Pre-treatment methods for stable oxygen and carbon isotope analyses of structural carbonates of bones in marine teleost fishes.

Rationale: Although the proportion of structural carbonates in vertebrate bones is low, the values of isotopes, namely stable oxygen (δ O) and carbon (δ C), in structural carbonates provide environmental and physiological information, which can be beneficial for estimating the palaeontological and ecological parameters of vertebrates. However, a few studies have analysed the isotopes of structural carbonates in modern teleost fishes, and a well-developed protocol for sample preparation is lacking.

Methods: We examined different pre-treatment methods of preparing bone samples of three marine teleost fishes (Japanese flounder, Pacific bluefin tuna and yellowtail) and investigated the effects of the cleaning methods on the stable isotope values of structural carbonates among vertebrae in the same individual.

Ocean acidification stunts molluscan growth at CO seeps.

Ocean acidification can severely affect bivalve molluscs, especially their shell calcification. Assessing the fate of this vulnerable group in a rapidly acidifying ocean is therefore a pressing challenge. Volcanic CO seeps are natural analogues of future ocean conditions that offer unique insights into the scope of marine bivalves to cope with acidification.

Periostracum of bivalve mollusk shells for sampling engineered metal nanoparticles: A case study of silver-based nanoparticles in Canada's experimental lake.

Given the ability of engineered metal nanoparticles to be transformed in natural waters in unpredictable manners, various sampling methods must be developed. Here, we took a novel approach to collection silver nanoparticles (AgNPs) that involved the use of the intact periostracum, the outer proteinaceous organic layer, of freshwater unionid mussels Pyganodon sp. Eight adult mussels were collected in August 2019 from a small boreal lake (L222) at the International Institute for Sustainable Development - Experimental Lakes Area (northwestern Ontario), which had been dosed with 15 kg of poly(vinylpyrrolidone)-coated silver nanoparticles (PVP-AgNPs) in 2014-2015.

Using neodymium isotope ratio in Ruditapes philippinarum shells for tracking the geographical origin.

Geographical traceability of marine bivalves is becoming increasingly important to assure their quality and to defend the interest of consumers and producers. This study verifies the neodymium isotopic ratio (Nd/Nd) in Ruditapes philippinarum shells as a tracer of the geographic origin, based on the geochemical aspect that Nd/Nd of their habitats strongly depends on the geology of its catchment areas. The Nd/Nd ratios of clam shells from the Japanese and Chinese coastal areas displayed a heterogeneous pattern from local to international scales, reflecting the geological age of the catchment area.

Influence of normal tide and the Great Tsunami as recorded through hourly-resolution micro-analysis of a mussel shell.

We report here hourly variations of Mg/Ca, Sr/Ca, and Ba/Ca ratios in a Mediterranean mussel shell (Mytilus galloprovincialis) collected at the Otsuchi bay, on the Pacific coast of northeastern Japan. This bivalve was living in the intertidal zone, where such organisms are known to form a daily or bidaily growth line comprised of abundant organic matter. Mg/Ca ratios of the inner surface of the outer shell layer, corresponding to the most recent date, show cyclic changes at 25-90 μm intervals, while no interpretable variations are observed in Sr/Ca and Ba/Ca ratios.

Spatiotemporal change of cesium-137 in the Pacific coast of Tohoku, Japan: The mussel watch approach.

We measured radiocesium in mussel tissue collected from the Pacific coast of Tohoku from 2011 to 2015 to investigate the temporal and spatial dynamics of radiocesium in the coastal area. Radioactive Cs was detected in all the samples collected in 2011, but it was not found in samples from localities north of Sendai after 2012. In contrast, Cs was detected in many sites in the Fukushima area even from 2012 to 2015.

Divalent metal transporter-related protein restricts animals to marine habitats.

Utilization and regulation of metals from seawater by marine organisms are important physiological processes. To better understand metal regulation, we searched the crown-of-thorns starfish genome for the divalent metal transporter (DMT) gene, a membrane protein responsible for uptake of divalent cations. We found two DMT-like sequences.

Identification of timing of scallop morphological deformity and mortality from shell oxygen isotope records.

The Yesso scallop, Patinopecten yessoensis (Jay), is one of the most important bivalve species in the Japanese and Chinese mariculture industry. In recent years, however, high incidences of scallop shell deformity and mortality have occurred with increasing frequency, but timing of onset and underlying causes are often unclear. Here, we proposed a promising δO-based method for constraining the onset of shell deformity and mortality of P.

Determination of the geographical origin of marine mussels (Mytilus spp.) using Nd/Nd ratios.

Geographical traceability of marine bivalves is critical to guarantee their quality and safeguard the interest of both consumers and producers. The neodymium isotopic ratio (Nd/Nd) of the coastal water mainly reflects the geology of its neighboring watershed, displaying the distinct and systematic variability at high level of geographical detail and thereby shedding light on its potential as a geochemical tracer. For the first time, the present study investigated the utility and robustness of Nd/Nd archived in mytilid mussel shells for geographical traceability purposes.

Retrospective monitoring of salinity in coastal waters with mussel shells.

Sea surface salinity (SSS) is a key parameter to understand and predict many physical, chemical and biological processes in dynamic coastal environments. Yet, in many regions, instrumental measurements are spatially sparse and insufficiently long, hindering our ability to document changes, causes, and consequences of SSS across different time scales. Therefore, there is an need to develop a robust proxy to extend SSS records back in time.

Stimpson's hard clam Mercenaria stimpsoni; A multi-decadal climate recorder for the northwest Pacific coast.

A sclerochronological and radiocarbon-based study of life history traits of Stimpson's hard clam (Mercenaria stimpsoni), collected alive from Funakoshi Bay, northeast Japan, showed the lifespan of the species to be at least 92 years (determined from annual growth line counts). Three M. stimpsoni specimens exhibited the following synchronous growth pattern, suggestive of environmental control; annual increment width increasing after 1955 to a maximum value between 1970 and 1980, subsequently decreasing gradually until 2000, and thereafter remaining constant or increasing slightly.

Using tsunami deposits to determine the maximum depth of benthic burrowing.

The maximum depth of sediment biomixing is directly related to the vertical extent of post-depositional environmental alteration in the sediment; consequently, it is important to determine the maximum burrowing depth. This study examined the maximum depth of bioturbation in a natural marine environment in Funakoshi Bay, northeastern Japan, using observations of bioturbation structures developed in an event layer (tsunami deposits of the 2011 Tohoku-Oki earthquake) and measurements of the radioactive cesium concentrations in this layer. The observations revealed that the depth of bioturbation (i.

Spatial Distribution and Temporal Trend of Anthropogenic Organic Compounds Derived from the 2011 East Japan Earthquake.

The tsunami caused by the Great East Japan Earthquake on March 11, 2011 disturbed coastal environments in the eastern Tohoku region in Japan. Numerous terrestrial materials, including anthropogenic organic compounds, were deposited in the coastal zone. To evaluate the impacts of the disaster, we analyzed PCBs, LABs, PAHs, and hopanes in mussels collected from 12 locations in the east of Tohoku during 2011-2015 (series A) by GC-ECD or GC-MS and compared them with results from mussels collected from 22 locations around Japan during 2001-2004 (series B).