Multicellular Primary Producers

WELCOME!!

Most of the primary production in marine ecosystems is done by phytoplankton, but seaweeds and flowering plants also contribute.

Seaweeds are multi cellular algae that inhabit the oceans. There are three groups of seaweed that will be discussed. Red algae, Brown algae and Green algae.

Most species of seaweed are benthic. growing on rock, sand, mud and coral on the sea bottom, on other organisms. Seaweeds inhabit about 2% of the sea floor.

Seaweeds can reproduce both sexually and asexually. This type of asexual reproduction is called fragmentation.

Green algae are a diverse group of organisms that contain the same kind of pigments in land plants: chlorophylls a and b and carotenoids. Most species are freshwater and phytoplankton.

Important as seasonal sources of food for marine animals and also contribute to the formation of coral reefs.

Red algae are primarily marine organisms. About 98% of the 6,000 species are marine, which means red algae has the highest diversity among seaweeds. Red algae contain the accessory pigments phycoerythrin and phycocyanins.

Several red algae species are used commercially because of their gelling(stiffening) qualities. For example Agar is used primarily for making petri dishes. Another kind of algae carrageenan is also used as a thickening and binding agent in ice cream, pudding and salad dressings.

Brown algae are represented in forms such as rockweeds, kelps, and sargassum.

The 1500 species of brown algae are almost exclusively marine inhabitants.

They range in size from microscopic to the largest of all algae, the giant kelps which can attain lengths of 330 feet!! Much of the familiar seaweed seen along the shore and in shallow water is brown algae.

The life cycle of most brown algae consists of an alteration of generations between a sporophyte and a gametophyte.

Brown algae is also harvested for commercial use as thickening agents in dental, cosmetic and food industries.

Free floating clumps of sargassum weed forma complex three dimensional habitat that is home to a variety of unique organisms like this sargassum fish!!

http://www.youtube.com/watch?v=Grh6cYcPfBk Here is an awesome video about a Sargassum Fish and how it utilizes the seaweed as its habitat!

"Sea" you real soon!!