Hope Bay Research Articles

Enzymes and biosurfactants of industrial interest produced by culturable fungi present in sediments of BoeckellaLake, Hope Bay, north-east Antarctic Peninsula.

This study characterized cultivable fungi present in sediments obtained from BoeckellaLake, Hope Bay, in the north-east of the Antarctic Peninsula, and evaluated their production of enzymes and biosurfactants of potential industrial interest. A total of 116 fungal isolates were obtained, which were classified into 16 genera within the phyla Ascomycota, Basidiomycota and Mortierellomycota, in rank. The most abundant genera of filamentous fungi included Pseudogymnoascus, Pseudeurotium and Antarctomyces; for yeasts, Thelebolales and Naganishia taxa were dominant. Overall, the lake sediments exhibited high fungal diversity and moderate richness and dominance. The enzymes esterase, cellulase and protease were the most abundantly produced by these fungi. Ramgea cf. ozimecii, Holtermanniella wattica, Leucosporidium creatinivorum, Leucosporidium sp., Mrakia blollopis, Naganishia sp. and Phenoliferia sp. displayed enzymatic index > 2. Fourteen isolates of filamentous fungi demonstrated an Emulsification Index 24% (EI24%) ≥ 50%; among them, three isolates of A. psychrotrophicus showed an EI24% > 80%. BoeckellaLake itself is in the process of drying out due to the impact of regional climate change, and may be lost completely in approaching decades, therefore hosts a threatened community of cultivable fungi that produce important biomolecules with potential application in biotechnological processes.

Proximity to infrastructure and ecotype influence breeding bird abundance at an Arctic mine, the Hope Bay Project, Nunavut, Canada

Proximity to infrastructure and ecotype influence breeding bird abundance at an Arctic mine, the Hope Bay Project, Nunavut, Canada

Correction to: The relevance of fish in the summer diet of the Antarctic fur seal (Arctocephalus gazella) at Hope Bay, Antarctic Peninsula and Stranger Point, South Shetland Islands

Correction to: The relevance of fish in the summer diet of the Antarctic fur seal (Arctocephalus gazella) at Hope Bay, Antarctic Peninsula and Stranger Point, South Shetland Islands

The relevance of fish in the summer diet of the Antarctic fur seal (Arctocephalus gazella) at Hope Bay, Antarctic Peninsula and Stranger Point, South Shetland Islands

The relevance of fish in the summer diet of the Antarctic fur seal (Arctocephalus gazella) at Hope Bay, Antarctic Peninsula and Stranger Point, South Shetland Islands

Baseline concentrations, spatial distribution and origin of trace elements in marine surface sediments of the northern Antarctic Peninsula

Increased human activity in the Antarctic Peninsula combined with accelerated melting of its glaciers highlights the importance of monitoring trace element concentrations. Surface sediment samples were collected around King George Island, Hope Bay and in the Bransfield Strait in February 2020 and were analysed by X-ray fluorescence spectroscopy and inductively coupled plasma mass spectrometry. The methods display a good correlation. Our results show clear distinctions between these regions for selected elements with high local heterogeneities. Hope Bay exhibited lower concentrations of Fe, Mn, Co, V, Zn while most stations in the Bransfield Strait and around King George Island showed moderate to significant enrichment in Cu, As and Cd. Twelve stations presented a moderate ecological risk. The consistency of our values supports a natural rather than anthropogenic origin, possibly related to volcanism and the geology of the area. However, our results suggest an increase in Cr that should be further investigated.

UAV-based classification of maritime Antarctic vegetation types using GEOBIA and random forest

