Cold-Water Corals (CWCs), and most marine calcifiers, are especially threatened by ocean acidification (OA) and the decrease in the carbonate saturation state of seawater. The vulnerability of these organisms, however, also involves other global stressors like warming, deoxygenation or changes in sea surface productivity and, hence, food supply via the downward transport of organic matter to the deep ocean. This study examined the response of the CWC Desmophyllum dianthus to low pH under different feeding regimes through a long-term incubation experiment. For this experiment, 152 polyps were incubated at pH 8.1, 7.8, 7.5 and 7.2 and two feeding regimes for 14 months. Mean calcification rates over the entire duration of the experiment ranged between -0.3 and 0.3 mg CaCO3 g-1d-1. Polyps incubated at pH 7.2 were the most affected and 30% mortality was observed in this treatment. In addition, many of the surviving polyps at pH 7.2 showed negative calcification rates indicating that, in the long term, CWCs may have difficulty thriving in such aragonite undersaturated waters. The feeding regime had a significant effect on skeletal growth of corals, with high feeding frequency resulting in more positive and variable calcification rates. This was especially evident in corals reared at pH 7.5 (ΩA = 0.8) compared to the low frequency feeding treatment. Early life-stages, which are essential for the recruitment and maintenance of coral communities and their associated biodiversity, were revealed to be at highest risk. Overall, this study demonstrates the vulnerability of D. dianthus corals to low pH and low food availability. Future projected pH decreases and related changes in zooplankton communities may potentially compromise the viability of CWC populations.
While large mass mortality events (MMEs) are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behaviour. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions, such as harmful algal blooms (HABs).In southern Chile, HABs can be triggered by the ocean-atmosphere phenomenon El Niño. The frequency of the strongest El Niño events is increasing due to climate change. In March 2015, by far the largest reported mass mortality of baleen whales took place in a gulf in southern Chile. Here we show that the synchronous death of at least 343, primarily sei, whales can be attributed to HABs during a building El Niño. Although considered an oceanic species, the sei whales died while feeding near to shore in previously unknown large aggregations. This provides evidence of new feeding grounds for the species. The combination of older and newer remains of whales in the same area indicate that MMEs have occurred more than once in recent years.Large HABs and reports of marine mammal MMEs along the north-east Pacific coast may indicate similar processes in both hemispheres. Increasing MMEs through HABs may become a serious concern in the conservation of endangered whale species.
The Chilean fjord region includes many remote and poorly known areas where management plans for the marine living resources and conservation strategies are urgently needed. Few data are available about the spatial distribution of its marine invertebrate fauna, prevalently influenced by complex interactions between biotic and abiotic factors, animal behavior and human activities. Patagonian fjords are a hotspot for finfish aquaculture, elevating Chile to the world’s second producer of farmed salmon, after Norway, a condition that emphasizes the necessity to develop strategies for a sustainable aquaculture management. The present study focuses on the emblematic cold-water coral Desmophyllum dianthus, dwelling the Comau Fjord from shallow to deep waters, with the aim to illustrate population structure, demography and adaptation of the species and its potential use for the development of a sustainable conservation and management plan for human activities. The analyses of microsatellite loci of D. dianthus individuals from four sampling localities along horizontal and vertical gradients of Comau Fjord, lead to identify them as panmictic population. The results also contributed to consider a careful examination the synchrony between the temporal and spatial variations of environmental factors and biological cycle of the species as key role player in the inference of autecology of the species. This study also highlights the importance of oceanographic data in the entire process of the genetic analyses and interpretation of results. The discussion stresses the importance of molecular analyses as extremely helpful tools for studies focussing on remote areas and non-model organisms, where logistic difficulties and limited scientific knowledge hamper a better management and conservation of marine resources, and in particular the relevance of multidisciplinary approaches to reduce the extensive knowledge gap on the remote fjord ecosystems of Patagonia.
