Anales del Instituto de la Patagonia
On-line version ISSN 0718-686X
VASQUEZ, Osvaldo et al. The relationships between Chlorophyll-A and oceanographic variables in the periglacial area of the Seno Gallegos (Cordillera Darwin, Chile): under winter conditions . Anales Instituto Patagonia (Chile) [online]. 2012, vol.40, n.1, pp.139-151. ISSN 0718-686X. http://dx.doi.org/10.4067/S0718-686X2012000100018.
The relationships between chlorophyll a concentration, physical-chemical variables (temperature, salinity, density, total suspended particulate matter) and nutrients (silicate, nitrate, nitrite and phosphate) were determined in the marine periglacial area of the Gallegos sound (54° 28'58''S - 69° 50'55''W) in August 2010 (austral winter). Twelve stations were studied out directly from the glacier edge to mouth of the sound. At each station, a CTD was deployed and water samples were collected. The water tempera-tures ranged from 3.74 to 6.55 °C, the salinity from 28.39 to 30.14 psu and chlorophyll a concentrations varied from 0.24 to 2.69 mg m-3; the total particulate matter concentrations varied between 0.12 and 14.0 mg L-1. The silicate concentrations varied between 2.58 and 9.57 µM, phosphate between 0.01 and 8.02 µM, and nitrate and nitrite values ranged from 0.02 to 30.34 µM and 0.01 to 2.99 µM, respectively. The chlorophyll a concentration in the sound was significantly correlated with depth, total particulate matter and density (ρ = 0.477), whereas lower correlation values resulted with silicate and phosphate (ρ = 0.463). The lowest significant correlation value was observed with nitrate concentrations (ρ = 0.397). Our result suggest that the water column stratification is linked to total particular matter maintaining high chlorophyll a concentrations in the euphotic layer of this cold water estuarine system.
Keywords : Brookes Bay; Patagonia; oceanography; particulate matter; estuarine.