Gulf Of Maine

Two Tides Blog

Cold water sea life blog. Gulf of Maine biologists share their experiences and marine musings from Cobscook Bay on the coast of Maine! Sea life photos, science, and aquarium discussion. Comment and share your stories and questions!

The blog of Gulf of Maine



Live Aquarium Filtration


Seaweed is a robust carbon dioxide processor, releasing dissolved oxygen into the water as a product of photosynthesis. By growing seaweed in your tank you are harnessing a macroalgal filter for your water! One of my tank favorites is coral weed.

Corallina is a unique type of macroalgae or seaweed.  As it grows, it adds parts like a string of tiny beads. Taking calcium from the seawater, it uses this mineral to reinforce its frond structure. Because it has calcium in the growing fronds, this makes it tougher and keeps it from being eaten by ordinary bottom grazers like sea urchins or snails. 


When we collect Corallina we often put the clusters into a pail of seawater alone. Over time the coral weed fronds will reveal an entire host of isopods, worms, larval fish, and other organisms that have been feeding and taking shelter in this seaweed. Very interesting to see how this fauna supports a medley of other marine life. Our best specimens are supplied attached to horse mussels and small rocks. These look great in any aquarium because of their color and longevity.

Their branching structure lends itself well to the positive functions of seaweed in aquatic systems. Seaweeds take up heavy metals and excess nutrients from the water it lives in while providing dissolved oxygen to the tank. Coral weed combs the water, refreshing the tank.

Tidepool Tim