Joint Seminar: Multiple timescales of variability in pH and dissolved inorganic carbon in a dynamic coastal marine estuary

Increases in atmospheric carbon dioxide from anthropogenic sources are causing the acidification of marine environments with potential dramatic implications for the physical, chemical and biological functioning of these ecosystems.  Unmitigated, ocean pH is expected to decrease by ~0.2 units over the next ~100 years, but there is substantial spatial variability in pH and other carbon system parameters that exceeds this projected change.  Recent evidence has also shown that some locations are temporally dynamic, with a continuum of pH variability that can exceed 1 unit suggesting the high frequency variability may be important to marine ecosystems as well.  Here we describe results from monitoring pH and DIC at time scales spanning 1 hour to >1 year in a dynamic coastal marine estuary in a temperate environment.  We find that there exist multiple time scales of variability for both carbon parameters and that the current magnitude of change exceeds predictions for longer term trends.  The balance between production and respiration drives much of the variability on daily and seasonal timescales, but higher frequency variability (hours to days) is further influenced by water mass movement and stochastic events (e.g. storms).  We suggest that subdecadal variability of ocean carbon parameters may already exert significant pressure on some ecosystems with implications for ecology, biogeochemistry and evolution and this variability needs to be considered in addition to projected longer term trends.

Date

08.05.2012

Time

10:30 h

Place

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

Speaker

Zackary Johnson, Duke University

Organizers

Tatiana Ilyina

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