Research

18 pages, 5164 KiB

Open AccessArticle

Pluridecadal Temporal Patterns of Tintinnids (Ciliophora, Spirotrichea) in Terra Nova Bay (Ross Sea, Antarctica)

by Marina Monti-Birkenmeier, Tommaso Diociaiuti, Pasquale Castagno, Giorgio Budillon and Serena Fonda Umani

Diversity 2022, 14(8), 604; https://doi.org/10.3390/d14080604 - 28 Jul 2022

Cited by 2 | Viewed by 1366

Abstract

During the next century, the Ross Sea is expected to reduce summer sea ice concentrations and consolidate the presence of shallower mixed layers. Those changes may have a potentially catastrophic effect on the zooplankton community. To investigate if Ross Sea’s past physical and [...] Read more.

During the next century, the Ross Sea is expected to reduce summer sea ice concentrations and consolidate the presence of shallower mixed layers. Those changes may have a potentially catastrophic effect on the zooplankton community. To investigate if Ross Sea’s past physical and biological condition changes have affected the tintinnids population, and to understand future tintinnids’ role in the plankton community, seawater samples collected in the Terra Nova Bay polynya area during eleven summer expeditions from 1988 to 2017 were analyzed. During this time period, tintinnids’ abundance ranged from 0 to a maximum of 4980 indL⁻¹. The most representative species were Cymatocylis drygalskii, Codonellopsis gaussi and Laackmanniella naviculifaera. These species can be considered keystone species and they can be used to monitor the long-term evolution of the whole microzooplankton community in Terra Nova Bay polynya. The tintinnids’ abundance presented minimum values in 2001 after which there has been a significant increase in the most recent years. The increase in tintinnids’ abundance showed a positive correlation with the temperature, while salinity did not indicate any relationship. In particular, the majority of genera detected showed a significant temperature correlation, with the only exception of Amphorides genus, recorded for the first time in the study area. Our results provide new insights into the spatial distribution and structure of the Antarctic tintinnids community. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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21 pages, 6997 KiB

Open AccessArticle

Not All That Glitters Is Gold: Barcoding Effort Reveals Taxonomic Incongruences in Iconic Ross Sea Sea Stars

by Alice Guzzi, Maria Chiara Alvaro, Bruno Danis, Camille Moreau and Stefano Schiaparelli

Diversity 2022, 14(6), 457; https://doi.org/10.3390/d14060457 - 07 Jun 2022

Cited by 3 | Viewed by 2284

Abstract

The Southern Ocean is one of the most exposed regions to climate-related changes on our planet. Better understanding of the current biodiversity and past speciation events, as well as implementation of conservation actions and accurate identification of organisms to species level in this [...] Read more.

The Southern Ocean is one of the most exposed regions to climate-related changes on our planet. Better understanding of the current biodiversity and past speciation events, as well as implementation of conservation actions and accurate identification of organisms to species level in this unique environment, is fundamental. In this study, two species of sea stars, Odontaster roseus Janosik & Halanych, 2010 and Odontaster pearsei Janosik & Halanych, 2010, are reported for the first time from the Terra Nova Bay area (TNB, Ross Sea, Antarctica) by using a combination of molecular (DNA barcoding) and morphological (coloration and skeletal features) analyses. Molecular results agree with external morphological characters of the two identified species, making occurrence in the area unequivocal. The two species were recently described from the Antarctic Peninsula, and went unnoticed for a long time in TNB, possibly having been confused with O. meridionalis (E.A. Smith, 1876), with which they share a bright yellow coloration. This latter species seems to be absent in the Ross Sea. Thus, the past literature referring to O. meridionalis in the Ross Sea should be treated with caution as these “yellow morphs” could be one of the two recently described species or even orange–yellow morphs of the red-colored congeneric O. validus Koehler, 1906. This work highlights the paucity of knowledge even in purportedly well-studied areas and in iconic Antarctic organisms. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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19 pages, 4332 KiB

Open AccessArticle

Is It the Same Every Summer for the Euphausiids of the Ross Sea?

by Andrea De Felice, Ilaria Biagiotti, Giovanni Canduci, Ilaria Costantini, Sara Malavolti, Giordano Giuliani and Iole Leonori

Diversity 2022, 14(6), 433; https://doi.org/10.3390/d14060433 - 28 May 2022

Cited by 4 | Viewed by 1594

Abstract

The pelagic ecosystem in the Ross Sea has one central component that is very important for energy exchanges between upper and lower trophic levels: the Middle Trophic Level. Krill species are the most important and abundant organisms within this level. Several acoustic surveys [...] Read more.