La region de los fiordos del sur de Chile alberga tres especies de corales azooxantelados (Cnidaria: Anthozoa: Scleractinia) capaces
de vivir a pocos metros de profundidad. Estas especies corresponden a Desmophyllum dianthus, Caryophyllia huinayensis y
Tethocyathus endesa, las cuales representan una oportunidad unica para el estudio in situ de estas comunidades. El aumento
en la deforestacion asi como el elevado numero de instalaciones acuicolas en esta region generan un impacto en los sistemas
de sedimentos de la zona, razon por la cual se realizo un experimento en laboratorio para evaluar los efectos potenciales de un
incremento en las tasas sedimentarias en estos organismos. Se sometio a los corales a tasas de sedimentacion de 16, 164, 698 y 995
mm ano-1 y se estudiaron las respuestas conductuales (apertura de los polipos) y fisiologicas (consumo de oxigeno y concentracion
de lactato). Tethocyathus endesa, a diferencia de las otras dos especies, presento un aumento significativo en el numero de
polipos abiertos y escasa variacion en el consumo de oxigeno al ser sometido a mayores tasas sedimentarias, indicando una menor
sensibilidad a la sedimentacion en comparacion con las otras dos especies. Desmophyllum dianthus aumento significativamente
su consumo de oxigeno al ser sometido a una tasa sedimentaria de 995 mm ano-1, lo cual se explicaria por la necesidad de invertir
energia en mecanismos activos de limpieza. Caryophyllia huinayensis, por su parte, disminuyo significativamente su consumo
de oxigeno al ser sometida a tasas sedimentarias de 164 y 698 mm ano-1, presumiblemente en espera de mejores condiciones
ambientales. El contenido de lactato en los tejidos de estos organismos no presento diferencias significativas entre los distintos
tratamientos. Los resultados indican que un aumento en la sedimentacion en la region tiene el potencial de alterar la conducta y
metabolismo de las especies de corales de agua fria presentes en el area, lo cual podria resultar perjudicial para estas comunidades.
Fundacion San Ignacio del Huinay, Centro de Investigacion y Desarrollo Tecnologico en Algas (CIDTA) y proyectos CARO PCCI2012060
(proyecto bilateral de BMBF-CONICYT), Fondecyt 1150843, Fondef D10|1038 y Fondecyt 1120469.
With a wide latitudinal (Chile, Argentina: ~28-56 °S) and altitudinal (0-2000 m) distribution range, the greenbacked fire crown Sephanoides sephaniodes (Lesson, 1826) represents the southernmost hummingbird species of the world. Recently an amplification of its distribution in Argentina has been reported which is probably due to its plasticity in the use of different habitats as well as its use of flowers and tiny insects as food source (Marinero et al. 2012). The species can be found in forests and different open environments including urban areas. A. Brauning and M. Konnecke have observed approx. 10 hummingbirds bathing in a hot river in a half open environment in Northern Chile, at the Socos hot springs (30.732234 °S, 71.493837 °W), close to Ovalle, during a cold winter morning around 9 a.m. on August 15, 2008 during 16 minutes (Fig. 1). The birds were sitting in the hand warm river for up to approx. one minute, shooing each other out of the water to enter the river again a short time later. Between baths they were resting on the branches of a fallen dead tree, on rocks and on a fence next to the river. They had been already bathing before and kept bathing after the observation. V. Haussermann and G. Forsterra have seen three birds of the same species bathing in a small, shallow, hand warm pool which is part of the hot Porcelana river (up to 62 °C) in the Valdivian rain forest in Comau Fjord, Chilean Patagonia (42.458222 °S, 72.466080 °W) in late April 2004 (autumn), during the late afternoon (approx. 6 p.m.). Between baths the birds have been resting on the trees above the hot springs. Due to its small size but proportionally major exposed body surface this hummingbird species loses major amounts of heat, and also dehydrates fast, especially during the night or during periods without food or water intake (Hartmann Bakken & Sabat 2007). During night time its body temperature drops from nearly 40 °C to 18-20 °C (Hainsworth & Wolf 1972). The consumption of cold liquid food, typical for humming birds and practically all other nectarivorous birds, also has high energetic costs (Lotz et al. 2003). The bath in hot springs could help the birds to warm up and save energy during times of lower environmental temperatures. Acknowledgements. Many thanks to Ann Brauning and Markus Konnecke for the information and pictures of the hummingbirds at Termas de Socos. This is publication nr. 122 of Huinay Scientific Field Station.
Final dataset of microsatellites used in Addamo et al., 2022 "The shrunk genetic diversity of coral populations in North-Central Patagonia calls for management and conservation plans for marine resources" Scientific Reports 2022, 12:14894 DOI: 10.1038/s41598-022-19277-3: 28 microsatellites, 223 individuals,12 sampling locations
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