Guillen, J. E. et al. Evolution of Posidonia oceanica seagrass meadows and its implications for management. J. Sea Res. 83, 65–71 (2013).

Finally, Schueren et al. explored the role of a somatosensory illusion influencing the postural after-effects of standing on an inclined surface. Using a force plate, the authors showed that lower extremity manipulation is a useful intervention to treat postural stability. This study contributes to the growing body of evidence that manipulation of the lower extremities can drive global postural changes, as well as influence standing behavior. Marion, A. F. Esquisse d’une topographie zoologique du Golfe de Marseille. Ann. Muséum Hist. Nat. Marseille 1, 6–108 (1883). Swindale, N.V. & Spacek, M.A. Spike detection methods for polytrodes and high density microelectrode arrays. J. Comput. Neurosci. 38, 249–261 (2015). A loss of 30% of the meadows was reported along the Ligurian coasts since the 1960 s 20, whereas our estimate was 19%. In France, a P. oceanica regression of 23% was reported over the last 50 years, or, in more detail, 2% in Corsica (Cap Corse) in the last 15 years, 9.5% since the 1960’ (St. Florent), 4.3–5% in Marseille-Cortiou 49 and 90% along the coast of Marseille in the last 100 years 11. Our estimate for the French continental coast is equal to an average of 9%. In those cases where estimates differ, discrepancies are likely due to problems of accuracy of historical maps, which were identified by authors working in these areas 14, 20, 21.

Alex Belluscio’s tracks

Roland Belluscio, M.D. completed his fellowship training in cardiology at Beth Israel Hospital following his residency training in internal medicine at the University of Medicine and Dentistry of New Jersey in Newark, where he also received his medical degree. Dr. Belluscio has held numerous leadership and membership positions throughout his career, including director of critical care and medical director of the cardiac life support training program at Riverview Medical Center, as well as president of the Monmouth County Division of the American Heart Association.

Gobert, S. et al. Biology of Posidonia in Seagrasses: biology, ecology and conservation (eds Larkum, W. D., Orth, R. J. & Duarte, C. M. ) 387–408 (Springer, 2006). Quiroga, R.Q., Nadasdy, Z. & Ben-Shaul, Y. Unsupervised spike detection and sorting with wavelets and superparamagnetic clustering. Neural Comput. 16, 1661–1687 (2004). The comparison of current distribution maps with available historical ones allowed us to assess the changes undergone by meadows over time. As we mentioned in the Results, in areas for which historical data were available, the estimated regression of P. oceanica meadows was 34% in the last 50 years. With reference to the IUCN’s draft of Red List criteria for ecosystems 47, that estimate makes P. oceanica habitat an “endangered” ecosystems. Zeater, N., Cheong, S.K., Solomon, S.G., Dreher, B. & Martin, P.R. Binocular visual responses in the primate lateral geniculate nucleus. Curr. Biol. 25, 3190–3195 (2015). Rodriguez, A. & Laio, A. Machine learning. Clustering by fast search and find of density peaks. Science 344, 1492–1496 (2014).Gold, C., Henze, D.A., Koch, C. & Buzsáki, G. On the origin of the extracellular action potential waveform: A modeling study. J. Neurophysiol. 95, 3113–3128 (2006). Rossant, C. & Harris, K.D. Hardware-accelerated interactive data visualization for neuroscience in Python. Front. Neuroinform. 7, 36 (2013). On his arrival at the bungalow, Briskin found Wallace weeping and still trying to revive Belushi. “John’s dead!” Wallace cried. An ambulance arrived and after EMTs assessed Belushi’s state he was declared him dead. Gonzalez-Correa, J. M., Bayle Sempere, J. T., Sanchez-Jerez, P. & Valle, C. Posidonia oceanica meadows are not declining globally. Analysis of population dynamics in marine protected areas of the Mediterranean Sea. Mar. Ecol-Prog. Ser. 336, 111–119 (2007).

The regressive trend of seagrasses is a phenomenon which has been observed along the majority of the world’s coasts 5. The main causes are combinations of natural and human impacts (i.e. trawling, anchoring, fish farming, coastal constructions, warming, acidification, alien species invasion) 4, 5, 23, 24. A global review of scientific literature indicates that 29% of the known areal extent of seagrasses has disappeared since 1879 5. In the Mediterranean Sea, meadows regression trends have already been reported since 1952 and early studies have suggested that it is due to a limited adaptation of the plant to the existing hydrological and climatic conditions in the Mediterranean Sea, mainly along the north-western coasts 50. Later, the low genetic variability of this species was highlighted as a major contributor to the low resilience of P. oceanica; however, the availability of different powerful molecular markers revealed a higher meadow genetic variability than previously thought 51, 52. During the twentieth century and especially in the 1950 s, P. oceanica meadows have considerably regressed, mainly near large urban developments and ports such as Barcelona, Marseille, Toulon, Genoa, Trieste, Alexandria and Gabès 53, 54 Recently, it was suggested that the warming of the basin may lead to the functional extinction of P. oceanica meadows by 2050 55. Peres, J. M. La régression des herbiers a Posidonia oceanica in International Workshop on Posidonia oceanica beds (eds Boudouresque, C. F., Jeudy de Grissac, A. & Olivier, J. ) 445–454 (GIS Posidonie, 1984).VBel: Methodology, Writing—original draft, Writing—review and editing. VBet: Writing—review and editing. AM: Writing—review and editing. DD: Writing—review and editing, Conceptualization, Investigation, Methodology, Project administration, Supervision, Writing—original draft. Funding Moreover, the MediSeH project can be considered the first effort to make an extensive collection of P. oceanica distribution data available online. Indeed, previous works 26 provided online access to seagrass spatial data at a broad resolution. As part of the MediSeH project, the collated current and historical data on the P. oceanica distribution were stored within a geodatabase and were made available through the development of an online GIS data viewer ( http://www.mareaproject.net/medviewer/), enabling their visualization. Celebi, B., Cemal-Gucu, A., Ok, M., Sakinan, S. & Akoglu, E. Hydrographic indications to understand the absence of Posidonia oceanica in the Levant Sea (Eastern Mediterranean). Biol. Mar. Mediterr. 13, 34–38 (2006).