Marine and terrestrial biological and biogeochemical proxies in three sediment cores from North and SE Aegean and northern Levantine Seas record continuous warm and humid conditions between 5.5 and 4.0 ka BP related to the establishment of relatively stratified conditions in the upper water column. These conditions may have resulted from the concordant albeit weak Mid-Holocene South Asian monsoon forcing, combined with lighter Etesian winds. During this interval, sea surface temperatures fluctuate in the Aegean Sea, although exhibiting a strong positive shift at*4.8 ka BP. The warm and humid climatic conditions triggered upper water column stratification and enhancement of the deep chlorophyll maximum (DCM), leading to dysoxic conditions and the deposition of a sapropel-like layer, but only in the SE Aegean site. In contrast to the shallow water SE Aegean, the deeper North Aegean and the northern Levantine sites, although experiencing stratification in the upper parts of the water column, did not achieve bottom-water dysoxia. Thus, a top–bottom mechanism of stratification–DCM development accompanied by fast transport and burial of organic matter is a likely explanation for the preservation of productivity signal in the shallow sites of the SE Aegean and establishment of sapropelic conditions during the warm and humid Mid-Holocene. The termination of the Mid-Holocene warm and humid phase coincides with the ‘‘4.2 ka’’ climate event. Our data exhibit an N–S time transgressive aridification gradient around the Aegean Sea, most probably associated with the reorganization of the general atmospheric circulation during the Mid-Holocene.
The Collective Article ‘New Mediterranean Biodiversity Records’ of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided in two parts, for records of alien and native species respectively. The new records of alien species include: the red alga Asparagopsis taxiformis (Crete and Lakonikos Gulf, Greece); the red alga Grateloupia turuturu (along the Israeli Mediterranean shore); the mantis shrimp Clorida albolitura (Gulf of Antalya, Turkey); the mud crab Dyspanopeus sayi (Mar Piccolo of Taranto, Ionian Sea); the blue crab Callinectes sapidus (Chios Island, Greece); the isopod Paracerceis sculpta (northern Aegean Sea, Greece); the sea urchin Diadema setosum (Gökova Bay, Turkey); the molluscs Smaragdia souverbiana, Murex forskoehlii, Fusinus verrucosus, Circenita callipyga, and Aplysiadactylomela (Syria); the cephalaspidean mollusc Haminoea cyanomarginata (Baia di Puolo, Massa Lubrense, Campania, southern Italy); the topmouth gudgeon Pseudorasbora parva (Civitavecchia, Tyrrhenian Sea); the fangtooth moray Enchelycore anatine (Plemmirio marine reserve, Sicily); the silver-cheeked toadfish Lagocephalus sceleratus (Saros Bay, Turkey; and Ibiza channel, Spain); the Indo-Pacific ascidian Herdmania momus in Kastelorizo Island (Greece); and the foraminiferal Clavulina multicamerata (Saronikos Gulf, Greece). The record of L. sceleratus in Spain consists the deepest (350-400m depth) record of the species in the Mediterranean Sea. The new records of native species include: first record of the ctenophore Cestum veneris in Turkish marine waters; the presence of Holothuria tubulosa and Holothuria polii in the Bay of Igoumenitsa (Greece); the first recorded sighting of the bull ray Pteromylaeus bovinus in Maltese waters; and a new record of the fish Lobotes surinamensis from Maliakos Gulf.
Two specimens of the coccolithophore Calyptrolithophora pappilifera associated with single exothecal and endothecal coccoliths of Syracosphaera histrica,collected from the North Aegean Sea (NE Mediterranean), have been verified by Scanning Electron Microscopy. The two specimens strengthen previous reported hints that Syracosphaera histrica and Calyptrolithophora pappilifera represent a life-cycle association, documenting accordingly the relationships between the different phases within the genus Syracosphaera.
This is the first documentation of a combination coccosphere from samples collected in the field (North Aegean Sea, NE Mediterranean) between the heterococcolithophore species Coronosphaera mediterranea (Lohmann 1902) Gaarder in Gaarder & Heimdal (1977) and the holococcolithophore species “Zygosphaera hellenica”. This specimen verifies previous combination coccosphere evidence found in culture and again demonstrates that “Zygosphaera hellenica” can be developed from cells of Coronosphaera mediterranea in a life-cycle association.
TheElefsis Bay is a typical coastal setting characterized by a semi-closed shallow environment with intense anthropogenic activity. This study describes a peculiar low cell density and species poor late-winter coccolithophore assemblages from Elefsis Bay compared to those from further offshore of the Aegean Sea. Helicosphaera carteri contributes significantly to the assemblage inside the Elefsis Bay and together with Emiliania huxleyi both represent the dominant component of the calcareous nannoplankton. Water column data confirmed the opportunistic behavior of H. carteri, thus providing new evidence for the ecology of the species. It is suggested that an increase in this species can be associated with distinct pollution in neritic environments.
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