Terrestrial records of glacial terminations V and IV and insights on deglacial mechanisms

40Ar/39Ar geochronology constraints to aggradational phases and grainsize variations show that the sedimentary filling of the Liri fluvial-lacustrine basin (central Italy) recorded the occurrence of deglaciation events associated with global meltwater pulses. Integrating these data with those from the Tiber River catchment basin, we find a precise match between the ages of gravel deposition and the occurrence of moderate sea-level rise events which anticipate those more marked during the glacial termination V and IV in the Red Sea relative sea level curve. Such correspondence suggests that gravel deposition is facilitated by melting of Apennine mountain range glaciers, which provide the water transport energy and a surplus of clastic input to the rivers draining the mountain regions and flowing into the Tyrrhenian Sea. Therefore, the thick gravel beds intercalated in the sedimentary filling of the catchment basins of the major rivers in central Italy may be regarded as an equivalent proxy of large deglaciation events, similar to the ice-rafted debris in northern Atlantic. Consistent with this hypothesis, we also show the close correspondence between the occurrence of particularly mild (warmer) minima of the mean summer insolation at 65° N and these early aggradational phases, as well as with other anomalous early sea-level rises occurred 750 ka and 540 ka at the onset of glacial termination VIII and VI, and 40 ka at the onset of the so-called Heinrich events.

Assessment of flood discharge sensitivity to climate indexes in West Africa

Floods are natural disasters that widely affect people and goods. Its frequency and magnitude are projected to substantially increase due to the ongoing environmental change. At regional and national levels, some efforts have been made in predicting floods at a short-term range. However, the usefulness of flood prediction increases as the time lead increases. The objective of this work is therefore to investigate flood sensitivity to climate indexes in West Africa as a basis for seasonal flood forecasting. The methodology consists of optimizing the relationship between Annual Maximal Discharge (AMD), a proxy for flood discharge and various climate indexes using correlation coefficient, linear regression and statistical modeling based on 56 river gauging stations across West Africa. The climate indexes considered are the Sea Surface Temperature (SST) of the Tropical Northern Atlantic (TNA), SST of the Tropical Southern Atlantic (TSA), the Sea Level Pressure (SLP) of the Southern Oscillation Indexes (SOI) and the detrended El-Nino Southern Oscillation indexes. It was found that SOI/SLP indexes are the most strongly related to the AMD for the investigated stations with generally high, positive, and statistically significant correlation. The TSA/SST indexes indicated both positive and negative statistically significant correlations with river discharge in the region. The percentage change in AMD per unit change in SOI/SLP for most of the statistically significant stations is within 10 % and 50 % indicating a strong relationship between these two variables. This relationship could serve as a basis for seasonal flood forecasting in the study area.

Adding pieces to the puzzle: insights into diversity and distribution patterns of Cumacea (Crustacea: Peracarida) from the deep North Atlantic to the Arctic Ocean

The Nordic Seas have one of the highest water-mass diversities in the world, yet large knowledge gaps exist in biodiversity structure and biogeographical distribution patterns of the deep macrobenthic fauna. This study focuses on the marine bottom-dwelling peracarid crustacean taxon Cumacea from northern waters, using a combined approach of morphological and molecular techniques to present one of the first insights into genetic variability of this taxon. In total, 947 specimens were assigned to 77 morphologically differing species, representing all seven known families from the North Atlantic. A total of 131 specimens were studied genetically (16S rRNA) and divided into 53 putative species by species delimitation methods (GMYC and ABGD). In most cases, morphological and molecular-genetic delimitation was fully congruent, highlighting the overall success and high quality of both approaches. Differences were due to eight instances resulting in either ecologically driven morphological diversification of species or morphologically cryptic species, uncovering hidden diversity. An interspecific genetic distance of at least 8% was observed with a clear barcoding gap for molecular delimitation of cumacean species. Combining these findings with data from public databases and specimens collected during different international expeditions revealed a change in the composition of taxa from a Northern Atlantic-boreal to an Arctic community. The Greenland-Iceland-Scotland-Ridge (GIS-Ridge) acts as a geographical barrier and/or predominate water masses correspond well with cumacean taxa dominance. A closer investigation on species level revealed occurrences across multiple ecoregions or patchy distributions within defined ecoregions.

