Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes

Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples'' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes may affect coastal processes, food web dynamics and marine resources on which many traditional ways of life rely. Here, we examine how future projected increases in runoff and permafrost thaw from two permafrost-dominated Siberian watersheds—the Kolyma and Lena, may alter carbon turnover rates and OC distributions through river networks. We demonstrate that the unique composition of terrestrial permafrost-derived OC can cause significant increases to aquatic carbon degradation rates (20 to 60% faster rates with 1% permafrost OC). We compile results on aquatic OC degradation and examine how strengthening Arctic hydrological cycles may increase the connectivity between terrestrial landscapes and receiving nearshore ecosystems, with potential ramifications for coastal carbon budgets and ecosystem structure. To address the future challenges Arctic coastal communities will face, we argue that it will become essential to consider how nearshore ecosystems will respond to changing coastal inputs and identify how these may affect the resiliency and availability of essential food resources.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01666-z.     

HCH contamination from former pesticide production in Brazil—a challenge for the Stockholm Convention implementation

Hexachlorocyclohexane (HCH) isomers (α-, β- and γ- HCH [lindane]) were recently added to the list of persistent organic pollutants regulated by the Stockholm Convention, and therefore, the legacy of HCH and lindane production has become an issue of global relevance. The production of lindane with the much larger quantities of associated waste isomers has generated large waste deposits and contaminated sites. This article presents an overview of HCH-polluted sites in Brazil as a basis for further activities related to the Stockholm Convention. The locations of HCH stockpiles and contaminated sites in Brazil arising from production and formulation have been compiled and mapped. This shows that the measures taken over the past 25 years have not resulted in remediation of the HCH pollution. An exposure risk study has been summarised for one major site and is included to demonstrate the contemporary relevance of the contamination. Major site remediation efforts are planned at one site but people live close to several other sites, and there is an urgent need of further assessments and remediation to ensure the protection of human health and the environment. The Stockholm Convention requires a systematic approach and should be adopted for the assessment of all sites and appropriate isolation/remediation measures should be facilitated. The appropriate planning of these activities for the production site in Rio de Janeiro could be a positive contribution for Rio+20 highlighting that green economy and sustainable production also include the appropriate management of legacies of historic production of an industrial sector (here the organochlorine industry).     

Proximate composition and energy content of mesopelagic fishes from the eastern Gulf of Mexico

The proximate composition of 33 species of mesopelagic fishes collected from the eastern Gulf of Mexico during May–June 1984, July–November 1985 and January 1986 was determined. Water level increased and ash-free dry weight (% dry weight) and protein level (% wet weight) decreased with increasing species' minimum depth of occurrence (that depth below which 90% of a species' population lives). Lipid level (% wet weight or % ash-free dry weight), did not change with species' minimum depth of occurrence. Skeletal ash level (% wet weight) generally decreased with minimum depth of occurrence, whereas carbohydrate level did not change with depth. The variable water level, low lipid level, and high protein level in eastern Gulf of Mexico fishes resulted in a low energy content. These results are generally characteristic of fishes from warm, stable regions of low productivity, such as the eastern North Pacific Gyre. The constant food supply provided by a stable environment may obviate the need for large lipid reserves, in contrast to colder waters at higher latitudes where food availability is seasonal. In addition, the large energy requirements for diel excursions into high-temperature surface waters by the many vertically migrating fishes of this region may influence lipid deposition. The relatively high protein level found in migrators compared to that in non-migrators or weak migrators indicates that locomotory demands influence the percentage of protein found in Gulf fishes. The lack of a positive correlation between protein level and the food availability of a zoogeographic region, suggested in previous studies, is supported here.     

