DEVONIAN CALCAREOUS ALGAE, TABULATE CORALS AND BIOCLAUSTRATIONS FROM THE KARAKORUM MOUNTAINS (NORTHERN PAKISTAN)

During several field work campaigns to the Karakorum Mountains samples containing Devonian macrofossils were collected by M. Gaetani and P. Le Fort, mostly in the uppermost Yarkhun Valley (Northern Pakistan). Generally, Devonian rocks are outcropping rather extensively in several thrust sheets of the Northern Karakorum Terrain, namely in the Chillinji, Baroghil/Lashkargaz, and the Karambar Units. The dolostones of the Tash Kupruk Zone, similar to the Chilmarabad Fm. of the previous units, are also Devonian in age. Fossils mentioned below originate from measured logs (Yarkhun River, Chillinji, Ribat), others from isolated localities. Identification of most of the fossils on species, or even at genus-level is difficult due to their moderate to poor state of preservation. Recrystallisation phenomena that had affected particularly porous skeletons, especially those with small-sized intra-skeletal cavities (i.e. intra-tabular spaces of small-sized tabulate corallites, and inter-laminar spaces of stromatoporoid skeletons) often preclude reliable determination. Nevertheless, from the following formations tabulate corals and calcareous green-algae could be determined: Chilmarabad Fm. (Lashkargaz/Baroghil Unit,), Shogram Fm. (Yarkhun River section), Margach Fm. (Ribat section), the Tash Kupruk dolostones (loose blocks north of Inkip). The taxa described are Pseudopalaeoporella ? sp., Receptaculites cf. chardini, Pachyfavosites polymorphus, Thamnopora grandis, Thamnopora cf. longdongshuiensis, Thamnopora cf. reticulata, Celechopora devonica, Alveolites (Alveolites) hudlestoni, Heliolites ? sp., Pachycanalicula ? sp., "Caunopora", and Helicosalpix asturiana. Most of the fossils described point to Middle to Upper Givetian age, although they are not particularly age diagnostic.

Functional morphology of coral shape and passive hydrodynamic self-righting in recent Manicina areolata

The scleractinian Manicina areolata is a common coral on Caribbean hard and soft substrata and was studied at Lee Stocking Island (Exuma Cays, Bahamas). It is not only found in reefal areas but also on bioclastic sand with seagrasses. The meandroid coralla typically grow to sizes of 2 to 10 cm and are morphologically variable. Growth form can vary from conical with round to oval cross-section to turbinate forms with few meanders and flat oval cross-section. The conical morphotype is usually attached to hard substratum, while the turbinate morphotype tends to live unattached, usually upright, in soft substratum. In infratidal areas, both attached and unattached turbinate forms were found in close vicinity, however, conical attached forms were rare. Habitats with sandy softgrounds, where free-living turbinate morphotypes were common, were influenced by strong tidal currents with concurrent danger of burial or \u27disorientation\u27 of the coralla. Therefore, strategies are necessary for the corals to remain in the upright position. Besides a high self-cleaning potential (FABRICIUS 1964), the colony shape itself leads to passive cleaning and self-righting, which is achieved by the flat-turbinate morphology of the corallum, with a concave side and a flat to slightly convex opposite side, under high current speeds. The concave side, and particularly the median lobes formed by many meandroid coralla, are the critical morphological factors. Particularly the grooves formed inbetween the lobes channel currents in a way that scour underneath the coral and drag produced by the lobes act together to allow passive self-righting

Hydrodynamic Self-Righting in Manicina Areolata, A Strategy with Palaeoecolgical Significance

The scleractinian Manicina areolata is a common coral on Caribbean hard and soft substrata and was studied at Lee Stocking Island (Exuma Cays, Bahamas). It is not only found on reefs but also on bioclastic sand with seagrasses. Investigated corolla ranged in size from 2 to 10 cm, growth form varied from conical with round to oval cross-section to turbinate forms with few meanders and flat oval cross-section. The conical morphotype was usually attached to hard substratum, while the turbinate morphotype was usually unattached and upright, in soft substratum. In infratidal areas, both attached and unattached turbinate forms were found in close vicinity, however, conical attached forms were rare. Habitats with sandy softgrounds, where free-living turbinate morphotypes were common, were influenced by strong tidal currents with concurrent danger of burial or “disorientation” of the corolla. Investigations in the flume channel showed that the colony shape itself led to passive cleaning and self-righting, which was achieved by the flat-turbinate morphology, with a concave side and a flat to slightly convex opposite side, under high current speeds. The concave side, and particularly the median lobes formed by many meandroid coralla, were the critical morphological factors. Grooves formed in between the lobes channeled currents in a way that scour underneath the coral and drag produced by the lobes allowed passive self-righting. This could be used to explain ecological strategies in similar-shaped fossil solitary corals

Devonian calcareous green algal flora of the Rannach Nappe (Graz Palaeozoic, Austria)

The Lower to Middle Devonian (Emsian – Eifelian) calcareous green algal flora of the Graz Palaeozoic (Austria) contains halimedalean representatives of Pseudolitanaia, Pseudopalaeoporella, Zeapora, Maslovina and a new lanciculoid taxon. Occurrences within the Graz thrust complex are restricted to four localities in the Rannach Nappe and may be characterised as monogeneric mass occurrences. Consequently, they are interpreted as algal bafflestones originating from halimedalean meadows

Controlled Reservoir Drawdown—Challenges for Sediment Management and Integrative Monitoring: An Austrian Case Study—Part A: Reach Scale

For Europe, a reduction of 80% of the potential storage volume due to reservoir sedimentation is predicted by 2080. Sedimentation processes trigger the decrease of the storage volume and a related restriction in hydropower production. Further, the artificial downstream flushing of deposited fines has manifold effects on the aquatic ecology, including changes in morphology and sediment quality, as well as increased turbidity and subsequent stress for aquatic species. However, it is common to lower the water surface of reservoirs for technical inspections, which is not comparable to reservoir flushing operations. The presented case study deals with such a controlled drawdown beyond the operational level of the Gepatsch reservoir (Tyrol, Austria). Based on the awareness of possible ecological consequences, an advanced set of measures and an integrative monitoring design, consisting of a detailed event-based quantification of suspended sediments, changes in the morphology, especially with respect to fine sediments, and analyses of the biological quality element fish on the reach scale along the Inn River have been developed