scholarly journals Benthic algal biomass and assemblage changes following environmental flow releases and unregulated tributary flows downstream of a major storage

2014 ◽  
Vol 65 (12) ◽  
pp. 1059 ◽  
Author(s):  
Alec W. Davie ◽  
Simon M. Mitrovic
Keyword(s):  
Algal Biomass ◽  
Environmental Flows ◽  
Suspended Sediments ◽  
Environmental Flow ◽  
Filamentous Algae ◽  
Algal Succession ◽  
Before And After ◽  
Algal Assemblages ◽  
Large Dam ◽  
Flow Velocities

A large dam reducing the magnitude of flows regulates the Severn River, Australia. Environmental flows (EFs) are designed to increase the magnitude of flow and improve ecological outcomes such as reducing filamentous algal biomass and re-setting algal succession. The effectiveness of EF releases to alter benthic algal assemblages is poorly understood. We examined benthic algal biomass and assemblage structure at two cobble-dominated riffle sites downstream of Pindari Dam, before and after two EFs. Both EFs had discharges of ~11.6 m3 s–1 (velocity of ~0.9 m s–1). Neither EF reduced benthic algal biomass, and sometimes led to increases, with density of some filamentous algae increasing (Stigeoclonium and Leptolyngbya). An unregulated flow from a tributary between the two sites increased discharge to 25.2 m3 s–1 (velocity of ~1.2 m s–1), decreasing biomass and density of filamentous algae. The similarity in flow velocities between scouring and non-scouring events suggests that thresholds may exist and/or suspended sediments carried from unregulated tributaries may contribute to reduce algal biomass. Identifying velocities needed to reduce algal biomass are useful. Accordingly, EFs with flow velocities ~1.2 m s–1 may achieve this in river cobble-dominated riffle sections dominated by filamentous algae. Lower flow velocities of <0.9 m s–1 may result in no change or an increase in filamentous algae.

Intraoperative transesophageal assessment of coronary artery flow can predict 5 type myocardial infarction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Zagatina ◽  
M Novikov ◽  
N Zhuravskaya ◽  
V Balakhonov ◽  
S Efremov ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Surgery ◽  
Coronary Artery ◽  
Flow Velocity ◽  
Coronary Flow ◽  
Index Number ◽  
Left Main ◽  
Coronary Flow Velocity ◽  
Before And After ◽  
Flow Velocities

Abstract Background Stenosis of a coronary artery results in an increase in flow velocity in the pathologic segment. Effective grafting should decrease the stenotic native coronary velocity according to hemodynamic law. The range of decreased velocity before and after cardiac surgery can hypothetically reflect the effectiveness of a graft. The aim of the study is to determine if measuring coronary flow velocity changes during coronary artery bypass grafting (CABG) can predict intraoperative myocardial infarction. Methods One hundred sixty-six (166) consecutive patients (121 men, 64±9 years old) referred for cardiac surgery, were prospectively included in the study. A standard basic perioperative transesophageal echocardiography (TEE) examination was performed with additional scans of the left main, left anterior descending (LAD), and circumflex (LCx) arteries' proximal segments. Measurements of coronary flow velocities were performed before and after grafting in the same sites of the arteries. The maximal value of cardiac troponin I (cTnI) after CABG and the additive criteria were accounted for in the analysis as it is described in the expert consensus document for Type 5 myocardial infarction (MI) definition. Results One hundred sixty-three patients (98%) had arterial hypertension, 28 patients (17%) had diabetes mellitus, 35 patients (21%) were currently smokers. The feasibility of coronary flow assessment during cardiac operations was 95%. Before grafting, the mean velocity in the left main artery was 91±49 cm/s, in LAD 101±35 cm/s, and in LCx 117±49 cm/s. There was a significant correlation between changes in coronary flow velocities during operation and the value of cTnI (R=0.34, p&lt;0.0001). Ten patients met the criteria for Type 5 MI. There were no differences in age, body mass index, number of coronary arteries with stenoses, frequency of prior MI, ejection fraction or coronary flow velocity before surgery in patients with and without Type 5 MI. The group of patients with Type 5 MI had an increase in native artery velocities during surgery in comparison with patients without MI, who had a significant decrease in coronary flow velocity after grafting (30±48 vs. −10±30 cm/s; p&lt;0.0006). Increases in native coronary velocities greater than 3 cm/s predicted Type 5 MI with 81% accuracy (sensitivity 88%, specificity 70%). Conclusion Coronary flow velocity assessment during cardiac surgery could predict an elevation of cardiac troponins and Type 5 MI. Funding Acknowledgement Type of funding source: None

Respiratory variation of mitral and pulmonary venous doppler flow velocities in constrictive pericarditis before and after pericardiectomy