Development of vegetation communities in areas of Antarctica without permanent ice cover emphasizes the need for effective remote sensing techniques for proper monitoring of local environmental changes. Detection and mapping of vegetation by image classification remains limited in the Antarctic environment due to the complexity of its surface cover, and the spatial heterogeneity and spectral homogeneity of cryptogamic vegetation. As ultra-high resolution aerial images allow a comprehensive analysis of vegetation, this study aims to identify different types of vegetation cover (i.e., algae, mosses, and lichens) in an ice-free area of Hope Bay, on the northern tip of the Antarctic Peninsula. Using the geographic object-based image analysis (GEOBIA) approach, remote sensing data sets are tested in the random forest classifier in order to distinguish vegetation classes within vegetated areas. Because species of algae, mosses, and lichens may have similar spectral characteristics, subclasses are established. The results show that when only the mean values of green, red, and NIR bands are considered, the subclasses have low separability. Variations in accuracy and visual changes are identified according to the set of features used in the classification. Accuracy improves when multilayer information is used. A combination of spectral and morphometric products and by-products provides the best result for the detection and delineation of different types of vegetation, with an overall accuracy of 0.966 and a Kappa coefficient of 0.946. The method allowed for the identification of units primarily composed of algae, mosses, and lichens as well as differences in communities. This study demonstrates that ultra-high spatial resolution data can provide the necessary properties for the classification of vegetation in Maritime Antarctica, even in images obtained by sensors with low spectral resolution.

Fungal diversity in a sediment core from climate change impacted Boeckella Lake, Hope Bay, north-eastern Antarctic Peninsula assessed using metabarcoding.

We studied the fungal DNA present in a lake sediment core obtained from Trinity Peninsula, Hope Bay, north-eastern Antarctic Peninsula, using metabarcoding through high-throughput sequencing (HTS). Sequences obtained were assigned to 146 amplicon sequence variants (ASVs) primarily representing unknown fungi, followed by the phyla Ascomycota, Rozellomycota, Basidiomycota, Chytridiomycota and Mortierellomycota. The most abundant taxa were assigned to Fungal sp., Pseudeurotium hygrophilum, Rozellomycota sp. 1, Pseudeurotiaceae sp. 1 and Chytridiomycota sp. 1. The majority of the DNA reads, representing 40 ASVs, could only be assigned at higher taxonomic levels and may represent taxa not currently included in the sequence databases consulted and/or be previously undescribed fungi. Different sections of the core were characterized by high sequence diversity, richness and moderate ecological dominance indices. The assigned diversity was dominated by cosmopolitan cold-adapted fungi, including known saprotrophic, plant and animal pathogenic and symbiotic taxa. Despite the overall dominance of Ascomycota and Basidiomycota and psychrophilic Mortierellomycota, members of the cryptic phyla Rozellomycota and Chytridiomycota were also detected in abundance. As Boeckella Lake may cease to exist in approaching decades due the effects of local climatic changes, it also an important location for the study of the impacts of these changes on Antarctic microbial diversity.

U–Pb age constraints on the Jurassic succession and paleoflora of Mount Flora, Antarctic Peninsula

The spectacular fossil plant assemblage preserved in the non-marine Mount Flora Formation of the northern Antarctic Peninsula represents the diverse Jurassic flora that once covered the Gondwanan continents at high paleolatitudes. The depositional facies of the formation plays a key role in the tectonic interpretations and basin evolution models that attempt to reconcile large igneous province magmatism, continental break up, and magmatic arc development throughout the Jurassic and Cretaceous. Limited U–Pb in situ geochronology reported from the Mount Flora Formation and adjacent units lack the necessary resolution to overcome ambiguous correlations and biostratigraphic discrepancies. We present two high-precision U–Pb zircon ages (CA-ID-TIMS method) from a distinct tuffaceous interval of the Mount Flora Formation at Hope Bay, which document a terminal Middle Jurassic age (Callovian Stage) for the formation and its paleoflora. In excess of 1400 new collected fossil plant specimens exhibit a highly diverse Jurassic plant association that dominated the Antarctic Peninsula nearly 17 million years after its disappearance from northern Patagonia. This suggests similar paleoecological conditions were established diachronously throughout basins of southern Gondwana, possibly facilitating floral migrations in response to local climate change. The depositional facies of the Mount Flora Formation, its age proximity to the marine Nordenskjöld Formation in the Antarctic Larsen Basin and its coincidence with a regional unconformity in the northern Patagonia point out to a complex interplay among magmatic arc development, tectonic extension and continental break up that dominated the geologic and paleoenvironmental evolution of southern Gondwana near the end of the Middle Jurassic.

