The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean)

During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna

Alien foraminifers from Greek coastal areas (Aegean Sea, Eastern Mediterranean)

The present study provides additional data on the distributional range of six alien foraminiferal species in living assemblages from Greek coastal areas (Aegean Sea, Eastern Mediterranean). Amphistegina lobiferaLARSEN 1976, Sorites orbiculus (FORSK L 1775) and Coscinospira hemprichii EHRENBERG 1839 are well established in Greek coastal areas, whereas Triloculina fichteliana D'ORBIGNY 1839, Planogypsina acervalis (BRADY 1884) and Cymbaloporetta plana (CUSHMAN 1924), are recorded for the first time in this paper. The occurrence of these species in a number of sites in the Aegean Sea establishes their presence in the Eastern Mediterranean

Live and dead benthic foraminiferal assemblages from coastal environments of the Aegean Sea (Greece): Distribution and diversity

Benthic foraminiferal composition assemblages and their temporal changes, ecological indices and foraminiferal densities are used to compare three coastal environments with different physicogeographical features in the Aegean Sea (coastal environment of Avdira-Vistonikos Gulf and Kitros-Thermaikos Gulf and open lagoonal environment of Vravron-South Evoikos Gulf). Three main foraminiferal assemblages have been recognized: a) "Assemblage A" high degree of similarity between living and dead foraminiferal species, dominated by Ammonia beccarii, Elphidium spp. and relatively abundant and diverse miliolids, b) "Assemblage B1" intermediate degree of similarity between live and dead assemblages, characterized by highly-abundant and well-diversified foraminiferal assemblages including the algal symbiont bearing Peneroplis pertusus together with Ammonia tepida and several small epiphytic rotaliids and miliolids, and c) "Assemblage B2" absence of living individuals, strongly dominated by the opportunistic species A. tepida. Our results suggest a good comparison between living and dead assemblages from different coastal environments in the Aegean Sea, however the prevailing environmental conditions (vegetation cover, hydrodynamics, fresh water influx) have a strong impact on the taphonomic processes. © 2015 Published by Elsevier Masson SAS

Alien foraminifers from Greek coastal areas (Aegean Sea, Eastern Mediterranean)

The present study provides additional data on the distributional range of six alien foraminiferal species in living assemblages from Greek coastal areas (Aegean Sea, Eastern Mediterranean). Amphistegina lobifera LARSEN 1976, Sorites orbiculus (FORSKÅL 1775) and Coscinospira hemprichii EHRENBERG 1839 are well established in Greek coastal areas, whereas Triloculina fichteliana D'ORBIGNY 1839, Planogypsina acervalis (BRADY 1884) and Cymbaloporetta plana (CUSHMAN 1924), are recorded for the first time in this paper. The occurrence of these species in a number of sites in the Aegean Sea establishes their presence in the Eastern Mediterranean

Observations on the life cycle of the symbiont-bearing foraminifer Amphistegina lobifera Larsen, an invasive species in coastal ecosystems of the aegean sea (Greece, E. Mediterranean)

Members of the family Amphisteginidae have been nearly ubiquitous contributors to shelf carbonate facies through most of the Cenozoic. The most prolific carbonate producer of modern representatives is Amphistegina lobifera Larsen, which is the largest and shallowest dwelling of the IndoPacific taxa. This epiphytic, symbiont-bearing foraminifer is also a remarkably successful invasive species in coastal ecosystems of the eastern Mediterranean, where its shell production is altering the composition of shoreline sediment. This paper reports a temporal study of an A. lobifera population collected monthly between June 2008-May 2009 in the Vravron/Attica coastal ecosystem of the south Evoikos Gulf (Aegean Sea), where winter temperatures can drop below previously reported minima for the species. Monthly variations in size, frequency distribution, and abundance indicate that this population reproduced primarily during the summer (July-September), when both asexual and sexual reproduction occurred simultaneously, suggesting a predominantly coeval, one-year life span for each generation. However, a modest increase in juveniles in January indicates some winter reproduction. Comparison of these findings with previous studies shows that a) tolerance of low winter temperatures, b) adaptation of the life cycle to strong seasonality, and c) the mixotrophic feeding strategy have allowed A. lobifera to proliferate in the exceptionally clear, low nutrient, coastal waters of the Mediterranean Sea. These attributes elucidate how previous Cenozoic populations of Amphistegina were able to rapidly expand their latitudinal ranges and invade shallow epeiric seas during episodes of climatic warming

Evidence for a possible life-cycle association between Syracosphaera protrudens (heterococcolithophore) and Syracosphaera pulchra HOL pirus-tyjte (holococcolithophore)

An apparently unambiguous combination coccosphere from the Eastern Mediterranean (Aegean Sea, Greece) is documented involving Syracosphaera protrudens Okada & Mclntyre, 1977 and Syracosphaera pulchra Lohmann, 1902 HOL pirus-type. This finding is difficult to interpret in terms of the current understanding of Syracosphaera taxonomy and adds evidence to the hypothesis of a distinctly complex Syracosphaera pulchra life cycle. © 2009 The Micropalaeontological Society

