Mercury Concentrations in Two Populations of the most Endangered Dolphin (Pontoporia blainvillei) from the Southwestern Atlantic Ocean.

Mercury contamination has been aggravated by emerging environmental issues, such as climate change. Top predators present concerning Hg concentrations once this metal bioaccumulates and biomagnifies. This study evaluated total mercury (THg) concentrations in tissues of 43 franciscanas (Pontoporia blainvillei) from two populations: the Franciscana Management Area (FMA) IIb and FMA IIIa. Animals from FMA IIIa showed mean concentration 5-times and 2.5-times higher in the liver and kidney (4.73 ± 6.84 and 0.52 ± 0.51 µg.g-1, w.w., respectively) than individuals from FMA IIb (0.89 ± 1.04 and 0.22 ± 0.15 µg.g-1, w.w., respectively). This might be due to: (I) individuals sampled from FMA IIIa being larger and older, and/or (II) the area near FMA IIIa presents environmental features leading to higher THg availability. Coastal contamination can affect franciscanas' health and population maintenance at different levels depending on their life history and, therefore, it should be considered to guide specific conservation actions.

Anthropogenic debris in three sympatric seal species of the Western Antarctic Peninsula.

Litter pollution is a growing concern, including for Antarctica and the species that inhabit this ecosystem. In this study, we investigated the microplastic contamination in three seal species that inhabit the Western Antarctic Peninsula: crabeater (Lobodon carcinophaga), leopard (Hydrurga leptonyx) and Weddell (Leptonychotes weddellii) seals. Given the worldwide ubiquity of this type of contaminant, including the Southern Ocean, we hypothesized that the three seal species would present anthropogenic debris in their feces. We examined 29 scat samples of crabeater (n = 5), leopard (n = 13) and Weddell (n = 11) seals. The chemical composition of the items found were identified using micro-Raman and micro-FTIR spectroscopies. All the samples of the three species presented anthropic particles (frequency of occurrence - %FO - 100 %). Fibers were the predominant debris, but fragments and filaments were also present. Particles smaller than 5 mm (micro debris) were predominant in all the samples. Leopard seals ingested significantly larger micro-debris in comparison with the other seal species. The dominant color was black followed by blue and white. Micro-Raman and micro-FTIR Spectroscopies revealed the presence of different anthropogenic pigments such as reactive blue 238, Indigo 3600 and copper phthalocyanine (blue and green). Carbon black was also detected in the samples, as well as plastic polymers such as polystyrene, polyester and polyethylene terephthalate (PET), polyamide, polypropylene and polyurethane These results confirm the presence of anthropogenic contamination in Antarctic seals and highlight the need for actions to mitigate the effects and reduce the contribution of debris in the Antarctic ecosystem.

Genomic Divergence and the Evolution of Ecotypes in Bottlenose Dolphins (Genus Tursiops).

Climatic changes have caused major environmental restructuring throughout the world's oceans. Marine organisms have responded to novel conditions through various biological systems, including genomic adaptation. Growing accessibility of next-generation DNA sequencing methods to study nonmodel species has recently allowed genomic changes underlying environmental adaptations to be investigated. This study used double-digest restriction-site associated DNA (ddRAD) sequence data to investigate the genomic basis of ecotype formation across currently recognized species and subspecies of bottlenose dolphins (genus Tursiops) in the Southern Hemisphere. Subspecies-level genomic divergence was confirmed between the offshore common bottlenose dolphin (T. truncatus truncatus) and the inshore Lahille's bottlenose dolphin (T. t. gephyreus) from the southwestern Atlantic Ocean (SWAO). Similarly, subspecies-level divergence is suggested between inshore (eastern Australia) Indo-Pacific bottlenose dolphin (T. aduncus) and the proposed Burrunan dolphin (T. australis) from southern Australia. Inshore bottlenose dolphin lineages generally had lower genomic diversity than offshore lineages, a pattern particularly evident for T. t. gephyreus, which showed exceptionally low diversity. Genomic regions associated with cardiovascular, musculoskeletal, and energy production systems appear to have undergone repeated adaptive evolution in inshore lineages across the Southern Hemisphere. We hypothesize that comparable selective pressures in the inshore environment drove similar adaptive responses in each lineage, supporting parallel evolution of inshore bottlenose dolphins. With climate change altering marine ecosystems worldwide, it is crucial to gain an understanding of the adaptive capacity of local species and populations. Our study provides insights into key adaptive pathways that may be important for the long-term survival of cetaceans and other organisms in a changing marine environment.

