title: Synechococcus production and grazing loss rates in nearshore tropical waters.
abstract: Temporal variation of Synechococcus, its production (μ) and grazing loss (g) rates were studied for 2 years at nearshore stations, i.e. Port Dickson and Port Klang along the Straits of Malacca. Synechococcus abundance at Port Dickson (0.3-2.3 × 105cell ml-1) was always higher than at Port Klang (0.3-7.1 × 104cell ml-1) (p < 0.001). μ ranged up to 0.98 day-1(0.51 ± 0.29 day-1), while g ranged from 0.02 to 0.31 day-1(0.15 ± 0.07 day-1) at Port Klang. At Port Dickson, μ and g averaged 0.47 ± 0.13 day-1(0.29-0.82 day-1) and 0.31 ± 0.14 day-1(0.13-0.63 day-1), respectively. Synechococcus abundance did not correlate with temperature (p > 0.25), but nutrient and light availability were important factors for their distribution. The relationship was modelled as log Synechococcus = 0.37Secchi - 0.01DIN + 4.52 where light availability (as Secchi disc depth) was a more important determinant. From a two-factorial experiment, nutrients were not significant for Synechococcus growth as in situ nutrient concentrations exceeded the threshold for saturated growth. However, light availability was important and elevated Synechococcus growth rates especially at Port Dickson (F = 5.94, p < 0.05). As for grazing loss rates, they were independent of either nutrients or light intensity (p > 0.30). In nearshore tropical waters, an estimated 69 % of Synechococcus production could be grazed.
authors.affiliation: Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Pei Li
authors.initials: PL
authors.lastname: Heng
authors.affiliation: Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia.|Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia.|Institute of Graduate Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia.
authors.forename: Joon Hai
authors.initials: JH
authors.lastname: Lim
authors.affiliation: Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia. lee@um.edu.my.|Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia. lee@um.edu.my.|Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan. lee@um.edu.my.
authors.forename: Choon Weng
authors.identifier: http://orcid.org/0000-0001-9805-9980
authors.initials: CW
authors.lastname: Lee
mesh_terms: D004784:Environmental Monitoring; D012623:Seawater; D046940:Synechococcus / Q000502:physiology*; D013696:Temperature
keywords: Grazing loss rates; Growth rate; Nearshore waters; Straits of Malacca; Synechococcus