Posted this Citra / Cascade IPA recipe a while ago. Drinking it today and thinking about a re-brew. Tasting notes are at the bottom of the post.
The site is called Home Brew Answers. Let me know what you think.
I don't know if there is a term for it but I have had similar looking beer after primary. I thought it was just little clumps of yeast and also something you get a lot of bubbles accumulate on the surface which makes it look worse.
I have fermented a Belgian Ale at slightly cooler than that before now and it has been ok. You might want to check your yeast strain though to be sure it won't go dormant. I'd take a hydrometer reading every now and again if poss to make sure fermentation is progressing and not getting stuck
I had the same thing happen to me a couple of times and I took the airlock off and sanitized it. There will be a layer of CO2 protecting the wort whilst you do it anyway so next to no risk of infecting anything.
My brews are usually pretty cloudy at the point of bottling them but give it a week or two and it'll clear up. I guess it depends on how dark your porter is and how much proteins are in it as well as to how clear it gets.