The Mediterranean hydrologic budget from a Late Miocene global climate simulation

During the Late Miocene the Mediterranean experienced a period of extreme salinity fluctuations known as the Messinian Salinity Crisis (MSC). The causes of these high amplitude changes in salinity are not fully understood but are thought to be the result of restriction of flow between the Mediterranean and Atlantic, eustatic sea level change and climate. Results from a new Atmospheric General Circulation Model (AGCM) simulation of Late Miocene climate for the Mediterranean and adjacent regions are presented here. The model, HadAM3, was forced by a Late Miocene global palaeogeography, higher CO₂ concentrations and prescribed sea surface temperatures. The results show that fluvial freshwater fluxes to the Mediterranean in the Late Miocene were around 3 times greater than for the present day. Most of this water was derived from North African rivers, which fed the Eastern Mediterranean. This increase in runoff arises from a northward shift in the intertropical convergence zone caused by a reduced latitudinal gradient in global sea surface temperatures. The northwards drainage of the Late Miocene Chad Basin also contributes. Numerical models designed to explore Late Miocene salt precipitation regimes in the Mediterranean, which typically make use of river discharge fluxes within a few tens of percent of present-day values, may therefore be grossly underestimating these fluxes.Although the AGCM simulated Late Miocene river discharge is high, the model predicts a smaller net hydrologic budget (river discharge plus precipitation minus evaporation) than for present day. We discuss a possible mechanism by which this change in the hydrologic budget, coupled with a reduced connection between the Mediterranean and the global ocean, could cause the salinity fluctuations of the MSC.     

Fossil record of a silurid catfish from the Middle Miocene Sanuki Group of Ohkawa, Kagawa Prefecture, Japan

A fossil specimen identified as a silurid catfish (92.5 mm SL) was collected from the Middle Miocene Sanuki Group (15.8±0.9 Ma) of Ohkawa, Kagawa Prefecture, Japan. This is the oldest certain record of a silurid catfish. Morphological characteristics of the specimen are as follows: 52 or 53 vertebrae, 61 or 62 anal fin rays, a stout, short spine (11%SL) and 10 or more soft rays of the pectoral fin, 8 or more pelvic fin rays, 8 or more branchiostegal rays, head length of ca. 24%SL, and most probably not forked caudal fin. The fossil specimen is clearly distinct from three extant silurids in Japan, and probably belongs to an undescribed form considering its geological age.     

Potential response to climate change of a semi-arid coastal ecosystem in eastern Mediterranean

Eastern Mediterranean gulfs, adjacent to small semi-arid watersheds are particularly susceptible to climate changes. In this study, an analysis was performed for air temperature and rainfall during 1955–2010 over a coastal ecosystem in NE Aegean, and potential effects of recent changes on the physical setting and ecological status of the marine system were studied. A trend toward drier conditions was revealed, and in order to assess possible effects on the surrounding basin, a watershed model was applied. In addition, the hydrology and ecology of the marine ecosystem were studied using a water budget model along with available field data. Based on local climatological data, dryness may lead to a decrease of one to two orders of magnitude in the amount of runoff during a dry annual cycle, resulting to a fivefold increase in the residence time of the marine system. High residence time associated with terrestrial nutrient inputs and strong stratification result to phytoplankton blooms during winter, including harmful algal blooms. Integrated approaches, modeling both the hydrology and ecology of watersheds and adjacent water bodies, are essential toward forecasting, understanding and management of potential alterations in functioning of coastal ecosystems due to recent climate changes.     

Fossil record and dynamics of Late Miocene small mammal faunas of the Vienna Basin and adjacent basins,Austria

The Late Miocene small mammal assemblages of the hinterland of Lake Pannon in Austrian Basins are represented by 99 species-level taxa and 30,400 specimens. The fossil-bearing localities can be grouped into eight intervals spanning about three million years from the Early Vallesian to the Middle Turolian. Each time slice is characterised by the occurrence and/or dominance of certain species. The retreat of Lake Pannon is reflected by a distinct diversification. This pattern may be a regional signal due to increasing habitat availability but may also be taphonomically biased due to a rather poor Earliest Vallesian record. Nevertheless, the overall community structure is quite stable throughout the Vallesian and no indication of a Vallesian Crisis can be detected. Instead, a moderate turnover occurs with the onset of the Turolian, reflected by the increasing abundance of xerophilic taxa.     