Spatiotemporal patterns in early life stage winter flounder Pseudopleuronectes americanus highlight phenology changes and habitat dependencies

Decadal changes in the life history events of marine species are becoming increasingly important to identify under a warming climate, yet many long-term monitoring programs do not collect data at the spatiotemporal resolution needed to describe them. Such data are vital for understanding the southern New England/Mid-Atlantic winter flounderPseudopleuronectes americanusstock, a species hypothesized to be adversely impacted by warming waters via increased temporal overlap between its early life stages and predators. To provide insight into winter flounder early life history dynamics and context for resiliency of the stock, we examined ichthyoplankton data collected from 2 monitoring programs within Narragansett Bay, Rhode Island, USA: one spatially comprehensive dataset across the bay proper (2001-2008, 2016-2017), and the other a longer time series centered in one of the sub-estuaries of the bay (Mount Hope Bay, 1972-2017). By leveraging these datasets together, we conducted a spatiotemporal synthesis of early life stage winter flounder by evaluating changes in larval phenology, decadal coherence in larval spatial patterns, and correspondence between larvae and their subsequent life stage. We identified changes in larval phenology via earlier seasonal peaks in density through time. Results also indicated stable larval spatial patterns during a period of larval decline, as well as spatial coherence between larval and young-of-the-year stages. Using winter flounder as a model species, our results highlight the importance of high-resolution spatiotemporal ichthyoplankton sampling to identify changes in phenology and site fidelity for marine fishes.

Contextualizing Thermal Effluent Impacts in Narragansett Bay Using Landsat-Derived Surface Temperature

This work utilizes remotely sensed thermal data to understand how the release of thermal pollution from the Brayton Point Power Station (BPPS) affected the temperature behavior of Narragansett Bay. Building upon previous work with Landsat 5, a multi-satellite analysis is conducted that incorporates 582 scenes from Landsat 5, Landsat 7, and Landsat 8 over 1984–2021 to explain seasonal variability in effluent impacts, contrast data after the effluent ceased in 2011, identify patterns in temperature before and after effluent ceased using unsupervised learning, and track how recent warming trends compare to the BPPS impact. Stopping the thermal effluent corresponds to an immediate cooling of 0.26 ± 0.1°C in the surface temperature of Mt. Hope Bay with respect to the rest of Narragansett Bay with greater cooling of 0.62 ± 0.2°C found near Brayton Point; though, cooling since the period of maximal impact (1993–2000) totals 0.53 ± 0.2°C in Mt. Hope Bay and 1.04 ± 0.2°C at Brayton Point. During seasons with lower solar radiation (winter) and lower mean river input (autumn and late summer), the BPPS effluent impact is more prominent. The seasonal differences between the high impact and low impact periods indicate that river input played an important role in the heat balance when emissions were lower, but surface fluxes dominated when emissions were higher. Putting the BPPS effluent in context, Landsat data indicates that Narragansett Bay warmed 0.5–1.2°C over the period of measurement at an average rate of 0.23 ± 0.1°C/decade and that net warming in Mt. Hope Bay is near zero. This trend implies that Narragansett Bay has experienced climatic warming over the past four decades on the scale of the temperature anomaly in Mt. Hope Bay caused by the BBPS effluent.

Consistent Predictability of the Ocean State Ocean Model Using Information Theory and Flushing Timescales

AbstractThe Ocean State Ocean Model (OSOM) is an application of the Regional Ocean Modeling System spanning the Rhode Island waterways, including Narragansett Bay, Mt. Hope Bay, larger rivers, and the Block Island Shelf circulation from Long Island to Nantucket. This study discusses the physical aspects of the estuary (Narragansett and Mount Hope Bays and larger rivers) to evaluate physical circulation predictability. This estimate is intended to help decide if a forecast and prediction system is warranted, to prepare for coupling with biogeochemistry and fisheries models with widely disparate timescales, and to find the spin‐up time needed to establish the climatological circulation of the region. Perturbed initial condition ensemble simulations are combined with metrics from information theory to quantify the predictability of the OSOM forecast system–i.e., how long anomalies from different initial conditions persist. The predictability timescale in this model agrees with readily estimable timescales such as the freshwater flushing timescale evaluated using the total exchange flow (TEF) framework, indicating that the estuarine dynamics rather than chaotic transport is the dominant model behavior limiting predictions. The predictability of the OSOM is ∼7–40 days, varying with parameters, region, and season.