The deep dive of organohalogen compounds: Bioaccumulation in the top predators of mesopelagic trophic webs, pygmy and dwarf sperm whales, from the Southwestern Atlantic ocean.

Kogia sima and Kogia breviceps are apex predators of mesopelagic trophic webs being far from most anthropogenic threats. However, chemical pollutants and naturally synthesized compounds may travel long distances. This study aimed to use kogiid whales as sentinels of mesopelagic trophic webs in the Southwestern Atlantic Ocean. Persistent organic pollutants (POPs), e.g., polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, mirex, hexachlorobenzene (HCB), polybrominated diphenylethers (PBDEs), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBB), and the naturally produced methoxylated BDE (MeO-BDEs) were determined in the blubber of 16 K. sima and 15 K. breviceps. Among the organochlorine compounds, DDTs were the main group found in K. sima and in K. breviceps (1636.6 and 3983.3 ng g-1 lw, respective medians), followed by PCBs (425.9 and 956.1 ng g-1 lw, respectively), mirex (184.1 and 375.6 ng g-1 lw, respectively), and HCB (132.4 and 340.3 ng g-1 lw, respectively). As for the organobromine, the natural MeO-BDEs were predominant (1676.7 and 501.6 ng g-1 lw, respectively), followed by PBDEs (13.6 and 10.3 ng g-1 lw, respectively) and PBEB (2.2 and 2.9 ng g-1 lw, respectively). In general, POPs concentration was higher in K. breviceps than in K. sima. Conversely, MeO-BDEs concentration was higher in K. sima than in K. breviceps. Differences in concentrations in these sympatric odontocetes were attributed to distinct species, sampling sites, and biological parameters and suggest some level of niche segregation. It is noteworthy the long-range reach and bioaccumulation of these synthetic compounds in an unexplored habitat, that present an increasing economic interest.

Mobilization of persistent organic pollutants in humpback whales: Insights from feeding areas in the Antarctic peninsula and Strait of Magellan to migration, breeding, and calving grounds along the Brazilian coast.

Southern Hemisphere Megaptera novaeangliae undertake the longest migration, which reflect their exposure to lipophilic contaminants. To assess these changes, persistent organic pollutants were analyzed in blubber samples of humpback whales from three regions: the Antarctic Peninsula (n = 46), the Strait of Magellan, Chile (n = 22), and the Brazilian coast (n = 38). The similarity in PCB and HCB levels between individuals from feeding grounds and breeding grounds suggests contamination during feeding. The whales around the Antarctic Peninsula exhibited a predominance of tetrachlorobiphenyl PCBs. Whales feeding in the Strait of Magellan showed a slight prevalence of 5Cl biphenyls, likely due to their consumption of subantarctic krill species as well as small fishes potentially contaminated by industrial activities in Chile. The dominance of 5-6Cl congeners in whales in Brazil, may be attributed to the extreme physiological changes during fasting when whales utilize blubber reserves and metabolize lighter congeners, or transfer them to their calves.

Physical-biological drivers modulating phytoplankton seasonal succession along the Northern Antarctic Peninsula.

