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

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.

Download Full-text

Field Spectroscopy as a Tool for Enhancing Water Quality Monitoring in the ACE Basin, SC

The Journal of South Carolina Water Resources ◽

10.34068/jscwr.04.04 ◽

2017 ◽

pp. 41-55 ◽

Cited By ~ 1

Author(s):

Caitlyn C. Mayer ◽

Khalid A. Ali

Keyword(s):

Water Quality ◽

South Carolina ◽

Chlorophyll A ◽

Algal Species ◽

Water Quality Monitoring ◽

Water Systems ◽

Quality Monitoring ◽

Least Squares Regression ◽

Monitoring Methods

The Ashepoo, Combahee, Edisto (ACE) Basin in South Carolina is one of the largest undeveloped estuaries in the Southeastern United States. This system is monitored and protected by several government agencies to ensure its health and preservation. However, as populations in surrounding cities rapidly expand and land is urbanized, the surrounding water systems may decline from an influx of contaminants, leading to hypoxia, fish kills, and eutrophication. Conventional in situ water quality monitoring methods are timely and costly. Satellite remote sensing methods are used globally to monitor water systems and can produce an instantaneous synopsis of color-producing agents (CPAs), including chlorophyll-a, suspended matter (TSM), and colored-dissolved organic matter by applying bio-optical models. In this study, field, laboratory, and historical land use land cover (LULC) data were collected during the summers of 2002, 2011, 2015, and 2016. The results indicated higher levels of chlorophyll, ranging from 2.94 to 12.19 μg/L, and TSM values were from 60.4 to 155.2 mg/L between field seasons, with values increasing with time. A model was developed using multivariate, partial least squares regression (PLSR) to identify wavelengths that are more sensitive to chlorophyll-a (R2 = 0.49; RMSE = 1.8 μg/L) and TSM (R2 = 0.40; RMSE = 12.9 mg/L). The imbrication of absorption and reflectance features characterizing sediments and algal species in ACE Basin waters make it difficult for remote sensors to distinguish variations among in situ concentrations. The results from this study provide a strong foundation for the future of water quality monitoring and for the protection of biodiversity in the ACE basin.

Download Full-text

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

Water ◽

10.3390/w12010002 ◽

2019 ◽

Vol 12 (1) ◽

pp. 2 ◽

Cited By ~ 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.

Download Full-text

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

International Journal of Oceanography ◽

10.1155/2012/263946 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 20

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.

Download Full-text

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

Journal of Water and Health ◽

10.2166/wh.2018.187 ◽

2018 ◽

Vol 16 (3) ◽

pp. 414-424 ◽

Cited By ~ 5

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.

Download Full-text

On extreme atmospheric and marine nitrogen fluxes and chlorophyll-a levels in the Kattegat Strait

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-3-1651-2003 ◽

2003 ◽

Vol 3 (2) ◽

pp. 1651-1692

Author(s):

C. B. Hasager ◽

J. Carstensen ◽

T. Ellermann ◽

B. G. Gustafson ◽

O. Hertel ◽

...

Keyword(s):