What's Water Got to Do with It? Place-Related Symbolic Meanings Alter Residents' Perceived Effects of Coastal Infrastructure

The symbolic meanings residents associate with their local bodies of water and coastal infrastructure can shape their perceptions of the infrastructure's effects. In this case, we conduct a survey (N = 168) to examine residents' perceptions of visibly disruptive, yet environmentally protective cooling towers attached to a long-standing coal-fired power plant on Mount Hope Bay. Residents' symbolic meanings of the bay corresponded predominantly with aesthetic, ecological, or recreational themes, whereas their symbolic meanings of the towers also focused on aesthetics as well as the towers' function or uselessness. Although residents generally perceived the towers as having negative effects on different aspects of the bay community overall, those who reported ecological meanings of the bay or functional meanings of the towers perceived that the towers offered significantly more positive ecological and health impacts. They were also more likely to differentiate positive ecological and health effects from the towers' more negative aesthetic and financial impacts. This offers evidence for the important role of symbolic meanings in shaping perceptions of coastal infrastructure and demonstrates how specific understandings of the bay and the infrastructure itself can lead to more nuanced perceptions of the positive and negative effects of such projects. IRB Registration Number: [850913-8].

Phylogenetic diversity and dominant ecological traits of freshwater Antarctic Chrysophyceae

Previous studies conducted in summer in the lakes at Hope Bay (Antarctic Peninsula) between 1991 and 2007 showed a large numerical contribution of flagellated Chrysophyceae to the phytoplankton communities, particularly in the oligotrophic lakes, as evidenced by light microscopy observations and molecular fingerprinting. Given the ecological relevance of this group in these Antarctic microbial foodwebs, we carried out further molecular analyses (clone libraries and 18S Illumina high throughput sequencing) to characterize their phylogenetic diversity. The results of this study significantly increased the retrieved Chrysophyceae biodiversity. Clone libraries in two selected lakes (one oligotrophic and one mesotrophic) yielded 12 different chrysophycean OTUs, whereas 81 Swarm OTUs were recovered from six lakes using Illumina HiSeq. With the combination of both methods, we observed sequences of all the chrysophyte known clades, although most of the diversity belonged to Clade D, a group comprising mixotrophic and heterotrophic species. The percentage of reads for this clade in Illumina HiSeq ranged from 30% to 96% of the total Chrysophyceae reads. Based on experiments and observations, we also describe the main ecological traits of this group: the dominant taxa were small pigmented flagellates, well adapted to survive in oligotrophic systems, sometimes abundant under ice-cover subjected to low light intensities, and that have phagotrophic behavior. The used combination of methods allowed us to characterize the biodiversity and ecology of the Chrysophyceae, the dominant phytoplankton group in the oligotrophic lakes of this Maritime Antarctic region.

Benthic macroinvertebrate community response to environmental changes over seven decades in an urbanized estuary in the northeastern United States

Narragansett Bay is representative of New England, USA urbanized estuaries, with colonization in the early 17th century, and development into industrial and transportation centers in the late 18th and early 20th century. Increasing nationwide population and lack of infrastructure maintenance led to environmental degradation, and then eventual improvement after implementation of contaminant control and sewage treatment starting in the 1970s. Benthic macroinvertebrate community structure was expected to respond to these environmental changes. This study assembled data sets from the 1950s through 2010s to examine whether quantitative aggregate patterns in the benthic community corresponded qualitatively to stressors and management actions in the watershed. In Greenwich Bay and Providence River, patterns of benthic response corresponded to the decline and then improvement in sewage treatment at the Fields Point wastewater treatment plant. In Mount Hope Bay, the benthos corresponded to changes in bay fish populations due to thermal discharge from the Brayton Point power plant. The benthos of the Upper West Passage corresponded to climatic changes that caused regime shifts in the plankton and fish communities. Future work will examine the effects of further environmental improvements in the face of continued climatic changes and population growth.

