Which future for Italian high altitude lakes?

Abstract: High altitude lakes and their fauna are one of the most threatened and less investigated ecosystems in Italy. Alpine lakes are highly influenced by climate harshness and by air pollution, and because of their small dimensions are extremely vulnerable to global climate warming. Italy, in addition to the Alps, hosts another mountain range: the Apennines, reaching in some cases comparable altitudes, and therefore subject to the same risks. Moreover, the gentler slope of the Apennines makes them extremely vulnerable even to direct human impacts. In the present work, for the first time, high altitude lakes belonging to the Alps and to the Apennines are compared to highlight which meteo-climatic or chemical characteristics could be considered key drivers for their macrinvertebrate structure. The study area was explicitly focused on natural lakes placed above 1300 m of altitude and above the 44° parallel, thus in the alpine area and subject to a continental climate. 25 lakes were chosen (19 in the central-western Alps and 6 in the Modenese Apennines) with surface areas lower than 1 km2 and with maximum depths lower than 15 m. Physico-chemical parameters and macroinvertebrates were studied and compared. Samples were taken through the use of an hand-net (250 μm mesh size) along the littorals on different substrates following standardised methodologies during the richerfauna season to allow an easier identification of species. Parallel to that, water samples were collected and analysed. Species richness and the Taxonomic Distinctness Indices were applied to underline the different complexity of the community structure of the two areas. Results showed different macroinvertebrates communities with peculiar characteristics and highlighted a more structured and diverse composition on the Apennines. Predictive models on the future climate scenarios show how the peninsular portion of Italy will be even more affected by the increase in temperatures than the Alpine area. Thus, this work could be highly informative, mainly for central Italy, where proximity to towns encourage tourists to reach these type of lakes, even if placed in protected areas or parks. Therefore, protection and management plans, and conservation efforts of high altitudes cannot overlooked a thorough understanding of the biological diversity of these environments, which still appears fragmented and limited to some sector of the Alps. Furthermore, the fundamental role of high altitude lakes as water resource needs a specific management regime, as they are not included under the monitoring programs of the Water Framework Directive legislation

Status quo of knowledges on Italian high altitude lacustrine macroinvertebrates

High altitude lakes and their fauna are one of the most threatened and less investigated ecosystems in Italy. Alpine lakes are highly influenced by climate harshness and by air pollution, and because of their small dimensions are extremely vulnerable to global climate warming. Italy, in addition to the Alps, hosts another mountain range: the Apennines, reaching in some cases comparable altitudes, and therefore subject to the same risks. Moreover, the gentler slope of the Apennines makes them extremely vulnerable even to direct human impacts. In the present work, for the first time, high altitude lakes belonging to the Alps and to the Apennines are compared to highlight which meteo-climatic or chemical characteristics could be considered key drivers for their macroinvertebrate structure. The study area was explicitly focused on natural lakes placed above 1300 m of altitude and above the 44\ub0 parallel, thus in the alpine area and subject to a continental climate. 25 lakes were chosen (19 in the central-western Alps and 6 in the Modenese Apennines) with surface areas lower than 1 km2 and with maximum depths lower than 15 m. Physico-chemical parameters and macroinvertebrates were studied and compared. Samples were taken through the use of a hand-net (250 \u3bcm mesh size) along the littorals on different substrates following standardised methodologies during the richer-fauna season to allow an easier identification of species. Parallel to that, water samples were collected and analysed. Species richness and the Taxonomic Distinctness Indices were applied to underline the different complexity of the community structure of the two areas. Results showed different macroinvertebrates communities with peculiar characteristics and highlighted a more structured and diverse composition on the Apennines. Predictive models on the future climate scenarios show how the peninsular portion of Italy will be even more affected by the increase in temperatures than the Alpine area. Thus, this work could be highly informative, mainly for central Italy, where proximity to towns encourage tourists to reach these type of lakes, even if placed in protected areas or parks. Therefore, protection and management plans, and conservation efforts of high altitudes cannot overlooked a thorough understanding of the biological diversity of these environments, which still appears fragmented and limited to some sector of the Alps. Furthermore, the fundamental role of high altitude lakes as water resource needs a specific management regime, as they are not included under the monitoring programs of the Water Framework Directive legislation

Bearded versus thorny: The fireworm Hermodice carunculata preys on the sea urchin Paracentrotus lividus