Chlorophyll A ◽

Deep Water ◽

Dry Deposition ◽

Wet Deposition ◽

Algal Blooms ◽

Limiting Factor ◽

Nitrogen Inputs ◽

Chlorophyll Level ◽

Water Entrainment

Abstract. A retrospective analysis is carried out to investigate the importance of the vertical fluxes of nitrogen to the marine sea surface layer in which high chlorophyll a levels may cause blooms of harmful algae and subsequent turn over and oxygen depletion at the bottom of the sea. Typically nitrogen is the limiting factor for phytoplankton in the Kattegat Strait during summer periods (May to August) and the major nitrogen inputs come from the atmosphere and deep-water entrainment. The extreme reoccurence values of nitrogen from atmospheric wet and dry deposition and deep-water flux entrainments are calculated by the periodic maximum method and the results are successfully compared to a map of chlorophyll return periods based on in-situ observations. The one-year return of extreme atmospheric wet deposition is around 70 mg N m−2 day−1 and 30 mg N m−2 day−1 for deep-water entrainment. Atmospheric nitrogen dry deposition is insignificant in the context of algal blooms. At longer time-scales e.g. at 10-year return, the nitrogen deep-water entrainment is larger than the extreme of atmospheric wet deposition. This indicates that the pool of nitrogen released from the sea bottom by deep-water entrainment forced by high winds greatly exceeds the atmospheric pool of nitrogen washed out by precipitation. At the frontal zone of the Kattegat Strait and Skagerrak, the nitrogen deep-water entrainment is very high and this explains the high 10-year return chlorophyll level at 8 mg m−3 in Kattegat. In the southern part, the extreme chlorophyll level is only 4 mg m−3 according to the statistics of a multi-year time-series of water samples. The chlorophyll level varies greatly in time and space as documented by a series of SeaWiFS satellite maps (OC4v4 algorithm) of chlorophyll, ScanFish and buoy observations from an experimental period in Kattegat and it is recommended to sample in-situ chlorophyll observation collocated in time to the satellite overpasses of e.g. SeaWiFS and ENVISAT MERIS to ensure improved mapping of the chlorophyll levels in the Danish waters.

Download Full-text

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

F1000Research ◽

10.12688/f1000research.7955.1 ◽

2016 ◽

Vol 5 ◽

pp. 151 ◽

Cited By ~ 3

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.

Download Full-text

Trophic status assessment of small turbid lakes comparing remote sensing and in situ data: case study at lower Danube floodplain

Aerospace Research in Bulgaria ◽

10.3897/arb.v32.e05 ◽

2020 ◽

Vol 32 ◽

pp. 53-63

Author(s):

Stefan Kazakov ◽

Valko Biserkov ◽

Luchezar Pehlivanov ◽

Stoyan Nedkov

Keyword(s):

Remote Sensing ◽

Chlorophyll A ◽

Satellite Data ◽

Suspended Matter ◽

Trophic Status ◽

Remote Sensing Data ◽

Water Quality Monitoring ◽

Floodplain Lakes ◽

In Situ Data

The aim of the study was to compare in situ and remote sensing data, in order to assess the applicability of satellite images in water quality monitoring of floodplain lakes. Two indicators of trophic status were compared: chlorophyll a and total suspended matter. Two lakes on Lower Danube floodplain were selected: Srebarna and Malak Preslavets. Data were obtained in July and August 2018. Sentinel 2 MSI L1c images were analyzed in SeNtinel Application Platform (SNAP), (v. 6.0). According to in situ data, Srebarna Lake indicated status of eutrophication, while Malak Preslavets experienced hypertrophic conditions. Satellite data indicated eutrophic conditions for both lakes. Comparing the results from in situ and satellite data, chlorophyll a showed higher correlation (r = 0.66) and comparable results. On the other hand, significantly overestimation of suspended matter according to satellite data were found, as well weaker correlation (r = 0.57) between both methods. Remote sensing i.e. Sentinel products are emerging as a powerful tool in environmental observation. Although weather conditions could have significant impact on environmental dynamic especially in floodplain lakes, combining and comparing of different methods could improve the preciseness of the methodology as well as assessment reliability.

Download Full-text

ESTIMATING AND MAPPING CHLOROPHYLL-A CONCENTRATION OF PHEWA LAKE OF KASKI DISTRICT USING LANDSAT IMAGERY

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-iv-5-w2-127-2019 ◽

2019 ◽

Vol IV-5/W2 ◽

pp. 127-132

Author(s):

N. Wagle ◽

R. Pote ◽

R. Shahi ◽

S. Lamsal ◽

S. Thapa ◽

...

