Sara Kaleb

Calcareous Bio-Concretions in the Northern Adriatic Sea: Habitat Types, Environmental Factors that Influence Habitat Distributions, and Predictive Modeling

Habitat classifications provide guidelines for mapping and comparing marine resources across geographic regions. Calcareous bio-concretions and their associated biota have not been exhaustively categorized. Furthermore, for management and conservation purposes, species and habitat mapping is critical. Recently, several developments have occurred in the field of predictive habitat modeling, and multiple methods are available. In this study, we defined the habitats constituting northern Adriatic biogenic reefs and created a predictive habitat distribution model. We used an updated dataset of the epibenthic assemblages to define the habitats, which we verified using the fuzzy k-means (FKM) clustering method. Redundancy analysis was employed to model the relationships between the environmental descriptors and the FKM membership grades. Predictive modelling was carried out to map habitats across the basin. Habitat A (opportunistic macroalgae, encrusting Porifera, bioeroders) characterizes reefs closest to the coastline, which are affected by coastal currents and river inputs. Habitat B is distinguished by massive Porifera, erect Tunicata, and non-calcareous encrusting algae (Peyssonnelia spp.). Habitat C (non-articulated coralline, Polycitor adriaticus) is predicted in deeper areas. The onshore-offshore gradient explains the variability of the assemblages because of the influence of coastal freshwater, which is the main driver of nutrient dynamics. This model supports the interpretation of Habitat A and C as the extremes of a gradient that characterizes the epibenthic assemblages, while Habitat B demonstrates intermediate characteristics. Areas of transition are a natural feature of the marine environment and may include a mixture of habitats and species. The habitats proposed are easy to identify in the field, are related to different environmental features, and may be suitable for application in studies focused on other geographic areas. The habitat model outputs provide insight into the environmental drivers that control the distribution of the habitat and can be used to guide future research efforts and cost-effective management and conservation plans.

Methane-Related Carbonate Cementation of Marine Sediments and Related Macroalgal Coralligenous Assemblages in the Northern Adriatic Sea

Publisher Summary This chapter presents a multidisciplinary study of the major characteristics of a set of submarine rock outcrops in the Northern Adriatic Sea: the rock occurrence, embedded down to about 1 m from the seafloor in the bottom sediments; numerous gas accumulations in the proximity of the outcrops; small-scale mud volcanoes; and microbial mats around the seepage site. From the biological point of view, a total of 112 macroalgal taxa were recorded. The different number of taxa recorded at the San Pietro and Bardelli sampling sites have been related to the different distance from the coast and to water depth. The data highlights that the seabed is almost flat, locally showing the occurrence of rock outcrops, with a range of sizes, shapes, and spatial orientations. On the side-scan survey (SSS) data, they appear as high backscatter features. The seabed is mainly composed of sands. Some species that characterize these outcrops are acknowledged as important bioconstructors distinctive of the Mediterranean area. The seafloor sedimentary deposits show a gradual increase of the fine fraction from the coast toward the offshore; then a progressive increase in the coarse fraction in the central part of the study area (residual sands of the TST) is recognized. The fragile biological equilibrium of these structures, the slow-growing calcareous organisms considered as nonrenewable resources, and the dredging and bottom trawling pressure that strongly threatens the physical characteristics of the habitat, and negatively affect the associated biota, all motivate the need to protect the Trezze and their surrounding seabed.

First freshwater coralline alga and the role of local features in a major biome transition

Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group.

Species composition and spatial variability of macroalgal assemblages on biogenic reefs in the northern Adriatic Sea

Abstract We sampled macroalgal assemblages on 37 rocky outcrops in the northern Adriatic over the last 2 decades by SCUBA. Macroalgal assemblages were rich (173 taxa), but there was high variability in the number of species and coverage. The morphology of the outcrops, the distance from the coast and the depth were identified as the main factors accounting for this variability. Both the mean total algal coverage (14.8%) and encrusting layer coverage (8.0%) were low when compared to typical Mediterranean coralligenous habitats. Four main groups of algal assemblages were distinguished on the basis of their species composition and coverage. Groups 1 and 3 were located inshore off the Lido inlet and south of it, and had, respectively, low or intermediate total algal cover. Group 2 included outcrops situated offshore from the Venice lagoon along with all outcrops off the Grado-Marano lagoon; these had the highest total algal cover. Finally, group 4 included assemblages comprising algae that were widespread on outcrops in the inshore habitats of the Venice lagoon, between Malamocco and Chioggia inlets. Offshore outcrops subject to low turbidity and eutrophication levels had several characteristic Mediterranean coralligenous taxa.

Phymatolithon lamii (Hapalidiaceae, Corallinales, Rhodophyta): a first report for the Mediterranean Sea

Abstract Phymatolithon lamii (Hapalidiaceae, Corallinales, Rhodophyta) is reported for the first time in the Mediterranean Sea. A morphological-anatomical account of Gulf of Trieste specimens is presented along with comparisons with P. lamii specimens from other regions, comparisons with other Mediterranean species of Phymatolithon and a dichotomous key to known Mediterranean species of Phymatolithon. Whether P. lamii occurs naturally in the Mediterranean Sea but was previously misidentified as P. lenormandii or is, alternatively, an alien species, or both, has not been resolved.

