Using lake sediment P records to estimate internal and external P loading and historic long-term lake water mean TP: a case study using published records from Søbygaard Sø, Denmark.

2021 ◽  
Author(s):  
John Boyle ◽  
Maddy Moyle
Keyword(s):  
Lake Sediment ◽  
Lake Water ◽  
Balance Model ◽  
Sediment Record ◽  
Internal P Loading ◽  
A Site ◽  
External P Loading ◽  
Modelling Approach

<p>Lake sediment records offer the opportunity to quantify past changes in catchment P exports, information essential if we are to understand the long-term drivers that control P cycling. However, the interpretation of such records generally depends on the assumption that sediment P concentration profiles remain intact after burial. This assumption appears to be in conflict with the phenomenon of internal P loading, whereby P is exported from sediment to the water column. Here we apply a simple long-term mass balance model to published sediment record data from Søbygaard, a site that has an exceptionally high internal P loading, and an exceptionally well-studied sediment P record (Søndergaard and Jeppesen, 2019). Repeat cores collected from 1985 to 2004 constrain the temporal evolution of a sediment P peak arising from past sewage inflows, providing a critical test of our modelling approach. We find that useful sediment inference of long-term mean lake water TP is preserved in the sediment record, and predict also useful inference of long-term mean external P loading. Limitation on temporal resolution of the records is examined.</p>

Investigation of a New Approach to Predict Water Quality Extremes with a Case Study of Chemical Determinands in Stream Water

1991 ◽  
Vol 24 (6) ◽  
pp. 25-33
Author(s):  
A. J. Jakeman ◽  
P. G. Whitehead ◽  
A. Robson ◽  
J. A. Taylor ◽  
J. Bai
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Probability Distributions ◽  
Management Strategies ◽  
Hybrid Modelling ◽  
Trend Model ◽  
Environmental Extremes ◽  
Modelling Approach

The paper illustrates analysis of the assumptions of the statistical component of a hybrid modelling approach for predicting environmental extremes. This shows how to assess the applicability of the approach to water quality problems. The analysis involves data on stream acidity from the Birkenes catchment in Norway. The modelling approach is hybrid in that it uses: (1) a deterministic or process-based description to simulate (non-stationary) long term trend values of environmental variables, and (2) probability distributions which are superimposed on the trend values to characterise the frequency of shorter term concentrations. This permits assessment of management strategies and of sensitivity to climate variables by adjusting the values of major forcing variables in the trend model. Knowledge of the variability about the trend is provided by: (a) identification of an appropriate parametric form of the probability density function (pdf) of the environmental attribute (e.g. stream acidity variables) whose extremes are of interest, and (b) estimation of pdf parameters using the output of the trend model.

Using a lake sediment record to infer the long-term history of cyanobacteria and the recent rise of an anatoxin producing Dolichospermum sp.

Harmful Algae ◽  
2021 ◽  
Vol 101 ◽  
pp. 101971
Author(s):  
William O. Hobbs ◽  
Theo W. Dreher ◽  
Edward W. Davis ◽  
Rolf D. Vinebrooke ◽  
Siana Wong ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Sediment Record ◽  
History Of

Towards a history of Holocene P dynamics for the Northern Hemisphere using lake sediment geochemical records

2021 ◽  
Author(s):  
Madeleine Moyle ◽  
John Boyle ◽  
Richard Chiverrell
Keyword(s):  
Human Impact ◽  
Lake Sediment ◽  
Northern Hemisphere ◽  
Human Activity ◽  
Lake Water ◽  
Process Model ◽  
P Cycling ◽  
History Of ◽  
P Supply

<p>Present day phosphorus (P) enrichment and accelerated P cycling are changes superimposed on a dynamic Holocene history of landscape recovery from glaciation, changes in climate, and long-term low-intensity human activity. Knowledge of the changing role of human activity in driving long-term P dynamics is essential for understanding landscape P export and managing both terrestrial and aquatic environments.</p><p>Here we apply a simple process model to published lake sediment geochemical P records from 24 sites distributed across the Northern Hemisphere, producing Holocene records of landscape P yield and reconstructions of lake water TP concentrations. These records are a first attempt to produce values for average P export for the Northern Hemisphere over the Holocene, which can be used for constraining long-term landscape P cycling models.</p><p>Individual site trajectories of reconstructed Holocene landscape P yield and lake water TP varied systematically, with differences attributable to landscape development history, in turn driven by climate, human impact and other local factors. Three distinct traits are apparent across the records. Mountain sites with minimal direct human impact show falling Holocene P supply, and conform to conceptual models of natural soil development (Trait 1). Lowland sites  where substantial (pre-)historic agriculture was present show progressively increasing Holocene P supply (Trait 2). Lowland sites may also show a rapid acceleration in P supply over the last few centuries, where high intensity land use, including settlements and farming, are present (Trait 3).</p><p>This long-term perspective is pivotal to understanding drivers of change in coupled terrestrial and aquatic P cycling. Our reconstructions of long-term lake water TP are particularly useful for target-driven management of aquatic systems.</p>

scholarly journals Energy Monitoring in the Wild: Platform Development and Lessons Learned from a Real-World Demonstrator

