Thesis
Seasonal stability in time series of zooplankton abundance
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2010
- Thesis identifier
- T12572
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- We investigate ways to test for various aspects of seasonality in marine time series. In particular, we analyze series from the Stonehaven Ecosystem long-term monitoring station, run by Marine Scotland, Aberdeen. Our main focus is in identifying any systematic changes in seasonality as these may be attributed to climate change. We explore existing methodologies and introduce simple and robust Resampling tests. Generalized Additive Models (GAMs) are used to seasonally decompose each series and test the significance of individual components. We study the seasonal patterns of some environmental series but also phytoplankton and zooplankton species series from Stonehaven. Climate change will have a direct effect on phytoplankton communities as they are influenced by changes in the currents, the water temperature and salinity, as well as the availability of nutrients. The zooplankton species feed on the phytoplankton biomass and are themselves prey to larger fish and other top predators. Evaluating the seasonal patterns of phytoplankton and zooplankton populations is in itself important because plankton species are at the heart of the marine food web. Of the environmental series from Stonehaven which we examined, Salinity, Ammonia and Nitrate have patterns that are systematically shifting earlier in the year. Chlorophyll a, which is an indicator of the phytoplankton biomass, has a pattern whose amplitude is gradually decreasing while it is also shifting slightly earlier in the year. Amongst the zooplankton series analyzed, Acartia clausi copepodite stage 6 males (C6m), Calanus finmarchicus C5 and Calanus helgolandicus C5 have patterns systematically shifting earlier in time. Calanus helgolandicus C6f and C6m and Juvenile Calanus copepods C1 - 4 have seasonal patterns whose amplitude is systematically increasing as well as shifting earlier in the year. These zooplankton species are important because of their role as prey in the life cycle of the most commercially important fish. Our results indicate the nature and magnitude of the effect that climate change has on marine life and provide a basis for further analyses.
- Resource Type
- Note
- Previously held under moratorium from 22/09/2010 - 22/09/2012.
- DOI
- Date Created
- 2010
- Former identifier
- 814393
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