The Northern Antarctic Peninsula (NAP) shows shifts in phytoplankton distribution and composition along its warming marine ecosystems. However, despite recent efforts to mechanistically understand these changes, little focus has been given to the phytoplankton seasonal succession, remaining uncertainties regarding to distribution patterns of emerging taxa along the NAP. To fill this gap, we collected phytoplankton (pigment and microscopy analysis) and physico-chemical datasets during spring and summer (November, February and March) of 2013/2014 and 2014/2015 off the NAP. Satellite measurements (sea surface temperature, sea ice concentration and chlorophyll-a) were used to extend the temporal coverage of analysis associated with the in situ sampling. We improved the quantification and distribution pattern of emerging taxa, such as dinoflagellates and cryptophytes, and described a contrasting seasonal behavior and distinct fundamental niche between centric and pennate diatoms. Cryptophytes and pennate diatoms preferentially occupied relatively shallower mixing layers compared with centric diatoms and dinoflagellates, suggesting differences between these groups in distribution and environment occupation over the phytoplankton seasonal succession. Under colder conditions, negative sea surface temperature anomalies were associated with positive anomalies of sea ice concentration and duration. Therefore, based on sea ice-phytoplankton growth relationship, large phytoplankton biomass accumulation was expected during the spring/summer of 2013/2014 and 2014/2015 along the NAP. However, there was a decoupling between sea ice concentration/duration and phytoplankton biomass, characterizing two seasonal periods of low biomass accumulation (negative chlorophyll-a anomalies), associated with the top-down control in the region. These results provide an improved mechanistic understanding on physical-biological drivers modulating phytoplankton seasonal succession along the Antarctic coastal waters.

An additional threat to populations predicted to collapse: Organobromine compounds of natural and anthropogenic sources in rough-toothed dolphins from the Southwestern Atlantic Ocean.

Organic contaminants with toxic effects, like the conventional brominated flame retardants (BFRs) and BFRs of emergent concern, and their synergistic effects with other micropollutants, can be an additional threat to delphinids. Rough-toothed dolphins (Steno bredanensis) populations strongly associated with coastal environments already face a potential risk of decline due to high exposure to organochlorine pollutants. Moreover, natural organobromine compounds are important indicators of the environment's health. Polybrominated diphenyl ethers (PBDEs), pentabromoethylbenzene (PBEB), hexabromobenzene (HBB) and the methoxylated PBDEs (MeO-BDEs) were determined in the blubber of rough-toothed dolphins from three ecological populations from the Southwestern Atlantic Ocean (Southeastern, Southern and Outer Continental Shelf/Southern populations, SE, S, and OCS/S, respectively). The profile was dominated by the naturally produced MeO-BDEs (mainly 2'-MeO-BDE 68 and 6-MeO-BDE 47), followed by the anthropogenic BFRs PBDEs (mainly BDE 47). Median ΣMeO-BDE concentrations varied between 705.4 and 3346.0 ng g-1 lw among populations and ΣPBDE from 89.4 until 538.0 ng g-1 lw. Concentrations of anthropogenic organobromine compounds (ΣPBDE, BDE 99 and BDE 100) were higher in SE population than in OCS/S, indicating a coast - ocean gradient of contamination. Negative correlations were found between the concentration of the natural compounds and age, suggesting their metabolization and/or biodilution and maternal transference. Conversely, positive correlations were found between the concentrations of BDE 153 and BDE 154 and age, indicating low biotransformation capability of these heavy congeners. The levels of PBDEs found are concerning, particularly for SE population, because they are similar to concentrations known for the onset of endocrine disruption in other marine mammals and may be an additional threat to a population in a hotspot for chemical pollution.

Cryptophytes: An emerging algal group in the rapidly changing Antarctic Peninsula marine environments.

