Abstract
Abstract. Zooplankton aggregation, hydrographic and remote sensing data were employed to relate the spatial dynamics of neustonic communities with chlorophyll a (Chl a) and suspended organic matter (SOM) at a spatial mesoscale (10 to 1000 km) in the southern Chilean fjords system along Magellan Strait, Chile (CIMAR 16: October/November 2010 and CIMAR 25; September/October 2019) in order to identify oceanographic process producing aggregation of neuston. Preliminary evidence of CIMAR 25 shows significant concentrations of Chl a and SOM around Dawson Island (DI), Magellan Strait. During CIMAR 16 important aggregation of specific neustonic taxa (copepodites of Microsetella rosea, larvae of the polychaete Polygordius sp and cyphonautes of the bryozoan Membranipora isabelleana) was observed around DI, Magellan Strait. Satelital images in the area of CIMAR 16 provide evidence of important aggregation of chlorophyll a/SOM around DI. CIMAR Cimar 25 showed that the Chl a and SOM aggregation around DI is recurrent and could to explain the high concentration of neuston around this island to spite of mesotrophic conditions. Remote sensing in this study area provides a tool to understanding oceanographic and topographic factors that potentially regulate the abundance and spatial distribution of surface zooplankton to spatial meso-scale along Magellan Strait.
Highlights
The biodiversity levels and densities of neustonic organisms their spatial and temporal variation, their roles in sustaining biogeochemical cycling and atmosphere-ocean exchange processes, as well as a nutritional source for important trophic networks in significant areas of the oceans, all remain unknown (Hardy, 2005)
The present study describes the structure and biodiversity of neustonic communities in Southern Chile, which includes an extended estuarine environment with roughly 1,500 km of fragmented coastline
These salinity gradients create strong biological consequences, including a stratification effect caused by buoyancy, which is a key regulator of primary production and biomass, a limitation on the depth of turbulent mixing, keeping algal cells within the photic zone; the concentration of an important fraction of organic matter and planktonic communities; and a change in the abundance and spatial distribution of the neuston (Dávila et al, 2002; Silva, Palma, 2008; Pantoja et al, 2011; Iriarte et al, 2014; Cañete et al, 2016)
Summary
The biodiversity levels and densities of neustonic organisms their spatial and temporal variation, their roles in sustaining biogeochemical cycling and atmosphere-ocean exchange processes, as well as a nutritional source for important trophic networks in significant areas of the oceans, all remain unknown (Hardy, 2005). The present study describes the structure and biodiversity of neustonic communities in Southern Chile, which includes an extended estuarine environment with roughly 1,500 km of fragmented coastline This area is characterized by the largest fjord systems in the world where salty Subantarctic Surface Water and Modified Subantarctic Waters mix with freshwater, generating sharp vertical and horizontal salinity gradients. These salinity gradients create strong biological consequences, including a stratification effect caused by buoyancy, which is a key regulator of primary production and biomass, a limitation on the depth of turbulent mixing, keeping algal cells within the photic zone; the concentration of an important fraction of organic matter and planktonic communities; and a change in the abundance and spatial distribution of the neuston (Dávila et al, 2002; Silva, Palma, 2008; Pantoja et al, 2011; Iriarte et al, 2014; Cañete et al, 2016). The aim of this study is the integration of zooplankton, hydrographic (sea surface temperature, salinity and dissolved oxygen) and remote sensing analysis (Chlorophyll a) to relate the spatial dynamics of neustonic communities with Chl a gradients to identify potential oceanographic processes of spatial mesoscale producing aggregation of zooplankton (Garcon et al, 2001) during cruise CIMAR 25 Fjord (C25F, 2019), and compare it with a previous neustonic study carriedout during CIMAR 16 Fjord (C16F, 2010), where aggregation of three taxa (copepodites of Microsetella rosea, larvae of the polychaete Polygordius sp and cyphonautes of the bryozoan Membranipora isabelleana) were studied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
