Detecting long-term temporal trends in sediment-bound trace metals from urbanised catchments

2016 ◽  
Vol 219 ◽  
pp. 705-713 ◽  
Author(s):  
David J. Sharley ◽  
Simon M. Sharp ◽  
Sophie Bourgues ◽  
Vincent J. Pettigrove
Keyword(s):  
Trace Metals ◽  
Temporal Trends ◽  
Urbanised Catchments

scholarly journals Long term patterns in dissolved organic carbon, major elements and trace metals in boreal headwater catchments: trends, mechanisms and heterogeneity

2012 ◽  
Vol 9 (12) ◽  
pp. 19121-19163 ◽  
Author(s):  
S. K. Oni ◽  
M. N. Futter ◽  
K. Bishop ◽  
S. J. Köhler ◽  
M. Ottosson-Löfvenius ◽  
...  
Keyword(s):  
Water Quality ◽  
Trace Metals ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Temporal Trends ◽  
Control Surface ◽  
Surface Water Hydrology ◽  
Organic Carbon Concentration ◽  
Increasing Trend

Abstract. The boreal landscape is a complex, spatio-temporally varying mosaic of forest and mire landscape elements that control surface water hydrology and chemistry. Here, we assess long-term water quality time-series from three nested headwater streams draining upland forest (C2), peat/mire (C4) and mixed (C7) (forest and mire) catchments. Temporal trends in weather and runoff (1981–2008); dissolved organic carbon concentration [DOC] (1993–2010) and other water quality parameters (1987–2011) were assessed. There was no significant annual trend in precipitation or runoff but a significant monotonic increasing trend existed in air temperature and length of growing season. Stream [DOC] was positively correlated with some trace metals (copper, iron and zinc) and negatively with several other chemical parameters (e.g. sulfate, conductivity, calcium). Both sulfate and conductivity showed declining trends, while a significant increase was observed in pH during winter and spring. Calcium and magnesium showed monotonic decreasing trends. The declining trajectories of stream base cation and sulfate concentrations during other times of the year were not accompanied by changes in pH and alkalinity. Water temperature increased significantly both annually and in most months while iron and DOC concentrations showed significant increases in autumn months. Though all streams showed significant positive trends in [DOC] in autumn, only C2 had a significant annual increasing trend. There was also a shift in the magnitude of variability in spring [DOC] and increasing trend of summer baseflow [DOC] in C2 and C7.

scholarly journals Long-term patterns in dissolved organic carbon, major elements and trace metals in boreal headwater catchments: trends, mechanisms and heterogeneity

2013 ◽  
Vol 10 (4) ◽  
pp. 2315-2330 ◽  
Author(s):  
S. K. Oni ◽  
M. N. Futter ◽  
K. Bishop ◽  
S. J. Köhler ◽  
M. Ottosson-Löfvenius ◽  
...  
Keyword(s):  
Water Quality ◽  
Trace Metals ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Temporal Trends ◽  
Monotonic Increase ◽  
Surface Water Hydrology ◽  
Organic Carbon Concentration ◽  
Recovery From Acidification

Abstract. The boreal landscape is a complex, spatio-temporally varying mosaic of forest and mire landscape elements that control surface water hydrology and chemistry. Here, we assess long-term water quality time series from three nested headwater streams draining upland forest (C2), peat/mire (C4) and mixed (C7) (forest and mire) catchments. Acid deposition in this region is low and is further declining. Temporal trends in weather and runoff (1981–2008), dissolved organic carbon concentration [DOC] (1993–2010) and other water quality parameters (1987–2011) were assessed. There was no significant annual trend in precipitation or runoff. However, runoff increased in March and declined in May. This suggested an earlier snowmelt regime in recent years. Significant monotonic increasing trends in air temperature and length of growing season suggested a decrease in snowfall and less spring runoff. Stream [DOC] was positively correlated with some trace metals (copper, iron and zinc) and negatively with several other chemical parameters (e.g. sulfate, conductivity, calcium). Both sulfate and conductivity showed declining trends, while a significant increase was observed in pH during winter and spring. Calcium and magnesium showed monotonic decreasing trends. The declining trajectories of stream base cation and sulfate concentrations during other times of the year were not accompanied by changes in pH and alkalinity. These results indicate subtle effects of recovery from acidification. Water temperature increased significantly both annually and in most months. A simultaneous monotonic increase in iron (Fe) and [DOC] in autumn suggests co-transport of Fe-DOC in the form of organometallic complexes. A monotonic increase in UV absorbance in most months without co-occurring changes in DOC trend suggests a shift in DOC quality to a more humic-rich type. The observed increase in soil solution [DOC] and subtle trends in stream [DOC] suggest that climate rather than recovery from acidification is the dominant driver of DOC trends in the Svartberget catchment.

