As you have surmised...they are SWCN (single walled carbon nanotubes)
Found more description of the image after clicking "about". Interesting ref to "bundles" and iron.
About 2020 Science ABOUT THE IMAGES:
The images forming the header backdrop is of single walled carbon nanotubes. It was taken some years back while I was working on carbon nanotube aerosolization, characterization and exposure.
The material was formed using the High Pressure Carbon Monoxide (HiPCO) process, and is in its unprocessed state. 
The image is dominated by self-aligned bundles of carbon nanotubes (green), with some small-diameter bundles. The red dots are iron particles that act as the catalyst for nanotube growth in the HiPCO process – they are around 5 nm in diameter.
For the technically minded, the image was taken on an aging Philips EM 420 TEM, using a Gatan CCD. It was processed in ImageJ and Adobe Photoshop.
The panel displays currently shows a second TEM image of the same HiPCo material. Andrew Maynard. September 2009 Where this technology is headed & it's implications is really hard to fathom..for me anyway.
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