Annual and seasonal variability in high latitude dust deposition, West Greenland

High latitude regions (≥ 50°N and ≥ 40°S) are thought to contribute substantially to contemporary global dust emissions which can influence biogeochemical cycling as well as geomorphic, cryospheric and atmospheric processes. However, there are few measurements of the emission or deposition of dust derived from these areas that extend beyond a single event or season. This article reports the deposition of locally-derived dust to an ice-free area of West Greenland over 2 years from 23 traps distributed across five sampling sites. Local dust sources include glacial outwash plains, glacially-derived delta deposits and the reworking of loessic soils. Annual dust deposition is estimated at 37.3 to 93.9 g m−2 for 2017–2018 and 9.74 to 28.4 g m−2 in 2018–2019. This annual variation is driven by high deposition rates observed in spring 2017 of 0.48 g m−2 d−1 compared to the range of 0.03 to 0.07 g m−2 d−1 during the rest of the monitoring period. The high deposition rates in spring 2017 were due to warmer than average conditions and high meltwater sediment supply that delivered large quantities of sediment to local outwash plains in 2016. For other seasons, dust deposition was lower over both autumn–winter periods (0.03 g m−2 d−1) than during the spring and summer (0.04–0.07 g m−2 d−1). When sediment availability is limited, dust deposition increases with increasing temperature and wind speed. Secondary data from dust-related weather type/observation codes and visibility records were found to be inconsistent with measured dust deposition during the period of study. One possible reason for this is the complex nature of the terrain between the observation and sample sites. The dust deposition rates measured here and the infidelity of the observed dust with secondary data sources reveal the importance of direct quantification of dust processes to accurately constrain the dust cycle at high latitudes

Discovery of a morphologically and genetically distinct population of Black-tailed Godwits in the East Asian-Australasian Flyway

Occurring across Eurasia, the Black-tailed GodwitLimosa limosahas three recognized subspecies,melanuroides,limosaandislandicafrom east to west, respectively. With the smallest body size,melanuroideshas been considered the only subspecies in the East Asian-Australasian Flyway. Yet, observations along the Chinese coast indicated the presence of distinctively large individuals. Here we compared the morphometrics of these larger birds captured in northern Bohai Bay, China, with those of the three known subspecies and explore the genetic population structuring of Black-tailed Godwits based on the control region of the mitochondrial genome (mtDNA). We found that the Bohai Godwits were indeed significantly larger thanmelanuroides, resemblinglimosamore thanislandica, but with relatively longer bills thanislandica. The level of genetic differentiation between Bohai Godwits and the three recognized subspecies was of similar magnitude to the differentiation among previously recognized subspecies. Based on these segregating morphological and genetic characteristics, we propose that these birds belong to a distinct population, which may be treated and described as a new subspecies

Bar-tailed Godwits Limosa l. lapponica eat polychaete worms wherever they winter in Europe

<p>Capsule Across the European wintering range Bar-tailed Godwits Limosa lapponica lapponica selected polychaete worms and especially Ragworms Hediste diversicolor, with differences between areas due to variations in prey availability.Aims To determine the diet of Bar-tailed Godwits across their wintering range in Europe by the analysis of droppings, collected at five important wintering sites.Methods Diet was estimated by the identification of undigested prey remains in droppings. We provide the rationale for quantifying the contributions of jawed and non-jawed polychaetes.Results We identified 18 different prey species in the diet of wintering Bar-tailed Godwits. The Ragworm was the most common prey item and the only one actively selected. Ragworms, on average, contributed 79% to the diet in terms of biomass, followed by King Ragworm Alitta virens (with 17% biomass) and Lugworms Arenicola marina (with 2%). Polychaetes such as Alitta succinea and Scoloplos armiger were also regularly found in the diet. Bivalves, snails and crustaceans contributed less than 1% to the diet.Conclusion This study highlights and confirms the importance of polychaete worms in the diet of European-wintering Bar-tailed Godwits.</p>