The pelagic ecosystem in the Ross Sea has one central component that is very important for energy exchanges between upper and lower trophic levels: the Middle Trophic Level. Krill species are the most important and abundant organisms within this level. Several acoustic surveys were conducted in the western Ross Sea over the past 25 years, revealing that Euphausia superba is by far the most abundant species of krill in the Ross Sea during austral summer, and that its core distribution is concentrated in the northern part, bordering the Southern Ocean. Euphausia crsytallorophias, the second most abundant krill species, is more concentrated in the central Ross Sea, generally near the coast. Data on krill biomass were collected in December and January from 1994 to 2016 and analyzed together with key environmental parameters by means of two-way ANOVA in order to explain species behavior and identify possible environmental drivers. Temperature and dissolved oxygen influenced the biomass of both species of krill, while other environmental parameters only affected one species. In conclusion, the biomass of both species has varied over the years, possibly due to a complex synergy of environmental drivers. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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17 pages, 2722 KiB

Open AccessArticle

Breeding Ecology of Adélie Penguins in Mid Victoria Land, Ross Sea Antarctica

by Silvia Olmastroni, Francesco Ferretti, Lucia Burrini, Nicoletta Ademollo and Niccolò Fattorini

Diversity 2022, 14(6), 429; https://doi.org/10.3390/d14060429 - 27 May 2022

Cited by 3 | Viewed by 2368

Abstract

Identifying the factors influencing seabird breeding output is critical for their conservation because breeding performance in turn influences population dynamics. This is particularly important in sensitive environments, where ecological disturbances can lead to changes in population trends of extremely specialized species in a [...] Read more.

Identifying the factors influencing seabird breeding output is critical for their conservation because breeding performance in turn influences population dynamics. This is particularly important in sensitive environments, where ecological disturbances can lead to changes in population trends of extremely specialized species in a relatively short time. Here, we have reported on the breeding output of the Adélie penguin Pygoscelis adeliae in three colonies of the Mid Victoria Land, Ross Sea (Antarctica), in 2017/2018–2018/2019 to provide scientific information for the Ross Sea Marine Protected Area research and management plan. Breeding chronology, breeding success and chick growth did not differ between study colonies and were in line with data reported for other penguin colonies across Antarctica. Penguin breeding success was higher in central than in peripheral nests and decreased with an increasing number of neighboring nesting skuas; conversely, at-nest weather conditions experienced by chicks did not seem to play a role. Our findings suggest that the quality of the nesting environment seems more important than the general condition of the colony in determining breeding output. Therefore, along with marine habitat characteristics for the planning of management and conservation of seabirds, the importance of the terrestrial environment must be also duly considered. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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21 pages, 4820 KiB

Open AccessArticle

Diversity in Zooplankton and Sympagic Biota during a Period of Rapid Sea Ice Change in Terra Nova Bay, Ross Sea, Antarctica

by Antonia Granata, Christine K. Weldrick, Andrea Bergamasco, Maria Saggiomo, Marco Grillo, Alessandro Bergamasco, Kerrie M. Swadling and Letterio Guglielmo

Diversity 2022, 14(6), 425; https://doi.org/10.3390/d14060425 - 26 May 2022

Cited by 5 | Viewed by 1929

Abstract

Sea ice is a major driver of biological activity in the Southern Ocean. Its cycle of growth and decay determines life history traits; food web interactions; and populations of many small, ice-associated organisms. The regional ocean modelling system (ROMS) for sea ice in [...] Read more.

