Bioinvasion impacts on biodiversity, ecosystem services, and human health in the Mediterranean Sea

Este artículo contiene 45 páginas, 20 figuras, 5 tablas.Biological invasions have become a defining feature of marine Mediterranean ecosystems with significant impacts on biodiversity, ecosystem services, and human health. We systematically reviewed the current knowledge on the impacts of marine biological invasions in the Mediterranean Sea. We screened relevant literature and applied a standardised framework that classifies mechanisms and magnitude of impacts and type of evidence. Overall, 103 alien and cryptogenic species were analysed, 59 of which were associated with both negative and positive impacts, 17 to only negative, and 13 to only positive; no impacts were found for 14 species. Evidence for most reported impacts (52%) was of medium strength, but for 32% of impact reports evidence was weak, based solely on expert judgement. Only 16% of the reported impacts were based on experimental studies. Our assessment allowed us to create an inventory of 88 alien and cryptogenic species from 16 different phyla with reported moderate to high impacts. The ten worst invasive species in terms of reported negative impacts on biodiversity include six algae, two fishes, and two molluscs, with the green alga Caulerpa cylindracea ranking first. Negative impacts on biodiversity prevailed over positive ones. Competition for resources, the creation of novel habitat through ecosystem engineering, and predation were the primary reported mechanisms of negative effects. Most cases of combined negative and positive impacts on biodiversity referred to community-level modifications. Overall, more positive than negative impacts were reported on ecosystem services, but this varied depending on the service. For human health, only negative impacts were recorded. Substantial variation was found among Mediterranean ecoregions in terms of mechanisms of impact and the taxonomic identity of impacting species. There was no evidence that the magnitude of impact increases with residence time. Holistic approaches and experimental research constitute the way forward to better understanding and managing biological invasions.The present study was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project ALAS – “ALiens in the Aegean – a Sea under siege”; Project Number: HFRI-FM17-1597; Katsanevakis et al. 2020b). FaCr was partially funded by the project PO FEAMP CAMPANIA 2014-2020 (DRD n.35 of 15th March 2018). XT obtained partial funding from project MARGECH (PID2020-118550RB, MCIN/AEI/10.13039/501100011033) from the Spanish Government. AR received grants from the University of Catania through “PiaCeRi-Piano Incentivi per la Ricerca di Ateneo 2020–22 linea di intervento 2”.Peer reviewe

New Mediterranean biodiversity records (October, 2014)

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 Aplysia dactylomela (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 anatina (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.peer-reviewe

Observations on the Life Cycle of the Symbiont-Bearing Foraminifer \u3cem\u3eAmphistegina Lobifera\u3c/em\u3e 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 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

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

Effects of sampling site, season, and substrate on foraminiferal assemblages grown from propagule banks from lagoon sediments of Corfu Island (Greece, Ionian Sea).

Foraminiferal propagule banks occur in fine sediment fractions that contain small individuals of benthic foraminifera. These sediments include locally sourced juveniles and propagules, as well as allochthonous propagules that have dispersed from surrounding areas. Such propagules can remain viable even under unfavorable local conditions. When exposed to more favorable conditions, they may grow to adult stages. Accordingly, during environmental changes, propagule banks have the potential to function as species pools and allow quick assemblage reactions. The propagule method was designed to study responses of foraminiferal assemblages by exposing propagule banks to controlled conditions in the laboratory, an approach that is applicable to a variety of ecological questions. Therefore it is important to understand the nature and dynamics of propagule banks, including local and seasonal influences. To obtain insights into the composition of local propagule banks, we studied experimentally grown assemblages from two shallow-water lagoons on Corfu Island in western Greece, and compared the results with in situ assemblages. We sampled in spring and autumn of 2017 and experimental treatments included the use of different substrates in our experiments to account for potential effects on assemblage compositions. Results revealed that sediments from each lagoon contained a distinct propagule bank. We found abundant allochthonous taxa among specimens grown in all experimental treatments, indicating dispersal of propagules, and possibly also juveniles, from adjacent regions into both lagoons. The time of sampling had a significant effect on experimental assemblages, indicating that the composition of propagule banks can vary throughout the year. However, no significant differences were found in assemblages grown in different substrata, suggesting a stronger influence of water variables (e.g., temperature or salinity) on assemblage compositions. Moreover, the experimental set-ups favored small, fast-growing, sediment-dwelling species tolerant of relatively high organic content. Our findings highlight the potential of propagule banks as species pools and will help to refine and improve future applications of the method

Holocene Centenial-scale Paleoceanographic and Paleoenvironmental Patterns in the NE Mediterranean Sea

International audienceThe Eastern Mediterranean Sea lies in a climatological transition zone, under the influence of both tropical and mid-latitude climate processes. Within this basin, the Aegean Sea has been recognized as a highly sensitive area to global/regional climate change. Sediment archives provide robust evidence for changes in its hydrological properties and biogeochemical functioning as a response to past climate variability. In order to investigate the region's paleoclimatic and paleoceanographic patterns during the Holocene, with a special emphasis on the sapropel S1 interval, we have investigated marine sediment cores along a N-S transect in the Aegean and the S. Cretan Seas. We focus on combined geochemical, micropaleontological and palynological proxies, namely organic biomarkers, organic carbon and nitrogen stable isotopes, coccolithophore and pollen assemblages, aiming at reconstructing climate-related parameters such as sea surface temperature (SST), marine productivity patterns, stratification and nutricline fluctuations, continental vegetation patterns and land-sea interactions. SST patterns depict major global/regional climate fluctuations during the last glacial and deglaciation periods, depict the warm transition to the Holocene optimum, when the formation of the S1 sapropel takes place, a distinct cool episode around 8 ka BP (coeval with the S1 interruption), a conspicuous mid-Holocene warm phase (5.4-4.3 ka BP) as well as other distinct fluctuations. Diagnostic marine lipids, δ15N, and coccolithophore assemblages allow documenting the variability of primary productivity and associated organic carbon accumulation in sediments, as well as fluctuations in water column stratification and nutricline, especially during the deposition of the S1 sapropel. Combined terrigenous proxies record warm/cool and dry/humid time intervals, allowing land-sea correlations, and document changes in the delivery of terrestrial material to the sea related to climate-driven fluctuations in freshwater discharges. The network of sediment cores studied provide a better constrain of the regional climate patterns in the northeastern Mediterranean Sea and enables assessing potential time lags and gradients