First record of White-rumped Sandpiper (Calidris fuscicollis) at Esperanza/Hope Bay, Antarctica

The White-rumped Sandpiper (Calidris fuscicollis) (Vieillot 1819) is one of the longest migrating birds that breeds in the high Arctic in Alaska and Canada and spends the post-breeding period in South America. This bird is a frequent vagrant visitor of Islas Georgias del Sur/South Georgia and the South Shetland islands. Here we provide the first record for the White-rumped Sandpiper at the Continental Antarctica. The individual was observed the 2 February 2019 at Esperanza/Hope Bay (63° 23′ 56″ S, 56° 59′ 06″ W), the north of the Antarctic Peninsula, in an ice-free rockery close to a melt-water-run-off area. At the moment of the observation, the temperature was above 0 °C and the wind calm. However, strong winds from the north-west and west directions were registered during the last week of January 2019 at Esperanza Station (peak 65 knots) and at the Drake Passage (peak 49 knots) which might explain the presence of the White-rumped Sandpiper individual at Hope Bay. Our report contributes to list the non-native species observed in Antarctica. One plausible explanation could be related to changes in migratory routes of flying birds.

Evaluation of UAV and satellite-derived NDVI to map maritime Antarctic vegetation

Expansion of Antarctic vegetation in ice-free areas underlines the need for effective remote sensing techniques to properly monitor the changes. Detection and mapping of vegetation remains limited in the Antarctic environment given the complexity of its surface coverage. Some cryptogamic species exhibit low reflectance in the near-infrared region and are not easily detected by vegetation indices, such as the normalized difference vegetation index (NDVI). In addition, spectral reflectance of Antarctic vegetation is highly variable according to seasonal conditions, which may influence NDVI results. As ultra-high resolution aerial imagery allows for a detailed analysis of vegetation and enables the validation of satellite imagery, in this study we assess the ability of the NDVI from unmanned aerial vehicle (UAV), Sentinel-2, and Landsat 8 to identify vegetated areas in the ice-free environment of Hope Bay, Antarctic Peninsula. NDVI classification with class ranges set by statistical parameters (i.e., mean and standard deviation) is performed. The results show that different sensors provide different NDVI values for the same vegetation class. NDVI classification enabled the identification of areas showing vegetation cover, which are in accordance with the manually mapped areas in the UAV image. Correspondence in vegetation distribution and classes can be observed across all classifications, demonstrating that aerial and satellite imagery may be used for Antarctic vegetation monitoring. A close association between NDVI classes and Antarctic vegetation type is identified, where lichens are generally classified in lower probability classes, and algae and moss in higher probability classes. This article shows the potential of NDVI applied to Antarctic vegetation and the significance of data statistical parameters in the selection of thresholds, reducing the need for ground-truth information in remote areas.

The (truly) first fossil freshwater molluscs from Antarctica

New collection work in Mount Flora, Hope Bay, Antarctic Peninsula, has confirmed the presence of bivalve moulds in the Jurassic Mount Flora Formation. In contrast to a twenty-first century article claiming to report the first discovery of fossil freshwater molluscs in Antarctica, evidence of these molluscs was first reported for Antarctica more than 110 years ago by J. Gunnar Andersson. The bivalve was formally described and named some 50 years later, by Camacho, as Antediplodon esperanzaensis. The species was subsequently transferred to the genus Diplodon for unknown reasons. Here, we illustrate specimens from the same locality for the first time with photographs, considering them Unionida incertae saedis, in view of the absence of diagnostic characters. In fact, two morphotypes are present, one elongated, very similar to the nominal species A. esperanzaensis, and another one subelliptical in shape.

