Harmful Algal Blooms

Home , Algal bloom, Harmful algal bloom, Marine habitats

NSF GK-12 Graduate Fellows Program Award # DGE-0139171 University of North Carolina at Wilmington

by Tika Knierim, Department of Chemistry

This activity is aligned with the 2001 North Carolina Standard Course of Study for 8th Grade Science: Goal # 1 & 2

Algal species sometimes make their presence known as a massive “bloom” of cells that may discolor the water

These “blooms” alter marine habitats Every coastal state has reported major blooms Although they are referred to as harmful algal blooms, not all HABs are toxic

Toxic blooms are caused by algae that produce potent toxins that can cause massive fish kills, marine mammal deaths, and human illness There are several types of toxins produced by these harmful algae. . .commonly the toxins affect the functioning of nerve and muscle cells

Toxic blooms have been responsible for causing diarrhea, vomiting, numbness, dizziness, paralysis, and even death

The key is how the toxins move through the food web The key to this scenario is bioaccumulation!!

BIOACCUMULATION is the process by which compounds accumulate or build up in an organism at a faster rate than they can be broken down.

Some organisms, such as krill, mussels, anchovies, and mackerel, have been found to retain toxins in their bodies Today we are going to do a little activity in order to better understand the concept of bioaccumulation and how toxins are transferred through the food chain. Each person will be assigned one of the following organisms:

Krill: Seal:

Fish: Killer Whale: There is an outbreak of a Harmful Algal Bloom within the boundaries of this classroom, and there is algae (green beads) spread all over the area. The only organisms that are able to eat the algae are the krill. The fish can then eat the krill, the seals can eat the fish, and the whale can eat the seals. Each organism (person) will receive specific instructions as to how they will react to this bloom. The krill will have 30 seconds to “graze” the area and “eat” as much algae (place algae into “food bag”) as possible.

The fish will then do what is indicated on their card. . .the fish will “eat” the krill by tagging them and taking their food bag. Once a krill is tagged, he/she should sit down to indicate that they have been eaten. The living krill can continue to “graze” during this time.

Once the fish have accomplished their tasks as indicated by the cards, the seals will then do as their cards say, and so on. Now that everyone has “eaten. . .” This Harmful Algal Bloom contained toxic algae!!! If you consumed the large green beads, you have consumed toxic algae! Sort the toxic algae from the non-toxic algae small green beads Count the total number of algae Count the number of toxic algae Calculate the amount of toxic algae you consumed as a percent of your total consumption: 100 x (# of large green) / (total #) Are there any krill that are still alive? If you (krill) ate ANY toxic algae, you are now dead Are there any fish still alive? If you consumed 20% or more toxic algae, you are now dead Are there any seals still alive? If you consumed between 20-30% toxic algae, you are now sick If you consumed over 30% toxic algae, you are now dead If the killer whale ate between 20-30% toxic algae, you are now sick If the killer whale are over 30% toxic algae, you are now dead So how many of us are still alive at this point?

How many are sick? References

• www.bigelow.org/edhab/tracing- toxins.html