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Ref. No. [UMCES] CBL 2016-013
ACT VS16-04
27
Figure L.
Assessment of the sensor response time for the Onset HOBO logger with RDO (sn 10603120).
Top Panel
: Time series of 10s reads of instruments during transfers between high and low DO buckets
maintained adjacent in a common water bath equilibrated at 15
o
C. Indicated DO levels were maintained by
airstone bubblers (high DO) or air+N2 (low DO) and verified by Winkler assays.
Bottom Panels
: All high
DO to low DO transitions were normalized to last reading before condition switch for the indicated time
post transition (left).
Data was fit with a 3 parameter exponential decay function: DO
rel
= DO
relMin
+ a
e
-bt
and indicated τ calculated from fit. Data for low DO to high DO transitions (
lower right
) were treated
similarly but normalized to steady state value in subsequent high DO tank and subsequently fit with an
analogous 3 parameter exponential rise function: DO
rel
= DO
relMin
+ a(1-
e
-bt
) with indicated τ being directly
calculated from fit.