Sea ice is a major driver of biological activity in the Southern Ocean. Its cycle of growth and decay determines life history traits; food web interactions; and populations of many small, ice-associated organisms. The regional ocean modelling system (ROMS) for sea ice in the western Ross Sea has highlighted two modes of sea ice duration: fast-melting years when water temperature warms quickly in early spring and sea ice melts out in mid-November, and slow-melting years when water temperature remains below 0 °C and sea ice persists through most of December. Ice-associated and pelagic biota in Terra Nova Bay, Ross Sea, were studied intensively over a 3-week period in November 1997 as part of the PIPEX (Pack-Ice Plankton Experiment) campaign. The sea ice environment in November 1997 exhibited features of a slow-melting year, and the ice cover measured 0.65 m in late November. Phytoplankton abundance and diversity increased in the second half of November, concomitant with warming air and water temperatures, melting sea ice and progressive deepening of a still weak pycnocline. Water column phytoplankton was dominated by planktonic species, both in abundance and diversity, although there was also some input from benthic species. Pelagic zooplankton were typical of a nearshore Antarctic system, with the cyclopoid copepod Oithona similis representing at least 90% of total abundance. There was an increase in numbers coinciding with the period of ice thinning. Conversely, ice-associated species such as the calanoid copepods Stephos longipes and Paralabidocera antarctica decreased over time and were found in low numbers once the water temperatures increased. Stratified sampling under the sea ice, to 20 m, revealed that P. antarctica was mainly found in close association with the under-ice surface, while S. longipes, O. similis, and the calanoid copepod Metridia gerlachei were dispersed more evenly. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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13 pages, 7930 KiB

Open AccessArticle

Chaetarcturus cervicornis sp. n., a New Ross Sea Isopod of the Genus Chaetarcturus Brandt, 1990 (Crustacea, Malacostraca)

by Nicholas Francesco Noli, Angelika Brandt, Davide Di Franco and Stefano Schiaparelli

Diversity 2022, 14(5), 386; https://doi.org/10.3390/d14050386 - 13 May 2022

Viewed by 1819

Abstract

In the framework of the PNRA (Italian National Antarctic Research Program) project CARBONANT focusing on biogenic carbonates and held in January–February 2002, several Ross Sea banks were sampled to obtain samples of biogenic carbonates. In the Mawson Bank, species belonging to the isopod [...] Read more.

In the framework of the PNRA (Italian National Antarctic Research Program) project CARBONANT focusing on biogenic carbonates and held in January–February 2002, several Ross Sea banks were sampled to obtain samples of biogenic carbonates. In the Mawson Bank, species belonging to the isopod genus Chaetarcturus Brandt, 1990 were recorded, including a specimen that did not match any described species. In this paper we describe Chaetarcturus cervicornis sp. n., which is characterized by supraocular spines and two pairs of tubercle-like protrusions on the cephalothorax. The new species is very similar to C. bovinus (Brandt & Wägele, 1988) and C. adareanus (Hodgson, 1902), but has a clearly different spine pattern. The study of the species of the genus Chaetarcturus in the Ross Sea contributes to increase our knowledge on the diversity of the Antarcturidae in the Southern Ocean. Ross Sea banks seem to hold an interesting and not-well-known fauna, deserving attention in future research. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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9 pages, 1101 KiB

Open AccessArticle

First Record of the Phylum Gnathostomulida in the Southern Ocean

by Wolfgang Sterrer, Martin V. Sørensen, Matteo Cecchetto, Alejandro Martínez, Raffaella Sabatino, Ester M. Eckert, Diego Fontaneto and Stefano Schiaparelli

Diversity 2022, 14(5), 382; https://doi.org/10.3390/d14050382 - 12 May 2022

Viewed by 1810

Abstract

We report for the first time the occurrence of at least two species of the phylum Gnathostomulida in the Southern Ocean, along the shores of the Ross Sea in Antarctica. At least one species for each of the orders of the phylum (Filospermoidea [...] Read more.

We report for the first time the occurrence of at least two species of the phylum Gnathostomulida in the Southern Ocean, along the shores of the Ross Sea in Antarctica. At least one species for each of the orders of the phylum (Filospermoidea and Bursovaginoidea) was found using both morphological inspection and DNA metabarcoding of the shallow marine sediments collected with a Van Veen grab or by scuba diving in the area facing the Italian research station “Mario Zucchelli”. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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15 pages, 3716 KiB

Open AccessArticle

Three-Dimensional Quantification of Copepods Predictive Distributions in the Ross Sea: First Data Based on a Machine Learning Model Approach and Open Access (FAIR) Data

by Marco Grillo, Falk Huettmann, Letterio Guglielmo and Stefano Schiaparelli

Diversity 2022, 14(5), 355; https://doi.org/10.3390/d14050355 - 30 Apr 2022

Cited by 6 | Viewed by 2192

Abstract

Zooplankton is a fundamental group in aquatic ecosystems representing the base of the food chain. It forms a link between the lower trophic levels with secondary consumers and shows marked fluctuations in populations with environmental change, especially reacting to heating and water acidification. [...] Read more.