2001 ◽  
Vol 14 (11) ◽  
pp. 1119-1126 ◽  
Author(s):  
Jing Ping Sun ◽  
Ibrahim A. Abdalla ◽  
Xing Sheng Yang ◽  
Navin Rajagopalan ◽  
William J. Stewart ◽  
...  
Keyword(s):  
Constrictive Pericarditis ◽  
Respiratory Variation ◽  
Doppler Flow ◽  
Before And After ◽  
Flow Velocities

scholarly journals Response of the Snowy River Estuary to two environmental flows

2015 ◽  
Vol 127 (2) ◽  
pp. 28
Author(s):  
Errol J. McLean ◽  
Jon B. Hinwood
Keyword(s):  
Fresh Water ◽  
Peak Flow ◽  
Environmental Flows ◽  
River Estuary ◽  
Environmental Flow ◽  
River Channel ◽  
Salinity Gradients ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Major River

The Snowy River is a major river in south-eastern Australia, discharging to the Tasman Sea via a barrier estuary, with its entrance constricted by marine sands. Since the construction of the Snowy Mountains Scheme, river flows have not been sufficient to maintain the river channel. A program of environmental flow releases (EFR) is returning water to the river to restore the fluvial reaches and is now trialling flow regimes that may also benefit the estuarine reaches. This paper documents the response of the estuarine segments of the Snowy River to two EFRs; the release in 2010 was designed to scour the upper reaches of the Snowy River while the larger 2011 release was intended to extend the scouring downstream. For each release, the effects on the entrance morphology, tides and salinity through the flow peak and recovery are described. Each EFR caused minor increases in depth and very minor longshore movement of the entrance channel, although each EFR had been preceded by a larger fresh flow that would have scoured the channels. The small increase in fresh water inflow in the 2010 EFR pushed salinity contours seawards and steepened vertical salinity gradients. The larger inflow in the 2011 EFR purged the upper estuary of saltwater. After the peak flow, salinity recovery was rapid in the principal estuarine channels but took weeks where poorly connected wetlands could store fresh flood waters. Critical flows for scouring the entrance and purging salinity are estimated.

Application of Methodologies for Environmental Flow Determination in an Andean and a Mediterranean Basin

2013 ◽  
pp. 296-314
Author(s):  
Yesid Carvajal-Escobar ◽  
Ziad Mimi ◽  
Saed Khayat ◽  
Saleh Sulieman ◽  
Wilson Garces ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Significant Variation ◽  
Environmental Flows ◽  
Environmental Flow ◽  
Base Flow ◽  
Point Sources ◽  
Local Context ◽  
Mediterranean River ◽  
Hydrological Indices ◽  
Hydrological Parameter

The demand for sustainable water management has promoted the development of methodologies for estimating environmental flows (EF). In this paper, the EF in an Andean river (Pance, Colombia) for conservation and a Mediterranean river (Wadi-Zomar, Palestine) for restoration purposes is made. Different methodologies are applied given the objectives for each river. The authors used hydrological indices proposed for watersheds with different water regimes and adaptations and validations were made to the local context. These methods allow for estimating the EF at various points in the river and the assessment of disruption scenarios for decision-making. In the Wadi Zomar River, three sampling points were selected. The water samples were then examined for the presence of pathogens. No one indicator or simple hydrological parameter is entirely suitable for all environmental systems and pathogens. In the base flow conditions, the amount of pollutant load varied temporally according to the amount of load from point sources along the Wadi, and spatially with distance from the same sources. Significant variation was observed in response to the hydrological behavior of the catchment. The assessment for the water quality in the Zomar reflects a potentially serious threat to the environment. The results emphasize the need for regulating the seepage effluent from industries and sewage system along the stream.

Environmental Flows Legislation and Regulations in Foreign Countries and the Enlightenment to China

2013 ◽  
Vol 295-298 ◽  
pp. 2181-2186
Author(s):  
Chang Chun Chen ◽  
La Chun Wang ◽  
Xue Zhang Cao ◽  
Jie Song
Keyword(s):  
Water Demand ◽  
Aquatic Ecosystems ◽  
Environmental Flows ◽  
Environmental Flow ◽  
International Agreement ◽  
The Enlightenment ◽  
Foreign Countries ◽  
The World ◽  
Key Factor ◽  
Legislative Proposals

Environmental flow is a key factor to protect river ecological system, however, there is no international agreement concerned with environmental flows exclusively so far. This paper demonstrated the importance and urgency of environment water demand in the world and presented summary and analysis of environmental flows legislation and regulations. Europe and other countries have been investigated and compared systematically. At last, specialized legislative proposals were provided for protection of aquatic ecosystems and their environment in China.