scholarly journals Linking population size structure, heat stress and bleaching responses in a subtropical endemic coral

Coral Reefs ◽  
2021 ◽  
Author(s):  
Liam Lachs ◽  
Brigitte Sommer ◽  
James Cant ◽  
Jessica M. Hodge ◽  
Hamish A. Malcolm ◽  
...  
Keyword(s):  
Heat Stress ◽  
Size Structure ◽  
Temporal Trends ◽  
Early Recovery ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Community Organisation ◽  
Size Frequency ◽  
Eastern Australia

AbstractAnthropocene coral reefs are faced with increasingly severe marine heatwaves and mass coral bleaching mortality events. The ensuing demographic changes to coral assemblages can have long-term impacts on reef community organisation. Thus, understanding the dynamics of subtropical scleractinian coral populations is essential to predict their recovery or extinction post-disturbance. Here we present a 10-yr demographic assessment of a subtropical endemic coral, Pocillopora aliciae (Schmidt-Roach et al. in Zootaxa 3626:576–582, 2013) from the Solitary Islands Marine Park, eastern Australia, paired with long-term temperature records. These coral populations are regularly affected by storms, undergo seasonal thermal variability, and are increasingly impacted by severe marine heatwaves. We examined the demographic processes governing the persistence of these populations using inference from size-frequency distributions based on log-transformed planar area measurements of 7196 coral colonies. Specifically, the size-frequency distribution mean, coefficient of variation, skewness, kurtosis, and coral density were applied to describe population dynamics. Generalised Linear Mixed Effects Models were used to determine temporal trends and test demographic responses to heat stress. Temporal variation in size-frequency distributions revealed various population processes, from recruitment pulses and cohort growth, to bleaching impacts and temperature dependencies. Sporadic recruitment pulses likely support population persistence, illustrated in 2010 by strong positively skewed size-frequency distributions and the highest density of juvenile corals measured during the study. Increasing mean colony size over the following 6 yr indicates further cohort growth of these recruits. Severe heat stress in 2016 resulted in mass bleaching mortality and a 51% decline in coral density. Moderate heat stress in the following years was associated with suppressed P. aliciae recruitment and a lack of early recovery, marked by an exponential decrease of juvenile density (i.e. recruitment) with increasing heat stress. Here, population reliance on sporadic recruitment and susceptibility to heat stress underpin the vulnerability of subtropical coral assemblages to climate change.

scholarly journals Studies of insect temporal trends must account for the complex sampling histories inherent to many long-term monitoring efforts

2021 ◽  
Author(s):  
Ellen A. R. Welti ◽  
Anthony Joern ◽  
Aaron M. Ellison ◽  
David C. Lightfoot ◽  
Sydne Record ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Complex Sampling ◽  
Long Term Monitoring ◽  
Term Monitoring

scholarly journals Long-Term Temporal Trends of Polychlorinated Biphenyls and Their Controlling Sources in China

2017 ◽  
Vol 51 (5) ◽  
pp. 2838-2845 ◽  
Author(s):  
Shizhen Zhao ◽  
Knut Breivik ◽  
Guorui Liu ◽  
Minghui Zheng ◽  
Kevin C. Jones ◽  
...  
Keyword(s):  
Polychlorinated Biphenyls ◽  
Temporal Trends

Temporal trends in pulmonary arterial hypertension: Results from the COMPERA registry

