There is one interesting difference regarding the impacts of vents, described in part of this paper (starting at the bottom of page 7, then jumping in more detail to page 10), which is that Earth's oceans are stratified (i.e composed of distinct layers, stemming from effects of heating, cooling, and convection), whereas Europa's ocean may be unstratified and uniform. On page 10, the authors explain this by saying:

Earth's ocean is stratified because it is both heated and cooled at different locations along the upper surface. Water cooled at the poles slides beneath warm tropical water, forming stable stratification. If the dominant source of buoyancy in Europa's ocean is heat input at the base, the situation is more reminiscent of a pot of water on a stove, or of convection in the Earth's liquid core. The fluid should be convectively unstable everywhere, and stable stratification should not occur.

The authors say that they can apply this unstratified model to plumes from vents and therefore better explain ocean dynamics on Europa.

Sources:

National Oceanic and Atmospheric Administration

Woods Hole Oceanographic Institution

"Hydrothermal Plume Dynamics on Europa: Implications for Chaos Formation" by Goodman et al.