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| dissolved oxygen experiment in controlled temperature room |
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Full Title
Zooplankton and the effects of blackwater
Contact Person
Daryl Nielsen
Project Team
Stephanie Suter, Susanne Watkins
Funding Body
MDFRC vacation scholarship
Duration
20 November 2006 to 23 February 2007
Outcomes
Oral presentation
Summary
Blackwater events occur due to excessive accumulations of organic matter on the floodplain. Research has indicated that when leaf litter is present there is initial depletion of oxygen from the water column. The resultant low dissolved oxygen appears to be impacting either on the emergence of microfauna (rotifers and microcrustaceans) from dormant eggs or survivorship after emergence.
Our study is looking at how dissolved oxygen levels in the water column affect the emergence of rotifers from dormant egg banks present in floodplain/wetland sediments. This study will investigate two hypotheses;
(1) that low dissolved oxygen concentrations have a negative impact on the ability of microfauna to emerge from dormant eggs, and
(2) that low dissolved oxygen levels only provide a temporary block to emergence and are not lethal to dormant eggs
These hypotheses will be tested by conducting a series of experiments exposing dormant eggs to water with differing dissolved oxygen concentrations. This experiment will run for 21 days, with samples being taken during this period in order to assess microfaunal abundance and diversity. At the end of the initial 21 days all of the sediment will be exposed to high dissolved oxygen concentrations and allowed to incubate for a further 21 days to determine if the impact of low dissolved oxygen was lethal to the dormant eggs.
