Sediments

Description

This project made use of a suite of palaeoecological approaches to reconstruct a chronology of change in coastal water quality over the last approximately 100 years. The biogeochemical proxies addressed phytoplankton composition and biomass, temperature and terrestrial influences. Where possible these were matched to historical land/water use, meteorological or hydrological observational records.

The project examined sediment cores from three coastal locations in the Kimberley region, Koolama Bay (King George River), Cygnet Bay and Roebuck Bay. Each sampling location provided a contrast with which to evaluate changes over either a spatial or temporal gradient of human or natural influences.

Aims

• Reconstruct a timeline of inferred water quality changes from the sediment record for a selected set of sites in the Kimberley.
• Use the results to determine the level of variability and change in water quality over the last 100 years and provide a baseline against which future changes can be assessed.

Methods

• Sediment cores to 1.5 metres were collected from three sites.
• Cores were tested for a set of parameters ever 1-2 cm, incling 210 Pb, 15N, 13C, C/N ratio, sedimentation rate, grain size, total organic carbon and nitrogen, phytoplankton biomass and type (diatom skeletons and dinoflagellate cysts and biochemical markers (brassicasterol and dinosterol).

Outcomes

• An understanding of the historical and baseline environmental conditions ahead of these impacts.
• Established baseline and historical water quality in the Kimberley information ahead of major local impacts and will help enable interpretation of the changes that may have occurred in recent years from climate change.

Project News

Sediment timeline reveals climate change influence on Kimberley

Field report from research vessels in Camden Sound, Kimberley region

Reports

Liu D, Peng Y, Keesing JK, Wang Y, Richard P (2016) Paleo-ecological analyses to assess long-term environmental effects of pearl farming in Western Australia. Marine Ecology Progress Series doi:10.3354/meps11740

Yuan Z, Liu D, Masqué P, Zhao M, Song X, Keesing J K (2020) Phytoplankton Responses to Climate‐Induced Warming and Interdecadal Oscillation in North‐Western Australia. Paleoceaonography and Paleoclimatology doi:10.1029/2019PA003712

Yuan Z, Liu D, Keesing, J K, Zhao M, Guo S, Peng Y, Zhang H (2018) Paleoecological evidence for decadal increase in phytoplankton biomass off northwestern Australia in response to climate change. Ecology and Evolution doi:10.1002/ece3.3836

 

Presentations

Historical reconstructions of water quality in the Kimberley using sediment records (2017 WAMSI Research Conference)

Historical reconstructions of water quality in the Kimberley using sediment records (Parks and Wildlife Lunch and Learn Seminar)

Historical changes in water quality inferred from the sediment record (2015 WAMSI Research Conference)