Blowin' in the wind: Dispersal, structure, and metacommunity dynamics of aeolian diatoms in the McMurdo Sound region, Antarctica.

Diatom metacommunities are structured by environmental, historical, and spatial factors that are often attributed to organism dispersal. In the McMurdo Sound region (MSR) of Antarctica, wind connects aquatic habitats through delivery of inorganic and organic matter. We evaluated the dispersal of diatoms in aeolian material and its relation to the regional diatom metacommunity using light microscopy and 18S rRNA high-throughput sequencing. The concentration of diatoms ranged from 0 to 8.76 * 106 valves · g-1 dry aeolian material. Up to 15% of whole cells contained visible protoplasm, indicating that up to 3.43 * 104 potentially viable individuals could be dispersed in a year to a single 2 -cm2 site. Diatom DNA and RNA was detected at each site, reinforcing the likelihood that we observed dispersal of viable diatoms. Of the 50 known morphospecies in the MSR, 72% were identified from aeolian material using microscopy. Aeolian community composition varied primarily by site. Meanwhile, each aeolian community was comprised of morphospecies found in aquatic communities from the same lake basin. These results suggest that aeolian diatom dispersal in the MSR is spatially structured, is predominantly local, and connects local aquatic habitats via a shared species pool. Nonetheless, aeolian community structure was distinct from that of aquatic communities, indicating that intrahabitat dispersal and environmental filtering also underlie diatom metacommunity dynamics. The present study confirms that a large number of diatoms are passively dispersed by wind across a landscape characterized by aeolian processes, integrating the regional flora and contributing to metacommunity structure and landscape connectivity.

Measuring novice-expert sense of place for a far-away place: Implications for geoscience instruction.

Individuals usually develop a sense of place through lived experiences or travel. Here we introduce new and innovative tools to measure sense of place for remote, far-away locations, such as Greenland. We apply this methodology within place-based education to study whether we can distinguish a sense of place between those who have visited Greenland or are otherwise strongly connected to the place from those who never visited. Place-based education research indicates that an increased sense of place has a positive effect on learning outcomes. Thus, we hypothesize that vicarious experiences with a place result in a measurably stronger sense of place when compared to the sense of place of those who have not experienced the place directly. We studied two distinct groups; the first are people with a strong Greenland connection (experts, n = 93). The second are students who have never been there (novices, n = 142). Using i) emotional value attribution of words, ii) thematic analysis of phrases and iii) categorization of words, we show significant differences between novice's and expert's use of words and phrases to describe Greenland as a proxy of sense of place. Emotional value of words revealed statistically significant differences between experts and novices such as word power (dominance), feeling pleasantness (valence), and degree of arousal evoked by the word. While both groups have an overall positive impression of Greenland, 31% of novices express a neutral view with little to no awareness of Greenland (experts 4% neutral). We found differences between experts and novices along dimensions such as natural features; cultural attributes; people of Greenland; concerns, importance, or interest in and feeling connected to Greenland. Experts exhibit more complex place attributes, frequently using emotional words, while novices present a superficial picture of Greenland. Engaging with virtual environments may shift novice learners to a more expert-like sense of place, for a far-away places like Greenland, thus, we suggest virtual field trips can supplement geoscience teaching of concepts in far-away places like Greenland and beyond.

Black carbon footprint of human presence in Antarctica.

Black carbon (BC) from fossil fuel and biomass combustion darkens the snow and makes it melt sooner. The BC footprint of research activities and tourism in Antarctica has likely increased as human presence in the continent has surged in recent decades. Here, we report on measurements of the BC concentration in snow samples from 28 sites across a transect of about 2,000 km from the northern tip of Antarctica (62°S) to the southern Ellsworth Mountains (79°S). Our surveys show that BC content in snow surrounding research facilities and popular shore tourist-landing sites is considerably above background levels measured elsewhere in the continent. The resulting radiative forcing is accelerating snow melting and shrinking the snowpack on BC-impacted areas on the Antarctic Peninsula and associated archipelagos by up to 23 mm water equivalent (w.e.) every summer.