2021 ◽  
pp. 2102024
Author(s):  
Marius M. Hoeper ◽  
Christine Pausch ◽  
Ekkehard Grünig ◽  
Gerd Staehler ◽  
Doerte Huscher ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Combination Therapy ◽  
Arterial Hypertension ◽  
Temporal Trends ◽  
Survival Rates ◽  
Term Survival ◽  
Pulmonary Arterial ◽  
Early Combination Therapy

BackgroundSince 2015, the European pulmonary hypertension guidelines recommend the use of combination therapy in most patients with pulmonary arterial hypertension (PAH). However, it is unclear to what extend this treatment strategy is adopted in clinical practice and if it is associated with improved long-term survival.MethodsWe analysed data from COMPERA, a large European pulmonary hypertension registry, to assess temporal trends in the use of combination therapy and survival of patients with newly diagnosed PAH between 2010 and 2019. For survival analyses, we look at annualized data and at cumulated data comparing the periods 2010–2014 and 2015–2019.ResultsA total of 2,531 patients were included. The use of early combination therapy (within 3 months after diagnosis) increased from 10.0% in patients diagnosed with PAH in 2010 to 25.0% in patients diagnosed with PAH in 2019. The proportion of patients receiving combination therapy 1 year after diagnosis increased from 27.7% to 46.3%. When comparing the 2010–2014 and 2015–2019 periods, 1-year survival estimates were similar (89.0% [95% CI, 87.2%, 90.9%] and 90.8% [95% CI, 89.3%, 92.4%]), respectively, whereas there was a slight but non-significant improvement in 3-year survival estimates (67.8% [95% CI, 65.0%, 70.8%] and 70.5% [95% CI, 67.8%, 73.4%]), respectively.ConclusionsThe use of combination therapy increased from 2010 to 2019, but most patients still received monotherapy. Survival rates at 1 year after diagnosis did not change over time. Future studies need to determine if the observed trend suggesting improved 3-year survival rates can be confirmed.

Effects of Long-Term Application of Biosolids for Mine Land Reclamation on Groundwater Chemistry: Trace Metals

2012 ◽  
Vol 41 (5) ◽  
pp. 1445-1451 ◽  
Author(s):  
Olawale O. Oladeji ◽  
Guanglong Tian ◽  
Albert E. Cox ◽  
Thomas C. Granato ◽  
Richard I. Pietz ◽  
...  
Keyword(s):  
Trace Metals ◽  
Land Reclamation ◽  
Groundwater Chemistry

scholarly journals Trends in urban storm water quality in Tallinn and influences from stormflow and baseflow

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Bharat Maharjan ◽  
Karin Pachel ◽  
Enn Loigu
Keyword(s):  
Temporal Trends ◽  
Oxygen Demand ◽  
Road Dust ◽  
Kendall Test ◽  
P Value ◽  
Upward Trend ◽  
Monotonic Trend ◽  
Acidic Rain ◽  
Interpretation Of Change

Temporal trends provide a good interpretation of change in stormwater quality over time. This study aimed to analyse trends and influences due to stormflow and baseflow. Grab samples of 18-19 years from 1995 to 2014 recorded at outlets of 7 Tallinn watersheds were analysed for monotonic trend through seasonal Mann Kendall test for long-term, short-term, baseflow and stormflow. Statistically significant downward trends (P-value (p) < 0.05) were found for 6 – hydrocarbon (HC), 1 – suspended solids (SS), 3 – biological oxygen demand (BOD), 4 – total nitrogen (TN) and 2 – total phosphorus (TP) out of 7 sampling outlets over the last 10 years. Less significant decreasing trends (p > 0.05 and < 0.2) for 3 – SS, 1 – BOD, 1 – TN and 1 – TP were identified. Statistically significant long-term upward trends of pH were re-vealed in 5 basins, which reduced to 2 with 5 less significant upward trends over the 10 year period, indicating improve-ments in pH reduction. Härjapea has the highest pH without trend but it includes an upward trend of TN at p = 0.051. The highly possible causes for downward trends are street sweeping, sewer network improvement, decline in sub-urban agri-cultural areas, etc. The upward trend results of pH are related to increased alkalinisation due to acidic rain, weathering of carbonate rocks, sewage discharge and alkaline road dust. In most of the basins, stormflow has more influence on trends than baseflow.

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