Orbital signatures in a late Miocene dinoflagellate record from Crete (Greece)

A high-resolution palynological study of the cyclically bedded Faneromeni section (upper Tortonian-lower Messinian) on Crete (Greece) is presented. This study aims to recognize orbitally-driven variations in the palynological record and to validate the age model based on the astronomical calibration of the sedimentary cycles. Four palynology-based environmental proxies were utilised using interpretations of fossil dinoflagellate associations based on modern ecological characteristics. Cross-spectral analysis between the proxy records and astronomical target curve, the 65°N summer insolation, yielded in most cases significant spectral power and coherence in the precession and/or obliquity frequency bands. Precession-controlled variations in the proxy records are related to lithology and indicate that maxima in continental input and minima in sea surface salinity coincide with sapropel formation. The influence of obliquity is most clearly reflected in the index of continental versus marine palynomorphs (S-D). The absence of a distinct time lag relative to obliquity indicates that the 41-kyr component in continental input is controlled by oscillations in regional Mediterranean climate rather than by glacial cyclicity. Phase relations in the different astronomical frequency bands of the spectrum, as compared with the Mediterranean Pliocene, essentially confirm the validity of the Miocene astronomical time scale. Finally, a major non-cyclic change in the palynological assemblage at 6.68 Ma indicates enhanced salinity and decreased river discharge. This shift coincides with a significant drop in sedimentation rate informally termed the “Early Messinian Sediment starvation Event”.     

Thaliacean distribution and abundance in the northern part of the Levantine Sea (Crete and Cyprus) during the eastern Mediterranean climatic transient, and a comparison with the western Mediterranean basin

First results are presented on the composition, abundance and vertical distribution of the thaliacean fauna in the Levantine basin obtained from stratified tows at three deep-sea sites in 1993: SE off Crete, and SW and NE off Cyprus. Samples with a 10 m²-MOCNESS (mesh size 1.67 mm) were poor in species and specimens as compared to samples with a 1 m²-double-MOCNESS (0.333 mm). Of the 12 species identified, six species belonged to the most abundant Doliolida, predominated by the phorozooids of Doliolum nationalis, five species belonged to the Salpida and one to the Pyrosomatida. Thaliaceans, most abundant by species and numbers SE off Crete, comprised ≤0.2% of the local mesozooplankton standing stocks. Presumably, they did not contribute substantially to the vertical flux generating the locally increased biomass and activity of the microbial benthos at the 4,300 m deep Cretean site. Most doliolids and salps were collected from the epipelagic and upper mesopelagic layers, and appeared to be most abundant close to the deep maximum of chlorophyll-a. Samples below 150 m were rarely rich in specimens, although two species performed diel migrations from the mesopelagic zone into the surface layers where some vertical segregation was evidenced. The aspect of niche separation is discussed.     

Fossil woods from Janggi Group (Early Miocene) in Pohang Basin,Korea

Sixty-four silicified fossil woods were collected from the Early Miocene Upper Coal-bearing Formation of Janggi Group in Pohang City, the Korean Peninsula. Out of them 23 specimens were identified as gymnosperms and 27 specimens as dicotyledons. The taxa identified include Picea palaeomaximowiczii Watari, Taxodioxylon cunninghamioides (Watari) Watari, T. sequoianum (Merckl.) Gothan, Fagus hondoensis (Watari) Watari, Cercidiphyllum sp., Camellia japonoxyla Suzuki et Terada, Distylium chiharu-hirayae Suzuki et Terada, Aesculus sp., Wataria miocenica (Watari) Terada et Suzuki and W. parvipora Terada et Suzuki. All of these species are reported for the first time from the Tertiary basins of Korea. Compared with those of the Miocene Formations in Japan, most taxa we found are common between the paleo-floras in Korea and Japan during the Early to Middle Miocene.     

First record of Miocene crustaceans from Hormozgan Province,Southern Iran

Four decapod crustacean species from the Middle Miocene Mishan Formation of Hormozgan Province, Southern Iran are described. Three species of leucosiid crabs represent the first fossil record for their respective genera outside the Indo-Pacific region. The oldest records for Leucosia sensu lato, Phylira sensu lato, and Arcania are from Middle Miocene deposits of the Indo-Pacific, and thus their paleobiogeographic distribution is extended for this lapse of time. Harpactocarcinus miocenicus n. sp. represents the youngest and most oriental occurrence for a typically Eocene genus, whose species are known mainly from Central Europe. This contribution represents the first formal report for Tertiary crustaceans from Iran.     

