Development of chironomid-based transfer functions for surface water quality parameters and temperature, and their application to Quaternary sediment records from the South Island, New Zealand (2006)
Type of ContentTheses / Dissertations
Degree NameDoctor of Philosophy
PublisherUniversity of Canterbury. Geological Sciences
This thesis resulted in the development of robust chironomid-based transfer-functions for February mean air temperature and the concentration of total nitrogen (TN) in lake-water. The New Zealand transfer-functions for both variables compare favourably with chironomid-based transfer-functions for equivalent variables from elsewhere in the world, and diatom-based transfer-functions for nutrients and lake production from New Zealand. The application of the temperature and TN transfer-functions provided insight into New Zealand climate conditions during the last glacial and served as validation for the reconstructions. Chironomid-based Temperature reconstructions from lake silts preserved in the banks of Lyndon Stream indicate a maximum cooling of ca 4 ℃ between 26.6 and 24.5 ka BP, which is consistent with estimates based on beetles and plant macrofossils. A cooling of 4 ℃ is insufficient to explain the lack of canopy tree pollen in many New Zealand pollen records at this time. Other environmental parameters additional to temperature may have limited the expansion forest cover. The chironomid-based TN reconstructions infer a trend of rapidly deteriorating water-quality in a small doline in north-west Nelson, in the South Island of New Zealand following deforestation immediately surrounding the lake ca. 1970 AD. The overall trend and timing of eutrophication inferred from the chironomids was consistent with other biological proxies and actual observations of changes in lake water quality. The chironomid-based transfer-functions provide a valuable new tool for the study of longterm climate variability and improving our understanding of the response of aquatic ecosystems to long-term natural and human induced environmental change in New Zealand lakes. I have identified some possibilities for future research which should improve the performance of these transfer-functions. The improvement of the chironomid taxonomy and the expansion of the training set should be the highest priorities.
KeywordsChironomid; paleolimnology; transfer-function; New Zealand; Quaternary; Holocene; climate; lakes; eutrophication; Lake Forsyth
RightsCopyright Craig Allan Woodward
Showing items related by title, author, creator and subject.
Allan, Jonathan C. (University of Canterbury, 1998)Scientific evidence suitable for documenting and evaluating evolution of a shoreline at field scale from an 'initial' state is rare in the literature. Thus, descriptions of shoreline development and the derivation of ...
Palaeolimnological studies on sediments from Lake Grasmere, South Island, New Zealand, with special reference to the chironomidae (Diptera) Schakau, Barbara L. (University of Canterbury. Zoology, 1993)Palaeolimnological studies were carried out on a 326 cm long sediment core from Lake Grasmere. The core covered the last 6000 years of the developmental history of the lake. A pollen analysis revealed that Nothofagus pollen ...
A Record of Environmental and Climatic Change from the West Coast, South Island, New Zealand, using Beetle Fossils Burge, Philip Ian (University of Canterbury. Geological Sciences, 2007)Fossil beetle based palaeoclimatic and palaeoenvironmental reconstructions are presented from the Westport region, West Coast, South Island, New Zealand for the last glacial cycle. They include the longest continuous fossil ...