Biological complexity behind plankton system functioning: Synthesis and perspectives from a marine Long Term Ecological Research

The functioning of natural communities is the cumulative outcome of multifaceted and intersecting ecological and evolutionary processes occurring at species level. Species are not stable entities but evolve in consequence of contingent factors including the relationships they establish with the environment and other co-occurring species. Studying ecosystems with an eco-evo approach, i.e., by explicitly considering species evolution and interactions, is thus an essential step to envisioning their adaptation to environmental changes. Such approach is particularly suitable for studying plankton, a community of both rapidly evolving and strongly interconnected species. In this context, Long Term Ecological Research studies (LTER) represent a promising approach to explore nature at different levels of complexity, from species to ecosystems. Herein, I examine the most recent results coming from the three-decades plankton LTER 'MareChiara' (LTER-MC) in the Gulf of Naples (Mediterranean Sea, Italy) and discuss their suitability in deepening knowledge on: i) evolutionary bases to plankton biodiversity (i.e., the founding property of both species and community adaptive potential); ii) ecological and evolutionary determinants of population and community dynamics; and iii) biological mechanisms behind plankton system functioning

Plankton food for benthic fish: de visu evidence of trophic interaction between rainbow wrasse (Coris julis) and pelagic tunicates (Pegea confoederata)

Salps (pelagic tunicates) are rarely observed in nature and trophic interactions involving them mainly rely on the inspection of stomach contents of their potential predators. Moreover, salps have soft bodies that are hardly identified in potential consumers. We involved recreational SCUBA-divers and photographers in collecting de visu evidence of i) massive occurrence of salps and ii) trophic interactions involving salps as preys and benthic animals as consumers. Direct evidence of trophic interactions between salps and benthic fish was documented by photographic frames. We detected a long colony of the salp Pegea confaederata being transported by currents close to the substrate on top of Banco di Santa Croce, an underwater rocky outcrop in the Gulf of Naples (Italy). An individual of the rainbow wrasse Coris julis attacked the above-mentioned salp colony by selectively detaching individuals and biting their stomach. Our report of a trophic interaction between labrids and salps is the second in fifty years and the previous one was only indirect. In this study, citizen science allowed detecting both neglected marine animals like salps and trophic interactions involving them. Visual, direct evidence of predation on salps by benthic fish adds further knowledge about patterns of living-matter fluxes between plankton and benthos, opening new questions on the potential of global change in modifying the efficient circulation of organic matter in marine systems

Present and future of aquatic sciences: The perspective of AIOL scientific community for a priority roadmap over the next five years

Water issues represent an increasing societal challenge, since the 70% of Planet Earth is covered by water. The intensive use of the hydrosphere is changing the structure and functions of aquatic ecosystems and their ability to produce goods and services that are useful to humans. It is therefore necessary that the scientific community makes citizens aware of the results of scientific research on these issues and informs them about the need to intensify the study of the mechanisms that underlie the ongoing changes in aquatic ecosystems. To help meet this need, within the 23rd Congress of the Italian Association of Oceanology and Limnology (AIOL; http://www.aiol.info/), entitled "Functioning, alteration and recovery of aquatic ecosystems: the aquatic sciences to understand global change and to make the citizens aware of it" (Cagliari, Italy, 26-29 September 2017), all participants, among which some renown experts in the field of aquatic sciences, were invited to give their contribution, via a shared and bottom-up built questionnaire, in assessing a set of actions needed to achieve an adaptive and proactive management of changes that the aquatic sciences are going to face in the next five years. The results of this survey allowed us to identify a set of priorities that funding agencies should include in their economic and financial planning in the next future. Among all, we pinpoint that there is an urgent need in: (i) promoting sustainable food production by exploiting aquatic systems; (ii) diffusing an opportune spatial planning integrating ecosystem-based management approaches; (iii) developing recovery/remediation plans for contaminated sites; iv) promoting conservation of ecosystems by assessing their conservation status, first of all the water/ecosystem quality; (v) fostering the technological development of sustainable and integrated tools and procedures for environmental monitoring; (vi) developing a better forecasting capacity, particularly of extreme events, by implementing long-term research networks; and, ultimately, (vii) supporting a wider society learning processes and a more effective transfer of knowledge from science to society

Ecological-network models link diversity, structure and function in the plankton food-web

