Examinando por Autor "Ord, Gillian K."

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    Ítem
    Influence of coastal oceanography on early life history traits of larval Patagonian sprat, Sprattus fuegensis along southeastern Pacific Ocean
    (Fisheries Oceanography, 2024) López Soto, Erika; Ord, Gillian K.; Castillo Silva, Manuel; Plaza, Guido; Cáceres Muñoz, Mario; González, María Teresa; Sepúlveda, Maritza; Guerrero, Alicia; Piñones, Andrea; Landaeta Díaz, Mauricio
    Early life history traits of small pelagic fish are usually affected by environmental conditions. Patagonian sprat, Sprattus fuegensis, is a small pelagic fish that inhabits the continental shelf, fjords and channels of Patagonia. Their larvae are usually exposed to large variations in physical and biological conditions. We evaluated the effects of environmental conditions on early life history traits of this key species encompassing over 20 years of information. The characterization of oceanographic features, larval abundance and distribution was carried out in western Patagonia between 1996 and 2019, while the growth and mortality rates were estimated for the austral spring 2019 between 49°54′S and 53°55′S. Larval abundance decreased three to ten times from 1996 to 1997 to the rest of the study period (2008–2010 and 2014–2019), with larger abundances being found over the shelf. In spring 2019, the growth rate was 0.20 ± 0.05 mm d−1 for larvae between 9 and 19 days after hatching. The growth rate was similar in partially stratified (7–50 J m−3) and stratified waters (50–100 J m−3), but slower in mixed waters (< 7 J m−3). GAM modelling showed that the faster larval growth occurred in partially stratified waters with temperatures above 7.5°C. Natural mortality rates were higher in partially stratified waters (24% of daily loss), lower in stratified areas (14%) and the lowest in the mixed water column (12%). Accordingly, larvae living in channels had faster growth rates but higher daily mortality, while those that hatched or were advected to water parcels on the continental shelf had slower growth but lower daily mortality. Finally, these latter traits may be an example of an inverse growth-selective survival strategy.
  • Miniatura
    Ítem
    Simulating the copper distribution in coastal waters and sediments in Quintero Bay and adjacent shores
    (Marine Pollution Bulletin, 2026) Ord, Gillian K.; Caceres Muñoz , Mario
    This study presents a 3D hydrodynamic simulation of coastal circulation coupled with copper advection emanating from Quintero Bay, in the Valparaíso region. The bay is home to an important industrial complex and has a history of heavy metal contamination due to a copper smelter located in its northern sector. This study aims to simulate the distribution of contamination from existing sources and identify potential risk scenarios associated with copper exposure in water and sediment. A simple data assimilation method has been developed to capture elements of coastal wind not well represented by existing models used for wind forcing. The simulation period represents an austral summer, and several circulation patterns have been identified in response to external forcings. Two different point sources are considered, one within the bay (source 1), and the other just outside the south side of the bay (source 2). Simulations show advection of copper towards coastal areas north of the bay in trace concentrations from both sources, with instances at certain points within the bay when recommended thresholds for chronic and acute exposure are surpassed. Source 1 shows advection predominantly leaving the north side of the bay in surface waters, while source 2 shows advection in bottom waters periodically entering the south side of the bay. These results are consistent with existing local studies of copper concentrations in the water and sediment.