Genetic and morphological variation in an ecosystem engineer, Lithophyllum byssoides (Corallinales, Rhodophyta)

Lithophyllum byssoides is a common coralline alga in the intertidal zone of Mediterranean coasts, where it produces biogenic concretions housing a high algal and invertebrate biodiversity. This species is an ecosystem engineer and is considered a target for conservation efforts, but designing effective conservation strategies currently is impossible due to lack of information about its population structure. The morphological and molecular variation of L. byssoides was investigated using morphoanatomy and DNA sequences (psbA and cox2,3) obtained from populations at 15 localities on the Italian and Croatian coasts. Lithophyllum byssoides exhibited a high number of haplotypes (31 psbA haplotypes and 24 cox2,3 haplotypes) in the central Mediterranean. The psbA and cox2,3 phylogenies were congruent and showed seven lineages. For most of these clades, the distribution was limited to one or a few localities, but one of them (clade 7) was widespread across the central Mediterranean, spanning the main biogeographic boundaries recognized in this area. The central Mediterranean populations formed a lineage separate from Atlantic samples; psbA pair‐wise divergences suggested that recognition of Atlantic and Mediterranean L. byssoides as different species may be appropriate. The central Mediterranean haplotype patterns of L. byssoides were interpreted as resulting from past climatic events in the hydrogeological history of the Mediterranean Sea. The high haplotype diversity and the restricted spatial distribution of the seven lineages suggest that individual populations should be managed as independent units.

Ex situ cultivation protocol for Cystoseira amentacea var. stricta (Fucales, Phaeophyceae) from a restoration perspective

Due to multiple impacts, Cystoseira forests are experiencing a significant decline, which is affecting the ecosystem services they provide. Despite conservation efforts, there is an urgent need to develop best practices and large-scale restoration strategies. To implement restoration actions, we developed an ex situ protocol for the cultivation of Cystoseira. amentacea var. stricta, aimed at reducing the time needed for laboratory culture, thus avoiding prolonged maintenance and minimizing costs. Specifically, we tested the effects of temperature, light and substratum on settlement and growth of early life stages using a factorial experiment. Temperature (20 and 24°C) and photoperiod (15L:9D) were selected to reflect the conditions experienced in the field during the reproductive period. Two light intensities (125 and 250 μmol photons m−2s−1) were selected to mimic the condition experienced in the absence of canopy (i.e. barren—higher light intensity) or in the understory (lower light intensity) during gamete release. The tested substrata were flat polished pebbles and rough clay tiles. The release of gametes and the successive survival and development of embryo and germlings were followed for two weeks. Regardless of the culture conditions, rougher tiles showed higher zygote settlement, but the substrata did not affect the successive development. Zygote mortality after one week averaged 50% and at the end of the second week, embryonic survival was higher under lower light and temperature conditions, which also determined the growth of larger embryos.

Old and new problems in the circumscription of Mediterranean species of Lithophyllum (Corallinales, Rhodophyta)

Station Biologique de Roscoff, Sorbonne Universités, Université Pierre et Marie Curie, CNRS, Roscoff 29688, France; Institut de Systématique, Evolution, Biodiversité, UMR 7205CNRS-EPHE-MNHN-UPMC, Muséum National d’Histoire Naturelle, Paris 75231, France; Station Biologique de Roscoff, CNRS, Sorbonne Universités, Université Pierre et Marie Curie, Roscoff 29688, France and Station Biologique de Roscoff, CNRS, Sorbonne Universités, Université Pierre et Marie Curie, Roscoff 29688, FranceEarly life-stage of the bladderwrack Fucus vesiculosus is highly influenced by the climate change factors temperature, CO2 and eutrophication. Intraspecific genetic diversity of Baltic Fucus vesiculosus populations is low, compared to e.g. Atlantic populations, which may limit their potential for adaptation. To assess the role of intraspecific genetic diversity on the tolerance towards environmental change we manipulated their diversity: Plots with full-sibling Keynote and Oral Papers 106 Downloaded by [University of Kiel] at 02:13 22 September 2015 groups of Fucus germlings each originating from one parental pair represents the low diversity level, whereas plots with sibling groups from multiple parental pairs represent the high diversity level. Climate change was simulated according to the year 2100 in the near-natural scenario Kiel Benthocosms by maintaining the environmental fluctuations of the Baltic Sea and adding 5°C warming, 600 μatm pCO2 and doubling the nutrient concentrations. Germlings responded to warming with higher mortality and enhanced growth rates. High pCO2 concentrations increased growth due to a fertilisation effect. Nonphotochemical quenching was lower under warmed than ambient temperatures. A positive co-tolerance among sibling groups towards warming and acidification indicates the possible attenuation in presence of the multiple factors. Considerable differences among sibling group performance indicate a higher adaptive potential for genetically diverse populations. The high diversity levels also showed higher survival, indicating possible facilitation processes among genotypes. Microsatellite genotyping is in progress for revealing whether and how selection processes took place in high diversity levels. We conclude that impacts on early life-stage bladderwrack depend on the combination of stressors and season and that genetic variation is crucial for local adaptation to climate change stress