Fossil representatives of the family Greenideidae (Hemiptera, Aphidoidea) from the Miocene of Europe

Four new aphid species (Hemiptera, Aphidoidea, Greenideidae) are described on the basis of imprints in oil-shales from the Miocene of Europe (Rubielos de Mora, Spain; Vishnevaya Balka ?Stavropol?, Russia): Eutrichosiphum europaeum nov. sp., Greenidea hispanica nov. sp., Greenideoida (Pentatrichosiphum) turolensis nov. sp. and Mollitrichosiphum rubusensis nov. sp. All the taxa are placed within recent genera of the subfamily Greenideinae. Miocene representatives of this subfamily have been found in the south of Europe. Later changes of climatic conditions limited its geographic range to south-eastern Asia, where it is now represented by over 130 species of seven genera.     

Age and growth of Lessepsian rabbitfish from the eastern Mediterranean

Rabbitfish are currently an important component of the eastern Mediterranean inshore fishery. This study estimates age and calculates growth of Siganus rivulatus and S. luridus from the Lebanese coastal waters based on otolith analysis and compares results with available data from different geographical locations. Annual periodicity of alternating zones was confirmed for S. rivulatus, in which one opaque and one translucent zone were observed to deposit each year, but not for S. luridus. Both species appear to have a maximum lifespan of 6 years. The von Bertalanffy growth functions were L_t = 318.9(1 ? e^{?0.225(t+1.307)}) for S. rivulatus and L_t = 274.9(1 ? e^{?0.330(t+1.039)}) for S. luridus and length–weight relationships were estimated as for S. rivulatus and for S. luridus. The rabbitfish catches of the Lebanese fishery consist mainly of individuals which have not reached their first maturity. Rabbitfish from the eastern Mediterranean coastal waters appear to grow rapidly most of the year and are thus able to maintain relatively important population size despite intensive fishing pressure.     

Quantitative reconstruction of palaeoclimate from the Middle Miocene Shanwang flora, eastern China

The fossil leaf flora from the Shanwang Formation, Linqu County, Shandong Province, eastern China, is diverse, abundant, well preserved and discretely spaced, all of which make it suitable for the recognition and application of leaf physiognomic characters. This article is the first study of Chinese Tertiary floras using the CLAMP (Climate Leaf Analysis Multivariate Program) approach. Numerous bedding planes yield leaf assemblages through over 20 m thickness of diatomaceous shales within the Middle Miocene Shanwang Formation. The diatomaceous shales, containing abundant fossils, have been divided into 19 units. A working platform (3×3 m) in the Diatomite Quarry of Shanwang was studied for about 3 months in 1998 and as many fossils as possible were recorded layer by layer. This collecting method, used for the first time in the history of Shanwang research, enabled us to record the presence or absence of megafossils in distinct units so that we could investigate leaf physiognomic characteristics and palaeoclimate for each time interval. Leaf fossils from six units (5, 6, 7, 13, 15 and 16) have been used to estimate palaeoclimate parameters of the Shanwang area using the CLAMP 3B dataset. The predicted climate is that of a lakeside setting, at over 1000 m above sea level and within the 17–15-Ma time interval. Meteorological factors have been estimated using the CLAMP approach, including mean annual temperature (MAT; 9.5–11.2°C), warmest month mean temperature (20.2–22.5°C), growing season length (5.9–6.8 months), mean growing season precipitation (83–165 cm) and relative humidity (73–79%). MAT estimates from leaf margin analysis (LMA) range from 12.5 to 15.2°C, which are a maximum of 4° higher than those from our CLAMP analyses and from previous results of LMA studies of the Shanwang flora (10–13°C). Nearest living relatives (NLR) of other biota (pollen, fish, insects, diatoms, microthyriaceous fungi, etc.) indicate warm and moist temperate to subtropical conditions in the Shanwang area during the Miocene. CLAMP predictions are similar to the climate predicted from NLRs although the MAT prediction is a few degrees cooler. The fact that the Shanwang leaf flora is from a lacustrine sequence may have biased the CLAMP analysis towards cooler (and possibly wetter) climates. The modern Yangtze River valley is a reasonable environmental analogue for the Shanwang Middle Miocene, though Shanwang may have had cooler summers, cooler MAT and less seasonality in rainfall. The climate was essentially constant during deposition of the sequence studied, with possible minor variations in precipitation.     