The western Antarctic Peninsula (WAP) is a climatically sensitive region where foundational changes at the basis of the food web have been recorded; cryptophytes are gradually outgrowing diatoms together with a decreased size spectrum of the phytoplankton community. Based on a 11-year (2008-2018) in-situ dataset, we demonstrate a strong coupling between biomass accumulation of cryptophytes, summer upper ocean stability, and the mixed layer depth. Our results shed light on the environmental conditions favoring the cryptophyte success in coastal regions of the WAP, especially during situations of shallower mixed layers associated with lower diatom biomass, which evidences a clear competition or niche segregation between diatoms and cryptophytes. We also unravel the cryptophyte photo-physiological niche by exploring its capacity to thrive under high light stress normally found in confined stratified upper layers. Such conditions are becoming more frequent in the Antarctic coastal waters and will likely have significant future implications at various levels of the marine food web. The competitive advantage of cryptophytes in environments with significant light level fluctuations was supported by laboratory experiments that revealed a high flexibility of cryptophytes to grow in different light conditions driven by a fast photo-regulating response. All tested physiological parameters support the hypothesis that cryptophytes are highly flexible regarding their growing light conditions and extremely efficient in rapidly photo-regulating changes to environmental light levels. This plasticity would give them a competitive advantage in exploiting an ecological niche where light levels fluctuate quickly. These findings provide new insights on niche separation between diatoms and cryptophytes, which is vital for a thorough understanding of the WAP marine ecosystem.

Potential biases in dietary interpretation derived from stable isotope analysis of small dolphin teeth.

We analyzed δ13C and δ15N values in different tooth portions (Growth Layer Groups, GLGs) of franciscanas, Pontoporia blainvillei, to investigate their effect on whole tooth (WT) isotopic values and the implications for dietary estimates. Tooth portions included the dentin deposited during the prenatal development (PND), the first year of life (GLG1) deposited during the nursing period and the central part of the tooth with no distinction amongst subsequent GLGs (Center). Isotopic mixing models estimating the contribution of PND, GLG1 and Center to WT showed that GLG1 has a strong effect on WT isotope values in juveniles, while Center only starts to affect WT isotopic values from age four. Isotopic mixing models estimating prey contribution to the diet of juveniles using WT vs Center tooth portions significantly differed in dietary outputs, demonstrating that GLG1 influence on WT isotope values affects dietary estimates in young franciscanas. As the small tooth size and narrowness of the last GLGs hinder the analysis of individual layers, we recommend excluding GLG1 in studies based on teeth isotope composition in franciscanas and caution when interpreting isotopic values from the WT of other small cetaceans.

Mitochondrial diversity and inter-specific phylogeny among dolphins of the genus Stenella in the Southwest Atlantic Ocean.

The genus Stenella is comprised of five species occurring in all oceans. Despite its wide distribution, genetic diversity information on these species is still scarce especially in the Southwest Atlantic Ocean. Some features of this genus can enhance opportunities for potential introgressive hybridization, e.g. sympatric distibution along the Brazilian coast, mixed known associations among species, karyotype uniformity and genome permeability. In this study we analyzed three genes of the mitochondrial genome to investigate the genetic diversity and occurrence of genetic mixture among eighty specimens of Stenella. All species exhibited moderate to high levels of genetic diversity (h = 0.833 to h = 1.000 and π = 0.006 to π = 0.015). Specimens of S. longirostris, S. attenuata and S. frontalis were clustered into differentiated haplogroups, in contrast, haplotypes of S. coeruleoalba and S. clymene were clustered together. We detected phylogenetic structure of mixed clades for S. clymene and S. coeruleoalba specimens, in the Southwest Atlantic Ocean, and also between S. frontalis and S. attenuata in the Northeast Atlantic Ocean, and between S. frontalis and S. longirostris in the Northwest Atlantic Ocean. These specimes were morphologically identified as one species but exhibited the maternal lineage of another species, by mitochondrial DNA. Our results demonstrate that ongoing gene flow is occurring among species of the genus Stenella reinforcing that this process could be one of the reasons for the confusing taxonomy and difficulties in elucidating phylogenetic relationships within this group.

Chemotaxonomic characterization of the key genera of diatoms in the Northern Antarctic Peninsula.

