Ecological and Biogeochemical Consequences of Collapsed Jellyfish Blooms

• Main Author: Chelsky, Ariella
• Other Authors: Kylie Pitt, Rod Connolly, David Welsh, Andrew Sweetman
• Format: Other/Unknown Material
• Language: English
• Published: Griffith University 2015
• Subjects: Jellyfish ecology; Jellyfish blooms; Jellyfish carrion; Griffith; Ocean acidification
• Online Access: http://hdl.handle.net/10072/365817

Jellyfish are distributed globally and often form blooms that last from weeks to months before they collapse. While blooms are sustained they can play an important role in carbon and nutrient cycling and can influence key ecosystem processes. When they collapse, the organic matter assimilated into their biomass is released into the system suddenly. This rapid input of organic matter could have significant implications for pelagic and benthic environments, however, post-bloom processes have rarely been studied. Furthermore, no work has investigated how rates of decomposition may alter with changing climate. Understanding how decomposition dynamics will change in the future has become increasingly important in light of recently observed shifts in the frequency of jellyfish blooms. The aim of this thesis was to investigate the ecological and biogeochemical effects of the decomposition of jellyfish carrion in pelagic and benthic environments. Decomposition dynamics were also investigated under present day and end-of-century conditions to resolve how rates of remineralisation will change with increasing temperature and ocean acidification. The rate of pelagic remineralisation of jellyfish carrion was investigated under present day and end-of-century temperatures (Chapter 2) to assess how climate change may influence the decomposition of jellyfish as they sink through the water column. The rate of microbial respiration increased with a 3°C increase in temperature, however, estimates of the overall quantity and quality of the gelatinous material reaching the benthos did not change significantly. Furthermore, after six days (a conservative estimate of the time it takes jellyfish carrion to sink to the benthos in the deep sea), the majority of the gelatinous tissue remained. Hence, most jellyfish carrion is likely to flux to the seafloor, under both present day and end-of-century temperature conditions, even for slow sinking carcasses in deep-water systems. Thesis (PhD Doctorate) Doctor of Philosophy (PhD) Griffith School of Environment Science, Environment, Engineering and Technology Full Text