Jumping the Shark: White Shark Representations in Great White Serial Killer Lives—The Fear and the (Pseudo-)Science

Sharks are among the most endangered nonhuman animals on the planet because of industrial fishing, the shark meat and fin trade, expanding recreational fishing, and other anthropogenic causes. White sharks (Carcharodon carcharias), the most visible in popular culture, remain vulnerable (VU, IUCN Red List) and understudied, although population recovery is having a measure of success in regions like the Eastern Pacific and the Northern Atlantic of the United States. As numbers rise, Jaws associations also remain in vogue in programming that emphasizes human–wildlife** conflict such as Shark Week’s Great White Serial Killer Lives. Network marketing typically promotes this content by hyping shark science. Textual analysis, however, suggests that exposure to pseudoscientific narratives and unethical fear-inducing images is counterproductive to wider support for conservation programs and public recognition for sharks’ rights to their habitats.

Rare specimen identification in an un-integrated taxonomy: implications of DNA sequences from a Taiwanese Philine (Mollusca, Philinidae)

Many species of the gastropod genus Philine have been named from northeastern Asia but scanty descriptions based predominantly on shells make it difficult to determine which are valid. This, plus the sporadic anatomical and genetic information available for many of these species has led to what may be described as an un-integrated taxonomy. In this situation, it is generally preferable to postpone dissection of rare and unusual specimens until relevant diagnostic characters can be established in broader studies. Micro-CT scanning and DNA sequencing were used to examine such a specimen collected recently from deep waters off northeastern Taiwan. Micro-CT examination of the morphology of the internal shell and gizzard plates suggested that, among named species, the sequenced specimen is most similar to P. otukai. It cannot, however, be definitively referred to P. otukai as that species lacks adequate anatomical description or known DNA sequences. Phylogenetic analyses of newly collected DNA sequences show the specimen to be most closely related to, but distinct from the northern Atlantic Ocean and Mediterranean species, Philine quadripartita. The sequences also confirm genetically that five or more species of Philine occur in northeast Asia, including at least three subject to considerable taxonomic uncertainty.

Odds and ends of atmospheric mercury in Europe and over northern Atlantic Ocean: Temporal trends of 25 years of measurements

The Global Monitoring Plan of the Minamata Convention on Mercury was established to generate long-term data necessary for evaluating the effectiveness of regulatory measures at a global scale. After 25 years monitoring (since 1995), Mace Head is one of the atmospheric monitoring stations with the longest mercury record, and has produced sufficient data for the analysis of temporal trends of Total Gaseous Mercury (TGM) in Europe and the Northern Atlantic. Using concentration-weighted trajectories for atmospheric mercury measured at Mace Head as well as other five locations in Europe, Amderma, Andøya, Villum, Waldhof and Zeppelin we identify the regional probabilistic source contribution factor and its changes for the period of 1996 to 2019. Temporal trends indicate that concentrations of mercury in the atmosphere in Europe and the Northern Atlantic have declined significantly over the past 25 years, at a non-monotonic rate averaging of 0.03 ng m-3 year-1. Concentrations of TGM at remote marine sites were shown to be affected by continental long-range transport, and evaluation of reanalysis back-trajectories display a significant decrease of TGM in continental air masses from Europe in the last two decades. In addition, using the relationship between mercury and other atmospheric trace gases that could serve as a source signature, we perform factorization regression analysis, based on positive rotatable factorization of non-singular matrix to solve probabilistic mass function. We reconstructed atmospheric mercury concentration and accessed the contribution of the major natural and anthropogenic sources. The positive matrix factorization (PMF) reveals that the downward trend is mainly associated with a factor with a high load of long-lived anthropogenic species.