Sponges are a diverse and abundant phylum, globally occupying many hard-bottom habitats. However, data on East-Mediterranean sponge communities are scarce, outdated, and mostly concern the shallow waters. This study aimed to expand the knowledge on poriferan fauna along Israel’s Mediterranean coast. A newly-discovered mesophotic sponge ground at ~100 m depth was studied using a Remotely-Operated Vehicle, while shallow-water surveys were conducted by scuba diving. In this mesophotic ecosystem, sponges serve as environmental engineers, creating complex 3D structures that attract invertebrates and fish. Quantitative surveys of the mesophotic sponge ground revealed a rich and diverse sponge community with a high percentage cover (~35%). Several mesophotic species are reported for the first time from the Levantine Sea, while others might be novel species. Here we report 111 sponge species along the Mediterranean coast of Israel (from our current surveys and previous studies), 36 of which were collected from the mesophotic habitat. The updated sponge list supports the hypothesis that the sponge diversity in the Levantine Sea is not as species-poor as previously considered. A comparison of the sponge community composition between the shallow waters and the mesophotic depth revealed only partial overlap, with merely a few species thriving along the entire depth range. The mesophotic habitat was found to harbor some species that seem to have disappeared from the shallow habitats decades ago, suggesting that the former may serve as refugia for species stressed by rising temperatures in shallow waters, and that this deeper habitat thus require protection from negative anthropogenic influences

Depth range
0- 130 m

Mesophotic “mentions”
56 x (total of 7374 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'temperate mesophotic ecosystem'

Fields
Biodiversity
Community structure

Focusgroups
Porifera (Sponges)

Locations
Israel - Mediterranean Sea

Platforms
Remotely Operated Vehicle (ROV)
SCUBA (open-circuit or unspecified)