Better than Whale Poop?: "Sea otters worth $700 million in carbon credits"

Oops. I must have had the stroke. A reader emails that 10¹⁰ kg is ten million tonnes.
Original post:
Last Month we had a look at "Whale Poo and You: Sperm Whale Feces Remove 200,000 Metric Tonnes of CO2 Annually" This month New Scientist reports:

...Want to slow global warming? Save a sea otter. So says Chris Wilmers at the University of California, Santa Cruz, whose team has calculated that the animals remove at least 0.18 kilograms of carbon from the atmosphere for every square metre of occupied coastal waters.

That means that if sea otters were restored to healthy populations along the coasts of North America they could collectively lock up a mammoth 10¹⁰ kg of carbon – currently worth more than $700 million on the European carbon-trading market. Wilmers explained this at the annual meeting of the Society for Conservation Biology in Edmonton, Canada, this month....

Figure 1: Sea otters, Enhydra lutris, in the wild. (Photograph by Ed Bowlby) Photo Gallery

I lifted the picture from the Journal of Young Investigators, back to NS:

Sink sizing

To estimate the minimum size of the carbon sink that could be provided by sea otters in North America, Wilmers and his colleagues determined the total available habitat for kelp – rocky reefs in up to 20 metres of water – and summed the amount of carbon that would be locked up in kelp either if no otters were present, or if the animals were present throughout in populations sufficient to control sea-urchin numbers.

The true size of the sink is likely to be larger than the calculated 10¹⁰ kg, Wilmers suggests, as some carbon drawn from the atmosphere by kelp forests may find its way into the deep ocean and be sequestered for long periods....

Unless I did have the stroke I feared earlier, 10¹⁰ kg is 5 times the 200,000 metric tonnes attributed to the whales.