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Ocean health, disaster impacts monitored from above by satellite remote sensing

New remote sensing technologies with applications such as predicting problems with ocean fish stocks and assessing natural disasters were reported at conferences sponsored recently in Prague by SPIE, the international society for optics and photonics. The papers and others from SPIE Remote Sensing have been published in the SPIE Digital Library, with freely accessible abstracts and full papers available by rental, pay-per-view or subscription.

Color tells the story

To better predict the health of ocean fish stocks, a team from the University of Malta and the European Commission Joint Research Centre statistically compared ocean color values from satellites with values collected in the field. Surface runoff from land can affect ocean fish stocks by inhibiting the vitality of chlorophyll in phytoplankton – the basis of marine food webs. Ocean color can be used to gauge the productivity of a marine area since it is the measure of suspended chlorophyll pigment found in the microscopic phytoplankton. Their report is published in “A first attempt at testing correlation between MODIS ocean colour data and in situ chlorophyll — measurements within Maltese coastal waters.”

Oil and fish

In the Gulf of Mexico, oil and dispersant chemicals left after the Deepwater Horizon spill covered critical fish spawning and larval areas. Researchers from Ocean Research and Conservation Association and the Florida Institute of Technology used biogeographical analyses to gain insights on these impacts of these substances. The team reported that oil on the sea surface and the timing of its occurrence likely impacted the developing eggs and larvae of bluefin tuna, blue marlin and other fishes whose eggs concentrate in the sea surface microlayer (SML) — the topmost millimeter. The SML also concentrates petroleum, petroleum-derived hydrocarbons, tar, pesticides, polychlorinated biphenyls (PCBs), heavy metals and plastics. Exposure to oil and oil dispersants causes acute toxicity, narcosis and eventual death in marine fish larvae. Surface oil has been detected in 100% of the northernmost whale shark sightings, 32.8% of the bluefin tuna spawning area and 38% of the blue marlin larval area. In their paper “Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes,” the research team reported how they georeferenced historical ichthyoplankton surveys and published literature to map targeted spawning and larval areas in the Gulf with daily satellite-derived images.

Earthquake impacts

Depending on its magnitude and location, an earthquake may have unexpectedly complex impacts, and affected areas may be difficult to access in order to assess the damage. After the 9.0-magnitude earthquake off the Pacific Coast of Japan on 11 March 2011, the Japan Aerospace Exploration Agency (JAXA) provided images acquired by the Advanced Land Observing Satellite (ALOS) to national and local governments of Japan, to aid in disaster recovery and restoration. JAXA also received and analyzed more than 5,000 scenes via the International Disaster Charter and Sentinel Asia, and supported the governments through its Disaster Management Support Systems Office. Their paper is titled “Disaster monitoring for Japan Earthquake with satellites by JAXA.”

More examples of applications of remote sensing, in monitoring wetlands and areas of coal mining and in certifying organic crops, are reported in the blog Photonics for a Better World.

SPIE, the international society for optics and photonics, was founded in 1955 to advance light-based technologies. Serving more than 180,000 constituents from 168 countries, the Society advances emerging technologies through interdisciplinary information exchange, continuing education, publications, patent precedent and career and professional growth. SPIE annually organizes and sponsors approximately 25 major technical forums, exhibitions and education programs in North America, Europe, Asia and the South Pacific. SPIE provided over $2.3 million in support of education and outreach programs in 2010.

Source SPIE