Formation and Evolution of
Galaxy Clusters Across Cosmic Time

We present our search for large molecular gas disks and halos among member galaxies of the Spiderweb protocluster at z=2.2. ATCA observations of ~500 hours of the molecular cold gas via the CO(1-0) transition of the galaxy protocluster revealed 46 robust sources. These observations are part of the ATCA Large Program COALAS (CO ATCA Legacy Archive of Star-forming galaxies)  and covered in total 21 acrmin^2 through a  mosaic of 13 pointings of this galaxy cluster in formation. Motivated by two previously discovered large molecular gas reservoirs in this structure, we combined collapsed images and position-velocity diagrams of all 46 sources to make a homogeneous census of this phenomena unseen before. We present the search procedure and one representative case. Quantifying the frequency of such large molecular gas reservoirs is crucial to understand the built-up of the progenitors of elliptical galaxies dominating local galaxy clusters.