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.

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.

Medium and large sized mammal assemblages in coastal dunes and adjacent marshes in southern Rio Grande do Sul State, Brazil / Assembleias de mamíferos de médio e grande porte em dunas costeiras e brejos adjacentes na região Sul do Estado do Rio Grande do Sul, Brasil

This paper presents data on species composition and use of habitat of medium and large sized mammal assemblages in a coastal dunes segment and adjacent marshes at Rio Grande municipality, southern Rio Grande do Sul State, Brazil. Records were obtained through visualization of living animals and identification of footprints, feces and remains. From November 2007 to September 2008, nine 600 m long and 5 m wide linear transects were settled on coastal dunes segment (frontal and intermediate dunes) and adjacent marshes, parallel to ocean shore on a 23 km section at Cassino Beach. Transects were settled in areas under high, medium and low levels of anthropic occupancy (A1, A2 and A3, respectively), being three transects on each area. Fourteen species were recorded, distributed in five orders and 10 families. Lepus europaeus was the most frequent species (81.9% of the transect walks), present in all areas and seasons, followed by Lycalopex gimnocercus (23.5%) and Conepatus chinga (10.3%). Five species were present on A1, seven on A2 and fourteen on A3. Seven species were recorded on frontal dunes, nine on intermediate dunes and 13 on adjacent marshes.

O presente estudo apresenta dados sobre a composição de espécies e uso do hábitat de assembleias de mamíferos de médio e grande porte em um trecho no cordão de dunas costeiras e brejos adjacentes no município de Rio Grande, região Sul da Planície Costeira do Rio Grande do Sul, Brasil. Os registros foram obtidos no período de novembro de 2007 a setembro de 2008 por meio da observação direta de indivíduos e carcaças e da identificação de vestígios (pegadas e fezes). Nove transectos lineares de 600 m de extensão e 5 m de largura, paralelos à praia oceânica, foram estabelecidos sobre um trecho de 23 km do cordão de dunas costeiras e brejos adjacentes no Balneário Cassino. Foram amostradas áreas sob alto, médio e baixo grau de antropização (A1, A2 e A3, respectivamente), sendo estabelecidos três transectos em cada área. Os métodos empregados possibilitaram o registro de 14 espécies sendo Lepus europaeus a mais frequente (81,9% do total de transecções) e presente em todas as áreas e em todas as estações, seguida de Lycalopex gymnocercus (23,52%) e Conepatus chinga (10,29%). Cinco espécies foram registradas em A1, sete em A2 e 14 em A3. Sete espécies foram encontradas nas dunas frontais, nove nas dunas intermediárias e 13 nos brejos adjacentes.