You may take a look to this paper that is on my page: Hyperspectral and multispectral ocean color inversions to detect Phaeocystis globosa blooms in coastal waters.

where we discuss about the advantage of hyper vs. multispectral for this kind of assesment (sse the link below). BEsides, take a look to some the IOCCG report: http://www.ioccg.org/groups_ioccg.html

and

http://www.geohab.info/

Best

hubert

https://www.researchgate.net/publication/229042366_Hyperspectral_and_multispectral_ocean_color_inversions_to_detect_Phaeocystis_globosa_blooms_in_coastal_waters?ev=prf_pub

Article Hyperspectral and multispectral ocean color inversions to de...

My research group has been working on this issue and. Identification of toxic algal bloom is just not possible in most cases. Toxicity of an slgal bloo

Can be just by shear concentration of a specific specie which under normal circumstances does exist at below toxic level. I sm still very concerned with this notion of utilization if RS and GIS for toxic algal blooms.

Dear Saif,

Many researches have been conduct in order to identify and map Harmful Algae Blooms in inland waters using Remote Sensing techniques. The most used is the bio-optical modeling of Phycocyanin (PC), which is, for inland waters, a unique pigment of cyanobacteria. There are several types of bio-optical models which you can apply in your case. Empirical and semi-empirical models will give you the concentration of PC while semi-analytical models will give you the Inherent Optical Properties of your water body. For both cases you will need to parametrize a model for your study area in order to have an accurate result.

About the important factors to be considerer the most important is the spectral resolution, since, PC has very limited spectral features, e.g. an absorpition peak at 620nm and fluorescence at 650nm. However it will limit your spatial resolution, since few sensors have these bands in a high spatial resolution. And these two factors will imply in the temporal resolution.

About your concern of toxicity, Hunter et al. 2010 showed that C-PC has a good correlation to microcystins concentration, so, if you could quantify the PC in your study area, you can try to relate it to the cyanotoxins.

Summarizing everything, it is possible to use remote sensing to identify and map HABs, however, to use remote sensing to monitor HABs we will need a new orbital sensor aquiring imagens with a high temporal resolution and with the specific spectral bands.

You may take a look to this paper that is on my page: Hyperspectral and multispectral ocean color inversions to detect Phaeocystis globosa blooms in coastal waters.

where we discuss about the advantage of hyper vs. multispectral for this kind of assesment (sse the link below). BEsides, take a look to some the IOCCG report: http://www.ioccg.org/groups_ioccg.html

and

http://www.geohab.info/

Best

hubert

https://www.researchgate.net/publication/229042366_Hyperspectral_and_multispectral_ocean_color_inversions_to_detect_Phaeocystis_globosa_blooms_in_coastal_waters?ev=prf_pub

Article Hyperspectral and multispectral ocean color inversions to de...

Thanks Igor and Hubert I will appreciate getting the cited paper. I am aware of the capabilities but have found a practical limitation in the Arabian gulf waters. I agree with and we are doing identification of HABs but classifying and identifying toxic HABs is a big challenge. I have observed that thou certain species present at lower concentration are not toxic they became toxic after crossing a certain threshold.

Low cost insitu instrumentation might help too. Especially if area of interest are inland water bodies that may be hard to resolve because of things like adjacency and low temporal frequency of satellite captured images. Low cost instrumentation at several sites can act as an early warning mechanism. These instruments could also be used to validate satellite data for ocean measurements. Hope this helps, even a little.

kind regards

Arshath

Arshath can your insitu instrument determine toxicity of HABs that is what is challenging

Abhijit, are you interested in coastal or inland waters? The optimal models may change based on the location of the water body of interest. Bio-optical models probably provide the best accuracy; however, they require a significant apriori knowledge of the spectral properties of the water you are interested in observing. Empirical and semi-empirical models do have increased transferability. If interested I can send you my paper in which I compare several different models for estimating CHL and PC in 3 inland lakes if you do not have access to PE&RS. http://digital.ipcprintservices.com/publication/?i=108955&p=&l=&m=&ver=&pp=

Papers by Gitelson and Simis are also good places to go (my paper cites some of their research too).

Saif, typically HABs can be present in sufficient quantities and not produce toxins (at least at levels of concern). In some cases no toxins are never produced; however, there is suggestive evidence that toxins are produced when the algae become stressed. They can extrude the toxins from their cells or when the algae are lysed. Understanding the conditions for which HAB toxins are produced is definitely a direction of research.

