scholarly journals Modulation of nearshore harmful algal blooms by in situ growth rate and water renewal

2007 ◽  
Vol 352 ◽  
pp. 53-65 ◽  
Author(s):  
G Basterretxea ◽  
E Garcés ◽  
A Jordi ◽  
S Anglès ◽  
M Masó
Keyword(s):  
Growth Rate ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
In Situ Growth ◽  
Water Renewal

scholarly journals Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1409
Author(s):  
Hamdhani Hamdhani ◽  
Drew E. Eppehimer ◽  
David Walker ◽  
Michael T. Bogan
Keyword(s):  
Chlorophyll A ◽  
Surface Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Water Quality Monitoring ◽  
Ambient Light ◽  
Calibration Equation ◽  
Field Samples ◽  
Potential Use

Chlorophyll-a measurements are an important factor in the water quality monitoring of surface waters, especially for determining the trophic status and ecosystem management. However, a collection of field samples for extractive analysis in a laboratory may not fully represent the field conditions. Handheld fluorometers that can measure chlorophyll-a in situ are available, but their performance in waters with a variety of potential light-interfering substances has not yet been tested. We tested a handheld fluorometer for sensitivity to ambient light and turbidity and compared these findings with EPA Method 445.0 using water samples obtained from two urban lakes in Tucson, Arizona, USA. Our results suggested that the probe was not sensitive to ambient light and performed well at low chlorophyll-a concentrations (<25 µg/L) across a range of turbidity levels (50–70 NTU). However, the performance was lower when the chlorophyll-a concentrations were >25 µg/L and turbidity levels were <50 NTU. To account for this discrepancy, we developed a calibration equation to use for this handheld fluorometer when field monitoring for potential harmful algal blooms in water bodies.

In situ growth rate measurements for plasma processing of opaque materials

2002 ◽  
Vol 418 (2) ◽  
pp. 151-155
Author(s):  
A Salifu ◽  
G Zhang ◽  
Edward A Evans
Keyword(s):  
Growth Rate ◽  
Plasma Processing ◽  
In Situ Growth

scholarly journals Synergistic Recapturing of External and Internal Phosphorus for In Situ Eutrophication Mitigation

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 2 ◽  
Author(s):  
Minmin Pan ◽  
Tao Lyu ◽  
Meiyi Zhang ◽  
Honggang Zhang ◽  
Lei Bi ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Pilot Scale ◽  
P Adsorption ◽  
Control Approach ◽  
P Concentration ◽  
Water Ph ◽  
Low Levels ◽  
P Removal

In eutrophication management, many phosphorus (P) adsorbents have been developed to capture P at the laboratory scale. Existing P removal practice in freshwaters is limited due to the lack of assessment of the possibility and feasibility of controlling P level towards a very low level (such as 10 μg/L) in order to prevent the harmful algal blooms. In this study, a combined external and internal P control approach was evaluated in a simulated pilot-scale river–lake system. In total, 0.8 m3 of simulated river water was continuously supplied to be initially treated by a P adsorption column filled with a granulated lanthanum/aluminium hydroxide composite (LAH) P adsorbent. At the outlet of the column (i.e., inlet of the receiving tanks), the P concentration decreased from 230 to 20 µg/L at a flow rate of 57 L/day with a hydraulic loading rate of 45 m/day. In the receiving tanks (simulated lake), 90 g of the same adsorbent material was added into 1 m3 water for further in situ treatment, which reduced and maintained the P concentration at 10 µg/L for 5 days. The synergy of external and internal P recapture was demonstrated to be an effective strategy for maintaining the P concentration below 10 µg/L under low levels of P water input. The P removal was not significantly affected by temperature (5–30 °C), and the treatment did not substantially alter the water pH. Along with the superior P adsorption capacity, less usage of LAH could lead to reduced cost for potation eutrophication control compared with other widely used P adsorbents.

In situ growth rate control of carbon nanotubes by optical imaging method

2007 ◽  
Vol 91 (19) ◽  
pp. 193102 ◽  
Author(s):  
Itaru Gunjishima ◽  
Takashi Inoue ◽  
Atsuto Okamoto
Keyword(s):  
Carbon Nanotubes ◽  
Growth Rate ◽  
Optical Imaging ◽  
Rate Control ◽  
Imaging Method ◽  
In Situ Growth ◽  
Growth Rate Control

scholarly journals Is Occurrence of Harmful Algal Blooms in the Exclusive Economic Zone of India on the Rise?

