Macroalgal Defenses Against Herbivory: Causes and Consequences of Intraspecific Variation

In marine benthic communities, herbivores consume a considerable proportion of primary producer biomass and, thus, generate selection for the evolution of resistance traits. According to the theory of plant defenses, resistance traits are costly to produce and, consequently, inducible resistance traits are adaptive in conditions of variable herbivory, while in conditions of constant/strong herbivory constitutive resistance traits are selected for. The evolution of resistance plasticity may be constrained by the costs of resistance or lack of genetic variation in resistance. Furthermore, resource allocation to induced resistance may be affected by higher trophic levels preying on herbivores. I studied the resistance to herbivory of a foundation species, the brown alga Fucus vesiculosus. By using factorial field experiments, I explored the effects of herbivores and fish predators on growth and resistance of the alga in two seasons. I explored genetic variation in and allocation costs of resistance traits as well as their chemical basis and their effects on herbivore performance. Using a field experiment I tested if induced resistance spreads via water-borne cues from one individual to another in relevant ecological conditions. I found that in the northern Baltic Sea F. vesiculosus communities, strength of three trophic interactions strongly vary among seasons. The highly synchronized summer reproduction of herbivores promoted their escape from the top-down control of fish predators in autumn. This resulted into large grazing losses in algal stands. In spring, herbivore densities were low and regulated by fish, which, thus,enhanced algal growth. The resistance of algae to herbivory increased with an increase in constitutive phlorotannin content. Furthermore, individuals adopted induced resistance when grazed and when exposed to water-borne cues originating from grazing of conspecific algae both in the laboratory and in field conditions. Induced resistance was adopted to a lesser extent in the presence of fish predators. The results in this thesis indicate that inducible resistance in F. vesiculosus is an adaptation to varying herbivory in the northern Baltic Sea. The costs of resistance and strong seasonality of herbivory have likely contributed to the evolution of this defense strategy. My findings also show that fish predators have positive cascading effects on F. vesiculosus which arise via reduced herbivory but possibly also through reduced resource allocation to resistance. I further found evidence that the spread of resistance via water-borne cues also occurs in ecologically realistic conditions in natural marine sublittoral. Thus, water-borne induction may enable macroalgae to cope with the strong grazing pressure characteristic of marine benthic communities. The results presented here show that seasonality can have pronounced effects on the biotic interactions in marine benthic communities and thereafter influence the evolution of resistance traits in primary producers.

Tapes, Transgression and Mundanity: the participatory engenderment of death metal and grindcore

Since its origins in the early 1980s, the popular rise of extreme metal throughout the globe has been phenomenal. The emergence of extreme metal's most sonically transgressive subgenres of death metal and grindcore between the mid 1980s and the early 1990s, however, was not an easy one. Indeed, during this period, the only way for globally dispersed extreme metal fans and unsigned extreme metal bands to stay musically connected was via the underground practice of tape-trading. The aim of this study is to illuminate the impact of tape-trading upon the global spread of extreme metal. The study will situate the historical context of extreme metal tape-trading by exploring how it emerged, and why it was necessary in the first place. Utilising the concept of 'extreme metal scene', the study will focus on the central scenic discourse of transgression and explore how this was negotiated into the mundane scenic practice of tape-trading. In relation to this, and utilising the concept of participatory culture, the study will further explore how the music arose and spread throughout the globe via the socially networked practice of both musician and non-musician tape-traders in relation to the tape cassette technology itself. Ethnographic interviews were undertaken with both types of traders in order to gain a deeper understanding of the phenomenon in question. The research concludes that the tape-traders were able to challenge the status quo of record company gatekeepers, by facilitating the engenderment and global distribution (including the later commercial distribution) of death metal and grindcore. Such powerfully affective music via its continual global spread, offers as it did for the original tape-traders, a pleasurable and empowering communal/personal space for disempowered people throughout the globe. Further research into extreme metal tape-trading would require deeper exploration into other extreme metal subgenres, especially black metal, tape-traders situated outside of North America and Europe, women tape-traders as well as exploration of the phenomenon after the early 1990s.

Tapes, Transgression and Mundanity: the participatory engenderment of death metal and grindcore

Since its origins in the early 1980s, the popular rise of extreme metal throughout the globe has been phenomenal. The emergence of extreme metal's most sonically transgressive subgenres of death metal and grindcore between the mid 1980s and the early 1990s, however, was not an easy one. Indeed, during this period, the only way for globally dispersed extreme metal fans and unsigned extreme metal bands to stay musically connected was via the underground practice of tape-trading. The aim of this study is to illuminate the impact of tape-trading upon the global spread of extreme metal. The study will situate the historical context of extreme metal tape-trading by exploring how it emerged, and why it was necessary in the first place. Utilising the concept of 'extreme metal scene', the study will focus on the central scenic discourse of transgression and explore how this was negotiated into the mundane scenic practice of tape-trading. In relation to this, and utilising the concept of participatory culture, the study will further explore how the music arose and spread throughout the globe via the socially networked practice of both musician and non-musician tape-traders in relation to the tape cassette technology itself. Ethnographic interviews were undertaken with both types of traders in order to gain a deeper understanding of the phenomenon in question. The research concludes that the tape-traders were able to challenge the status quo of record company gatekeepers, by facilitating the engenderment and global distribution (including the later commercial distribution) of death metal and grindcore. Such powerfully affective music via its continual global spread, offers as it did for the original tape-traders, a pleasurable and empowering communal/personal space for disempowered people throughout the globe. Further research into extreme metal tape-trading would require deeper exploration into other extreme metal subgenres, especially black metal, tape-traders situated outside of North America and Europe, women tape-traders as well as exploration of the phenomenon after the early 1990s.