TY - JOUR
T1 - Assessing the micro-phytoplankton response to nitrate in Comau Fjord (42 S) in Patagonia (Chile), using a microcosms approach
AU - Iriarte, José Luis
AU - Pantoja, Silvio
AU - González, Humberto E.
AU - Silva, Gabriela
AU - Paves, Hector
AU - Labbé, Pamela
AU - Rebolledo, Lorena
AU - Van Ardelan, Murat
AU - Häussermann, V.
N1 - Funding Information:
Acknowledgments This research was funded by FONDE-CYT 1080187 (J.L. Iriarte). We thank the Huinay Foundation for providing marine laboratories and vessel facilities, as well as phytoplankton data from the Comau Fjord, and our colleagues G. Försterra and V. Häussermann for their help at the Huinay Scientific Station. We appreciate the valuable help of Patricio Ampuero and Caroll García during the experimental work and microscopic analysis, and Pirjo Huovinen for allowing us to use her submersible Ramses-ACC2-UV-VIS hyperspectral radiometer sensor (Trios Optical Sensors). This research was also partially funded by the Centro de Investigación de Ecosistemas de la Patagonia (CIEP), Programa de Financiamiento Basal COPAS–Sur Austral, and WAFOW/NTNU–Norwegian Research Council Latin American–Norway Programme. The winter experiment was part of the MSc. Thesis of Ms. Pamela Labbe at Universidad de Concepción, who was funded by a 1-year scholarship from COPAS–Sur Austral. This is publication 55 of Huinay Scientific Field Station.
PY - 2013/6
Y1 - 2013/6
N2 - 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.
AB - 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.
KW - Chlorophyll-a
KW - Diatoms
KW - Nitrate
KW - Patagonian fjords
KW - Phytoplankton structure
UR - http://www.scopus.com/inward/record.url?scp=84879063761&partnerID=8YFLogxK
U2 - 10.1007/s10661-012-2925-1
DO - 10.1007/s10661-012-2925-1
M3 - Article
C2 - 23054289
AN - SCOPUS:84879063761
SN - 0167-6369
VL - 185
SP - 5055
EP - 5070
JO - Environmental Monitoring and Assessment
JF - Environmental Monitoring and Assessment
IS - 6
ER -