Evidências Geomorfológicas de Mudanças Ambientais na Baía Esperança, Península Antártica

A geomorphological interpretation of the glacial geomorphology of the proglacial environments of the Buenos Aires, Kenney and Flora glaciers in Hope Bay, Antarctica, between the coordinates 63° 23'S and 63° 26'S latitude and 56° 8'W and 57° 4'W longitude. Sedimentary, granulometric and morphological analyzes were carried out on 15 samples collected in 2017 for the identification of depositional geomorphological features and subsequent geomorphological mapping. The glacier fronts were delineated from Sentinel-2 and Quickbird images of 1988, 2008 and 2017 using the ArcGIS® software to identify the landforms chronology of the shapes. The higher number of coarse grains, low selection, and high values of C40 in all samples indicate modification by erosive processes in supraglacial environment and/or transport distance after substrate quarrying process and grain fracturing by post-depositional physical weathering. The reconstruction of the Hope Bay’s Holocene landscape of indicates glaciers with tens of meters of advance compared to the current front during the Little Ice Age (LIA). The geomorphological mapping and sedimentary analyzes showed recent environmental changes in the proglacial system, with formation of hummocky moraines indicating the retreat/stabilization of the glaciers in the LIA. Furthermore, they set evidences of recent recession moraines, which prevail in the Buenos Aires Glacier predominate in the 2008-2017 phase, on the Flora Glacier in 1988-2008 period and the Kenney Glacier in the 2008-2017 period.

Effects of glacier melting on the planktonic communities of two Antarctic coastal areas (Potter Cove and Hope Bay) in summer

Climate change has contributed to the regional retreat and melting of glaciers in the Antarctic Peninsula. This phenomenon is expected to affect the composition of plankton communities. The aim of this study is to analyze the influence of glacier melting on the composition and structure of phytoplankton and micro- and mesozooplankton assemblages in two coastal areas located in the northwest (Potter Cove) and in the northern end (Hope Bay) of the Antarctic Peninsula during summer 2013. We expect differences in plankton assemblages between PC and HB related to the fact that these areas are subjected to different climatic and environmental conditions and that the glacier meltwater is accumulated in lakes in HB whereas the meltwater directly reaches the adjacent sea at PC. However, plankton communities differed according to their proximity to the glaciers in both areas investigated, with a transition from herbivorous to microbial plankton food webs towards the glacier. The microbial food web was favored under the effects of glacier meltwater due to the stratification of the water column that favors the development of small eukaryotic algae. These are potential prey for ciliates and heterotrophic dinoflagellates which, in turn, favors the development of small omnivorous copepods. Further away from the glaciers, the herbivorous food web consists of large phytoplankton and a greater representation of herbivorous mesozooplankton organisms. It can be inferred from this study that increases in atmospheric temperatures may favor the development of microbial plankton food webs in the Antarctic coastal seas during summer due to increased glacier meltwater.

A discussion of 2D induced polarization effects in airborne electromagnetic and inversion with a robust 1D laterally constrained inversion scheme

Recently, the interest in the induced polarization (IP) phenomenon in airborne time-domain electromagnetic (ATEM) data has increased considerably. IP may affect the ATEM data significantly and mask underlying geologic structures. To simulate 2D airborne IP data, a 2D finite-element forward-modeling algorithm has been developed with the dispersive conductivity described by the well-known Cole-Cole model. We verify our algorithm by comparison with the 1D solution of the AarhusInv code. Two-dimensional forward responses on six synthetic models, mimicking archetypal 2D conductive and chargeable anomalies, have been generated, and the results indicate that 2D IP affects the data significantly. Differences between the 2D IP responses and the 1D IP responses are evident above the 2D anomalies and at their edges. These differences are similar to what is found when comparing 2D and 1D forward responses over conductive 2D anomalies without considering IP. We evaluate an effective robust inversion scheme to recover the 2D IP parameters using the 1D laterally constrained inversion (LCI) scheme. The inversion of the synthetic data using the robust scheme indicates that not only can the IP parameters be recovered, but also the IP inversions can provide more accurate resistivity sections than a resistivity-only inversion, in terms of resistivity values and anomaly thickness/depth. The field example from Hope Bay area in Canada is even more valuable, considering that part of the profile consists of only negative data, which cannot be inverted with a resistivity-only scheme. Furthermore, the edge effects at the anomaly boundaries are less pronounced in the IP parameters than in the resistivity parameter on the synthetic models with more conductive backgrounds.