The effects of water-level changes on periphytic algal assemblages in Poyang Lake

2020 ◽  
Author(s):  
Kuimei Qian ◽  
Martin Dokulil ◽  
Wan Lei ◽  
Yuwei Chen
Keyword(s):  
Water Level ◽  
Algal Biomass ◽  
Environmental Changes ◽  
Poyang Lake ◽  
Temporal Variations ◽  
Algal Community ◽  
Temperature Conductivity ◽  
Periphytic Algae ◽  
Water Level Changes ◽  
Algal Assemblages

Poyang Lake, which is the largest freshwater lake in China, has a seasonal flooding cycle that significantlychanges the water level every year. The aim of this study was to research the effects of water-level changeson periphytic algal assemblages in Poyang Lake. Dynamic shift of periphytic algal biomass were studied fromNovember 2016 to July 2019. Periphytic algal biomass and species composition were analyzed microscopically, andphysicochemical conditions were measured. There were significant seasonal variations in the community distributionof periphytic algae. The biomass of the periphyton ranged from 8 to 22,636 mg m-2. Periphytic algal biomassranged from 30 to 622 mg m-2 with the average of 204 mg m-2 in the LWL phase; periphytic algal biomass rangedfrom 8 to 21,839 mg m-2, with the average of 3,399 mg m-2 in the IWL phase. It ranged from 166 to 22,636 mgm-2, with the average 4,320 mg m-2 in the HWL phase and from 16 to 3,231 mg m-2 with the average of 585 mgm-2 in the DWL phase. There were temporal variations in periphytic algal community structure in Poyang Lake.Cryptophyceae dominated in algal periphyton from November 2016 to February 2017. Bacillariophyceae dominatedfrom March to July 2017 (increasing water-level phases). Pyrrophyceae and Euglenophyceae were dominant fromAugust and September (high-water-level phase) in 2017. Bacillariophyceae dominated through 2018 with occasionaldominance of Cryptophyceae from January to June and the occasional dominance of Chlorophyceae fromJuly to December. Chlorophyceae dominated from January to July in 2019 with occasional dominance of Bacillariophyceae.The water-level variations led to environmental heterogeneity in Poyang Lake, creating heterogeneoushabitats for algal periphyton. Our study revealed the primary importance of water level, water temperature, conductivity,total nitrogen, nitrite and total phosphorus as abiotic local factors structuring the periphytic algal communityin Poyang Lake. The water-level changes did not prevent growth of periphytic algae, but it did change the periphyticalgal community assemblages. This research provides data on the periphytic algae in Poyang Lake and will beuseful for establishing biological indicators of environmental changes and protecting Poyang Lake in the future.

scholarly journals From an irrigation system to an ecological asset: adding environmental flows establishes recovery of a threatened fish species

2019 ◽  
Vol 70 (9) ◽  
pp. 1295 ◽  
Author(s):  
Ivor Stuart ◽  
Clayton Sharpe ◽  
Kathryn Stanislawski ◽  
Anna Parker ◽  
Martin Mallen-Cooper
Keyword(s):  
Water Level ◽  
Fish Species ◽  
Life Histories ◽  
Environmental Flows ◽  
Irrigation System ◽  
Spatial Scales ◽  
Environmental Water ◽  
Environmental Flow ◽  
Murray Cod ◽  
Riverine Fish

Worldwide, riverine fish are the target of environmental water because populations have declined in lotic river habitats following river regulation. Murray cod is an endangered Australian riverine fish with remaining populations associated with lotic river reaches with instream habitat, including some creeks operated as part of irrigation systems. Our objectives were to develop a life history model, apply the building block method of environmental flows to enhance the abundance of juvenile Murray cod and promote population recovery. From 2008 to 2018 we evaluated changes to Murray cod juvenile abundance before and after implementation of a perennial environmental flow regime that began in 2013. During the first year of the environmental flow, larvae were collected as evidence of spawning. Murray cod abundance can be enhanced with environmental flows that target: (1) an annual spring spawning or recruitment flow with no rapid water level drops; (2) maximising hydrodynamic complexity (i.e. flowing habitats that are longitudinally continuous and hydrodynamically complex); and (3) an annual base winter connection flow. Recognition that incorporating hydraulics (water level and velocity) at fine and coarse time scales, over spatial scales that reflect life histories, provides broader opportunities to expand the scope of environmental flows to help restore imperilled fish species in regulated ecosystems.

