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The Geoswim project: Snorkel-surveying along 250 kilometres of the Southern and Western Istrian Coast
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Downwearing rates of vertical limestone surfaces in the intertidal zone (Gulf of Trieste, Italy)
No full textIn 2007, we installed seven micro-erosion meter stations on a vertical limestone slab located in the intertidal
zone in the Gulf of Trieste (Italy) in order to observe rock surface changes at elevations ranging between
−0.75 m and +0.75 m m.s.l. (Furlani et al., 2010). In this paper, we present the micro-erosion metre
(MEM) data for most months between February 2008 and May 2013 and the traversing micro-erosion
metre (TMEM) data collected twice a year since 2007. The MEM and TMEM data were consistent and indicated
that the mean lowering rate ranged between 0.007 mm/yr and 0.205 mm/yr and −0.001 mm/yr and
0.260 mm/yr, according to the elevation of the stations. Maximum downwearing rates were observed in the
mid-lower intertidal zone and decreased upward and downward. The natural trend of erosion started in 2010,
after 2 years of exposure, when the slab, formerly smoothed and not colonized by marine organisms, started to
be acclimated to the local environment. After 2010, the erosion rate increased to a maximum of 0.31 mm/yr.
This value can be more representative for long-term studies and is similar to the downwearing rates locally
collected on natural limestone surfaces.
This dataset represents the first collection of downwearing rates mainly measured using MEMs, but also
TMEMs on vertical limestone surfaces in an intertidal zone and provides interesting new information for addressing
the debate on notch genesis and development. The shape of a tidal notch has been found to be consistent
with the distribution of erosion rates along the slab, even if the present-day notch was not surveyed in
the Gulf of Trieste due to the local tectonic subsidence
The swim-survey archive of the Mediterranean rocky coasts: Potentials and future perspectives
Full text linkThe Geoswim programme is an expedition-type project which is aiming to survey, monitor and measure the entire perimeter of rocky coasts of the Mediterranean Sea. The project officially started in 2012 with the first one-man survey of 193.4 km by snorkeling along the northeastern Adriatic coasts, and is ongoing. So far, 559.5 km of rocky coasts have been surveyed, over 98 days of survey, and several hundred thousand time-lapse images, continuous videos and outline images have been collected, both above and below the waterline. Bathymetric data and physical/chemical parameters, such as temperature and electrical conductivity have also been collected during the snorkel surveys. Instruments are hosted on a specially-built raft, called instrumental-supported raft (ISR). The data are not homogeneous because over the years the approach has changed following the introduction of new technologies and some redesign of the instruments used, and, in part, also the type of data collected. Moreover, observational data for use in coastal studies and for integrating instrumental data are collected. The paper presents and take stock of the geometry of the database and discusses the main results of the Geoswim programme.
Data analysed highlighted that the database is a significant archive that provides 1) images and videos as a baseline for subsequent comparisons, 2) large amount of images to be used to build 3D models of coastal landforms, 3) data for statistics, and 4) a valuable source of possible discoveries of unknown coastal objects, such as sea caves, tidal notches at unexpected sites, ecological observations, etc
Is the present the key to the future?
No full textThe empirical and conceptual relationships between Earth surface processes and global changes are very
complex. The concept that “the present is the key of the future” implies that we know enough the present to
be able to extend our knowledge forward to focus on the future. Field and remote observations on the
present-day Earth surface processes represent the methodological instruments for the forecasting. At the end
of the 1980s, the scientific community predicted a significant increase of global warming followed by changes
in the trends of related surface processes. Some processes, such as the Arctic and Antarctic snow melting are
now accelerating and even irreversible; thus these trends showthat we are nowin an ‘out of scale’ discontinuity
moment. Present-day measures and observations could be scarcely significant and may add uncertainty in the
prediction of future trends. The ‘out-of-scale’ trend raises a fundamental question regarding the present, since
it may provide a new angle of thought for contemporary theoretical approaches. The need for reducing the uncertainty
in the trends of future processes requires a deep rethinking of the current paradigms in order to consider
also the ‘out of scale‘ trends
Field surveying of intertidal limestone erosion susceptibility in the Gulf of Trieste: The "geoSwim Project"
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A new method to study microtopographical changes in the intertidal zone: one year of TMEM measuremets on a limestone removable rock slab (RRS).
No full textA new approach to the problem of measuring microtopographical changes on vertical limestones in the intertidal zone, simple and cost-effective, is discussed. It is based on the positioning of a rock removable slab (RRS) in the intertidal zone. The RRS method allows to use the traversing micro erosion meter (TMEM) on vertical rock surfaces, temporarily removing the slab from the operating position, so that measurements can be collected horizontally. Sources of errors and preliminary results, besides the limits and applicability of the method, are discussed.
We have tested the RRS method in the Gulf of Trieste, on a micro-tidal rock coast, collecting data from 7 stations between -0.75 m and +0.75 m m.s.l. The rock surface of the slab was surveyed between November 2007 and November 2008. During this period, the surface varied between -0.127 mm/yr (rising) and 0.034 mm/yr (lowering), according to the elevation of the stations. In the same period, standard deviation increased downward and varied between 0.003 and 0.045.
Beside the TMEM surveying, we have acquired near-monthly photographic images, in order to observe the biological colonisation of the slab. Monthly photographic comparison of the vertical slab indicates that biological colonisation affected mainly the mid-lower portion of the slab, sometimes preventing the collection of measurements.
Preliminary data suggests that the limestone surface lowered mostly in the upper part, while the lower part is strongly affected by algal growth. Consequently, data indicating surface rising is statistically less significant than data indicating surface lowering. Even the RRS used in the intertidal zone provides new interesting data to study weathering and erosion processes on limestone coasts, the first year of surveying suggests that this technique requires longer periods to address the TMEM data to explain geomorphological questions
Late Holocene widening of karst voids by marine processes in partially submerged coastal caves (Northeastern Adriatic Sea)
No full textThe coastal scenery of the Northeastern Adriatic sea is widely interested
by caves and related coastal features, which are developed in correspondence
of geological weaknesses of sea cliffs. We present the preliminary
surveying of five partially submerged coastal caves cut in limestone
cliffs, relating the dissolutionally widened vadose karst voids and the present-
day forms. The analysis pointed out two well-defined morphological
zones inside the caves. The boundary between the zones roughly coincides
with the mean sea level. The submerged zone is mainly affected by
abrasion processes on the bottom and the lateral walls, while the emerged
zone is interested by karst processes and collapse of blocks from the roof.
Their effects produce a bell-shaped cross-section, in which the submerged
part of the caves is significantly larger than the emerged one.
Considering the tectonic behaviour of the area inferred from literature
the caves were flooded about 6 ka BP, when marine processes started
to shape their submerged part. Our results allowed, in particular, to
evaluate processes shaping the partially submerged coastal caves in the
Northeastern Adriatic Sea after the marine transgression. Considering the
very preliminary surveyed data, we suggest that the early phases of cave
evolution was mainly dissolutionally-controlled and produced the widening
of pre-existing joints or faults, as demonstrated by the occurrence of
karst features in the upper part of the caves. Recent evolution is instead
marine-controlled and the widening is mainly due to the overlapping of
marine processes effects on karst voids, since they are closely related to
the Late Holocene sea level rise
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