13 páginas, 5 figuras, 1 tabla.-- This work is licensed under a Creative Commons Attribution 4.0 International LicenseA planktonic food-web model including sixty-three functional nodes (representing auto- mixo- and heterotrophs) was developed to integrate most trophic diversity present in the plankton. The model was implemented in two variants - which we named ‘green’ and ‘blue’ - characterized by opposite amounts of phytoplankton biomass and representing, respectively, bloom and non-bloom states of the system. Taxonomically disaggregated food-webs described herein allowed to shed light on how components of the plankton community changed their trophic behavior in the two different conditions, and modified the overall functioning of the plankton food web. The green and blue food-webs showed distinct organizations in terms of trophic roles of the nodes and carbon fluxes between them. Such reorganization stemmed from switches in selective grazing by both metazoan and protozoan consumers. Switches in food-web structure resulted in relatively small differences in the efficiency of material transfer towards higher trophic levels. For instance, from green to blue states, a seven-fold decrease in phytoplankton biomass translated into only a two-fold decrease in potential planktivorous fish biomass. By linking diversity, structure and function in the plankton food-web, we discuss the role of internal mechanisms, relying on species-specific functionalities, in driving the ‘adaptive’ responses of plankton communities to perturbationsThe authors thank the Flagship RITMARE - The Italian Research for the Sea - coordinated by the Italian National Research Council and funded by the Italian Ministry of Education, University and Research within the National Research Program 2011–2013 for funding this study via the post-doc fellowship to D.D’A. and grants provided to M.R.d’A. and S.L.Peer reviewe

What is at stake for scientists when communicating ecology? Insight from the informal communication initiative “Cammini LTER”

What is at stake for scientists when communicating ecology? This is the basic question tackled in this paper, that we explored through reflections about an initiative of informal communication of ecological research called “Cammini LTER”: itineraries connecting a number of sites belonging to the Italian Long-Term Ecological Research network (LTER-Italy). LTER-Italy ecologists walked and cycled together with citizens creating a physical and visible movement of researchers ‘towards’ and ‘with’ citizens, aiming at providing the public with the opportunity to get familiar with Italian ecosystems, from the sea to alpine tundra. We address here the debates and the critical considerations among researchers themselves, stimulated by the overall experience, with focus on some relevant issues pertaining science communication, and even research production, evidencing the need for a cultural shift, which go far beyond the national context and the LTER – Italy network. Using a participant observations approach, through researchers’ words used to describe - formally and informally - the experience, we report and comment here the main narratives emerged, showing different attitudes of LTER researchers in Cammini towards the society and the role of ecology in it. Relationship and knowledge exchange appear crucial for communicating ecology, which can thus become an opportunity for building new qualities of knowledge and for creating a shared civic culture, able to make all players feel mutual responsible and contribute to the solution of particular socio-ecological challenges

Plankton food-webs: to what extent can they be simplified?

Plankton is a hugely diverse community including both unicellular and multicellular organisms, whose individual dimensions span over seven orders of magnitude. Plankton is a fundamental part of biogeochemical cycles and food-webs in aquatic systems. While knowledge has progressively accumulated at the level of single species and single trophic processes, the overwhelming biological diversity of plankton interactions is insufficiently known and a coherent and unifying trophic framework is virtually lacking. We performed an extensive review of the plankton literature to provide a compilation of data suitable for implementing food-web models including plankton trophic processes at high taxonomic resolution. We identified the components of the plankton community at the Long Term Ecological Research Station MareChiara in the Gulf of Naples. These components represented the sixty-three nodes of a plankton food-web. To each node we attributed biomass and vital rates, i.e. production, consumption, assimilation rates and ratio between autotrophy and heterotrophy in mixotrophic protists. Biomasses and rates values were defined for two opposite system's conditions; relatively eutrophic and oligotrophic states. We finally identified 817 possible trophic links within the web and provided each of them with a relative weight, in order to define a diet-matrix, valid for both trophic states, which included all consumers, fromn anoflagellates to carnivorous plankton. Vital rates for plankton resulted, as expected, very wide; this strongly contrasts with the narrow ranges considered in plankton system models implemented so far. Moreover, the amount and variety of trophic links highlighted by our review is largely excluded by state-of-the-art biogeochemical and food-web models for aquatic systems. Plankton models could potentially benefit from the integration of the trophic diversity outlined in this paper: first, by using more realistic rates; second, by better defining trophic roles of consumers in the planktonic web. We suggest that most trophic habits present in planktonic organisms must be contemplated in new generation plankton models.</p

Time series and beyond: multifaceted plankton research at a marine Mediterranean LTER site

