Check out http://www.bact.wisc.edu/microtextbook/Definitions.html.

My previous comments were with regard to autotrophs being pathogens. A pathogen is not simply an organism capable of producing toxins. It is one that lives on or inside another organism and causes damage. Most Autotrophs including cyanobacteria do not fit that definition. Your example does not contradict either the NRC, Zubrin, or my previous comments.

I specifically noted that some autotrophs produce toxins. That one responder chose to assume that meant I hadn't heard of red tide indicates a certain yellow vegetable residue where the sun doesn't shine as far as I'm concerned. This despite the fact that I usually agree with his opinions if not the way he chooses to conduct himself in BBS debates.

The effects mentioned in your link fall under the NRC's comment on the possibility of nonpathogenic organisms producing environmental toxins. It is this type of hazard that Zubrin is accused of overlooking by many interested in PP issues.

A couple of additional notes on your example.

Are you aware that your own body produces toxins?

Are a failure of your body to excrete these toxins is can be fatal?

Are you aware that the by-products of many metabolic pathways are toxic if allowed to build up due simply to basic principles of chemical equilibrium which dictate a limiting balance between reactants and products?

According to your source, the toxic effects mentioned occur primarily where the toxins are allowed to concentrate. In most environments these organisms are not a threat.

In short we have evolved in an environment full of moderate toxins and our bodies defenses have evolved to deal with them in the form of our nonspecific defenses. True pathogens are considered more dangerous because they can overcome our general defenses and cause relatively higher build ups of toxins within our bodies.

Your example supports the NRC's conclusions that although pathogenicity is not expected from Martian organisms toxicity is still a possibility. The NRC was quite comfortable that the risk level was low and that suitable containment technology exists for this level of hazard.

http://www.nas.edu/ssb/mrsrmenu.html9

Regards,
Mark