Ferdinando Boero

The continuity of living matter and the discontinuities of its constituents: do plankton and benthos really exist?

Plankton and benthos are popular concepts identifying two ways of life of aquatic organisms. Their spatial separation led to the development of different sampling techniques and to separate conceptualizations of the principles governing these subsets of the aquatic environment. Reciprocal connections between plankton and benthos, however, are very strong both from a functional (energy fluxes) and a structural (life cycle dynamics) point of view. A full appreciation of such links is forcing marine ecology towards a more integrated approach.

Taxonomic sufficiency and the increasing insufficiency of taxonomic expertise.

Taxonomic sufficiency (TS) involves the identification of taxa only to a level of taxonomic resolution sufficient to permit the detection of changes in stressed assemblages. Recently, however, TS has been proposed also for conservation issues as a tool to estimate biodiversity over large areas and in poorly known environments. This paper briefly reviews the use of TS in environmental impact studies and the effects of TS on sampling procedures and data analyses. The risk of possible loss of information depending on TS and the studied environment are discussed. Concluding remarks deal with the dangers of loss of taxonomic expertise in marine biological studies and assess critically the proposal of TS as a tool to describe biodiversity at a taxonomic level higher than species.

Zoogeography and life cycle patterns of Mediterranean Hydromedusae (Cnidaria)

The distribution of the 346 hydromedusan species hitherto recorded from the Mediterranean is considered, dividing the species into zoogeographical groups. The consequences for dispersal due to possession or lack of a medusa stage in the life cycle are discussed, and related to actual known distributions. There is contradictory evidence for an influence of life cycle patterns on species distribution. The Mediterranean hydromedusan fauna is composed of 19.5% endemic species. Their origin is debatable. The majority of the remaining Mediterranean species is present in the Atlantic, with various world distributions, and could have entered the Mediterranean from Gibraltar after the Mcssinian crisis. Only 8.0% of the fauna is classified as Indo-Pacific, the species being mainly restricted to the eastern basin, some of which have presumably migrated from the Red Sea via the Suez Canal, being then classifiable as Lessepsian migrants. The importance of historical and climatic factors in determining the composition of the Mediterranean fauna of hydromedusae is discussed.

Reversing the Life Cycle: Medusae Transforming into Polyps and Cell Transdifferentiation in Turritopsis nutricula (Cnidaria, Hydrozoa)

Organisms develop through a series of stages leading to sexually mature adults. In a few cases ontogeny reversal is possible, but it does not occur typically after the onset of sexual reproduction. All stages of the medusa Turritopsis nutricula, from newly liberated to fully mature individuals, can transform back into colonial hydroids, either directly or through a resting period, thus escaping death and achieving potential immortality. This is the first metazoan known to revert to a colonial, juvenile morph after having achieved sexual maturity in a solitary stage. Selective excision experiments show that the transformation of medusae into polyps occurs only if differentiated cells of the exumbrellar epidermis and part of the gastrovascular system are present, revealing a transformation potential unparalleled in the animal kingdom.

‘Double trouble’: the expansion of the Suez Canal and marine bioinvasions in the Mediterranean Sea

‘‘Egypt to build new Suez canal... ‘This giant project will be the creation of a new Suez canal parallel to the current channel’ said Mohab Mamish, the chairman of the Suez Canal Authority, in a televised speech.’’ (http://www.theguardian.com/world/2014/aug/05/ egypt-build-new-suez-canal, viewed August 13, 2014). This is ominous news. Expected to double the capacity of the Suez Canal, the expansion is sure to have a diverse range of effects, at local and regional scales, on both the biological diversity and the ecosystem goods and services of the Mediterranean Sea. Of nearly 700 multicellular non-indigenous species (NIS) currently recognized from the Mediterranean Sea, fully half were introduced through the Suez Canal since 1869 (Galil et al. 2014). This is one of the most potent mechanisms and corridors for invasions by marine species known in the world. Further, molecular methods demonstrate high levels of gene flow between the Red Sea and the Mediterranean populations

Coastal fish indicate human-induced changes in the Mediterranean littoral

Coastal fish assemblages were studied to assess two sorts of human impacts in southwestern Apulia (SE Italy, Mediterranean Sea). Fish assemblages were evaluated by visual census along two rocky locations impacted by a sewage outfall discharging nearshore (S) and by date-mussel (Lithophaga lithophaga) fisheries (F), respectively, and at two control locations (Cs). Multivariate analyses showed that fish assemblage structures at S and F differed from those at Cs. Asymmetric ANOVAs indicated that species richness were significantly lower both at S (approximately 27%) and at F (approximately 35%) compared with Cs. Total fish abundance was 5- to 7-fold higher at S than at Cs, while the values recorded at F were comparable to those of Cs. At S, average abundances of planktivorous fish and POM feeders were higher, and those of labrids and sparids of the genus Diplodus were lower, respectively, than at Cs. Labrids of the genus Symphodus and small serranids were significantly less abundant at F than Cs. Data suggested that coastal fish respond to the impact caused by the sewage discharge and provided a framework to assess potential benefits of its future displacement to deeper waters. For the first time, moreover, this study provided suggestive evidence that the habitat destruction caused by the illegal date-mussel fisheries may affect fish assemblages.

