I built this with Geometry Nodes to make it easy to add objects on curves easily. This is customized with a fast and light procedural algae.With this you can use the curve drawing tool to add algae to anything you need.

The shader is also simple and procedural.

You also get controls for randomizing scale, rotation, density of leafs and deformation.The node tree can of course be used for other objects as well.

This was built in Blender 3.4.1If you have any questions feel free to reach out at all times. :)