Recursos Naturales

Anthropogenic (aquaculture) changes in environment nutrient concentrations may affect phytoplankton (biomass and taxa composition) in marine coastal waters off the Chilean Patagonia. The effects of adding nitrate (NO₃(-)) to natural phytoplankton assemblages were evaluated considering biomass, cell abundance, and taxonomic composition. Microcosm experiments were performed in the spring, summer, and winter in the Comau Fjord located in Subantarctic Patagonia. At the end of the experiments, NO₃(-) decreased rapidly and was undetectable in treatments, indicating a strong NO₃(-) deficiency associated with an exponential increase in Chl-a concentrations, particulate organic nitrogen, and carbon in these treatments. Moreover, given the depleted nitrate concentrations of the spring and summer experiments, the micro-phytoplankton taxa structure shifted from mixed diatom and dinoflagellate assemblages (Ceratium spp., Dinophysis spp., Coscinodiscus sp., Rhizosolenia pungens) to assemblages dominated by blooms of the classic chain-forming diatoms found in temperate and cold waters such as Chaetoceros spp., Skeletonema spp., and Thalassiosira spp. Thus, nitrogen sources (i.e., nitrate, ammonia) may influence phytoplankton abundance and biomass accumulation dynamics in the northern section of Patagonia. It also emphasizes the importance of diatom taxa in regards to the short-term response of phytoplankton to changing environmental nutrient conditions due to natural (decreasing freshwater stream flow) and anthropogenic (aquaculture) events. This situation may be one of the future scenarios in the Patagonian fjords, thus stressing the needs for active environmental monitoring and impact assessment.

In Patagonia, Chile, an extensive Fjord system can be found. The Comau Fjord is located in the northern part and is characterized by steep walls, a high tidal range and is approximately 500 m deep. Along its course from mouth to head (horizontally, along isobaths) and with ...

ABSTRACT: Mutualistic relationships of corals from warm, oligotrophic waters are best known with endocytic and scarcely with endolithic phototrophic organisms. We describe relationships of the microboring phototrophic green alga Ostreobium queckettii and the ...

ABSTRACT We redescribe and illustrate Halcurias pilatus McMurrich, 1893 and H. mcmurrichi Uchida, 2004 (Endocoelantheae, Halcuriidae) from newly collected specimens from Southern Chile and deep-water reefs off Florida, respectively. Halcurias pilatus was previously considered to have a disjunct distribution until Uchida (2004) described a new species for the material from the Bahamas. However, the description of H. mcmurrichi does not meet modern taxonomic standards. We provide new anatomical and cnidae data for H. pilatus and H. mcmurrichi. Both species differ in the distribution and cnidom of nematocyst batteries in the column, development of microcnemes mesenteries, cnidae and geographical distribution. We find that H. pilatus can have a weak mesogleal marginal sphincter and amend accordingly the diagnoses of the genus Halcurias, family Halcuriidae, and suborder Endocoelantheae. These new records represent the first time both species have been collected since their original descriptions.

... Edit Item. General Information: Citation: Försterra, G. , Häussermann, V. , Mayr, C. , Jantzen, C. and Hassenrück, C. (2012): Low pH and the role of endolithic algae in cold-water corals , 5th Symposium on deep-sea corals, Amsterdam, 02 April 2012 - 06 April 2012 . ...

The taxonomy of the order Zoantharia (=Zoanthidea=Zoanthiniaria) is greatly hampered by the paucity of diagnostic morphological features. To facilitate discrimination between similar zoanthids, a combination of morphological and molecular analyses is applied here. The three most abundant zoanthid species in shallow waters of the southern Chilean fjord region are described. Comparison with other zoanthids using molecular markers reveals that two

We analysed carbon (δ13C) and nitrogen (δ15N) isotope ratios of organisms and biogenic tissues from Comau Fjord (southern Chile) to characterise benthic food webs and spatial isotope variability in this ecosystem. These values were intended to serve as a baseline for detecting anthropogenic impacts on Patagonian marine fjord ecosystems in later studies. Benthic macroalgae and
invertebrate suspension feeders were primarily considered, with some supplementary data from cyanobacteria, plankton, fish, and coastal vertebrates. Six depth transects typified the lateral salinity
gradients from the innermost part of the fjord to its mouth, as well as the vertical density gradients
caused by freshwater inflow. Carbon isotope signatures indicated predominant consumption of either
CO2 or HCO3– for benthic macroalgal. All CO2 users belonged to rhodophytes. The δ15N values of benthic macrophytes decreased with decreasing salinity, both vertically and along the fjord axis. This implies the influence of 15N-poor terrestrial dissolved inorganic nitrogen (DIN) at these sites.
Enhanced influence of freshwater influx also lowered N contents and increased C/N ratios in algal tissues. Exceptionally high macroalgae δ15N values at the seabird and sealion colony Isla Liliguapi
point to animal faeces as an additional source of 15N-enriched DIN. Thus, DIN sources not originating from the open sea are additionally utilised by the benthic macroalgae in the fjord. In contrast,
mussel tissue from the same locations was much less influenced by varying DIN sources. Among benthic suspension feeders, mytilids (Mytilus chilensis, Aulacomya ater) had the lowest and scleractinian
corals (Desmophyllum dianthus) had the highest δ15N values, and Balanidae (Elminius kingii) and
gorgonians (Primnoella sp.) showed values in between. The preference for specific size classes of
marine particulate organic matter (seston) as food serves as an explanation for the δ15N variability
observed between the different benthic suspension feeders.

The southern Chilean system of fjords (41-52°S) is thus far very poorly investigated with regard to its marine invertebrate fauna. The present study summarises new distributional and biological information on nudipleuran gastropods from the Comau Fjord (42°10'-42°30'S) that has been obtained by general biodiversity related activities since the establishment of the Huinay Scientific Field Station in 2001 and by a joint expedition in March 2004. In total, 12 nudipleuran species (1 Pleurobranchoidea, 11 Nudibranchia) were found, including the southernmost records of Doto uva Er. Marcus, 1955, Phidiana lottini (D'Orbigny, 1837), and Tergipedidae sp. 1, as well as the southernmost Pacific record of Cadlina sparsa (Odhner, 1921). All these species appear to be part of the warm-temperate adapted fauna. Unlike congeners, Berthella platei Bergh, 1898, was observed to feed on sea anemones in aquaria. Photographs of living specimens as well as descriptions of habitats and biological observations are given. The poorly known Polycera priva Er. Marcus, 1959, is redescribed anatomically and detailed information on the formerly unknown reproductive system is presented.

... nov. Specimens of D. dianthus found on a shipwreck allowed for growth rate estimations. ... It is described from 35-2460 m (Cairns, 1994) and common on seamounts, guyots and on deep-water coral banks associated with framework building species (Cairns & Stanley, 1982). ...