Anthony this is precisely what I am trying to make a point.The HABs may not necessarily be toxic.

Saif, I see that now. My original understanding was that you were saying that HABs became toxic only when in sufficient quantity. This is true, however, there could be large algal blooms and few toxins are produced as well . For inland waters (at least in the USA), toxins are not the major concern but rather taste and odor compounds that make the water appear foul but is safe to drink. My M.S. research was funded by the local water company in part to identify cyanobacteria in order to control the quantities of the taste/odor compounds MIB and geosmin. Usually these compounds are in significant quantities during blooms well before toxins could be detected or at least at a level determined to be threatening to human health.

I do know that the testing methods for microcystin have been improving since my research between 2006-2009. I believe what we found in Indiana was that microcystin were present during these blooms but at a very low persistent quantity until the blooms were stressed (nutrient limitation/temperature changes). I wasn't specifically working on that project and left before it was completed to know what the final conclusions were. Especially on a multi-year scale (I was only aware of these preliminary results).

Incase of Gulf (Arabian/Persian) we have frequently observed this phenomena that due to nutrient supply certain conditions prevail in which the blooms flourish and sometimes produce toxins.

I have been working for some years on satellite methods for discriminating HABs from normal algal blooms. This is only possible for high biomass, dominant species blooms, so does not address toxic species that are harmful without dominating the bloom.

Here is an earlier paper:

https://www.researchgate.net/publication/255670081_SeaWiFS_discrimination_of_harmful_algal_bloom_evolution?ev=prf_pub

We have a much improved method currently in revision for Harmful Algae, and if you are interested I can send you a copy once it is in press.

Article SeaWiFS discrimination of harmful algal bloom evolution

Peter will appreciate getting a copy of your paper. If you may please send at [email protected]

Peter, I respectfully disagree with you in that identifying HABs using satellite imagery requires high biomass, dominant species blooms. However, most satellite systems do not have the appropriate spectral resolution. There are satellites that contain the required 620 nm band (as identified by my research and many other previous studies). MERIS (and hopefully soon-to-be launched Sentinel series of satellites) has such a band. Research has confirmed using this band can successfully identify the cyanobacteria specific pigment phycocyanin.

http://www.sciencedirect.com/science/article/pii/S0380133011001626

http://www.researchgate.net/publication/232041562_Remote_sensing_of_the_cyanobacterial_pigment_phycocyanin_in_turbid_inland_water/file/9fcfd50734733284e5.pdf

http://www.sciencedirect.com/science/article/pii/S0034425709003137

Article Remote sensing of the cyanobacterial pigment phycocyanin in ...

Peter please share your paper in press on improved method for Harmful Algae.

The earlier paper is:

Miller, P.I., Shutler, J.D., Moore, G.F. & Groom, S.B (2006) SeaWiFS discrimination of harmful algal bloom evolution. International Journal of Remote Sensing, 27(11), 2287-2301, doi:10.1080/01431160500396816.

http://www.neodaas.ac.uk/papers/miller_ijrs2006/

I will share the other one when it is in press.

Peter, it is a good paper. It would be interesting to see what the results would be using MERIS imagery. My research group and the the Simis et al. group both have published phycocyanin absorption coefficients that could be plugged into the model (assuming that they are not site-specific).

www.researchgate.net/publication/232041562_Remote_sensing_of_the_cyanobacterial_pigment_phycocyanin_in_turbid_inland_water/file/9fcfd50734733284e5.pdf

http://www.sciencedirect.com/science/article/pii/S0380133013000543

Article Remote sensing of the cyanobacterial pigment phycocyanin in ...

Yes we have used MERIS and MODIS in the new paper, tested on Phaeocystis and Karenia mikimotoi.

Peter Thanks for the paper.

Toxic algae, or the algae that produce biotoxins, could be identified by molecular methods, such as qPCR. You may also develop elisa kit for use in situ. The prediction of toxic algal blooms could be done by finding conditions that favored the growth of toxic algae, with the same factors for prediction of algal blooms.

What about detecting effluent plumes? Such that comes from sewerage pipes - especially near coral reefs?

Zijian we have been discussing about satellite capability the lab techniques are well known.

Peter, I would be interested in seeing your paper using MERIS data. One should expect that with proper spectral resolutions and accurately estimated absorption coefficients that cyanobacteria estimation, even at low concentrations, will be possible.

In the following publication, I investigated different MODIS products to detect harmful algal blooms:

Conference Paper Investigation the Behavior of MODIS Ocean Color Products und...