Monitoring the anthropogenic impacts in Admiralty Bay using meiofauna community as indicators (King George Island, Antarctica)

Abstract

Activities at the Brazilian Antarctic Station (EACF) may cause damage to surrounding environment. Meiofauna was used to evaluate this impact. One area possibly impacted by the stations' presence (CF) and a reference area (BP) were compared.Sediment samples for meiofauna and environmental variables were obtained in two periods, at two sites and depths in each area. Densities were higher at 20-30m and nematodes were the dominant taxa (90%). Nematode densities ranged from 1,278±599 (BP1 50-60m) to 16,021±12,298 ind.10 cm -² (BP2 20-30m). A total of 68 genera were found.Sample richness ranged from 8 to 26 and diversity from 1.4 to 3.6 bits/ind, both being higher at BP 50-60m, where dominance of epistrate feeders was lower. Selective and non-selective deposit feeders were codominant with similar proportions. Maturity index was high and constant between samples. Aponema, Sabatieria, Daptonema, Dichromadora and Halalaimus were dominant, with higher densities at 20-30m. In contrast, Actinonema, Molgolaimus, Oxystomina and Marylynnia were more abundant at 50-60m. Differences in meiofauna community were found mainly between depths, but not between sites or periods, suggesting no anthropogenic impact. Nevertheless, lower Nematoda diversities and maturity index at 50-60m in CF when compared to BP may indicate a possible anthropogenic effect near EACF.

Diversity and abundance of free-living nematodes from Carlini station, Isla 25 de Mayo/King George Island, Antarctica: A case study in pristine and disturbed soils

“…In this work, the lowest MI values (< 2) were observed in the areas with the highest anthropic activity AZ1, AZ2, and AZ3 (fuel storage area, water intake box, and water treatment plant, respectively). These results of MI values match the descriptions of other authors in the maturity analysis of nematode communities on 25 de Mayo Island/King George Island(Gheller et al 2022) and what has been described in other works from Antarctica where a weak organization in the nematode community structure was observed (Ileva-Makulec et al 2009). In contrast, the highest values of MI(2)(3)(4) were found in the PZ2, PZ3 and PZ4 sites where the anthropic presence is practically nil.The results of EI were congruent with the maturity values obtained from the trophic webs in the nematode community.…”

Glacier retreat effects on the distribution of benthic assemblages in Martel Inlet (Admiralty Bay, Antarctica)

“…All polychaete and bivalve species here identified are very common and abundant in Admiralty Bay (Sicinski et al 2011). Differences in benthic distribution are due to specific environmental characteristics (depth, type of sediment) and disturbances of each sampling site (ice impact, proximity to sewage outfall), as we have seen in Martel Inlet (Nonato et al 2000, Skowronski & Corbisier 2002, Echeverria et al 2005, Petti et al 2006, Corbisier et al 2014, Gheller & Corbisier 2022. The highest values of organic matter observed in IFA stations were also recorded by Skowronski et al (2009) and was attributed to the sheltered condition of such environment while the stations closer to the influence of glaciers had lower values.…”