This is not my specialty, per se, but just like we use vegetation, topographic and land use differences on terrestrial ecosystems, some of these light be used with marine ecosystems.  Coeardin et al classified wetlands and deep water habitats, and one of the systems mentioned was marine, classified by substrate, vegetation, water depth, perhaps sunlight, temperature variance, etc.  With aerial photography and LiDAR detail, it is easier to select out terrestrial openings or edges.  We probably do not have the similar level of available detail and resources applied for the analyses on marine systems.  

Areas of coastal ocean upwelling have been mapped, and these may be an example of relatively confined areas of diversity that may qualify as an edge.  My guess is that marine biologists may not discuss edge effects in same way as terrestial biologists and ecologists do, but in discussions they might quickly identify with your intent, and perhaps have examples to provide where studies were confined to specific areas.

Sorry for a couple typos.  "might" instead of "light" in sentence 1. Classification by Cowardin et al. in sentence 2.  When I get to my computer, I will try to send the digital copy I have.

Probably the easiest place to start would be closed or restricted areas in the marine environment.  A lot of work has been carried out looking at spill over effects from closed areas and in some cases fishers fishing along boundaries of closed areas to get the best catch.  A paper in 2007 looked at the "Effects of habitat edges on American lobsters abundance and survival".  There is also a huge amount of work published on intertidal systems looking at colonisation of cleared space from edge creep (e.g. in mussels).  I hope this helps to get you started.  There is a lot of published work out there for the marine environment.  What databases have you been searching and what were your key words?

That would be great, William, thanks! I find the idea of upwelling areas to be subjected to edge effects particularly interesting.

Richard: That certainly makes a lot of sense! Honestly, just Google Scholar for now. It was just a casual search at best; just thought of the question when I was checking students' ecology exams :) But thanks!

Here is a digital copy of Cowardin et al on Classification of Wetland and Deep Water Habitats, it may have something useful for identifying and describing certain edge effect areas, including coastal habitats of varying water presence, persistence, etc.  Most of the US is mapped with this system by US Fish and Wildlife Service, mapped remotely by aerial photos, etc. and field verified to a certain degree.  It has a marine system in its classification, but probably does not approach the detail that may be needed to differentiate edges within deep areas.

Thanks!

I don't have an exact answer as to whether edge effects exist in the marine environment, but since edge effects are found where different environments (ex: city and forest) interact, there seems to be some connection to built environments in the marine world. A student lecture in one of my classes (not my presentation) discussed some papers that may be relevant to your question. One of the papers discussed is a paper by Bishop et al. that talks about how ocean sprawl affects ecological connectivity. Another paper discussed is one by Airoldi et al. It deals with how ocean sprawl favours non-indigenous species. Both papers seem to be open access.

I hope this helps

http://www.sciencedirect.com/science/article/pii/S0022098117300618

http://onlinelibrary.wiley.com/doi/10.1111/ddi.12301/

Article Effects of ocean sprawl on ecological connectivity: Impacts ...

Thanks Ted!

intertidal zones are an edge effect, coral reef or rocky intertidal. Specific communities are adapted to specific environments. Drying out, sun exposure, surviving rainwater, strong currents or wave action, all create niches that certain creatures have adapted to in order to avoid competition or predation.