Book contents
- Frontmatter
- Contents
- Preface to the first edition
- Part 1 Introduction
- Part II The prokaryotic algae
- Part III Evolution of the chloroplast
- Part IV Evolution of one membrane of chloroplast endoplasmic reticulum
- Part V Evolution of two membranes of chloroplast endoplasmic reticulum and the Chlorarachniophyta
- 9 Cryptophyta
- 10 Heterokontophyta, Chrysophyceae
- 11 Heterokontophyta, Synurophyceae
- 12 Heterokontophyta, Eustigmatophyceae
- 13 Heterokontophyta, Pinguiophyceae
- 14 Heterokontophyta, Dictyochophyceae
- 15 Heterokontophyta, Pelagophyceae
- 16 Heterokontophyta, Bolidophyceae
- 17 Heterokontophyta, Bacillariophyceae
- 18 Heterokontophyta, Raphidophyceae
- 19 Heterokontophyta, Xanthophyceae
- 20 Heterokontophyta, Phaeothamniophyceae
- 21 Heterokontophyta, Phaeophyceae
- 22 Prymnesiophyta
- 23 Algae and the environment
- Glossary
- Index
23 - Algae and the environment
- Frontmatter
- Contents
- Preface to the first edition
- Part 1 Introduction
- Part II The prokaryotic algae
- Part III Evolution of the chloroplast
- Part IV Evolution of one membrane of chloroplast endoplasmic reticulum
- Part V Evolution of two membranes of chloroplast endoplasmic reticulum and the Chlorarachniophyta
- 9 Cryptophyta
- 10 Heterokontophyta, Chrysophyceae
- 11 Heterokontophyta, Synurophyceae
- 12 Heterokontophyta, Eustigmatophyceae
- 13 Heterokontophyta, Pinguiophyceae
- 14 Heterokontophyta, Dictyochophyceae
- 15 Heterokontophyta, Pelagophyceae
- 16 Heterokontophyta, Bolidophyceae
- 17 Heterokontophyta, Bacillariophyceae
- 18 Heterokontophyta, Raphidophyceae
- 19 Heterokontophyta, Xanthophyceae
- 20 Heterokontophyta, Phaeothamniophyceae
- 21 Heterokontophyta, Phaeophyceae
- 22 Prymnesiophyta
- 23 Algae and the environment
- Glossary
- Index
Summary
It is possible to write whole books on the relationships between algae and the environment. In this chapter I have chosen a few subjects which have generated the most interest in the last decade.
Toxic algae
Algae can be harmful in two basic ways (Hallegraeff et al., 2003).
Producing large populations in the aquatic environment Large growths of some algae (e.g., the diatom Chaetoceros (Figs. 17.44, 17.45) or the prymnesiophyte Chrysochromulina (Fig. 23.1(c))) can clog the gills of fish and can be particularly a problem in aquaculture systems. Anoxic conditions, resulting in fish kills, can occur at the end of blooms of other algae (e.g., green algae) as the algae die and decompose.
Production of toxins Some algae produce toxins that sicken and kill other organisms that prey on these algae. Indeed, this probably was the reason that these algae were selected for in the evolutionary process since it reduced predation by grazers (Gilbert, 1996). Filter-feeding shellfish can accumulate large quantities of these toxins as they filter the algae out of the water. Consumption of the shellfish by man, birds, and animals results in sickness and death.
The algae that produce phycotoxins are:
Cyanophyceae (cyanobacteria)
Neurotoxinsanatoxin (Fig. 23.2(c)) and saxitoxin (Fig. 23.2(c)) that block the transmission of signal from neuron to neuron. These alkaloids (nitrogen containing compounds) bind to voltage-activated Na+ -channels and block influx of Na+, thereby preventing the generation of an action potential (Shimizu, 2000).
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- Phycology , pp. 504 - 520Publisher: Cambridge University PressPrint publication year: 2008