Zooplankton is a fundamental group in aquatic ecosystems representing the base of the food chain. It forms a link between the lower trophic levels with secondary consumers and shows marked fluctuations in populations with environmental change, especially reacting to heating and water acidification. Marine copepods account for approx. 70% of the abundance of zooplankton and are a target of monitoring activities in key areas such as the Southern Ocean. In this study, we have used FAIR-inspired legacy data (dating back to the 1980s) collected in the Ross Sea by the Italian National Antarctic Program at GBIF.org. Together with other open-access GIS data sources and tools, it allows one to generate, for the first time, three-dimensional predictive distribution maps for twenty-six copepod species. These predictive maps were obtained by applying machine learning techniques to grey literature data, which were visualized in open-source GIS platforms. In a Species Distribution Modeling (SDM) framework, we used machine learning with three types of algorithms (TreeNet, RandomForest, and Ensemble) to analyze the presence and absence of copepods in different areas and depth classes as a function of environmental descriptors obtained from the Polar Macroscope Layers present in Quantartica. The models allow, for the first time, to map-predict the food chain per depth class in quantitative terms, showing the relative index of occurrence (RIO) in 3Dimensions and identifying the presence of each copepod species analyzed in the Ross Sea, a globally-relevant wilderness area of conservation concern. Our results show marked geographical preferences that vary with species and trophic strategy. This study demonstrates that machine learning is a successful method in accurately predicting the Antarctic copepod presence, also providing useful data to orient future sampling and the management of wildlife and conservation. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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15 pages, 10939 KiB

Open AccessArticle

Microglena antarctica sp. nov. a New Antarctic Green Alga from Inexpressible Island (Terra Nova Bay, Ross Sea) Revealed through an Integrative Approach

by Riccardo Trentin, Enrico Negrisolo, Emanuela Moschin, Davide Veronese, Matteo Cecchetto and Isabella Moro

Diversity 2022, 14(5), 337; https://doi.org/10.3390/d14050337 - 26 Apr 2022

Cited by 6 | Viewed by 2123

Abstract

One of the aims of the XXXIV Italian Antarctic Expedition is the study of the photosynthetic biodiversity of the Ross Sea. To achieve this goal, sea-ice samples were collected from Inexpressible Island and a strain of a green microalga (IMA076A) was isolated for [...] Read more.

One of the aims of the XXXIV Italian Antarctic Expedition is the study of the photosynthetic biodiversity of the Ross Sea. To achieve this goal, sea-ice samples were collected from Inexpressible Island and a strain of a green microalga (IMA076A) was isolated for morphological and molecular investigations. Combining: (1) phylogenetic analyses of the small subunit rDNA (18S rDNA) and of the internal transcribed spacer 2 (ITS-2) sequences; (2) species delimitation methods; (3) comparative analyses of the secondary structures of ITS-2 and compensatory base changes; (4) morphological, ultrastructural and ecological features, we described the strain IMA076A and its relatives as the new species Microglena antarctica sp. nov. The discovery of a new species of Chlorophyceae highlights that the biological diversity of Antarctic microalgae is more extensive than previously thought and that molecular phylogeny together with compensatory base changes (CBCs) approach are pivotal in the identification of cryptic microalgae. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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11 pages, 3692 KiB

Open AccessArticle

Underwater Photographic Survey of Coastal Fish Community of Terra Nova Bay, Ross Sea

by Mario La Mesa, Simonepietro Canese, Paolo Montagna and Stefano Schiaparelli

Diversity 2022, 14(5), 315; https://doi.org/10.3390/d14050315 - 21 Apr 2022

Cited by 5 | Viewed by 1588

Abstract

Although the extent of near-shore and coastal habitats around the Antarctic Continent is limited, they host an abundant and diversified fish fauna dominated by notothenioids. Nevertheless, the spatial distribution of fishes at small scales and their relationships with the surrounding habitat are still [...] Read more.

