Harmful Algae :: Geology

Abstract The purpose of this term paper is to provide information about the different kinds of algal blooms and their effect on our environment and ourselves. There are still a lot of things that are not known about the algal bloom phenomenon, and many different hypotheses have been presented to explain these. Throughout the course of this paper those hypotheses will be presented and discussed, allowing the reader to derive their own opinion about the origin of algal blooms and what will happen in the future. table of contents Table of Contents I. Harmful Algae II. What are Algal Blooms and Red Tides? III. Why do Algal Blooms occur? IV. What are the effects of Algal Blooms? V. Where and how often do Algal Blooms occur? VI. Resources I. Harmful Algae All algal species are not harmful. Only a few out of the thousands of species are associated with the phenomenon known as an algal bloom. These algae fall into two categories. The first category of harmful algae produces toxins that are released when ingested by animals or humans. The dinoflagellate Alexandrium tamarense (left) and the diatom Pseudo-nitzschia australis (right) are examples of toxin producing alga. The other category of harmful algae kill without toxins. These are equipped with structures such as spines and serrated edges that allow them to lodge in fish gill tissues. When this occurs it causes irritation which leads to overproduction of mucus which eventually leads to death. This Chaetoceros species (above) is an example of an algae that kills by using specialized serrated structures. back to table of contents II. What Are Algal Blooms and Red Tides? Algal blooms are when algae grows at a fast rate and accumulate near the surface, hence the term "algal bloom". The term "Red Tide" is a misnomer because it has nothing to do with the tides. It refers to a specific type of algal bloom that occurs when certain species of phytoplankton that contain red pigments "bloom" causing the water to look red. Red Tides are usually not harmful. The California Noctiluca Bloom is an example of a Red Tide back to table of contents III. Why Do algal blooms Occur? Scientists aren't exactly sure of how or why algal blooms get started. One theory is that when temperature, salinity, and nutrients reach certain levels there is a massive increase in the amount of algae.