Plankton are a pivotal component of the diversity and functioning of coastal marine ecosystems. A long time-series of observations is the best tool to trace their patterns and variability over multiple scales, ultimately providing a sound foundation for assessing, modelling and predicting the effects of anthropogenic and natural environmental changes on pelagic communities. At the same time, a long time-series constitutes a formidable asset for different kinds of research on specific questions that emerge from the observations, whereby the results of these complementary studies provide precious interpretative tools that augment the informative value of the data collected. In this paper, we review more than 140 studies that have been developed around a Mediterranean plankton time series gathered in the Gulf of Naples at the station LTER-MC since 1984. These studies have addressed different topics concerning marine plankton, which have included: i) seasonal patterns and trends; ii) taxonomic diversity, with a focus on key or harmful algal species and the discovery of many new taxa; iii) molecular diversity of selected species, groups of species or the whole planktonic community; iv) life cycles of several phyto- and zooplankton species; and v) interactions among species through trophic relationships, parasites and viruses. Overall, the products of this research demonstrate the great value of time series besides the record of fluctuations and trends, and highlight their primary role in the development of the scientific knowledge of plankton much beyond the local scale

The mediterranean sea we want

open58siThis paper presents major gaps and challenges for implementing the UN Decade of Ocean Science for Sustainable Development (2021-2030) in the Mediterranean region. The authors make recommendations on the scientific knowledge needs and co-design actions identified during two consultations, part of the Decade preparatory-phase, framing them in the Mediterranean Sea’s unique environmental and socio-economic perspectives. According to the ‘Mediterranean State of the Environment and Development Report 2020’ by the United Nations Environment Programme Mediterranean Action Plan and despite notable progress, the Mediterranean region is not on track to achieve and fully implement the Sustainable Development Goals of Agenda 2030. Key factors are the cumulative effect of multiple human-induced pressures that threaten the ecosystem resources and services in the global change scenario. The basin, identified as a climate change vulnerability hotspot, is exposed to pollution and rising impacts of climate change. This affects mainly the coastal zones, at increasing risk of extreme events and their negative effects of unsustainable management of key economic assets. Transitioning to a sustainable blue economy is the key for the marine environment’s health and the nourishment of future generations. This challenging context, offering the opportunity of enhancing the knowledge to define science-based measures as well as narrowing the gaps between the Northen and Southern shores, calls for a joint (re)action. The paper reviews the state of the art of Mediterranean Sea science knowledge, sets of trends, capacity development needs, specific challenges, and recommendations for each Decade’s societal outcome. In the conclusions, the proposal for a Mediterranean regional programme in the framework of the Ocean Decade is addressed. The core objective relies on integrating and improving the existing ocean-knowledge, Ocean Literacy, and ocean observing capacities building on international cooperation to reach the “Mediterranean Sea that we want”.openCappelletto M.; Santoleri R.; Evangelista L.; Galgani F.; Garces E.; Giorgetti A.; Fava F.; Herut B.; Hilmi K.; Kholeif S.; Lorito S.; Sammari C.; Lianos M.C.; Celussi M.; D'alelio D.; Francocci F.; Giorgi G.; Canu D.M.; Organelli E.; Pomaro A.; Sannino G.; Segou M.; Simoncelli S.; Babeyko A.; Barbanti A.; Chang-Seng D.; Cardin V.; Casotti R.; Drago A.; Asmi S.E.; Eparkhina D.; Fichaut M.; Hema T.; Procaccini G.; Santoro F.; Scoullos M.; Solidoro C.; Trincardi F.; Tunesi L.; Umgiesser G.; Zingone A.; Ballerini T.; Chaffai A.; Coppini G.; Gruber S.; Knezevic J.; Leone G.; Penca J.; Pinardi N.; Petihakis G.; Rio M.-H.; Said M.; Siokouros Z.; Srour A.; Snoussi M.; Tintore J.; Vassilopoulou V.; Zavatarelli M.Cappelletto M.; Santoleri R.; Evangelista L.; Galgani F.; Garces E.; Giorgetti A.; Fava F.; Herut B.; Hilmi K.; Kholeif S.; Lorito S.; Sammari C.; Lianos M.C.; Celussi M.; D'alelio D.; Francocci F.; Giorgi G.; Canu D.M.; Organelli E.; Pomaro A.; Sannino G.; Segou M.; Simoncelli S.; Babeyko A.; Barbanti A.; Chang-Seng D.; Cardin V.; Casotti R.; Drago A.; Asmi S.E.; Eparkhina D.; Fichaut M.; Hema T.; Procaccini G.; Santoro F.; Scoullos M.; Solidoro C.; Trincardi F.; Tunesi L.; Umgiesser G.; Zingone A.; Ballerini T.; Chaffai A.; Coppini G.; Gruber S.; Knezevic J.; Leone G.; Penca J.; Pinardi N.; Petihakis G.; Rio M.-H.; Said M.; Siokouros Z.; Srour A.; Snoussi M.; Tintore J.; Vassilopoulou V.; Zavatarelli M