Unfolding jellyfish bloom dynamics along the mediterranean basin by transnational citizen science initiatives

Science is addressing global societal challenges, and due to limitations in research financing, scientists are turning to the public at large to jointly tackle specific environmental issues. Citizens are therefore increasingly involved in monitoring programs, appointed as citizen scientists with potential to delivering key data at near to no cost to address environmental challenges, therein fostering scientific knowledge and advising policy- and decision-makers. One of the first and most successful examples of marine citizen science in the Mediterranean is represented by the integrative and collaborative implementation of several jellyfish-spotting campaigns in Italy, Spain, Malta, and Tunisia starting in 2009. Altogether, in terms of time coverage, geographic extent, and number of citizen records, these represent the most effective marine citizen science campaigns thus far implemented in the Mediterranean Sea. Here, we analyzed a collective database merging records over the above four countries, featuring more than 100,000 records containing almost 25,000 observations of jellyfish specimens collected over a period of 3 to 7 years (from 2009 to 2015) by citizen scientists participating in any of the national citizen science programs included in this analysis. Such a wide citizen science exercise demonstrates a valuable and cost-effective tool to understanding ecological drivers of jellyfish proliferation over the Western and Central Mediterranean basins, as well as a powerful contribution to developing tailored adaptation and management strategies; mitigating jellyfish impacts on human activities in coastal zones; and supporting implementation of marine spatial planning, Blue Growth, and conservation strategies

Population dynamics and predatory impact of the alien jellyfish Aurelia solida (Cnidaria, Scyphozoa) in the Bizerte Lagoon (southwestern Mediterranean Sea)

Understanding the life cycle strategies and predatory impact of alien jellyfish species is critical to mitigate the impact that these organisms may have on local populations, biodiversity, and ultimately on the functioning of food webs. In the Mediterranean Sea, little is known about the dynamics of alien jellyfish, despite this biodiversity hotspot being one of the most threatened areas by increasing numbers of alien jellyfish. Here, we investigated the population dynamics and predatory impact of a non-indigenous scyphomedusa, Aurelia solida Browne 1905, in the Bizerte Lagoon, Tunisia. The study was based on bimonthly surveys performed over two consecutive years, from November 2012 to August 2014. Field observations showed that the planktonic phase of A. solida occurs from winter to early summer. Prey composition was investigated by means of gut content and field zooplankton analyses. Calanoid copepods, mollusc larvae, and larvaceans represented the main food items of A. solida. To determine the jellyfish feeding rate and their predatory impact on zooplankton populations, the digestion time for zooplankton prey was assessed at three different temperatures: 13, 18, and 23 degrees C in laboratory conditions, corresponding to the average range of temperatures encountered by A. solida in the Bizerte Lagoon. We found that A. solida consumed 0.5-22.5% and 0.02-37.3% of the daily zooplankton standing stock in 2013 and 2014, respectively. These results indicate a non-negligible but restricted seasonal grazing impact on some mesozooplankton groups, explained by the relatively short lifespan of the medusa stage (5-6 months)

Ученые записки Латвийского государственного университета. Том 259. Система языка

The Australian spotted scyphomedusa Phyllorhiza punctata was recorded for the first time in Tunisian waters in August 2012, in the lagoon of Bizerte (Tunisia). Metaephyrae and juveniles occurred simultaneously in August 2012. The occurrence of adult medusae was detected from September to November 2012, and from August to October 2013. This is the second record of a reproducing population of P. punctata in the Mediterranean Sea. The low abundance of mesozooplankton in summer and autumn 2012 coincides temporally with the highest density of P. punctata recorded in the lagoon, suggesting that predation by this alien jellyfish may have been a limiting factor for the mesozooplankton abundance on site

La emergencia de China y su impacto en las relaciones comerciales entre Argentina y Brasil

i bien la expansión de las relaciones económicas entre China y los países de América Latina puede ofrecer oportunidades en el corto plazo, como se aprecia en las exporta- ciones de productos primarios, y la evolución favorable de los términos de intercambio, también plantea desafíos para el largo plazo que de no ser correctamente enfrentados, pueden dar lugar a procesos que aumenten su vulnerabilidad externa estructural. En este trabajo se analizan aquellos efectos que repercuten en forma directa e indirecta en los países de la región que más comercian con China y, particularmente, a Argentina y su relación con Brasil

Occurrence of epibenthic dinoflagellates in relation to biotic substrates and to environmental factors in Southern Mediterranean (Bizerte Bay and Lagoon, Tunisia) : an emphasis on the harmful Ostreopsis spp., Prorocentrum lima and Coolia monotis

Harmful events associated with epibenthic dinoflagellates, have been reported more frequently over the last decades. Occurrence of potentially toxic benthic dinoflagellates, on the leaves of two magnoliophytes (Cymodocea nodosa and Zostera noltei) and thalli of the macroalgae (Ulva rigida), was monitored over one year (From May 2015 to April 2016) in the Bizerte Bay and Lagoon (North of Tunisia, Southern Mediterranean Sea). The investigated lagoon is known to be highly anthropized. This is the first report on the seasonal distribution of epibenthic dinoflagellates hosted by natural substrates, from two contrasted, adjacent coastal Mediterranean ecosystems. The environmental factors promoting the development of the harmful epibenthic dinoflagellates Ostreopsis spp., Prorocentrum lima and Coolia monotis were investigated. The highest cell densities were reached by Ostreopsis spp. (1.9 x 10(3) cells g(-1) FW, in October 2015), P. lima (1.6 x 10(3) cells g(-1) FW, in June 2015) and C. monotis (1.1 x 10(3) cells g(-1) FW, in May 2015). C. nodosa and Z. noltei were the most favorable host macrophytes for C. monotis (in station L2) and Ostreopsis spp. (in station L3), respectively. Positive correlations were recorded between Ostreopsis spp. and temperature. Densities of the epibenthic dinoflagellates varied according to the collection site, and a great disparity was observed between the Bay and the Lagoon. Maximum concentrations were recorded on C. nodosa leaves from the Bizerte Bay, while low epiphytic cell abundances were associated with macrophytes sampled from the Bizerte Lagoon. The observed differences in dinoflagellate abundances between the two ecosystems (Bay-Lagoon) seemed not related to the nutrients, but rather to the poor environmental conditions in the lagoon