There are several categories of marine pollution. In this chapter, six categories of pollution encountered by macroalgae are discussed: metals, such as mercury, lead, cadmium, zinc, and copper; oil; synthetic organic chemicals, such as pesticides, industrial chemicals, and antifouling compounds; eutrophication (excessive nutrients, such as nitrogen or phosphorus); radioactivity, and thermal pollution. In the 1970s and ’80s, marine pollution was a hot topic and therefore some of these important early references have been retained. Over the last two decades, research on metals and eutrophication has been particularly active, followed by oil, antifouling paints, and organic wastes. There has been very little research on thermal pollution, even though it could be a good surrogate at local sites for assessing the potential long-term effects of global warming/climate change. Emerging anthropogenic issues are ocean acidification (see sec. 7.7 and Essay 4) and nanoparticles such as titanium dioxide (TiO2) (Miller et al. 2010, 2012).
General aspects of pollution
Several general considerations apply to studies on pollutants. Among these are the choice of test organisms, whether to study chronic or acute effects, the level of the effect such as lethal or sub-lethal, the complexities at various levels of organization from physiology to communities, and the issue of what is the biologically available quantity and form or species of the pollutant. Overall effects of a compound are assessed by acute or chronic exposure. Acute effects are the result of short-term exposure (e.g. 48–96 h) and are determined from the percent survival of an organism over a range of toxin concentrations. Chronic effects are the result of exposure for a relatively long time (e.g. 10% of the organism’s life span or longer (Walker et al. 2006)).