake of metals and there was a negative relationship between size and metal uptake.</p>


2017 ◽  
Author(s):  
Tatiana V. Raudina ◽  
Sergey V. Loiko ◽  
Artyom Lim ◽  
Ivan V. Krickov ◽  
Liudmila S. Shirokova ◽  
...  

Abstract. Mobilization of dissolved organic carbon (DOC) and related trace elements (TE) from the frozen peat to surface waters in the permafrost zone is one the major consequence of on-going permafrost thaw and active layer thickness (ALT) rise in high latitude regions. The interstitial soil solutions are efficient tracers of on-going bio-geochemical processes in the critical zone and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean. To this end, we collected, across a 640 km latitudinal transect of sporadic to continuous permafrost zone of western Siberia peatlands, soil porewaters from 30 cm depth using suction cups and we analyzed DOC, DIC and 40 major and TE in 0.45 µm filtered fraction of 80 soil porewaters. Despite an expected decrease of the intensity of DOC and TE mobilization from the soil and vegetation litter to the interstitial fluids with the increase of the permafrost coverage, decrease in the annual temperature and ALT, the DOC and many major and trace element did not exhibit any distinct decrease in concentration along the latitudinal transect from 62.2° N to 67.4° N. The DOC demonstrated a maximum of concentration at 66° N, on the border of discontinuous/continuous permafrost zone, whereas the DOC concentration in peat soil solutions from continuous permafrost zone was equal or higher than that in sporadic/discontinuous permafrost zone. Moreover, a number of major (Ca, Mg) and trace (Al, Ti, Sr, Ga, REEs, Zr, Hf, Th) elements exhibited an increasing, not decreasing northward concentration trend. We hypothesize that the effect of temperature and thickness of the ALT are of secondary importance relative to the leaching capacity of peat which is in turn controlled by the water saturation of the peat core. The water residence time in peat pores also plays a role in enriching the fluids in some elements: the DOC, V, Cu, Pb, REE, Th were a factor of 1.5 to 2.0 higher in mounds relative to hollows. As such, it is possible that the time of reaction between the peat and downward infiltrating waters essentially controls the degree of peat pore-water enrichments in DOC and other solutes. A two-degree northward shift in the position of the permafrost boundaries may bring about a factor of 1.3 decrease in Ca, Mg, Sr, Al, Fe, Ti, Mn, Ni, Co, V, Zr, Hf, Th and REE porewater concentration in continuous and discontinuous permafrost zones, and a possible decrease in DOC, SUVA, Ca, Mg, Fe and Sr will not exceed 20 % of their actual values. The projected increase of ALT and vegetation density, northward migration of the permafrost boundary, or the change of hydrological regime are unlikely to modify chemical composition of peat pore water fluids larger than their natural variations within different micro-landscapes, i.e., within a factor of 2.


Author(s):  
I. V. Fedorova ◽  
A. A. Chetverova ◽  
N. K. Alekseeva ◽  
T. V. Skorospekhova ◽  
S. G. Romanov ◽  
...  

The results of hydrological and hydrochemical research of on bodies of water: ducts and lakes of the delta of the Lena River are reported here. Studies were performed during the 2015/16 summer (July-August) and winter (April) expeditionary seasons. The present work also introduces the results of field hydrochemical analyzes made immediately after sampling. The values of hydrochemical and hydrophysical indicators of ducts and lakes such as electrical conductivity, pH, permanganate oxidability, concentration of dissolved organic carbon, water color and absorption of colored organic matter were received. This obtained values supplemented significantly the available information on the delta water bodies in winter.


2021 ◽  
Author(s):  
◽  
Monique Francis Holmes

<p>Heavy metals in the marine environment are a worldwide issue due to their toxicity, non-biodegradability and their ability to accumulate and magnify in organisms. Increased human activity has caused higher inputs of heavy metals, resulting in escalated pressures on delicate coastal ecosystems. A means of assessing the natural environment and how it is changing in response to pollution and other environmental degradation is through the use of biological indicator or biomonitor species. These organisms provide information on the bioavailability of metals present in the environment. In recent years amphipods, a diverse order of small crustaceans, have been increasingly used as bioindicators of disturbed aquatic communities. They are widespread and important components of many food webs, and likely to be frequently exposed to metal contamination through both sediment and seawater. The aim of this research was two-fold: 1) to use amphipods to examine variation across sites and species in concentration of 20+ trace elements and 2) to examine whether the uptake of two metals, copper (Cu) and neodymium (Nd), is mediated by the presence of the other metal or an elevated seawater temperature.  To investigate variation of trace element concentrations across sites, the amphipod Eusiroides monoculoides was collected from three sites in the Wellington region, approximately 5 km apart: Oriental Bay, Evans Bay and Point Halswell. To investigate differences amongst species comparisons were made between Eusiroides monoculoides, Apohyale papanuiensis and Sunamphitoe mixtura when they occurred at the same site. Analysing the trace element concentrations of 36 metals was done using an Inductively Coupled Mass Spectrometer (ICPMS). Overall, although these sites were not greatly distant from each other, there were differences among sites. Evans Bay in general had the highest concentration of trace elements. Further, there were also species-specific differences and S. mixtura was the species with the highest concentration of trace elements. There was also a size effect, where the average dry weight of S. mixtura was negatively related to the concentration of trace elements in the body.  To assess the effects of heavy metals Cu and Nd in both an ambient (14 °C) and elevated (20 °C) temperature, an experiment was run at Victoria University’s Coastal Ecology Lab (VUCEL). Sand hoppers, Bellorchestia quoyana, were collected from a single site in Wellington (Scorching Bay) and assigned to eight treatments: ambient and warm controls in raw seawater and ambient and warm seawater doped with Cu, Nd and Cu and Nd together. Amphipods from treatments with Cu and Nd added had significantly higher concentrations of these metals from the controls, however temperature had no effect, and neither was there an interaction between the metals. Similar to S. mixtura from the field study, dry weight of B. quoyana was negatively related to the concentration of trace elements in the body.  Results from this work demonstrate that when using amphipods as bioindicator species it is important to consider species and size specific effects. This thesis also provides baseline data for 20+ elements from three Wellington sites and demonstrates that there can be unexpected variation across relatively small spatial scales. The laboratory experiment did not yield results that coincided with the consensus of the literature. The experiment showed that at least in this case, temperature did not mediate the uptake of metals and there was a negative relationship between size and metal uptake.</p>


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