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5786
Author(s):  
Filipe Quintal ◽  
Daniel Garigali ◽  
Dino Vasconcelos ◽  
Jonathan Cavaleiro ◽  
Wilson Santos ◽  
...  
Keyword(s):  
Real World ◽  
Lessons Learned ◽  
Long Term Study ◽  
Consumption Data ◽  
Custom Made ◽  
In The Wild ◽  
Platform Development ◽  
A Site

This paper presents the development and evaluation of EnnerSpectrum, a platform for electricity monitoring. The development was motivated by a gap between academic, fully custom-made monitoring solutions and commercial proprietary monitoring approaches. EnnerSpectrum is composed of two main entities, the back end, and the Gateway. The back end is a server comprised of flexible entities that can be configured to different monitoring scenarios. The Gateway interacts with equipment at a site that cannot interact directly with the back end. The paper presents the architecture and configuration of EnnerSpectrum for a long-term case study with 13 prosumers of electricity for approximately 36 months. During this period, the proposed system was able to adapt to several building and monitoring conditions while acquiring 95% of all the available consumption data. To finalize, the paper presents a set of lessons learned from running such a long-term study in the real world.

scholarly journals Comparison Between Two Methods for Estimating the Vertical Scale of Fluctuation for Modeling Random Geotechnical Problems

2015 ◽  
Vol 37 (4) ◽  
pp. 95-103 ◽  
Author(s):  
Joanna M. Pieczyńska-Kozłowska
Keyword(s):  
Geotechnical Engineering ◽  
Soil Parameters ◽  
Penetration Test ◽  
Cone Penetration ◽  
Vertical Scale ◽  
Scale Of Fluctuation ◽  
A Site ◽  
Geotechnical Problems

Abstract The design process in geotechnical engineering requires the most accurate mapping of soil. The difficulty lies in the spatial variability of soil parameters, which has been a site of investigation of many researches for many years. This study analyses the soil-modeling problem by suggesting two effective methods of acquiring information for modeling that consists of variability from cone penetration test (CPT). The first method has been used in geotechnical engineering, but the second one has not been associated with geotechnics so far. Both methods are applied to a case study in which the parameters of changes are estimated. The knowledge of the variability of parameters allows in a long term more effective estimation, for example, bearing capacity probability of failure.

scholarly journals Acoustic Monitoring of a Bottlenose Dolphin (Tursiops truncatus) Population: Trends in Presence and Foraging beyond the Limits of the Lower River Shannon SAC

2021 ◽  
Vol 9 (6) ◽  
pp. 650
Author(s):  
Rachel Charish ◽  
Simon Berrow ◽  
Joanne O’Brien
Keyword(s):  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Environmental Predictors ◽  
Discrete Population ◽  
A Site ◽  
Glm Modelling ◽  
Important Habitat ◽  
Modelling Approach

The Shannon dolphins are a population of bottlenose dolphins resident year round within the Lower River Shannon SAC, Ireland, which has been designated to protect this relatively small, genetically discrete population. Although trends in habitat use and foraging have been studied within the estuary, little is known about the movements of the Shannon dolphins outside the boundaries of the SAC, and whether any other foraging hotspots exist for this population outside of the estuary. The purpose of this study was to explore the presence and foraging behavior of these dolphins in adjacent waters located 20–30 km to the southwest of the Lower River Shannon SAC. Static acoustic monitoring was carried out with C-PODs deployed in Ballyheigue Bay, Brandon Bay, and around the Maharees between May and November 2013. A GEE-GLM modelling approach was then used to analyze potential significant environmental predictors of presence and foraging by bottlenose dolphins at these sites. Brandon Bay was found to be a site of particular importance for the Shannon population, where dolphins were present on 92% of days monitored and foraging occurring on 20% of all monitored hours. The results of this study indicate that Brandon Bay is a potentially important habitat for the Shannon dolphins and further support designation of this site as a candidate SAC. However, long-term acoustic monitoring should be conducted at all sites to identify relative use of the areas at year-round and inter-annual scales.

scholarly journals Towards a history of Holocene P dynamics for the Northern Hemisphere using lake sediment geochemical records

2021 ◽  
Vol 18 (20) ◽  
pp. 5609-5638
Author(s):  
Madeleine Moyle ◽  
John F. Boyle ◽  
Richard C. Chiverrell
Keyword(s):  
Lake Sediment ◽  
Northern Hemisphere ◽  
Lake Water ◽  
Landscape Development ◽  
Development History ◽  
P Cycling ◽  
Sediment Records ◽  
History Of ◽  
P Supply

