Viruses, bacterioplankton, and phyloplankton in the southeastern Gulf of Mexico: distribution and contribution to oceanic DNA pools

Abstract

Little is known concerning the factors which might control the distribution of viral abundance in oceanic environments and the relationship of viruses to the oceanic DNA pool. We have measured the distribution of viruses, bacterioplankton and phytoplankton in the subtropical southeastern Gulf of Mexico and related these parameters to the distribution of DNA (dissolved and particulate) in these waters. Viral direct counts were 4.6 to 27 X 106ml-' in Tampa Bay (Florida, USA), 3.8 to 8.5 X 105 ml-' in all oceanic euphotic zone samples and 1.4 to 4.7 X 104 ml-' in deep (200 to 2500 m) waters, and were highly correlated with chlorophyll a concentrations (r = 0.97), particulate DNA (r = 0.96) and bacterial direct counts (BDC, r = 0.94). A vertical profile indicated a subsurface euphotic zone maximum in viral direct counts that corresponded with maxima for particulate and dissolved DNA, and picocyanobacterial direct counts. For all stations, the vertical distribution of viruses most closely followed the distribution of particulate DNA. Bacterioplankton made the largest contnbution ( z 50 %) to the particulate (> 0.2 pm) DNA pool while phytoplankton averaged 8 %. A predictive model for particulate DNA was determined to be: Particulate DNA (pg 1-') = 4.94 X 10-"BDC I-') + 2.31 [chlorophyll a (pg I-')] + 2.77. DNA in viral particles was estimated to comprise only ca 4 % of the dissolved DNA pool.

Distribution of marine viruses in the Central and South Adriatic Sea

“…The determined correlations suggest that bacteria were the main host for viral replication and are an important factor in the control of viral abundance. A similar correlation was found by et al (1993) and Stopar et al (2003) in the north Adriatic Sea, by Boehme et al (1993) in the Mexican Gulf and by Cochlan et al (1993) in the southern part of the Californian Bay and the Chucki Sea.…”

Seasonal Variation of Virioplankton in a Eutrophic Shallow Lake

“…At the hypertrophic site, the most possible reason is the phytoplankton bloom caused by dinoflagellates and cyanobacteria in spring (Lie et al, 2003), and because the peak of viral abundance recorded in April followed a marked chlorophyll a peak recorded in FebruaryMarch. It is suggested that high concentrations of phytoplankton might result in more planktonic viruses, and the significant correlation has been suggested by some previous studies (Boehme et al, 1993;Maranger & Bird, 1995;Weinbauer et al, 1995). In addition, phytoplankton had larger burst sizes than bacterioplankton, ranging from 92 to 500 (Bratbak et al, 1993;Suttle & Chan, 1994).…”

“…bacteria, cyanobacteria and algae), enumeration of viruses and their hosts in water samples is an important first step for elucidating the virus-host interaction. In most instances, viral abundance was significantly correlated with bacterioplankton abundance (Wommack & Colwell, 2000), but in a few studies, it showed significant correlation with chlorophyll a concentration (Boehme et al, 1993;Maranger & Bird, 1995). Temporal fluctuations in viral abundance have been studied at time scales ranging from hours (Bettarel et al, 2002) to seasons Fischer &Velimirov, 2002;Bettarel et al, 2003).…”

Spatial distribution and morphologic diversity of virioplankton in Lake Donghu, China

“…The highest viral abundance was found in hypertrophic region and the lowest in mesotrophic region. Similar to the previous reports in marine and other freshwater environments (Boehme et al, 1993;Maranger and Bird, 1995;Weinbauer et al, 1995;Riegman and Winter, 2003), the viral abundance in lake Donghu significantly related to the concentration of chlorophyll a, which suggested that a high concentration of phytoplankton might result in more planktonic viruses (cyanophages and algal viruses). In addition, phytoplankton had larger burst sizes than bacterioplankton, ranging from 92 to 500 (Bratbak et al, 1993;Suttle and Chan, 1994).…”

“…In marine environment, the distribution of viruses in different trophic statuses have been determined by Boehme et al (1993) in the Southeastern Gulf of Mexico from onshore eutrophic to offshore (oligotrophic), and Stopar et al (2004) in the Gulf of Trieste (eutrophic and oligotrophic). In freshwaters, Bettarel et al (2003) compared annual viral density between Lake Pavin (eutrophic) and Lake Aydat (oligomesotrophic), and Laybourn-Parry et al (2001) investigated nine lakes belonging to mesotrophic, oligotrophic and ultraoligotrophic conditions, respectively.…”