Assessment of recent sediment influence in an urban polluted subantarctic coastal ecosystem. Beagle Channel (Southern Argentina)

Seasonal and spatial variation of mesozooplankton biomass in Ushuaia and Golondrina bays (Beagle Channel, Argentina))

“…4). The observed increase in chlorophyll a values in both bays during late springsummer reflect a greater phytoplankton activity favored by an increase in temperature, optimal light condition, and high concentration of nutrients, especially near the coast in both bays (FERNANDEZ-SEVERINI;HOFFMEYER, 2005;BIANCALANA;TORRES, 2011;GIL et al, 2011). The highest mesozooplankton biomass observed in UB during late summer, apparently follows the annual phytoplankton maximum (FERNANDEZ-SEVERINI; HOFFMEYER, 2005).…”

“…4). Low salinities during warm seasons in both bays are direct consequences of freshwater inputs from several defrost fluxes such as streams, rivers and runoff (TORRES et al, 2009;AMIN et al, 2011b;GIL et al, 2011). Concerning mesozooplankton biomass in GB, the lowest (0.44 mg WW m -3 ) and the highest (12.71 mg WW m -3 ) values were recorded in late winter at stations 6 and 4, respectively (Fig.…”

“…Particularly, the northern zone of UB, has been suffering significant alterations as a result of domestic, industrial and harbor activities. As UB, GB has received noticeable contributions of wastewater through the sewage diffuser situated on the eastern coast of this bay (AMIN et al, 2011a, b;DUARTE et al, 2011;GIL et al, 2011). In addition, the coast of GB has suffered the increased development of surrounding urban centers and tourism infrastructure.…”

“…In addition, the coast of GB has suffered the increased development of surrounding urban centers and tourism infrastructure. Also, its coast has received the influence of the unloading of the Pipo River, which receives several urban untreated discharges (GIL et al, 2011). So, several deleterious effects on water quality have been observed as a consequence of the uncontrolled development of Ushuaia City and its industrial zones (TORRES et al, 2009;AMIN et al, 2011a, b;GIL et al, 2011).…”

“…These authors mentioned that the highly energetic flow of the Antarctic Circumpolar Current produce largest variances in temperature and salinity in the southern region between Tierra del Fuego and Isla de los Estados (SABATINI et al, 2004). Particularly in UB, a permanent and strong current which enters from the Beagle Channel (BALESTRINI et al, 1990) and freshwater inputs (Olivia River and Grande Stream) joined with wastewater discharges (GIL et al, 2011), could produce variability in temperature and salinity as well as changes in phytoplankton and mesozooplankton dynamics. Also, SABATINI et al (2004) suggested that the permanent mixture of the water column causes that algal cells to receive limited amount of light because of their continuously up and down movements.…”