Dear Cameron, I suggest to ask Natalie Pettorelli about his,

regards

Can you define more what mean by "health"? Do you mean surface productivity in terms of primary production? Measures of essential fish habitat? Species abundance or distribution? The new Ocean Health Index actually has 10 different goals that go into calculating various indicators of "health." Halpern et al., 2012, An index to assess the health and benefits of the global ocean: Nature, v. 488, p. 615-620.

I think you might be interested in this paper... Collin, A, et al. (2011). Predicting Species Diversity of Benthic Communities within Turbid Nearshore Using Full-Waveform Bathymetric LiDAR and Machine Learners. PLoS ONE, 6,

To complement Dawn's answer, an earlier Halpern paper incorporated global sea surface temperature from remote sensing into a measure of human impact on ocean ecosystems:

Halpern B, Walbridge S, Selkoe K, Kappel C, Micheli F, D'Agrosa C, Bruno J, Casey K, Ebert C, Fox H (2008) A global map of human impact on marine ecosystems. Science 319:948

That said, it sounds like you're more interested in macroalgal physiological state in nearshore ecosystems. I'm not familiar with that literature, but the following references are just two examples of uses of remotely sensed ocean color as measures of chl-a concentration and physiological state for open ocean phytoplankton:

Behrenfeld MJ, Westberry TK, Boss E, O'Malley RT, Siegel DA, Wiggert JD, Franz BA, McClain CR, Feldman GC, Doney SC (2009) Satellite-detected fluorescence reveals global physiology of ocean phytoplankton.

Broitman BR, Kinlan BP (2006) Spatial scales of benthic and pelagic producer biomass in a coastal upwelling ecosystem. Marine Ecology Progress Series 327:15–25

Thanks Filippo that looks at a glance like it will be useful! Thanks also dawn and Mauricio;

Dawn - That looks like a good summary of "health" which may be useful (I'll have to run it by my colleague who is more of a specialist in coastal ecology...)

Mauricio - Is Natalie Pettorelli doing anything around coastal or marine ecology that's not listed on her website? I don't see anything... mostly seems focused on terrestrial and large herbivore...

There have been studies of vegetation and thus habitat in shallow waters of estuaries using spectral sensors. I have seen studies of upwelling areas relating phytoplankton production and whale locations.

With regard to the seaweed the spectral absorption should be similar to phytoplankton so the same bands would be useful on something like SeaWiffs. However, you might need to change the algorithm, especially if you want to get a quantitative measure of either mass or production. The techniques would be similar to the above mentioned studies of marsh grasses. For methodological literature I would recommend you check out studies down be the Monteray Bay Aquarium. I would be surprised if they hadn't looked at some of this because they have three distinct ecosystem and I believe some confluence of currents.

Despite problems linked to land adjacency effects, diverse communities of primary producers and complex case 2 water types, take a look into:

(a) Coppini et al. 2012. Chl a trends in European seas estimated using ocean-colour products, Ocean Sci. Discuss., 9, 1481–1518.

(b) Druon et al. 2004. Comparative assessment of large-scale marine eutrophication: North Sea area and Adriatic Sea as case studies, Mar Ecol Prog Ser Vol. 272: 1–23.

(c) IOCCG, 2008. Why Ocean Colour? The Societal Benefits of Ocean-Colour Technology. Platt, T., Hoepffner, N., Stuart, V. and Brown, C. (eds.), Reports of the International Ocean-Colour Coordinating Group, No. 7, IOCCG, Dartmouth, Canada (see chapters 7 and 8; available at http://www.ioccg.org/reports/report7.pdf)

(d) Le et al., 2013. Climate-driven chlorophyll-a changes in a turbid estuary: Observations from satellites and implications for management, Remote Sensing of Environment 130: 11–24.

(e) Singh et al., 2013. A MODIS approach to predicting stream water quality in Wisconsin, Remote Sensing of Environment 128: 74–86.

Dear Cameron, if you are interested in near shore ecosystems there are three major problems in using Ocean-Color products, one is that these products use the blue section of the electromagnetic spectrum where there is major absorption by the Colored Dissolved Organic Matter (CDOM), which will interfere with the reflectance of chlorophyll. Other is that these products are 1km of spatial resolution, which may imply problems with land adjacency effects if your sites are near shore as Ana point out. A third one could be that near shore waters may be too shallow and the radiation in the blue penetrates deeper than for instance the red, which may imply problems with bottom reflectance contamination.

