At CIMA (Atlantic Center for Environmental Research, S.L.), we want to show you what we do—both in our offices and beyond.

On this page, you’ll find a series of short videos called "Things We Do at CIMA", which will help explain what we do and how we do it. All to bring you closer to the world of Marine Biology and Oceanography.

– «Things We Do At CIMA» #7: Underwater Quadrats:

Do you remember the video where we discussed mapping marine vegetation? In it, we mentioned conducting transects with video cameras to map underwater plant species (Cymodocea nodosa in that specific case).

Just as on land, sometimes we need to study populations in greater depth and sample underwater vegetation more detailedly.

To do this, we dive into an area where the presence of a Cymodocea nodosameadow is known, either from mapping conducted by the the company ompany or data from other studies. We mark new transects by randomly laying a measuring tape within the meadow and use hollow 25x25 cm quadrats placed along the transects. These quadrats help us determine shoot density , coverage and frecuency .

Sampling is performed using non-destructive methods with the quadrat and a slate engraved with a ruler on one side. Data and notable observations from the sampling point are recorded on the slate.

Each sampling consists of two parts: – Density determination: Counting the number of shoots (plants) within the 25x25 cm quadrat. – Shoot height: Measuring 10 shoots (leaves) within the quadrat. Each plant typically has 2-3 shoots, and the tallest shoot from each plant is measured.

This allows us to precisely characterize the meadow, identifying areas where the seagrass bed is dense, moderately dense, or sparse, and monitor its evolution in future studies.