"PIRANAs and PIRATAs -- Remote Sensing the Amazon River Plume" Guest Scientist: Ajit Subramanian

1. "PIRANAs and PIRATAs -- Remote Sensing the Amazon River Plume" Guest Scientist: Ajit Subramanian Earth2Class Workshops Originally Presented 23 Oct 2004

2. Dr. Ajit Subramanian … is interested in the use of remote sensing, ocean optics, phytoplankton physiology, biological and physical oceanography and geographical information systems to better understand how the marine ecosystem works and can be managed. …uses bio-optics and remote sensing as tools for monitoring coastal water quality.

3. Much of his work focuses on understanding the Nitrogen cycle in the global ocean system http://shell.pubnix.net/~spond/filter/nitrogen.html

4. Here is another way to represent the Nitrogen Cycle http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NitrogenCycle.html

5. The Nitrogen Cycle in the Oceans • Recent research reveals that human impacts have greatly enhanced the rate at which nitrogen moves from land to sea • In effect, we have doubled the amount of nitrogen “fertilizers” in the marine system http://scicom.ucsc.edu/SciNotes/9801/ice/nitro.htm

6. Much of this is taken up by the wide variety of marine phytoplankton http://seawifs.gsfc.nasa.gov/SEAWIFS/sanctuary_4.html

7. One of the most effective nitrogen-fixers is Trichodesmium • This cyanobacterium (blue-green algae) possesses nitrogenase enzymes • Much research is underway to learn how Fe, Mo, and other elements may serve as bio-limiting factors Trichodesmium http://www.princeton.edu/~cebic/N-cycle-intro1.html

8. Among the effects may be “algal blooms,” which can now be observed from space Shuttle Photograph of the Po River CZCS Image of the Po River http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/OCDST/classic_scenes/10_classics_rivers.html

9. HAB – Harmful Algae Blooms • Although most phytoplankton are harmless, some species contain toxins • The misnomer “red tide” has been used for blooms of these dangerous organisms http://www.whoi.edu/redtide/

10. http://www.whoi.edu/redtide/whathabs/whathabs.html

11. How Can We Observe Earth from Space? NASA provides an educational web site to explain remote sensing and other spatial information technologies at: http://education.ssc.nasa.gov/fad/default.asp The site includes a tutorial, lesson plans, and links to additional Internet resources.

12. SeaWIFS The “Sea-viewing Wide Field-of-view Sensor” provides quantitative data on global ocean bio-optical properties. http://seawifs.gsfc.nasa.gov/SEAWIFS/BACKGROUND/

13. http://seawifs.gsfc.nasa.gov/SEAWIFS/BACKGROUND/SEAWIFS_BACKGROUND.htmlhttp://seawifs.gsfc.nasa.gov/SEAWIFS/BACKGROUND/SEAWIFS_BACKGROUND.html http://seawifs.gsfc.nasa.gov/SEAWIFS/IMAGES/SEAWIFS_GALLERY.html SeaWIFS can detect subtle changes in ocean color that signify various types and quantities of marine phytoplankton (microscopic marine plants), the knowledge of which has both scientific and practical applications.

14. Techniques for studying plankton from space are explained at Created by Bigelow Labs, this site describes how NASA’s ocean color satellite instruments are used to study phytoplankton. http://www.bigelow.org/foodweb/

15. Dr. Ajit Subramanian …will provide much more information about remote sensing and the nitrogen cycle in marine ecosystems. His personal web site is: http://www.ldeo.columbia.edu/~ajit/ He also recommends: http://www.usc.edu/dept/LAS/biosci/tricho/trichohome/