A Seaweed Divided

What touches each of our lives on land, determines the destiny of millions of aquatic organisms, and is estimated to be worth over a million dollars a year per square mile?

What if we said they may thrust skyward from the sea floor forming canopies where assorted seabirds vie for perches, carpet rocks in intertidal zones, fortify coral reefs, or, dislodged and washed up on a beach, form a wrack line for beachcombers and a buffet for small crustaceans? Image ID: Giant Kelp, NOAA's Restoration Center Collection Location: Baja, California

Neither plants nor animals, seaweeds are classified into three major groups — the red algae, green algae and brown algae — distinctions which are not always obvious by their apparent color.

Seaweed Some Points for Discussion Food Oxygen Some live on tissues of other seaweeds Multicellular algae Macrophytes or macroalgae Eukaryotes Pigments Highly variable Nutrient rich Produce phycocolloids – algin – stabilizer; emulsifier in dairy products; carrageenan (Chondrus); agar

General Structure Blades – leaf-like, broad surface Stipe — stemlike support structure No transport system in stem or leaf Holdfast – not involved in absorption of water, lack transport tissues Thallus – complete body Question: How do they differ from land plants?

Green Algae Phylum Chlorophyta – green algae Mostly freshwater, 10% estuaries Many unicellular, Halimeda (calcareous green algae) Three Types of Seaweed

Green Algae Growing on a rock in the shallows of the Patuxent River Green Algae Image ID: line2273, NOAA's America's Coastlines Collection Location: Patuxent River, Maryland Photo Date: 2001 November Photographer: Mary Hollinger, NODC biologist, NOAA

Brown Algae Phylum Heterokontophyta – brown algae, olive to dark brown, fucoxanthin 1,500 species, all marine Kelps (largest) Temperate and polar rocky coasts Rockweeds, wrack, sargassum

Brown Algae Pelagic brown algae in the genus Sargassum. The berry-like structures are gas-filled bladders known as pneumatocysts, which provide buoyancy to the plant. NOAA’s Estuary to Abyss Expedition 2004 Brown Algae Image ID: expl1137, Voyage To Inner Space - Exploring the Seas With NOAA Collect Photographer: Image courtesy of H. Scott Meister, SCDNR Credit: Estuary to Abyss NOAA Office of Ocean Exploration.

Red Algae Phylum Rhodophyta – Red algae phycobilins Marine, shallow waters, largest group Some may be parasitic Some are calcareous (have a skeleton) – important in coral reef habitats Food for humans – Gracilaria

Red Algae North Inlet - Winyah Bay National Estuarine Research Reserve. Seaweeds like this red algae are important producers in estuaries, especially during winter months. Red Algae Image ID: nerr0319, NOAA's Estuarine Research Reserve Collection Location: Vicinity of Georgetown, South Carolina

Economic Importance Mariculture – Japan, China, Korea Nori, ogo, dulse, Irish moss Source of salts, trace elements, fiber, iodine 3 oz of dried seaweed = more vitamin A, B-1, B-2, half requirement vitamin C Carrageenan – thickener, smoother, emulsifier (puddings)

Food for Thought Algin – cell wall of brown algae (kelp), thickening, suspending, emulsifying such products as polishes, shampoos, cosmetics, ice cream; preventing frostings and pies from drying; thickening printer paste (sharper prints) Agar – jellylike from Gelidium – substitute for gelatin and as an anti-drying agent for foods like cheese, ice cream, and canned meats. Lab gels. Indigestible (laxatives, pharmaceuticals) Ash – burned seaweeds containing Na and KOH (potash) used in manufacturing glass and soap Fertilizers Fuel Question: Have you used something with seaweed today?

What are the limiting factors for algal growth? Numerous types of algae are visible in this image. Although over 50 meters deep, the light penetrates through the very clear water in this area of the Gulf of Mexico.

How would you classify this specimen? Image ID: line1320, NOAA's America's Coastlines Collection Location: Maine, Cousins Island Photographer: Mr. William Folsom, NOAA, NMFS

A Case Study A sea change, taking place in the Baltic Sea, worries scientists, fishermen, politicians and citizens. Something is happening in the Baltic Sea’s underwater forests. A new kind of seaweed that is less ideal for fish, crustaceans, barnacles and other organisms is spreading over hundreds of miles in the north. Extensive algal blooms caused by eutrophication and vast “dead zones” have formed on the sea bottom. Seven of the world’s ten biggest dead zones, where nothing can survive due to lack of oxygen, are found in the Baltic Sea.

A Seaweed Divided Illustration Patterson Clark, The Washington Post What is the impact of salinity changes on the growth of seaweed in the Baltic Sea?

Narrow Wrack — Super Female Clone Baltic Sea Offshoot Encroaches on a Vital Counterpart

What has concerned scientists since the discovery of the narrow wrack in the Baltic Sea? How is salinity related to the reproductive cycle of the bladder wrack and the narrow wrack seaweed?

What threats exist for all seaweed? What are the benefits of seaweed?

For more information about the bladder wrack and narrow wrack, read The Washington Post Science page article, “A Seaweed Divided Against Itself Upsets Oceanic Order.” This August 3, 2009, article may be found in The Post NIE program online curriculum guide: The Sea — Rich and Strange. Download at no cost at select lesson plans, September 10, 2009.