Although not studying microalgae but phytoplankton these two studies use a spatial algorithm using also the green besides the blue to ameliorate some of the problems I have just described.

Le, C., C. Hu, J. Cannizzaro, D. English, F. Muller-Karger, and Z. Lee. 2013. “Evaluation of Chlorophyll-a Remote Sensing Algorithms for an Optically Complex Estuary.” Remote Sensing of Environment 129: 75–89. http://dx.doi.org/10.1016/j.rse.2012.11.001

Le, C., C. Hu, D. English, J. Cannizzaro, Z. Chen, L. Feng, R. Boler, and C. Kovach. 2013. “Towards a Long-Term Chlorophyll-a Data Record in a Turbid Estuary Using MODIS Observations.” Progress in Oceanography 109: 75–89. http://dx.doi.org/10.1016/j.pocean.2012.10.002

Le, C., C. Hu, D. English, J. Cannizzaro, and C. Kovach. 2013. “Climate-Driven Chlorophyll-a Changes in a Turbid Estuary: Observations from Satellites and Implications for Management.” Remote Sensing of Environment 130: 11–24. http://dx.doi.org/10.1016/j.rse.2012.11.011

This other study below uses a NASA nonstandard product, fluorescence line height (FLH) to infer chlorophyll. The product used is based on an algorithm that uses the red section of the spectrum where there is less absorption by CDOM, less issues with bottom contamination, and the spatial resolution is better (250 m).

Moreno-Madriñán M. J.and A. Fischer. 2013. “Performance of the MODIS FLH algorithm in estuarine waters: a multi-year (2003–2010) analysis from Tampa Bay, Florida (USA).” International Journal of Remote Sensing. 34: 6467-6483.

Hope it helps,

Thanks Max. I'm actually looking at using multi-spectral aerial photography combined with LiDAR... those references look like they'll provide some insight into what bandwidths to focus on though, so I'll take a closer look.

You might like to explore NOAA's Coral Reef Watch website..www.coralreefwatch.noaa.gov....although these uses for coral health are for an ecosystem that is more tropical. Another source might be Dr. Pete Mumby at UQ. Cheers,

Al Strong

Yes, in the context of the European directives, it has been used as ecological status assessment and environmental status assessment. You can go to my profile and download some papers from there, published in collaboration with other colleagues from AZTI. If the full text of the papers are not there you can send me an e-mail

We have done some work with sardines in that area using aerial lidar. [J. H. Churnside, D. A. Demer, D. Griffith, R. L. Emmett, and R. D. Brodeur, “Comparisons of lidar, acoustic and trawl data on two scales in the northeast Pacific Ocean,” CalCOFI Rep. 50, 118-122 (2009)., D. C. Reese, R. T. O'Malley, R. D., Brodeur, and J. H. Churnside, “Epipelagic fish distributions in relation to thermal fronts in a coastal upwelling system using high-resolution remote-sensing techniques,” ICES J. Mar. Sci. 68, 1865–1874 (2011).] Kelp is very easy to identify in the lidar signal, but we have never published anything on that.

The papers I mentioned are:

- Novoa, S., G. Chust, J.M. Froidefond, C. Petus, J. Franco, E. Orive, S. Seoane, A. Borja, 2012. Water quality monitoring in Basque coastal areas using local chlorophyll-a algorithm and MERIS images. Journal of Applied Remote Sensing, 6: 1-27.

- Novoa, S., G. Chust, Y. Sagarminaga, M. Revilla, A. Borja, J. Franco, 2012. Water quality assessment using satellite-derived chlorophyll-a within the European directives, in the southeastern Bay of Biscay. Marine Pollution Bulletin, 64: 739-750.

- Novoa, S., G. Chust, Y. Sagarminaga, M. Revilla, J. Franco, V. Valencia, Á. Borja, 2012. Chlorophyll-a variability within Basque coastal waters and the Bay of Biscay, between 2005 and 2010, using MODIS imagery. Revista de Investigación Marina, 19(5): 92-107

If you refer to other issues (multibeam, Lidar, etc.), you can also consult my profile and see there examples for benthos and habitats

Dear Cameron, I suggest to have a look at http://www.eomap.de, there You will find convincing examples of monitoring marine ecosystem's health, and certainly You will find colleagues for good discussion of the problem.

I used satellite ocean color data to monitor water differences in the normal and red tide conditions in the Persian Gulf. To gain more information, you can refer to the following publication:  

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