Το ολοένα αυξανόμενο ενδιαφέρον σε Γεω-Περιβαλλοντικά θέματα, όπως η παγκόσμια κλιματική μεταβολή, η βιοποικιλότητα και η εξέλιξη των οικοσυστημάτων, που σχετίζονται με την ανθρωπογενή δραστηριότητα, συνέβαλαν στην ταχύτατη πρόοδο σε όλους τους τομείς της κατανόησης των θαλάσσιων μικροοργανισμών και των απολιθωμένων στοιχείων τους. Τα μικροαπολιθώματα, καθώς αποτελούν ή βρίσκονται κοντά στη βάση της τροφικής αλυσίδας και παρουσιάζουν γρήγορους ρυθμούς αναπαραγωγής, αναδεικνύονται ως ιδανικό εργαλείο στις περιβαλλοντικές και γεωπεριβαλλοντικές έρευνες, διαδραματίζοντας σημαντικό ρόλο στους βιογεωχημικούς κύκλους του άνθρακα, του πυριτίου και του ασβεστίου των ωκεάνιων συστημάτων και παράλληλα συμβάλλοντας στη βιογενή ανθρακική και πυριτική ιζηματογένεση. Το βιβλίο «Μικροπαλαιοντολογία και Γεωπεριβάλλον» πραγματεύεται αναλυτική εισαγωγή στην μελέτη των κύριων ομάδων μικροαπολιθωμάτων (κοκκολιθοφόρα/ασβεστολιθικό ναννοπλαγκτόν, τρηματοφόρα, διάτομα, πυριτομαστιγοφόρα, ακτινόζωα και δινομαστιγωτά) και στοιχεία φυσιολογίας, μορφολογίας, ταξινόμησης και βιοστρωματογραφίας. Ταυτόχρονα επιχειρείται συνοπτική παρουσίαση των δυνατοτήτων τους στη σύγχρονη γεω-περιβαλλοντική έρευνα - συμβολή στην ιζηματογένεση, αλληλεπίδραση με περιβάλλον και κλίμα - με έμφαση στις μελέτες στον ελλαδικό χώρο. Το βιβλίο κυκλοφορεί από τον εκδοτικό όμιλο ΙΩΝ

Detailed quantitative analyses of calcareous nannofossils/coccolithophores performed on the deep sea deposits of the north eastern Mediterranean Sea; two gravity core from North Aegean Sea (SL 152) and south Cretan continental margin (HCMR 2/22), with a focus on the regional expression of sapropel S1 deposition. In both sites, higher values of Florisphaera profunda, Helicosphaera spp., Braarudosphaera bigelowii and the concomitant increase of stratification S index, within sapropel intervals can be interpreted as the result of elevated marine production and enhanced inflow of fresh water input during the S1 period. A series of cooling events detected within the S1 depositional interval, may be linked to outbursts of cold northerly air masses and relevant pulses in the deep-intermediate water ventilation that caused the temporary cessation of S1 deposition between 7.8-7.5 ka uncal. BP in North Aegean and 8.1-7.8 ka uncal. BP at the south Cretan margin. During this interval the peak of Braarudosphaera bigelowii, the decrease in abundance of Florisphaera profunda, Helicosphaera spp., Rhabdosphaera spp. and a general increase in NPP are related to a shoaling of the nutricline and higher production in the surface layer.

Morphological abnormalities of recent and fossil benthic foraminiferal tests may be caused by environmental stress resulting from anthropogenic pollution and/or natural effects. In the present paper we document and describe morphological abnormalities of Ammonia tepida and some additional foraminiferal species from Holocene sedimentary successions of the Aegean Sea (Alykes Kitros and Vravron Attica). The abnormality types are manifested largely by siamese twins, whereas distorted chamber arrangement, overdeveloped or protruding chambers and the presence of multiple apertures have also been observed. Our observations on the distribution of abnormal tests in comparison to the characters of the accompanying fauna suggest that malformation was caused mainly by rapid and intense salinity fluctuations. 

Benthic foraminiferal composition of sedimentary successions during the last 7500 years, was investigated from boreholes drilled in three rather tectonically stable coastal areas of the Aegean Sea (Alykes Kitros, Lafrouda Thrace and Vravron Attica). The quantitative analysis of foraminiferal fauna enabled separation into two different groups that are supported by the analysis of modern benthic foraminiferal communities in the studied sites. Group A consists of Ammonia tepida and Haynesina germanica (closed lagoon assemblage), whereas the most common species of Group B (open lagoon assemblage) are Aubignyna perlucida, miliolids, Elphidium spp. and Ammonia spp. The foraminiferal composition integrated with radiometric dating provides information on Holocene paleoenvironmental changes in the studied coastal plains, related to seaeland interaction. Alykes Kitros and Lafrouda Thrace boreholes show a similar trend, with an open lagoonal fauna in the lower part, transitional upwards to closed lagoonal conditions. This environmental change has taken place after 6500 cal BP in Alykes Kitros and around 3000 cal BP at Lafrouda Thrace. The benthic communities of Vravron Attica borehole sediments seem to represent continuously an open lagoon/shallow marine environment from 4700 to 400 cal BP.

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 Indo- Pacific 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. 

Ocean acidification and the related changes in seawater chemistry may disrupt calcification by coccolithophores and departure from the normal growth process causing malformed coccoliths. Coccospheres with malformed were coccoliths collected from different locations in the Aegean Sea. Although most of these specimens in our work are restricted to Emiliania huxleyi, scarce coccospheres of Rhabdosphaera clavigera, Syracosphaera pulchra, Discosphaera tubifera and Calcidiscus quadriperforatus have also been detected. In this study we discuss our observations on malformed distribution in relation to seawater carbonate chemistry.