Epibiotic Vibrio Luminous Bacteria Isolated from Some Hydrozoa and Bryozoa Species

Luminous bacteria are isolated from both Hydrozoa and Bryozoa with chitinous structures on their surfaces. All the specimens of the examined hydroid species (Aglaophenia kirchenpaueri, Aglaophenia octodonta, Aglaophenia tubiformis, Halopteris diaphana, Plumularia setacea, Ventromma halecioides), observed under blue light excitation, showed a clear fluorescence on the external side of the perisarc (chitinous exoskeleton) around hydrocladia. In the bryozoan Myriapora truncata, luminous bacteria are present on the chitinous opercula. All the isolated luminous bacteria were identified on the basis of both phenotypic and genotypic analysis. The isolates from A. tubiformis and H. diaphana were unambiguously assigned to the species Vibrio fischeri. In contrast, the isolates from the other hydroids, phenotypically assigned to the species Vibrio harveyi, were then split into two distinct species by phylogenetic analysis of 16S rRNA gene sequences and DNA–DNA hybridization experiments. Scanning electron microscopy analysis and results of culture-based and culture-independent approaches enabled us to establish that luminous vibrios represent major constituents of the bacterial community inhabiting the A. octodonta surface suggesting that the interactions between luminous bacteria and the examined hydrozoan and bryozoan species are highly specific. These interactions might have epidemiological as well as ecological implications because of the opportunistic pathogenicity of luminous Vibrio species for marine organisms and the wide-distribution of the hydrozoan and bryozoan functioning as carriers.

Pre- and post-settlement events in benthic community dynamics

Abstract In all marine benthic environments, organism replacement depends on recruitment limitation, i.e. the impact of both pre- and post-settlement events on the success of recruitment. The relative contribution of pre- versus post-settlement processes in shaping adult populations has been extensively studied. Most analyses concluded that recruitment limitation is a strong determinant of adults’ density. The magnitude of its limitation depends on context, varies with species, and can be strongly modified by all the events preceding and following recruitment itself. A comparison of the outcome of recruitment limitation on hard- and soft-bottom communities has often been neglected. The rules governing these two environments, in both the inter- and the subtidal, might be inferred only by comparing and possibly integrating soft- and hard-bottom ecologies. The highly variable situation that larvae face in the water column is followed by the variability linked to local features, influencing, in its turn, larval settlement and juvenile survival (post-settlement period). A better knowledge of these processes will be possible only by focusing on their relative importance in the two environments and with research on the brief but significant time of larval settlement.