Diatoms are successful in occupying a wide range of ecological niches and biomes along the global ocean. Although there is a recognized importance of diatoms for the Southern Ocean ecosystems and biogeochemical cycles, the current knowledge on their ecology and distribution along the impacted Antarctic coastal regions remains generalized at best. HPLC-CHEMTAX approaches have been extensively used to this purpose, providing valuable information about the whole phytoplankton community, even for those small-size species which are normally difficult to identify by light microscopy. Despite that, the chemotaxonomic method has reserved minimal focus on great diversity of types associated with diatom genera or species. Here, we show a coupling between the key genera and the corresponding chemotaxonomic subgroup type-A or type-B of diatoms via HPLC-CHEMTAX and microscopic analysis, using chlorophyll-c 1 and chlorophyll-c 3 as biomarker pigments, respectively. The results demonstrated strong correlations for nine of the fifteen most abundant diatom genera observed along the Northern Antarctic Peninsula, from which five (four) were statistically associated with chlorophyll-c 1 (chlorophyll-c 3). Our study highlights the importance to observe diatoms in greater detail, beyond being only one functional group, for a better understanding on their responses under a climate change scenario.

Strong and lasting impacts of past global warming on baleen whales and their prey.

Global warming is affecting the population dynamics and trophic interactions across a wide range of ecosystems and habitats. Translating these real-time effects into their long-term consequences remains a challenge. The rapid and extreme warming period that occurred after the Last Glacial Maximum (LGM) during the Pleistocene-Holocene transition (7-12 thousand years ago) provides an opportunity to gain insights into the long-term responses of natural populations to periods with global warming. The effects of this post-LGM warming period have been assessed in many terrestrial taxa, whereas insights into the impacts of rapid global warming on marine taxa remain limited, especially for megafauna. In order to understand how large-scale climate fluctuations during the post-LGM affected baleen whales and their prey, we conducted an extensive, large-scale analysis of the long-term effects of the post-LGM warming on abundance and inter-ocean connectivity in eight baleen whale and seven prey (fish and invertebrates) species across the Southern and the North Atlantic Ocean; two ocean basins that differ in key oceanographic features. The analysis was based upon 7032 mitochondrial DNA sequences as well as genome-wide DNA sequence variation in 100 individuals. The estimated temporal changes in genetic diversity during the last 30,000 years indicated that most baleen whale populations underwent post-LGM expansions in both ocean basins. The increase in baleen whale abundance during the Holocene was associated with simultaneous changes in their prey and climate. Highly correlated, synchronized and exponential increases in abundance in both baleen whales and their prey in the Southern Ocean were indicative of a dramatic increase in ocean productivity. In contrast, the demographic fluctuations observed in baleen whales and their prey in the North Atlantic Ocean were subtle, varying across taxa and time. Perhaps most important was the observation that the ocean-wide expansions and decreases in abundance that were initiated by the post-LGM global warming, continued for millennia after global temperatures stabilized, reflecting persistent, long-lasting impacts of global warming on marine fauna.

Floating plastics and their associated biota in the Western South Atlantic.

The lack of information about plastic pollution in many marine regions hinders firm actions to manage human activities and mitigate their impacts. This study conducted for the first time a quali-quantitative evaluation of floating plastics and their associated biota from coastal and oceanic waters in South Brazil. Plastics were collected using a manta net, and were categorized according to their shape, size, malleability and polymer composition. Multi-marker DNA metabarcoding (16S, and 18S V4 and V9 rRNA regions) was performed to identify prokaryotes and eukaryotes associated to plastics. We found 371 likely plastic particles of several sizes, shapes and polymers, and the average concentration of plastics at the region was 4461 items.km-2 (SD ± 3914). Microplastics (0.5 - 5 mm) were dominant in most sampling stations, with fragments and lines representing the most common shapes. Diverse groups of prokaryotes (20 bacteria phyla) and eukaryotes (41 groups) were associated with plastics. Both the community composition and richness of epiplastic organisms were highly variable between individual plastics but, in general, were not influenced by plastic categories. Organisms with potential pathogenicity (e.g. Vibrio species. and Alexandrium tamarense), as well as potential plastic degraders (e.g. Ralstonia, Pseudomonas, and Alcanivorax species), were found. The information generated here is pivotal to support strategies to prevent the input and mitigate the impacts of plastics and their associated organisms on marine environments.

