The “tsunami break:” impact of the Great East Japan Earthquake and the accompanying tsunamis on the shell growth of the invasive clam-eating snail Laguncula pulchella
The Great East Japan Earthquake and accompanying tsunamis occurred on 11 March 2011, causing huge damage to marine organisms. The invasive naticid gastropod Laguncula pulchella (Euspira fortunei), which was introduced with the imported clam Ruditapes philippinarum from China and Korea, survived the earthquake. The “growth break line” observed on the shell surface in over 90% of the individuals collected in Matsushima Bay and Matsukawa-ura Lagoon after the tsunamis was examined by scanning electron microscopy. Each shell presented three layers before and three after the growth break. However, the fracture surface consisted of five layers—two prismatic and three crossed lamellar—around the growth break line. This suggests that shell formation temporarily ceased following the tsunamis and that the five-layered shell may have developed in response to the stress caused by the tsunamis. The newly formed middle layer became thinner after the “tsunami break,” which may be the result of a rapid change in the mineralization process, including rapid shell growth and/or repair. These results suggest that the damage to and forcible removal of habitats by the tsunamis was stressful for L. pulchella. A decrease in or the cessation of shell formation after a tsunami may be a common phenomenon in mollusks that inhabit tidal flats.
Evolution of Marine Coastal Ecosystems under the Pressure of Global Changes: Proceedings of Coast Bordeaux Symposium and of the 17th French-Japanese Oceanography Symposium
The economic systems of production and consumption, as well as the social models that have prevailed so far, are no longer adapted to serious contemporary situations. It is urgent that humans protect the ecosystems on which their present life depends and the existence of future generations, especially marine ecosystems. In France, Japan and other countries, man must now clearly differentiate the disturbances produced by natural phenomena, against which he can do nothing, from those which depend on his own activities. The meetings, the numerous colloquiums, the seminars organized between the members of the two Sociétés franco-japonaises d’Océanographie, and especially their fruitful cooperation, had, from the beginning, pragmatic objectives: to better know and compare the marine environments of the two countries and their various uses such as fishing, aquaculture, artificial reefs, shoreline developments. During their recent meetings, members of both societies have deepened many new concepts and made progress on the major changes affecting marine ecosystems and our societies. They are now orienting their future relationships by taking into account the need to study these themes in greater depth in the light of other disciplines. The dialogue between scientists sheds light on the new relationship between man and the marine environment, its resources and their exploitation. Traditions, eating habits, customs and even religions complete the basic scientific knowledge acquired so far. Our current objectives must be clearly defined to provide decision-makers with our knowledge and expertise, to understand the deep motivations and challenges of the professions and organizations that exploit marine resources, to enable man to live in a world in symbiosis with nature. Several new approaches have been identified integrating elements of economy, sociology, demography, law, foresight, culture, studies of traditions and certain religious activities. Beyond anthropocentric approaches, consideration should be given to the possibility of granting legal personality to non-human entities so that they can be protected. This multidisciplinary work will facilitate better integration of man within the ecosystems, especially marine ones and will help his survival. H.-J. Ceccaldi (B) Academy of Sciences, Letters, Arts of Marseille, and Société Franco-Japonaise d’Océanographie, 27, rue Rocca, Marseille 13008, France e-mail: ceccaldi.hubert@orange.fr © Springer Nature Switzerland AG 2020 H.-J. Ceccaldi et al. (eds.), Evolution of Marine Coastal Ecosystems under the Pressure of Global Changes, https://doi.org/10.1007/978-3-030-43484-7_2 7
Ecosystem Responses to Extreme Natural Events: Impacts of Three Sequential Hurricanes in Fall 1999 on Sediment Quality and Condition of Benthic Fauna in the Neuse River Estuary, North Carolina
A study was conducted in November 1999 to assess sediment quality and condition of benthic fauna in the Neuse River Estuary (NRE), North Carolina, USA, following the passage of three Atlantic hurricanes during the two months prior. Samples for analysis of macroinfauna (>0.5 mm sieve size), chemical contamination of sediments, and other abiotic environmental variables (salinity, dissolved oxygen, pH, depth, sediment granulometry) were collected at 20 sites from the mouth of the Neuse River at Pamlico Sound to approximately 90 km upstream. Results were compared to those obtained from the same area in July 1998 using similar protocols. Depressed salinity, caused by extreme rainfall and associated high freshwater flow, persisted throughout much of the estuary, which had experienced periods of water-column stratification and hypoxia of underlying waters. Fifteen of the 20 sites, representing 299 km2 (76% of the survey area), also showed signs of benthic stress based on a multi-metric benthic index of biotic integrity (B-IBI). Benthic impacts included reductions in the abundance, diversity, and numbers of species and shifts in taxonomic composition, with a notable increase in dominance of the opportunistic polychaete Mediomastus ambiseta as other former dominant species declined. There was no significant increase in the extent of chemical contamination compared to pre-hurricane conditions. Storm-related reductions in dissoved oxygen and salinity were the more likely causes of the observed benthic impacts, though it was not possible, based on these results, to separate storm effects from seasonal changes in the benthos and annual episodes of summer anoxia and hypoxia.