Light after dark: the partnership for enhancing expertise in taxonomy

The recognition of the value of biological diversity, especially after the famous Rio convention, has caused a flurry of national and international plans aimed at the exploration of biodiversity. Biodiversity is a magic word that opens many doors in funding agencies 1xAn international biodiversity observation year. Wall, D et al. Trends Ecol. Evol. 2001; 16: 52–54Abstract | Full Text | Full Text PDF | PubMed | Scopus (8)See all References1. The three definitions of biodiversity (subspecific, specific and supraspecific) involve genetic, organism, population and ecological approaches, even though the concern about biodiversity stems from the still unanswered question ‘How many species are there on earth?’ 2xHow many species are there on Earth?. May, R.M. Science. 1988; 241: 1441–1449Crossref | PubMedSee all References2.Genetics at a molecular level and ecology at a functional level were well represented in the scientific arena even before the biodiversity frenzy, whereas the science of species description, naming and classification (taxonomy and systematics) is passing through a world crisis that is far from being solved. There are two reasons for this crisis. One is the non-existent Impact Factor (IF) of most of the journals that publish species descriptions and taxonomic revisions. The IF is a widely used parameter to score the performance of researchers, leading to career opportunities and advancements. If you have a low IF, your future is dark. The other reason is that species description is seen as an old-fashioned way of doing research. The result is that experts in taxonomy retire and are not replaced, zoology and botany disappear from university curricula and new researchers in biodiversity end up being either molecular biologists or ecologists.Too extreme a statement? Consider this: a recent paper on animal evolution in Trends in Genetics 3xAnimal evolution, the end of intermediate taxa?. Adoutte, A et al. Trends Genet. 1999; 15: 104–108Abstract | Full Text | Full Text PDF | PubMed | Scopus (137)See all References3 included a glossary explaining the following terms: Bilaterians, Cambrian explosion, Clade or Natural group, Diploblasts, Evolutionary radiation, Metazoans, Monophyletic taxon, Phylum, Superphylum, Synapomorphy, Taxon, Triploblasts. This means that the editor of this journal supposes that a general reader interested in animal evolution is not familiar with these concepts. Look at a species list in a standard ecological paper and check how accurate are the data sets that, often, are then analyzed with the most sophisticated statistical packages.This is the dark. And here is the light. The dismissal of taxonomy worldwide originated from the USA. This mistake has now been recognized and a strategy has been implemented in the USA to correct it. The National Science Foundation of the USA has realized that taxonomy is dying and that the USA cannot have a scientific community that is deprived of taxonomists. This led to the launch of the Partnership for Enhancing Expertise in Taxonomy (PEET) (http://web.nhm.ukans.edu/∼peet/). Although other countries have begun to neglect their taxonomic expertise, they still have taxonomists and the situation is not as dire as that in the USA. Italy, for example, is the only country to have published a complete checklist of its fauna simply because it still has a breed of taxonomists 4xSystematics and biodiversity. Minelli, A. Trends Ecol. Evol. 1994; 9: 227Abstract | Full Text PDF | PubMed | Scopus (4)See all References4. Italian taxonomists are, however, getting older and are not being replaced, meaning that Italy is suffering today from the same mistake that affected the USA scientific community some 20 years ago. These non-USA countries harbor the experts in traditional taxonomy (those in the USA are very advanced in molecular aspects) and often provide the actual founders of the new breed of USA taxonomists. The PEET project on the Hydrozoa, for instance, is based on work by an Italian and a Brazilian student.A PEET taxonomist is a blend of a traditional morphological specialist and a molecular systematist. These two approaches to biodiversity rarely interact, producing paradox that traditional taxonomists have many problems that their techniques cannot solve, whereas molecular taxonomists have powerful techniques but not so many problems to solve, once the most obvious ones have been done. A standard product of a PEET project is a thorough revision of a taxon, which includes studying all the existing literature, inspecting type specimens, collecting new material, molecular analysis of specimens referred to as many nominal taxa as possible, disentangling of synonymies and production of a phylogeny based on both morphological and molecular approaches.Despite having no impact, taxonomic publications have eternal life and one cannot ignore old descriptions simply because they are old. A complete library is thus a prerequisite for good taxonomic work. Many PEET projects require that bibliographic data bases are made available through the Internet for free, also with the option of downloading articles in PDF format when possible. In this way, taxonomy will be enhanced not only in the USA but also in the rest of the world. As an example, refer to the bibliographic database on the Hydrozoa (http://siba2.unile.it/ctle/hydro/index.php3).The prominence of Europe as a land of taxonomists will not last long unless more PEET-like projects are launched soon, each with a carefully planned strategy of specialist training and proper career opportunities. If this does not happen, in 20 years, Europeans will send their youngsters to learn taxonomy in the USA.The problem of the decline of taxonomy, finally, is also due to taxonomists. Specialists in astrophysics are able to convince funding agencies to invest enormous amounts of money to look for extraterrestrial life. The same people who invest public money in these irrelevant enterprises 5xThe probability of extraterrestrial intelligent life. Mayr, E. : 67–74See all References5 are obviously not convinced by taxonomists that it is worthwhile investing money to explore the life of this planet!

The effects of sewage discharge on shallow hard substrate sessile assemblages.

On rocky shores, sewage discharges can modify natural distribution patterns of sessile organisms. The impact of sewage on shallow hard substrate assemblages has been assessed along SW Apulian coast (Ionian Sea, Italy), providing a framework to evaluate the benefits of future sewage displacement to deeper waters. Four locations (three controls and one putatively impacted) were selected and three sites were chosen at each location. Each site was sampled by 10 replicate photographic records. Univariate analyses revealed that the outfall did not affect the spatial distribution of number of taxa, total cover and abundance of some dominant taxa (mostly algae, sponges and bryozoans). The outfall negatively influenced the natural distribution pattern of filamentous green algae, whilst some algae (i.e. Gelidiales and Colpomenia sinuosa) were exclusively present at the impacted location. Multivariate analyses revealed that the outfall heavily modified the natural pattern of variability in the structure of the assemblage.