Abstract. Present-day lake water phosphorus (P) enrichment and accelerated P cycling are changes superimposed on a dynamic Holocene history of landscape development following glaciation, changes in climate, and long-term low-intensity human activity. Knowledge of the history of long-term P dynamics is essential for understanding present-day landscape P export and for managing both terrestrial and aquatic environments. This study is the first attempt to constrain the timing and magnitude of terrestrial changes in Holocene P dynamics across the Northern Hemisphere using lake sediment records. Here we reconstruct trajectories in terrestrial Holocene P dynamics for the Northern Hemisphere. We apply a simple process model to published lake sediment geochemical P records from 24 sites, producing records of landscape P yield and reconstructing lake water total phosphorus (TP) concentrations. Individual site trajectories of landscape P yield and lake water TP vary systematically, with differences attributable to local landscape development history. Three distinct traits are apparent. Mountain sites with minimal direct human impact show falling P supply and conform to conceptual models of natural soil development (Trait 1). Lowland sites where substantial (pre-)historic agriculture was present show progressively increasing P supply (Trait 2). Lowland sites may also show a rapid acceleration in P supply over the last few centuries, where high-intensity land use, including settlements and farming, is present (Trait 3). Where data availability permitted comparison, our reconstructed TP records agree well with monitored lake water TP data, and our sediment-inferred P yields are comparable to reported catchment export coefficients. Comparison with diatom-inferred TP reveals good agreement for recent records. Our reconstructions form the first systematic assessment of average terrestrial P export for the Northern Hemisphere over the Holocene and provide the empirical data needed for constraining long-term landscape P cycling models and values for terrestrial P export that could be used for ocean P cycling models. The long-term perspective provided by our sediment-inferred TP can be used to identify pre-disturbance baselines for lake water quality, information essential to target-driven lake management. We find the first detectable anthropogenic impacts on P cycling ca. 6000 BP, with more substantial impacts as early as 3000 BP. Consequently, to characterize pre-disturbance lake P conditions at Trait 2 and Trait 3 sites, it is necessary to consider time periods before the arrival of early farmers. Our use of trait classifications has a predictive power for sites without sediment records, allowing prediction of TP baselines and P trajectories based on regional landscape development history.

scholarly journals Appropriate resolution timescale to evaluate water saving and retention potential of rainwater harvesting for toilet flushing in single houses

2015 ◽  
Vol 17 (3) ◽  
pp. 331-346 ◽  
Author(s):  
Alberto Campisano ◽  
Carlo Modica
Keyword(s):  
Water Demand ◽  
Rainwater Harvesting ◽  
Water Saving ◽  
Balance Model ◽  
Time Step ◽  
Retention Efficiency ◽  
Daily Scale ◽  
Tank Water

The main objective of the paper is to identify the appropriate temporal scale for modeling the behavior of rainwater harvesting tanks in relation to the purpose they are built for, i.e., water saving, stormwater retention potential, etc. A tank water balance model coupled with a specific procedure to determine long-term series of rainfall (tank inflow) and toilet flushes (tank outflow) at different daily and sub-daily resolution timescales was developed. The model was applied to a household case study for which detailed water demand data are available from measurements. Simulations show that the daily scale may be reliably chosen to evaluate the tank water saving efficiency. In contrast, sub-daily resolutions (at least the hourly time step) are needed for the evaluation of the tank retention efficiency to limit inaccuracies, especially for small tanks and for high values of the water demand. Moreover, preliminary results at the 5 min time step show that rainwater tanks can help in reducing the rainfall intensity peak, basically depending on the tank storage and on the rainfall event characteristics.

Experimenting in Somalia: The new security empire

2017 ◽  
Vol 17 (3) ◽  
pp. 404-420 ◽  
Author(s):  
Catherine Besteman
Keyword(s):  
State Government ◽  
The State ◽  
Territorial State ◽  
The Past ◽  
The Us ◽  
A Site ◽  
Us Intervention ◽  
Security Regimes

The past several decades of US intervention in Somalia produced violent destabilization, dysfunction, and uncertainty, creating refugee outflows and terrorist networks against which the US is currently tightening its security cordons. This paper argues that Somalia’s recent history as a stateless region offers a cautionary and tragic case study of the long-term damages that ensue when wealthy states that intervene in poorer states in the name of their own security instead cause insecurity and inequities that enable violence, and then in response to that violence enact further securitization to protect themselves against the consequences of that damage. But rather than focusing on the state as a site of securitization, I focus on those whose lives are made insecure by the retreat of their state government and the imposition in its place of security regimes that are not created by their own state government. Such security regimes overlap and compete, are instituted by different state and nonstate actors for different purposes, and by their incoherence and multiplicity raise questions about the definition, location, and relevance of the state in such regions. The paper explores the emergence of new, interlinked security regimes that are partially or wholly constituted through the logics of a new security empire designed to respond to US security concerns. By turning attention to the situations faced by those who live within the insecurities of stateless regions, the paper asks, what happens to the concept of securitization when the national-territorial state is not the entity that operates as a ‘state’ in the lives of people, even though their lives are overlain with multiple and overlapping regimes of securitization?

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