BIOSTRATIGRAPHIC ANALYSIS OF THE OLIGOCENE-EARLY MIOCENE SUCCESSIONS FROM SULAIMANI AREA, KURDISTAN REGION, IRAQ

Three sections (Darzila, Hazar Kani and Basara) of the Oligocene –Early Miocene successions from Sulaimani area, Kurdistan region-NE Iraq, were measured and studied in order to interpret the biostratigraphic zonations at the Low and High Folded Thrust zones boundary, Low Folded Thrust zone, which are integrated with strontium stratigraphic dating. Accordingly, five biozones have been identified and they are:1- Nummulites vascus- Nummulites intermedius- Nummulites fichteli Assemblage Zone (Shallow Benthic Zone, SBZ 22A) represents the Rupelian age, 2- Lepidocyclina dilatata- Nummulites vascus - Nummulites fichteli Assemblage Zone (SBZ 22B-Early Chattian), 3- Praerhapydionina delicata- Archaias kirkukensis Assemblage Zone (SBZ23) representing the Late Chattian age, 4- Austrotrillina howchini- Peneroplis evolutus Assemblage Zone (SBZ24), almost point to the Aquitanian age and finally 5- Austrotrillina asmariensis- Dendritina rangi Assemblage Zone (equivalent to SBZ25) representing the Burdigalian age. Based on the distribution of the larger foraminifera and strontium stratigraphic dating, the Baba Formation is of Early to Late Oligocene age (Rupelian- Early Chattian), while the Bajawan Formation is of Chattian age, in addition to that, the Anah Formation is of Early Miocene age (Aquitanian) and the Jeribe Formation is of Burdigalian age. It is worthy to mention that the Oligocene-Miocene boundary has been identified in the studied area as well as, the gap duration between different formations of the Kirkuk Group, and the gap durations due to the absences of Serikagni, Euphrates and Dhiban formations.

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

<i>Abstract.</i>—The applicability of catchment indicators for predicting aquatic invertebrate responses in both vertical and lateral dimensions of river ecosystems is poorly understood. Therefore, our objective was to determine whether landscape indicators can predict coupled benthic-hyporheic responses in river and riparian environments. To do so, we assessed the relationships between the proportion of crop fields, instream habitat conditions, and abundance of larval and adult Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa in (and from) benthic and hyporheic zones of a 15-km segment of the Satsunai River (catchment area: 725 km2), eastern Hokkaido, northern Japan. Invertebrates were collected using colonization traps (hyporheic taxa), Surber sampler (benthic taxa), and Malaise traps (adults). We first identified insect taxa belonging to each of the benthic dwellers (EPT, excluding chloroperlid Plectoptera) and hyporheic dwellers (chloroperlid Plectoptera) based on the relative unit-volume abundances in benthic zone (7-cm surficial part of riverbed) and hyporheic zone (30 and 50 cm deep). Nitrate concentration and total chlorophyll, the abundance of larval insects in both zones, and adult insects from the benthic zone increased with an increasing proportion of crop fields. In contrast, the abundance of adult invertebrates originating from the hyporheic zone maximized in the area with an intermediate proportion of crop fields. We attributed this disparity to the spatial variability in total availability of functional hyporheic habitat in a vertical dimension, which could not be explained by the abundance estimates on a unit-volume basis. Overall, the proportion of crop fields in a catchment can be used to predict numerically similar (coupled) abundance responses of EPT larvae in river benthic and hyporheic zones. Furthermore, the use of landscape indicators in predicting coupled benthic-hyporheic responses in the riparian zone can be improved with information on the vertical extent of functional hyporheic habitat.

Ecology and biology of Hydrozetes paulista (Acari: Oribatida) in the benthic zone of a temporary lake in Brazil

Oribatid mites are mainly terrestrial animals, but some are aquatic, including all species of the genus Hydrozetes (Hydrozetidae). They have often been recorded in abundance on the water’s surface, while their presence in the benthic zone is poorly documented. A litterbag experiment was carried out in Coutos Lake, a shallow temporary lake in Southeast Brazil, in order to study the ecology and biology of Hydrozetes paulista. This mite species greatly dominated the benthic invertebrate community (82%), and at the end of the experiment it reached a density (652 individuals per 1 g of dry substrate) higher than that ever previously reported before for any Hydrozetes species. This density was correlated with some water parameters, stronger with conductivity, and less with temperature. The adults dominated in the stage structure (constituting over 80% of sample population), but the participation of the juveniles increased with the time. Larvae were first noticed on 25th day of experiment and after that were present for the rest of the season. During the course of this experiment, mite fecundity and body size decreased. This species is known as bisexual, but we observed only females in the 5354 adults we collected.