Chapter 11
Water Mass Measurements Around Benthic
Communities: A Comparative Study Between
Yo-Yo Conductivity-Temperature-Depth
(CTD) Casts and High-Resolution Time Series
Data Acquisition of Bottom Waters from
the Page `s Escarpment in the Southern Bay
of Biscay
Wolf-Christian Dullo, Sascha Fl€ ogel, and Andres R€ uggeberg
Abstract We performed a comparative test study applying conventional
Conductivity-Temperature-Depth (CTD) casts and a self designed mini lander
system, which was deployed on the Page `s Escarpment on the Cantabrian Margin
at 762 mbsl water depth for continuous bottom water measurements. Our lander
data demonstrate that the mechanical movement of CTD gear disturbs the internal
structure of the bottom water mass and extreme values are most likely to be missed.
This questions the reliability of repeated CTD casts at the same site (yoyo-CTD)
with respect to the detailed bottom water mass characteristics bathing the benthic
communities. Although, repeated CTD casts may provide information about the
amplitude in temperature and salinity variability, our data clearly exhibit that
temperature and salinity maxima and minima respectively do not coincide only
with the most obvious semi diurnal tidal dynamics but exhibit other tidal frequencies, mainly M4, which are not captured by yoyo-CTD analysis. High resolution
CTD measurements in combination with ADCP data reveal a comprehensive
picture of bottom water mass dynamics.
W.-C. Dullo (*) • S. Fl€ ogel
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
e-mail: cdullo@geomar.de; sfloegel@geomar.de
A. Rüggeberg
De ´partement des Ge ´osciences, Universite ´ de Fribourg, Fribourg, Switzerland
e-mail: andres.rueggeberg@unifr.ch
© Springer International Publishing AG 2018
C.W. Finkl, C. Makowski (eds.), Diversity in Coastal Marine Sciences, Coastal
Research Library 23, DOI 10.1007/978-3-319-57577-3_11
181
Water Mass Measurements Around Benthic
Communities: A Comparative Study Between
Yo-Yo Conductivity-Temperature-Depth
(CTD) Casts and High-Resolution Time Series
Data Acquisition of Bottom Waters from
the Page `s Escarpment in the Southern Bay
of Biscay
Wolf-Christian Dullo, Sascha Fl€ ogel, and Andres R€ uggeberg
Abstract We performed a comparative test study applying conventional
Conductivity-Temperature-Depth (CTD) casts and a self designed mini lander
system, which was deployed on the Page `s Escarpment on the Cantabrian Margin
at 762 mbsl water depth for continuous bottom water measurements. Our lander
data demonstrate that the mechanical movement of CTD gear disturbs the internal
structure of the bottom water mass and extreme values are most likely to be missed.
This questions the reliability of repeated CTD casts at the same site (yoyo-CTD)
with respect to the detailed bottom water mass characteristics bathing the benthic
communities. Although, repeated CTD casts may provide information about the
amplitude in temperature and salinity variability, our data clearly exhibit that
temperature and salinity maxima and minima respectively do not coincide only
with the most obvious semi diurnal tidal dynamics but exhibit other tidal frequencies, mainly M4, which are not captured by yoyo-CTD analysis. High resolution
CTD measurements in combination with ADCP data reveal a comprehensive
picture of bottom water mass dynamics.
W.-C. Dullo (*) • S. Fl€ ogel
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
e-mail: cdullo@geomar.de; sfloegel@geomar.de
A. Rüggeberg
De ´partement des Ge ´osciences, Universite ´ de Fribourg, Fribourg, Switzerland
e-mail: andres.rueggeberg@unifr.ch
© Springer International Publishing AG 2018
C.W. Finkl, C. Makowski (eds.), Diversity in Coastal Marine Sciences, Coastal
Research Library 23, DOI 10.1007/978-3-319-57577-3_11
181