Dataset: Cyanophage abundance

Viral abundance was estimated by Most Probable Number (MPN) assay as described in Marston and Sallee (2003) for the RI samples and Clasen et al (2013) for the CA samples. For the RI samples, the abundance of cyanophages capable of infecting Synechococcus sp. WH7803 was estimated. For the CA samples, the abundance of cyanophages capable of infecting Synechococcus sp. WH7803, WH8012, WH8018, WH 8101 was estimated. A subsample (60ml) of each replicate seawater sample was centrifuged to remove large particles and bacteria, and the supernatant was serially diluted with sterile natural seawater media (SN media (Waterbury et al. 1986)). A 100µl aliquot of this diluted seawater was added to 100µl of exponentially a growing Synechococcus strain in each well of 48-well microtiter plates (except control wells which received no seawater). After a 30 - 60 min incubation at room temperature, 500 ul of sterile SN media was added to each well. Plates were then incubated for two weeks at 25°C on a 14:10 hr day:night cycle at 19µE m-2 s-1 light intensity. After 14 days, the plates were visually monitored for lysis (wells with less visible pigmentation than control host-only wells), and the total number of lysed wells was recorded. Estimates of the concentration of infectious cyanophages were determined using MPN Calculator software.

Nutrient samples were filtered and sent to UC Santa Barbara's Marine Science Institute for analysis. Values are the mean of two samples. Nutrient detection limits: Phosphate 0.10; Silicate 1.00; Nitrite 0.10; Nitrite+Nitrate 0.20; Ammonia 0.10; all units are micromolar.

Seawater was collected from the shore surf zone.

Metadata taken prior to March 2009 are scattered and may be unreliable.

Salinity measured using a handheld refractometer and may be high.

Most Probable Numbers of cyanophage abundance are based on 3 dilutions and an MPN calculator (e.g., http://www.i2workout.com/mcuriale/mpn/index.html). 

For the CA sites, the MPN estimate is the average estimate calculated separately for the three replicates (using 48 wells for each of three dilutions), and standard errors for the mean value are reported.

For the RI sites, the MPN estimate is calculated by combining the results of all three replicates (a total of 30 wells for each of three dilutions), and the 95% CIs (as estimated by the MPN calculator) are reported. 

Detection limits for nutrients are indicated at top of the file. Nutrient values are average of two replicates, and may include values that are below detection limits.

Related files and references:

Clasen, J.L., C.A. Hanson, Y. Ibrahim, C. Weihe, M.F. Marston, & J.B.H. Martiny (2013) Diversity and temporal dynamics of Southern California coastal marine cyanophage isolates. Aquatic Microbial Ecology, 69:17-31.

Marston and Sallee (2003) Applied and Environmental Microbiology 69: 4639-4647.