Long-Term Consequences of High Polychlorinated Biphenyl Exposure: Projected Decline of Delphinid Populations in a Hotspot for Chemical Pollution.

Rough-toothed dolphins, Steno bredanensis, are closely associated with coastal waters in the Southwestern Atlantic Ocean, increasing the exposure to multiple stressors, such as chemical pollution. Persistent organic pollutants (POPs) are known to affect the health of cetacean species. To comprehend the potential impacts of POPs on populations' viability, it is necessary to distinguish populations and predict their risk of long-term exposure. Blubbers of rough-toothed dolphins (n = 28) collected along the southeastern (SE) and southern (S) Brazilian coast were screened for polychlorinated biphenyls (PCBs) and pesticides in a gas chromatograph coupled to a mass spectrometer. Based on the contamination profile, a discriminant function analysis separated the rough-toothed dolphins into three ecological populations: two coastal and one offshore. POP concentrations were the highest reported for the species worldwide and highest among the delphinids in Brazilian waters, reaching 647.9 µg g-1 lw for PCBs. The SE population presented 212.9 ± 163.0, S population presented 101.0 ± 96.7, and OCS/S population presented 183.3 ± 85.3 µg g-1 lw (mean ± SD) of PCBs. The potential risk of effects triggered by elevated PCB concentrations was assessed in an individual-based model. A risk of severe decline in population size is projected for the three populations in the next 100 years, especially in SE Brazil, varying between 67 and 99%.

Combining isotopic analysis of bulk-skin and individual amino acids to investigate the trophic position and foraging areas of multiple cetacean species in the western South Atlantic.

We investigated the trophic structure and habitat use of ten cetacean species occurring in the oceanic waters of the western South Atlantic using naturally-occurring stable isotopes. We analysed δ15N in individual amino acids (AA) to estimate cetacean trophic position (TP) and to evaluate the spatial differences in baseline δ15N (source AAs). We adjusted cetacean bulk-skin δ13C and δ15N for the effect of trophic level using their estimated TPs, obtaining δ13CAdjusted and δ15NAdjusted, respectively. These values were applied to estimate the overlap in the niche areas of cetacean baseline sources. Our analyses showed spatial segregation between Steno bredanensis and the remaining odontocetes, and the high δ15N in this species reflects its occurrence in neritic waters of the southern region. The highest TPs were observed in Physeter macrocephalus, Stenella attenuata and Globicephala melas, while the lowest TPs were reported for S. longirostris, S. clymene and Orcinus orca. Overall, source AA-δ15N showed similar patterns as those of baseline-δ15N (zooplankton) and were higher in species sampled in the southernmost region of the study area (e.g., Delphinus delphis). Isotopic niche areas estimated using δ13CAdjusted and δ15NAdjusted suggested high overlap in foraging area between S. frontalis and Tursiops truncatus, with the latter occupying a higher TP. Our analyses of δ15N in AAs provide a unique insight into the trophic ecology, forage areas and spatial segregation in resource use among these cetacean populations. Additionally, our work provides AA-δ15N baseline for future studies on the trophic ecology and habitat use of marine organisms in the western South Atlantic.

Ecological divergence and speciation in common bottlenose dolphins in the western South Atlantic.

Coastal and offshore ecotypes of common bottlenose dolphins have been recognized in the western South Atlantic, and it is possible that trophic niche divergence associated with social interactions is leading them to genetic and phenotypic differentiation. The significant morphological differentiation observed between these ecotypes suggests they represent two different subspecies. However, there is still a need to investigate whether there is congruence between morphological and genetic data to rule out the possibility of ecophenotypic variation accompanied by gene flow. Mitochondrial DNA (mtDNA) control region sequence data and 10 microsatellite loci collected from stranded and biopsied dolphins sampled in coastal and offshore waters of Brazil as well as 106 skulls for morphological analyses were used to determine whether the morphological differentiation was supported by genetic differentiation. There was congruence among the data sets, reinforcing the presence of two distinct ecotypes. The divergence may be relatively recent, however, given the moderate values of mtDNA nucleotide divergence (dA = 0.008), presence of one shared mtDNA haplotype and possibly low levels of gene flow (around 1% of migrants per generation). Results suggest the ecotypes may be in the process of speciation and reinforce they are best described as two different subspecies until the degree of nuclear genetic divergence is thoroughly evaluated: Tursiops truncatus gephyreus (coastal ecotype) and T. t. truncatus (offshore ecotype). The endemic distribution of T. t. gephyreus in the western South Atlantic and number of anthropogenic threats in the area reinforces the importance of protecting this ecotype and its habitat.

