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Earth's Changing Ecosystems Telecon Multimedia Page
04.29.08
 
Kevin Arrigo, Stanford University


Data from the arctic study region show the minimum sea ice extent  reached on Sept. 22, 2006, the minimum sea ice extent reached on Sept.16, 2007, and the difference in the minimum sea ice extent between 2006 and 2007.
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Figure 1: Data from the arctic study region show the minimum sea ice extent reached on Sept. 22, 2006 (left), the minimum sea ice extent reached on Sept.16, 2007 (middle), and the difference in the minimum sea ice extent between 2006 and 2007 (right). Red shading denotes areas with open water in 2007 that were ice covered in 2006. Much of this area, roughly equal to the combined areas of California and Montana, had never been ice-free for as long as measurements have been available.


Differences in the rate of photosynthesis in algae between 2006 and 2007 correspond to differences in the duration of open water between 2006 and 2007.


Figure 2: Differences in the rate of photosynthesis in algae between 2006 and 2007 correspond to differences in the duration of open water between 2006 and 2007. Clearly, longer growing seasons in the Arctic Ocean promote greater phytoplankton growth. This suggests that a more ice-free Arctic may be a more favorable habitat for phytoplankton growth than it has been in the past.



Alfredo Huete, University of Arizona


Huete slide for presentation
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Figure 3: Data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument show the response of the Amazon ecosystem to the seasonal drought period. In the dry season, light and dark green colors depict old-growth forests that are most active, while yellow and red colors show disturbed forest areas that become dry (top left). Seasonal forest and pasture activity, measured by the MODIS-derived "enhanced vegetation index," show this contrasting response (bottom left), as greenness in the forest is simultaneous with decreasing greenness (browning) in pastures throughout the dry season. Example photos show the difference between rainforest regions (top right) and converted pasture areas (bottom right).


TRMM sensor data depicts the rainfall anomaly that impacted the Amazon basin in 2005.


Figure 4: NASA's Tropical Rainfall Monitoring Mission (TRMM) sensor data depicts the rainfall anomaly that impacted the Amazon basin in 2005 (left). Red colors indicate areas in the Amazon most impacted by the drought. Moderate Resolution Imaging Spectroradiometer (MODIS) data depicts anomalous forest activity in 2005 (right). The green colors indicate areas in the Amazon that became greener and more productive in 2005, in response to the greater availability of sunlight, while red colors represent areas that were negatively affected by the drought and yellow colors mean there was no significant response.



Jorge L. Sarmiento, Princeton University


Slide 1 for Jorge Sarmiento


Figure 5: Satellite observations of ocean color have been used to determine how seasonal blooms of microscopic floating plants, or phytoplankton, are related the thickness of the ocean surface's mixed layer – water that to a particular depth has uniform properties. Most of the ocean divides cleanly into two regions of opposite behavior: The blue region has deep wintertime mixed layers with the highest productivity of phytoplankton occurring as the mixed layer shallows. The red region has much shallower wintertime mixed layers with the lowest productivity of phytoplankton occurring when the mixed layer shallows. Global warming will likely cause mixed layers to become shallower everywhere, increasing productivity in the blue region but depressing it in the red region.


Slide 2 for Jorge Sarmiento


Figure 6: Results from a model simulation show how global warming will affect the extent of area of biomes such as those of Figure 5, over the next 100 years. The shallow wintertime mixed layer biome, shown in red, expands almost everywhere and takes over the areas denoted by pink. By contrast, the deep wintertime mixed layer biome, shown in blue, retreats almost everywhere, though it gains the area denoted by light blue. The percent change in area of each biome are noted for each ocean basin in each hemisphere.



Gregory Asner, Carnegie Institution


This shows how it is feasible to measure leaf nitrogen and water content from aircraft.
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Figure 7: Gregory Asner and colleagues have used the NASA Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) to measure leaf nitrogen and water content from aircraft. Traditional remote sensing of the forest canopy is shown at on the bottom. The middle and top images show canopy water content and leaf nitrogen concentration, which act like chemical fingerprints and allow the scientists to identify invasive species. Image courtesy Gregory Asner


3D images show invasive tree species, depicted in reds and pinks, and Native Hawaiian Lowland Rainforest, depicted in green.


Figure 8: 3-D images show invasive tree species, depicted in reds and pinks, and Native Hawaiian Lowland Rainforest, depicted in green. Credit: Carnegie Airborne Observatory

 
 
Kathryn Hansen
NASA's Goddard Space Flight Center