Spring arrival response to climate change in birds: a case study from eastern Europe

This paper analyses the dependence of the first spring arrival dates of short/medium- and long-distance migrant bird species on climate warming in eastern Europe. The timing of arrival of the selected species at the observation site correlates with the North Atlantic Oscillation (NAO) index, air temperature, atmospheric pressure, precipitation and wind characteristics. A positive correlation of fluctuations in winter and spring air temperatures with variations in the NAO index has been established in eastern Europe. Positive winter NAO index values are related to earlier spring arrival of birds in the eastern Baltic region and vice versa—arrival is late when the NAO index is negative. The impact of climate warming on the bird’s life cycle depends on local or regional climate characteristics. We tested the hypothesis that differences in climate indices between North Africa and Europe can influence the timing of spring arrival. Our results support the hypothesis that differences in first spring arrival dates between European populations occur after individuals cross the Sahara. We assume that the endogenous programme of migration control in short/medium-distance migrants synchronises with the changing environment on their wintering grounds and along their migration routes, whereas in long-distance migrants it is rather with environmental changes in the second part of their migratory route in Europe. Our results strongly indicate that the mechanism of dynamic balance in the interaction between the endogenous regulatory programme and environmental factors determines the pattern of spring arrival, as well as migration timing.     

Fossil vertebrate faunas of the British Rhaetian (latest Triassic)

Rhaetian fossil vertebrate faunas of Britain represent rich but biased samples of taxonomic diversity during uppermost Triassic time. Review of the Westbury Formation, Penarth Group, in particular, reveals a combination of marine, littoral, and terrestrial elements. Minimally, six species of shark are preserved along with a myriacanthid holocephalan, at least four actinopterygian taxa, a characteristic lungfish, ichthyosaurs, plesiosaurs, dinosaurs, and potentially the earliest representative of the Choristodera. Rare mammalian occurrences in the Westbury beds are also possible. Severnichthys gen. nov. is a large osteichthyan, probably a palaeonisciform chondrostean, which historically has been mistaken for a labyrinthodont amphibian. At least two additional actinopterygian species and a holocephalan are known from die Lilstock Formation, and a mammal or mammallike reptile is recorded from the uppermost Blue Anchor Formation. Analysis of element abundance in the disarticulated Westbury Formation assemblage indicates that many parts of some taxa are never preserved while other elements of the same form are common. Such preservational bias suggests that many species may be missing entirely from this long-studied but poorly understood taphocoenosis. Possibly contemporaneous cave faunas from nearby upland areas give a similarly biased picture of the terrestrial fauna during this time of widespread marine transgression.     

Phenology and climate change: a long-term study in a Mediterranean locality

It is well documented that plant and animal phenology is changing in response to recent climate warming in the Palaearctic. However, few long-term data sets are currently available in the Mediterranean basin. The present study reports long-term temporal trends of several phenophases of 45 plants, 4 insects and 6 migratory insectivorous birds. Dynamic factor analyses performed with plant phenophases showed that most of those events occurring at spring and summer had common trends toward the advancement, especially since mid-1970s. However, during these last decades, insect phenology showed a steeper advance than plant phenology, suggesting an increase of decoupling of some plant–insect interactions, such as those between pollinators and flowers or herbivorous insects and their plant resources. All trans-Saharan bird species showed highly significant temporal trends in all studied phenophases (some of them covering most of the last century). In two species, the duration of stay is increasing due to both earlier arrivals and later departures. On the other hand, two wintering species showed a significant advancement in their arrival dates, while an opposite pattern were found for departures of each one. Only one of these species increased significantly its wintering stay. Bird departures were not related to local climate in any species. Our results demonstrate a key role of local temperatures behind interannual variability of most plant and insects phenophases, with especial emphasis in those occurring in spring and summer. Therefore, the common signal towards the advancement recorded since mid-1970s resulted from the recent rise in temperatures.