Effect of Western the Fourth Phase Project on Hydrodynamic Condition for Shijiu Port in Rizhao

2012 ◽  
Vol 204-208 ◽  
pp. 2369-2373
Author(s):  
Jia Rui Li ◽  
Die Shuang Yu
Keyword(s):  
Channel Flow ◽  
Water Area ◽  
Main Channel ◽  
Hydrodynamic Condition ◽  
Port Area ◽  
Before And After ◽  
Project Construction ◽  
Sheltering Effect ◽  
Sea Area ◽  
Flow Velocities

A hydrodynamic model of Shijiu port and its adjacent sea area was built to discuss the effect of western the fourth phase project on the flow condition for Shijiu port area. The results show that with the sheltering effect of breakwaters, flow velocity values are small inside the breakwaters. The water area near the project is affected more by the project construction. The flow velocities there are faster after the project construction than before it. In the main channel, flow velocities outside the breakwaters almost have no difference before and after the project. The project construction doesn’t have significant effect on it.

scholarly journals Accounting for environmental flow requirements in global water assessments

2014 ◽  
Vol 18 (12) ◽  
pp. 5041-5059 ◽  
Author(s):  
A. V. Pastor ◽  
F. Ludwig ◽  
H. Biemans ◽  
H. Hoff ◽  
P. Kabat
Keyword(s):  
Flow Regime ◽  
Environmental Flows ◽  
Environmental Flow ◽  
Ecological Condition ◽  
Freshwater Ecosystems ◽  
Low Flow ◽  
Human Needs ◽  
High Flows ◽  
The Mean ◽  
Global Vegetation

Abstract. As the water requirement for food production and other human needs grows, quantification of environmental flow requirements (EFRs) is necessary to assess the amount of water needed to sustain freshwater ecosystems. EFRs are the result of the quantification of water necessary to sustain the riverine ecosystem, which is calculated from the mean of an environmental flow (EF) method. In this study, five EF methods for calculating EFRs were compared with 11 case studies of locally assessed EFRs. We used three existing methods (Smakhtin, Tennant, and Tessmann) and two newly developed methods (the variable monthly flow method (VMF) and the Q90_Q50 method). All methods were compared globally and validated at local scales while mimicking the natural flow regime. The VMF and the Tessmann methods use algorithms to classify the flow regime into high, intermediate, and low-flow months and they take into account intra-annual variability by allocating EFRs with a percentage of mean monthly flow (MMF). The Q90_Q50 method allocates annual flow quantiles (Q90 and Q50) depending on the flow season. The results showed that, on average, 37% of annual discharge was required to sustain environmental flow requirement. More water is needed for environmental flows during low-flow periods (46–71% of average low-flows) compared to high-flow periods (17–45% of average high-flows). Environmental flow requirements estimates from the Tennant, Q90_Q50, and Smakhtin methods were higher than the locally calculated EFRs for river systems with relatively stable flows and were lower than the locally calculated EFRs for rivers with variable flows. The VMF and Tessmann methods showed the highest correlation with the locally calculated EFRs (R2=0.91). The main difference between the Tessmann and VMF methods is that the Tessmann method allocates all water to EFRs in low-flow periods while the VMF method allocates 60% of the flow in low-flow periods. Thus, other water sectors such as irrigation can withdraw up to 40% of the flow during the low-flow season and freshwater ecosystems can still be kept in reasonable ecological condition. The global applicability of the five methods was tested using the global vegetation and the Lund-Potsdam-Jena managed land (LPJmL) hydrological model. The calculated global annual EFRs for fair ecological conditions represent between 25 and 46% of mean annual flow (MAF). Variable flow regimes, such as the Nile, have lower EFRs (ranging from 12 to 48% of MAF) than stable tropical regimes such as the Amazon (which has EFRs ranging from 30 to 67% of MAF).

scholarly journals Algal community composition within territories of the damselfish Stegastes nigricans (Pomacentridae, Labroidei) in Fiji and the Cook Islands

2005 ◽  
Vol 23 (1) ◽  
pp. 43 ◽  
Author(s):  
L W Zemke-White ◽  
E L Beatson
Keyword(s):  
Species Composition ◽  
Community Composition ◽  
Algal Species ◽  
Abundant Species ◽  
Red Alga ◽  
Algal Community ◽  
Filamentous Algae ◽  
Cook Islands ◽  
Algal Assemblages

The species composition of algal assemblages inside territories of the damselfish Stegastes nigricans was examined from Nananu-i-ra Island, Fiji and Rarotonga, Cook Islands. A total of 32 algal species were identified, the majority of them Rhodophytes (24 species). Seven species were unique to Rarotonga, six were unique to Fiji, with the remaining 19 species recorded at both locations. The biodiversity of territories was similar at both locations. The red alga, Herposiphonia secunda, was the most abundant species found, comprising 40.33% � 3.51SE and 33.94% � 3.58SE from Rarotonga and Fiji respectively. Gelidiopsis intricata, Polysiphonia sp., Aglaothamnion cordatum, and various Cyanophytes were also abundant at both locations. As a group, filamentous algae accounted for 70.35% of the algae found within the territories at all sites. We suggest that if S. nigricans are actively weeding their territories, they are selecting filamentous algae, and particularly Herposiphonia sp. and Polysiphonia sp.

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