Although the extent of near-shore and coastal habitats around the Antarctic Continent is limited, they host an abundant and diversified fish fauna dominated by notothenioids. Nevertheless, the spatial distribution of fishes at small scales and their relationships with the surrounding habitat are still poorly known. The purpose of this study is to provide new insights on the inshore fish community of Terra Nova Bay, Ross Sea, which is now part of the largest marine protected area established so far in the Southern Ocean. As a low-impact and effective methodology of investigation, an underwater photographic survey was conducted through two remotely operated vehicle (ROV) transects set down to 300 m depth. The faunistic inventory consisted of twelve species of notothenioids, which complements previous data obtained by conventional samplings. The most abundant species exhibited wide depth distribution ranges, and they were generally associated with areas with a rich benthic macrofauna composed of alcyonaceans, sponges, bryozoans, polychaetes, and echinoderms. Nesting behavior was documented in two species, Trematomus bernacchii and Pagetopsis macropterus. The present data provide further evidence of the importance of inshore waters for the local fish community, representing a proper habitat for settling, foraging, and spawning activities. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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11 pages, 2339 KiB

Open AccessArticle

Chromosomal-Level Assembly of Antarctic Scaly Rockcod, Trematomus loennbergii Genome Using Long-Read Sequencing and Chromosome Conformation Capture (Hi-C) Technologies

by Euna Jo, Seung Jae Lee, Jeong-Hoon Kim, Steven J. Parker, Eunkyung Choi, Jinmu Kim, So-Ra Han, Tae-Jin Oh and Hyun Park

Diversity 2021, 13(12), 668; https://doi.org/10.3390/d13120668 - 14 Dec 2021

Cited by 2 | Viewed by 2729

Abstract

Trematomus species (suborder Notothenioidei; family Nototheniidae) are widely distributed in the southern oceans near Antarctica. There are 11 recognized species in the genus Trematomus, and notothenioids are known to have high chromosomal diversity (2n = 24–58) because of relatively recent and rapid adaptive [...] Read more.

Trematomus species (suborder Notothenioidei; family Nototheniidae) are widely distributed in the southern oceans near Antarctica. There are 11 recognized species in the genus Trematomus, and notothenioids are known to have high chromosomal diversity (2n = 24–58) because of relatively recent and rapid adaptive radiation. Herein, we report the chromosomal-level genome assembly of T. loennbergii, the first characterized genome representative of the genus Trematomus. The final genome assembly of T. loennbergii was obtained using a Pacific Biosciences long-read sequencing platform and high-throughput chromosome conformation capture technology. Twenty-three chromosomal-level scaffolds were assembled to 940 Mb in total size, with a longest contig size of 48.5 Mb and contig N50 length of 24.7 Mb. The genome contained 42.03% repeat sequences, and a total of 24,525 protein-coding genes were annotated. We produced a high-quality genome assembly of T. loennbergii. Our results provide a first reference genome for the genus Trematomus and will serve as a basis for studying the molecular taxonomy and evolution of Antarctic fish. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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Review

Jump to: Research, Other

14 pages, 848 KiB

Open AccessReview

A Summary of United States Research and Monitoring in Support of the Ross Sea Region Marine Protected Area

by Cassandra M. Brooks and David G. Ainley

Diversity 2022, 14(6), 447; https://doi.org/10.3390/d14060447 - 02 Jun 2022

Cited by 4 | Viewed by 2060

Abstract

Due to the remarkable ecological value of the Ross Sea, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted a large-scale Ross Sea region marine protected area (RSRMPA) in 2016. Since then, many CCAMLR Members have conducted research and monitoring [...] Read more.

Due to the remarkable ecological value of the Ross Sea, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted a large-scale Ross Sea region marine protected area (RSRMPA) in 2016. Since then, many CCAMLR Members have conducted research and monitoring in the region. In 2021, the U.S. Ross Sea science community convened a workshop to collate, synthesize, and coordinate U.S. research and monitoring in the RSRMPA. Here we present workshop results, including an extensive synthesis of the peer-reviewed literature related to the region during the period 2010–early 2021. From the synthesis, several things stand out. First, the quantity and breadth of U.S. Ross Sea research compares to a National Science Foundation Long Term Ecological Research project, especially involving McMurdo Sound. These studies are foundational in assessing effectiveness of the RSRMPA. Second, climate change and fishing remain the two factors most critical to changing ecosystem structure and function in the region. Third, studies that integrate ecological processes with physical oceanographic change continue to be needed, especially in a directed and coordinated research program, in order to effectively separate climate from fishing to explain trends among designated indicator species. Full article

(This article belongs to the Special Issue Biodiversity of the Ross Sea Region Marine Protected Area (Antarctica))

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