Degradation of L- and DL-lactic acid oligomers in the presence ofFusarium moniliforme andPseudomonas putida

Poly(-alkanoates) derived from lactic acid enantiomers are known to degrade easily hydrolytically in aqueous media. The ability of two microorganisms, a filamentous fungus,Fusarium moniliforme, and a bacterium,Pseudomonas putida, to assimilate the degradation by-products of poly(lactic acid) (PLA), namely, lactic acid, lactyllactic acid dimers, and higher oligomers, was investigated in liquid culture. To distinguish the influence of chirality on bioassimilation, two series of substrates were considered which derived from the racemic and the L-form of lactic acid, respectively. The fate of these compounds was monitored by HPLC. Under the selected conditions,DL- andL-lactic acids were totally used by the two microorganisms regardless of the enantiomeric composition. Both microorganisms degraded the LL-dimer rather rapidly. However,F. moniliforme acted more rapidly thanP. putida. It is likely that the DD-dimer also biodegraded but at a slower rate, especially in the case of the fungi. Higher racemic oligomers were slowly assimilated by the two microorganisms, whereas higher L-oligomers appeared biostable probably because of their crystallinity. A synergistic effect was observed when both microorganisms were present in the same culture medium containing racemic oligomers.Presented at the 4th International Workshop on Biodegradable Plastics and Polymers, October 11–14, 1995. Durham, New Hampshire.     

Evaluation and classification of severity for 176 genes on an expanded carrier screening panel

Background

Disease severity is important when considering genes for inclusion on reproductive expanded carrier screening (ECS) panels. We applied a validated and previously published algorithm that classifies diseases into four severity categories (mild, moderate, severe, and profound) to 176 genes screened by ECS. Disease traits defining severity categories in the algorithm were then mapped to four severity-related ECS panel design criteria cited by the American College of Obstetricians and Gynecologists (ACOG).

Methods

Eight genetic counselors (GCs) and four medical geneticists (MDs) applied the severity algorithm to subsets of 176 genes. MDs and GCs then determined by group consensus how each of these disease traits mapped to ACOG severity criteria, enabling determination of the number of ACOG severity criteria met by each gene.

Results

Upon consensus GC and MD application of the severity algorithm, 68 (39%) genes were classified as profound, 71 (40%) as severe, 36 (20%) as moderate, and one (1%) as mild. After mapping of disease traits to ACOG severity criteria, 170 out of 176 genes (96.6%) were found to meet at least one of the four criteria, 129 genes (73.3%) met at least two, 73 genes (41.5%) met at least three, and 17 genes (9.7%) met all four.

Conclusion

This study classified the severity of a large set of Mendelian genes by collaborative clinical expert application of a trait-based algorithm. Further, it operationalized difficult to interpret ACOG severity criteria via mapping of disease traits, thereby promoting consistency of ACOG criteria interpretation.

     

Mitochondrial energetics of benthic and pelagic Antarctic teleosts

Antarctic fauna are highly adapted to the frigid waters of the Southern Ocean. This study describes the in vitro temperature sensitivity of oxygen consumption rates measured in liver mitochondria from the pelagic notothenioid Pleuragramma antarcticum between 5 and 35 °C. Oxygen fluxes were measured after the addition of millimolar levels of pyruvate, malate, succinate and glutamate (state II, LEAK) and saturating levels of ADP [state III, oxidative phosphorylation (OXPHOS)]. State III respiration significantly decreased above 18.7 °C. A comparison of the oxidative capacities among P. antarcticum and other notothenioids showed significant differences in state III respiration, where benthic species exhibited about 50 % lower rates than P. antarcticum. In addition, state III respiration rates normalized per milligram of mitochondrial protein of P. antarcticum were up to eight times higher than state III rates reported in the literature for other notothenioids. The comparatively high respiration rates measured in this study may be explained by our approach, which engaged both complexes I and II under conditions of oxidative phosphorylation. State III rates of independently activated complexes I and II were found to range from 42 to 100 % of rates obtained when both complexes were activated simultaneously in the same species. The remarkable tolerance of P. antarcticum OXPHOS toward warmer temperatures was unexpected for an Antarctic stenotherm and may indicate that thermal sensitivity of their mitochondria is not the driving force behind their stenothermy.     