The bearded fireworm, Hermodice carunculata (Polychaeta: Amphinomidae) has rapidly increased in abundance in Mediterranean infralittoral rocky habitats. We have recently observed the bearded fireworm preying on the sea urchin Paracentrotus lividus, which is a major determinant of algal community structure in this system. To document the full sequence of behaviors in an attack, we observed interactions between H. carunculata and P. lividus under controlled conditions in the lab. Upon a fortuitous contact, a fireworm rapidly initiated an attack on the urchin, everting its pharynx over it and starting to suck and ingest the spines. The attack forced the detachment of the urchin from the substrate and the exposure of its oral side. Then, the fireworm moved toward the urchin mouth, placed its buccal mass over the Aristotle's lantern (the large powerful urchin “jaw”), removed it with a suction generated by the pharyngeal musculature and entered the test. When an increase in P. lividus mortality caused by predation occurs, a top–down control of communities may take place, triggering different habitat formation (algal forest vs. barren). Further research on the effects of the predation of the bearded fireworm on urchin populations is required to assess their potential repercussions for the structure and functioning of Mediterranean rocky reef ecosystem

Toxicity of the purple mucus of the polychaete Halla parthenopeia (Oenonidae) revealed by a battery of ecotoxicological bioassays

Mucus secretions play a number of functions related to polychaete physiology and ecology. Under stress conditions, the polychaete Halla parthenopeia (Oenonidae) produces a purple mucus after mechanical stimulation, whose function is still unknown. Here, we assessed the toxicity of this purple mucus by means of both acute toxicity bioassays on the polychaete Dinophilus gyrociliatus and commercial ecotoxicological kits (Microtox\uae, Rotoxkit\uae and Artoxkit\uae). Palatability was also tested with the fish Oryzias melastigma. After emitting purple mucus, H. parthenopeia quickly moves away and starts releasing transparent mucus. Acute toxicity bioassays showed that the mucus was harmless (transparent), or lethal even when diluted about 1000 times (purple). Purple mucus was toxic at different concentrations, the LC50 ranging from 0.7-0.3 g l\u20131 for D. gyrociliatus to 76 g l\u20131 for Artemia franciscana (Artoxkit\uae). Freeze-dried brine shrimp coated with transparent or purple muci were both consumed by O. melastigma. We hypothesized that the purple mucus is involved in the chemical defence of H. parthenopeia against competitors and parasites, and that its colour and toxicity are due to hallachrome, a 1,2-anthraquinone found in the skin of H. parthenopeia

Novel Natural Compounds and Their Anatomical Distribution in the Stinging Fireworm Hermodice carunculata (Annelida)

Increasing evidence in the field of bioprospection fosters the necessity of studying poorly investigated poisonous marine invertebrates to expand knowledge on animal venom biology. Among marine annelids, amphinomid fireworms are notorious for their bearded trunk equipped with a powerful stinging capacity. Here, a methodological workflow based on analytical chemistry techniques (compound isolation followed by mass spectrometry and spectroscopy analyses) was applied to gain new insights, leading to the identification and structural elucidation of an array of natural products from Mediterranean specimens of Hermodice carunculata. Eight betaine-derived unprecedented compounds, named "carunculines", were detected, bearing two terminal ammonium groups tri-and disubstituted at the Cα (A, B) and a series of different alkyl chains (I-VIII). The mixture of chemicals was found in all the body parts of H. carunculata, supporting a mechanism of action triggered by their vehiculation inside the dorsal chaetae, and subsequent injection when chaetae break off on contact. Preliminary investigations to understand adaptive features were also performed, showing a trend in carunculine abundance that fits into the evolutionary history of these worms. These findings shed light on the chemical ecology of amphinomids, giving reasons for the success of H. carunculata in benthic environments and providing promising novel metabolites for biotechnological implications

GROWTH-RATES OF PERINEREIS-RULLIERI (POLYCHAETA, NEREIDIDAE) UNDER DIFFERENT CONDITIONS OF TEMPERATURE AND DIET

The effects of temperature and diet on growth rates of the nereidid polychaete Perinereis rullieri have been investigated under controlled laboratory conditions from the beginning of larval feeding. Growth rate was evaluated under three diets (filamentous green algae, nauplii of Artemia salina, and Tetramin MikroMin dry fish-food), and three temperatures (15-degrees-C, 21-degrees-C, and 27-degrees-C). Growth rate was influenced both by diet and temperature. Diet appears the main factor strongly modifying the growth pattern

Reproduction and larval development of Perinereis rullieri Pilato in the Mediterranean Sea (Polychaeta : Nereididae)

The reproductive biology and larval development of a brackish water population of the nereidid polychaete Perinereis rullieri Pilato was investigated. About 100 specimens were collected monthly over the course of a year from the Venice Lagoon. Observation on gametogenesis indicates that oogenesis takes about 12 months while spermatogenesis is faster and takes about 6 months. The study showed that reproduction occurs once a year with a good synchronization between individuals and that spawning occurs without epitokal metamorphosis. Larval development was studied under laboratory conditions; the stages of trochophora and metatrochophora developed within the periovular jelly matrix and the first free living stage was the 3-setigers nectochaeta. In this species many life history traits can be interpreted as an adaptation to the brackish environments. In particular the adaptive significance of the variable age at maturity and the enclosing of the fertilized eggs in a jelly matrix are discussed