Diverse groups of fungi are associated with plastics in the surface waters of the Western South Atlantic and the Antarctic Peninsula.

Marine plastic pollution has a range of negative impacts for biota and the colonization of plastics in the marine environment by microorganisms may have significant ecological impacts. However, data on epiplastic organisms, particularly fungi, is still lacking for many ocean regions. To evaluate plastic associated fungi and their geographic distribution, we characterised plastics sampled from surface waters of the western South Atlantic (WSA) and Antarctic Peninsula (AP), using DNA metabarcoding of three molecular markers (ITS2, 18S rRNA V4 and V9 regions). Numerous taxa from eight fungal phyla and a total of 64 orders were detected, including groups that had not yet been described associated with plastics. There was a varied phylogenetic assemblage of predominantly known saprotrophic taxa within the Ascomycota and Basidiomycota. We found a range of marine cosmopolitan genera present on plastics in both locations, i.e., Aspergillus, Cladosporium, Wallemia and a number of taxa unique to each region, as well as a high variation of taxa such as Chytridiomycota and Aphelidomycota between locations. Within these basal fungal groups we identified a number of phylogenetically novel taxa. This is the first description of fungi from the Plastisphere within the Southern Hemisphere, and highlights the need to further investigate the potential impacts of plastic associated fungi on other organisms and marine ecosystems.

Persistent organic pollutants in blubber of fin whales (Balaenoptera physalus) from the Southern Ocean.

Persistent organic pollutants (POPs) were analyzed in eighteen blubber samples biopsied from fin whales (Balaenoptera physalus) during the feeding season near the Antarctic Peninsula in the summer of 2013. POP content (in ng g-1 lipid weight) ranged from 46.4 to 708 for polychlorinated biphenyls (∑PCBs), 6.77 to 123 for hexachlorobenzene (HCB), 10.1 to 489 for dichlorodiphenyltrichloroethane and derivatives (∑DDTs), 5.38 to 52.8 for hexachlorocyclohexanes (∑HCH) and <0.40 to 2.54 for polybrominated diphenyl ethers (∑PBDEs). The presence of those compounds in Southern Ocean fin whales is related to long-range transport and their diet based mainly on euphausiids (krill). Their contents were much lower compared to the same species in other locations, especially in the Northern Hemisphere, presumably due to differences in trophic position and the proximity of POP sources and contamination of prey items.

Integrative bioacoustics discrimination of eight delphinid species in the western South Atlantic Ocean.

This study presents an integrative bioacoustics approach to discriminate eight species of odontocetes found on the outer continental shelf and slope of the western South Atlantic Ocean. Spinner, Atlantic spotted, rough-toothed, Risso's, bottlenose, short-beaked common dolphins, killer and long-finned pilot whales were visually confirmed during recordings with a 3-element omnidirectional hydrophone array. Spectral and time parameters of whistles and echolocation clicks were used in a discriminant function analysis and a classification tree model. As a first step, whistles and clicks were analysed separately; a further analysis consisted of both vocalisations jointly classified. All species showed species-specific properties in their vocalisations. Whistles had greater misclassification rates when compared to clicks. The correct classification was enhanced by the joint step, given the 5.8% error in the discriminant function analysis and a misclassification rate of 18.8% in the tree model. In addition, Receiver Operating Characteristic curves resulting from the tree algorithm analysis exhibited better model efficiency for all species in the joint classification. These findings on acoustical discrimination of such abundant and cosmopolitan species contribute to delphinid classification systems.