Distribution and diel vertical movements of mesopelagic scattering layers in the Red Sea

The mesopelagic zone of the Red Sea represents an extreme environment due to low food concentrations, high temperatures and low oxygen waters. Nevertheless, a 38 kHz echosounder identified at least four distinct scattering layers during the daytime, of which the 2 deepest layers resided entirely within the mesopelagic zone. Two of the acoustic layers were found above a mesopelagic oxygen minimum zone (OMZ), one layer overlapped with the OMZ, and one layer was found below the OMZ. Almost all organisms in the deep layers migrated to the near-surface waters during the night. Backscatter from a 300 kHz lowered Acoustic Doppler Current Profiler indicated a layer of zooplankton within the OMZ. They carried out DVM, yet a portion remained at mesopelagic depths during the night. Our acoustic measurements showed that the bulk of the acoustic backscatter was restricted to waters shallower than 800 m, suggesting that most of the biomass in the Red Sea resides above this depth.     

Assessment of groundwater quality by means of self-organizing maps: application in a semiarid area

The Kohonen neural network was applied to hydrochemical data from the Detritic Aquifer of the Lower Andarax, situated in a semiarid zone in the southeast of Spain. An activation map was obtained for each of the sampling points, in which the spatial distribution of the activated neurons indicated different water qualities. To extract the information contained in the activation maps, they were divided into nine quadrats. Cartesian coordinates were assigned to each quadrant (x, y), and for each sampling point, three derived variables were selected, which were assigned the values x and y of the corresponding quadrat. A classification was defined based on this simple matrix system which allows an easy and rapid means of evaluating the water quality. This assessment highlights the various processes that affect groundwater quality. The method generates output that is easier to interpret than from traditional statistical methods. The information is extracted from the activation maps without significant loss of information. The method is proposed for assessing water quality in hydrogeochemically complex areas, where large numbers of observations are made.     

Bioluminescence in the Monterey Submarine Canyon: image analysis of video recordings from a midwater submersible

Video images of bioluminescence were recorded in situ during a 1985 study of the midwater environment of the Monterey Canyon, using a single-person, untethered submersible. Gelatinous organisms were responsible for the most brilliant bioluminescent displays, often exhibiting elaborate kinetics in response to mechanical stimulation. Images of bioluminescent displays recorded from identified organisms are shown and display patterns are described. All bioluminescence emission spectra from captured specimens were blue, with peak emissions between 460 and 494 nm. Image-analysis of recordings of mechanically stimulated bioluminescence revealed source densities between 43 and 175 m^-3 and intensities between 2.5 and 37.3 W sr^-1 m^-3. The predominant display type at all depths studied (between 100 and 560 m) was luminous secretions. Despite high intensities of mechanically stimulated bioluminescence, no spontaneous light production was recorded in the absence of mechanical stimulation.     

Forecasting of cyanobacterial density in Torrão reservoir using artificial neural networks

The ability of general regression neural networks (GRNN) to forecast the density of cyanobacteria in the Torr?o reservoir (Tamega river, Portugal), in a period of 15 days, based on three years of collected physical and chemical data, was assessed. Several models were developed and 176 were selected based on their correlation values for the verification series. A time lag of 11 was used, equivalent to one sample (periods of 15 days in the summer and 30 days in the winter). Several combinations of the series were used. Input and output data collected from three depths of the reservoir were applied (surface, euphotic zone limit and bottom). The model that presented a higher average correlation value presented the correlations 0.991; 0.843; 0.978 for training, verification and test series. This model had the three series independent in time: first test series, then verification series and, finally, training series. Only six input variables were considered significant to the performance of this model: ammonia, phosphates, dissolved oxygen, water temperature, pH and water evaporation, physical and chemical parameters referring to the three depths of the reservoir. These variables are common to the next four best models produced and, although these included other input variables, their performance was not better than the selected best model.