[4] As a seagrass, it is restricted to growing underwater and is found in shallow parts of the Mediterranean Sea and certain adjoining areas of the Atlantic Ocean.

[5] Inconspicuous grass-like flowers are sometimes produced at the end of long stems in the spring when water temperatures begin to rise after their winter minimum.

[2] It grows at depths of down to nineteen[7] metres in sandy sediments in sheltered locations and needs clear waters for photosynthesis.

[4] Off the Catalan coast in the western Mediterranean, a single meadow of this grass covering at least 800 hectares (2,000 acres) has been discovered.

Although it is adversely affected by mechanical disturbance such as trawling and by pollution, and although it is in competition with other seagrass species, C. nodosa is not considered to be threatened.

Patch death was mostly caused by erosion as roots were uncovered, encrusting and drilling organisms increased and plants were swept away.

[14] The fact that the pattern of C. nodosa growth changes as sand is deposited provides a means of measuring the travel of subaqueous dunes.

A study was undertaken near the island of Elba, Italy, in which slow release fertiliser sticks were added to test plots of the seabed where the seagrass and alga both grew.