Living benthic foraminifera as an environmental proxy in coastal ecosystems: A case study from the Aegean Sea (Greece, NE Mediterranean)

The species composition of the epiphytic benthic foraminiferal fauna was compared at two coastal locations in the Aegean Sea. Samples were collected during August 2001 and July 2003 along the southeastern coast of Andros Island at Korthi Gulf, where there are minimal anthropogenic activities, and at Kastro Gulf, with substantial anthropogenic influence. This study represents the first application of the FORAM Index (FI), which is a single-metric index for water quality originally developed for western Atlantic reef foraminiferal assemblages, to Mediterranean assemblages. Multivariate analyses distinguished three clusters of sample sites representing three foraminiferal assemblages. Samples dominated by the mixotrophic species, A. lobifera, were collected primarily from sites along the northern coasts of both gulfs. Characteristics of this assemblage, including relatively high dominance (D. = 0.27-0.51), lower Shannon-Wiener diversity (H'. = 1.3-2.1) and high FI (6.6-8.2), all reflect oligotrophic environmental conditions typical of pristine waters of the Aegean Sea. A. lobifera was typically the most common species in the second assemblage, though relative abundances of heterotrophic taxa were higher, resulting in somewhat higher diversity (H'. = 1.6-2.4) and lower dominance (D. = 0.14-0.36). These indices, as well as the FI range of 3.5-7.0 indicated somewhat more prevalent organic carbon resources but still relatively high water quality. This assemblage was found along the southern coast of Korthi Gulf and at more interior sites in northern Kastro Gulf. The third assemblage was dominated by smaller heterotrophic species, including notable proportions of the stress-tolerant taxa Ammonia spp. and Elphidium spp., and had few or no A. lobifera. Diversity (H'. = 1.4-2.0) and dominance (D. = 0.22-0.47) indices were similar to those for the first assemblage, but FI values were much lower (2.0-3.4). Samples characterized by this assemblage were collected only from the southern Kastro Gulf, in the vicinity of the primary sewage outfall. The results of this study document the sensitivity of benthic foraminiferal assemblages, and particularly A. lobifera populations, to sewage pollution in the Aegean Sea. These observations are consistent with studies from other biogeographic regions where the FORAM Index, which is based upon this genus and associated mixotrophic taxa, has been used as a water-quality indicator. This observation is particularly noteworthy because A. lobifera is an invasive species in the Mediterranean. © 2011 Elsevier B.V

Zanclean/Piacenzian transition on Cyprus (SE Mediterranean): calcareous nannofossil evidence of sapropel formation

Quantitative analyses of calcareous nannofossils in the sediments of Pissouri South section on the island of Cyprus have produced a paleoceanographic record reflecting the paleoclimatic conditions during the Zanclean/Piacenzian transition. Pissouri South cyclical lithological alternations between organic-rich laminated layers and grey marls reflect the Earth’s orbital precession. According to the calcareous nannofossil biostratigraphy which has been performed, the studied section is correlated with MNN14/15 and MNN16 calcareous nannofossil biozones and is astronomically dated between 4.065 and 3.217 Ma. Intervals of increased organic carbon content, along with the positive values of Florisphaera profunda, Helicosphaera sellii, Discoaster spp. and the subsequent increase of stratification S-index, correspond to the sapropel deposition during periods of wetter climate and intense continental runoff, especially from the river Nile. These layers alternate with grey marly intervals, featured by the increased values of small placoliths of Reticulofenestra and Gephyrocapsa species, which are indicative of eutrophic conditions during intense surface-water mixing. Our data support the prevalence of a generally warm phase characterized by the absence of high-frequency climate variations in the southeastern Mediterranean during the Zanclean/Piacenzian (Early/Late Pliocene) transition. © 2015, Springer-Verlag Berlin Heidelberg

Response of Living Benthic Foraminifera to Anthropogenic Pollution and Metal Concentrations in Saronikos Gulf (Greece, Eastern Mediterranean)

The Saronikos Gulf, including the industrial zone of Elefsis Bay, is subjected to a variety of urban and industrial impacts that significantly contribute to environmental degradation. Benthic foraminifera comprise a significant component of meiobenthic communities and they are widely used as reliable indicators for the determination of the natural environmental and anthropogenic impact in shallow coastal systems. The present study analyses the living benthic foraminifera composition and its relation to environmental parameters such as grain size, organic carbon content, and heavy metal concentrations, from the surficial sediment layer collected in the Elefsis Bay and the Inner Saronikos Gulf in February 2016. Canonical correspondence analysis and Spearman’s rho correlation show that the foraminiferal species composition is significantly influenced by the increase of organic carbon and Cu, Pb, Zn content. In particular, a relatively low diversity fauna dom-inated by the stress-tolerant species Ammonia tepida, Bulimina elongata, Bulimina marginata, and Nonionella turgida occurs in the restricted environment of the Elefsis Bay, demonstrating the nega-tive environmental impact caused by the relatively elevated organic carbon and heavy metal con-tents. © 2022 by the authors. Licensee MDPI, Basel, Switzerland