Keyword(s):

Regression Model ◽

Chlorophyll A ◽

Algal Blooms ◽

Landsat Imagery ◽

Measurement Data ◽

Landsat 8 ◽

Chl A ◽

Gis Techniques ◽

The One

Abstract. Water is a major component in the living ecosystem. As water quality is degrading due to human intervention, continuous monitoring is necessary. One of the indicators is Chlorophyll-a (Chl-a) which indicates algal blooms which are often driven by eutrophication phenomena in freshwater. Lakes should be monitored for Chl-a because Chla-a is related to eutrophication phenomena which are an enrichment of water by nutrients salt. When the environment becomes enriched with nutrients the excessive growth can lead to the death of fish. In this study, the Remote Sensing (RS) and Geographic Information System (GIS) techniques were utilized to determine Chl-a concentration of Phewa Lake of Kaski district. We used Landsat 8 satellite imagery for estimation and mapping of the Chl-a concentration. In-situ measurements from different sample points were taken and used to form a regression model for Chl-a and its concentration over the water body was calculated. The preceding year’s (2016) in situ measurement data of Chl-a concentration at a specific location were assessed with the one evaluated from the regression model thus produced for the succeeding year (2017) using Root Mean Square Error (RMSE) technique. As a result, we concluded that the estimation and mapping of Chl-a of a lake in Nepal can be done with the help of RS and GIS techniques.

Download Full-text

Temporal dynamics of the phytoplankton community associated with environmental factors and harmful algal blooms in Acapulco Bay, Mexico

Latin American Journal of Aquatic Research ◽

10.3856/vol49-issue1-fulltext-2525 ◽

2021 ◽

Vol 49 (1) ◽

pp. 110-124

Author(s):

Victor A. Cervantes-Urieta ◽

Ma. Nieves Trujillo-Tapia ◽

Juan Violante-González ◽

Giovanni Moreno-Díaz ◽

Agustín A. Rojas-Herrera ◽

...

Keyword(s):

Environmental Factors ◽

Chlorophyll A ◽

Rainy Season ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Temporal Dynamics ◽

Harmful Algal Bloom ◽

San Lorenzo ◽

Diatom Genus ◽

Physical And Chemical

The phytoplankton community's temporal variability associated with environmental factors and harmful algal blooms in Acapulco Bay was analyzed. Phytoplankton samples were taken monthly at three sites (MSL: Morro de San Lorenzo, CDO: Casa Díaz Ordaz, and PP: Playa Palmitas) over 11 months in 2018. The physical and chemical variables of surface water were measured in situ, and the composition and community structure of phytoplankton were analyzed. The physical and chemical characteristics studied varied significantly. The highest temperatures were obtained in September and October (September: 29.6 ± 3.58°C, October: 34.61 ± 1.83°C), whereas the highest salinities and chlorophyll-a concentrations occurred from February to May (salinity: 34.06 ± 0.38, chlorophyll-a: 2.73 ± 0.15 μg L-1). The highest oxygen concentrations were recorded during the rainy season (June 91.8% and December 100%). A total of 201 phytoplankton species were identified: 94 diatoms, 101 dinoflagellates, 4 cyanobacteria, and 2 silicoflagellates. Diatoms dominated during the rainy season, whereas dinoflagellates dominated during the dry season (June to December). A total of 17 harmful species were identified; four toxin-producing species included a diatom genus (Pseudonitszchia sp.) and three dinoflagellate species (Gymnodinium catenatum, Dinophysis caudata, and Phalacroma rotundata). One species that produces oxygen reactive species and hemolysis (Margalefidinium polykrikoides) caused a harmful algal bloom at the CDO and PP stations. The temperature is one of the most critical factors for its bloom in October.

Download Full-text

Associations between chlorophyll a and various microcystin health advisory concentrations

F1000Research ◽

10.12688/f1000research.7955.2 ◽

2016 ◽

Vol 5 ◽

pp. 151 ◽

Cited By ~ 2

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, has several advisory levels set for drinking water and recreational use. However, compared to other water quality measures, field measurements of microcystin 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 that are already widely available, can be estimated quickly and in situ, and used as a first defense against high levels of microcystin. Chlorophyll a is commonly measured, can be estimated in situ, and has been shown to be positively associated with microcystin. 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. 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 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 specific advisory microcystin concentrations of 0.3, 1, 1.6, and 2 μg/L is associated with chlorophyll a concentration thresholds of 23, 68, 84, and 104 μg/L, respectively. When managing for these various microcystin levels, exceeding these reported chlorophyll a concentrations should be a trigger for further testing and possible management action.

Download Full-text