Unless you anticipate shooting in very low light, the Nikon AF-S 28-70mm f/2.8 ED-IF has a lot of overlap with the 18-55mm kit lens you already have. It does have better optical image quality than your kit lens, but your kit lens is not that bad, either. The 28-70mm will also give you a bit more focal length reach at 70mm than the kit lens at 55mm, but you lose even more at the wide end comparing 18mm to 28mm (it's more about the ratios between the focal length numbers than the arithmetic differences).

The Nikon AF 80-200mm f/2.8D ED gives you a lot more reach to zoom in on distant vistas or to get closeups of things such as penguins without having to stand right over them.

If you're going on a packaged tourist trip to Antarctica, most such tours include visits to areas with large flocks of penguins that are highly acclimated to having humans walking around in their midst. You won't have to worry about shooting them from afar. You will get a different 'look' shooting from 20-30 feet with a telephoto lens compared to shooting with a wider angle lens from just a few feet.

But there is a catch with this particular 80-200mm lens when used on your D3100: It has no autofocus motor in the lens. The lens is only capable of autofocusing with Nikon bodies that have an autofocus drive motor built into the camera. The Nikon D3x00 and D5x00 series do not include such a motor in the camera body. If you choose to take this lens you will have to manually focus it for every shot you take with it using your D3100. Your camera does have a focus confirmation dot that will show in the viewfinder when the lens is in focus for your selected AF point.

You are going to have to weigh the additional focal length advantages of the AF 80-200mm f/2.8D ED against the ease of use of the AF-S 28-70mm f/2.8D ED-IF. (That '-S' after the 'AF' indicates that a "Silent Wave" focus motor is contained in the lens. The absence of that '-S' in the 80-200mm lens' name indicates there is not.)

My advice would be to try out both here at home before you leave if you can. The AF 80-200mm f/2.8D is a very good lens, but it takes some skill to manually focus it and it is a bit large and heavy if you are not used to it.

On the other hand, the AF-S 28-70mm f/2.8D is also a very good lens. While not as bulky and heavy as the 80-200mm, it is also quite a bit larger and weighs significantly more than any of the 18-55mm kit lenses Nikon has made over the years.