I just want to reiterate the hope that zarr could become a multi-language array storage format. The zarr specification is clearly written and is in no-way python-specific. The basic principles of compressed chunked array storage are so universal that two independent implementations (zarr and N5) are basically interoperable already (see Z5).
It would be fantastic to see a Julia implementation of the Zarr spec. The Zarr developers and the Pangeo project would be really happy to find some Julia collaborators interested in working on this.