Bermuda Atlantic Time Series Latitude:   31.6667     Longitude:   -64.1667 Associated Investigators: Nick Bates (PI) , Deborah Steinberg (zooplankton) ,   Michael Lomas (phytoplankton) ,   Craig Carlson (microbial plankton)   Related Web Sites: [bats.bios.edu/]   Related Time Series: [ Bermuda Atlantic Time Series (BATS) ]   [ Hydrostation S ]   The Bermuda Atlantic Time-series Study (BATS) site is located in the Sargasso Sea at 31 50'N 64 10'W and is monitored by the Bermuda Institute of Ocean Sciences (BIOS). Zooplankton is collected at least once a month with a ringnet (100 cm diameter, 202 µm mesh). Two replicate oblique tows are made during the day (between 09:00 and 15:00) and night (between 20:00 and 02:00) to a depth of approximately 200 m. Night-time biomass values on average are 1.7-3.4-fold higher than daytime biomass, indicating the importance of diel migrators at the site (Madin et al., 2001). Pleuromamma spp. copepods and the euphausiid Thysanopoda aequalis accounted for up to 70% of the night-only biomass (Steinberg et al., 2000). There is a limited seasonal variability within the BATS zooplankton biomass, with a relatively small March-April maximum that follows the spring chlorophyll maximum. On an annual basis, zooplankton biomass increased from the mid-1990s to the mid-2000s and may now be decreasing in what appears to be a decadal cycle. Long-term temperatures in the region are currently at the high end of an approximately 50-year multidecadal trend. Any relationship between zooplankton biomass and long-term temperature is inconclusive at this time.