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
K. B. Padmakumar ◽  
N. R. Menon ◽  
V. N. Sanjeevan
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Exclusive Economic Zone ◽  
Prorocentrum Lima ◽  
Clear Cut ◽  
The Past ◽  
Spatial Coverage ◽  
Indian Waters ◽  
Frequency Intensity

Occurrence, increase in frequency, intensity and spatial coverage of harmful algal blooms during the past decade in the EEZ of India are documented here. Eighty algal blooms were recorded during the period 1998–2010. Of the eighty algal blooms, 31 blooms were formed by dinoflagellates, 27 by cyanobacteria, and 18 by diatoms. Three raphidophyte and one haptophyte blooms were also observed. Potentially toxic microalgae recorded from the Indian waters were Alexandrium spp., Gymnodinium spp. Dinophysis spp., Coolia monotis, Prorocentrum lima, and Pseudo-nitzschia spp. Examination of available data from the literature during the last hundred years and in situ observations during 1998–2010 indicates clear-cut increase in the occurrence of HABs in the Indian EEZ.

scholarly journals In-situ electrochemical Fe(VI) for removal of microcystin-LR from drinking water: comparing dosing of the ferrate ion by electrochemical and chemical means

2018 ◽  
Vol 16 (3) ◽  
pp. 414-424 ◽  
Author(s):  
K. L. Dubrawski ◽  
M. Cataldo ◽  
Z. Dubrawski ◽  
A. Mazumder ◽  
D. P. Wilkinson ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Oxidation ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Normal Operation ◽  
Small Water ◽  
Initial Ph ◽  
Contaminate Drinking Water ◽  
Small Water Systems

Abstract Harmful algal blooms (HAB) release microtoxins that contaminate drinking water supplies and risk the health of millions annually. Crystalline ferrate(VI) is a powerful oxidant capable of removing algal microtoxins. We investigate in-situ electrochemically produced ferrate from common carbon steel as an on-demand alternative to crystalline ferrate for the removal of microcystin-LR (MC-LR) and compare the removal efficacy for both electrochemical (EC) and chemical dosing methodologies. We report that a very low dose of EC-ferrate in deionized water (0.5 mg FeO42− L−1) oxidizes MC-LR (MC-LR0 = 10 μg L−1) to below the guideline limit (1.0 μg L−1) within 10 minutes' contact time. With bicarbonate or natural organic matter (NOM), doses of 2.0–5.0 mg FeO42− L−1 are required, with lower efficacy of EC-ferrate than crystalline ferrate due to loss of EC-ferrate by water oxidation. To evaluate the EC-ferrate process to concurrently oxidize micropollutants, coagulate NOM, and disinfect drinking water, we spiked NOM-containing real water with MC-LR and Escherichia coli, finding that EC-ferrate is effective at 10.0 mg FeO42− L−1 under normal operation or 2.0 mg FeO42− L−1 if the test water has initial pH optimized. We suggest in-situ EC-ferrate may be appropriate for sporadic HAB events in small water systems as a primary or back-up technology.

scholarly journals Associations between chlorophyll a and various microcystin-LR health advisory concentrations

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 151 ◽  
Author(s):  
Jeffrey W. Hollister ◽  
Betty J. Kreakie
Keyword(s):  
Drinking Water ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Field Measurements ◽  
World Health ◽  
Health Advisory ◽  
Adverse Health Effects ◽  
Wide Range ◽  
Recreational Use

Cyanobacteria harmful algal blooms (cHABs) are associated with a wide range of adverse health effects that stem mostly from the presence of cyanotoxins. To help protect against these impacts, several health advisory levels have been set for some toxins. In particular, one of the more common toxins, microcystin-LR, has several advisory levels set for drinking water and recreational use. However, compared to other water quality measures, field measurements of microcystin-LR are not commonly available due to cost and advanced understanding required to interpret results. Addressing these issues will take time and resources. Thus, there is utility in finding indicators of microcystin-LR that are already widely available, can be estimated quickly and in situ, and used as a first defense against high concentrations of microcystin-LR. Chlorophyll a is commonly measured, can be estimated in situ, and has been shown to be positively associated with microcystin-LR. In this paper, we use this association to provide estimates of chlorophyll a concentrations that are indicative of a higher probability of exceeding select health advisory concentrations for microcystin-LR. Using the 2007 National Lakes Assessment and a conditional probability approach, we identify chlorophyll a concentrations that are more likely than not to be associated with an exceedance of a microcystin-LR health advisory level. We look at the recent US EPA health advisories for drinking water as well as the World Health Organization levels for drinking water and recreational use and identify a range of chlorophyll a thresholds. A 50% chance of exceeding one of the microcystin-LR advisory concentrations of 0.3, 1, 1.6, and 2 g/L is associated with chlorophyll a concentration thresholds of 23.4, 67.0, 83.5, and 105.8, respectively. When managing for these various microcystin-LR levels, exceeding these reported chlorophyll a concentrations should be a trigger for further testing and possible management action.

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