Biogeosciences Plankton in the open Mediterranean Sea: a review
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1560 I. Siokou-Frangou et al.: Mediterranean plankton Table 5. Bacterial abundance (BA), Heterotrophic Nanoflagellate abundance (HNF) and Bacterial Production (BP) in different Mediterranean Sea areas. Note that BP is expressed in different units depending on the data given by the authors and depth (m) indicates tha maximum depth considered in the study. (TdR: 3H-thymidine incorporation, other BP are measured by 3H-leucine incorporation) Location
Period BA (cells 10 8 l
1 ) BP HNF (cells 10 6 l − 1 ) Reference % BP consumption West Almeria-Oran front May 2.3–13.5
0.04–3.26 µg C l − 1 d − 1 Fern´andez et al. (1994) front (Alboran Sea) 124–199 mg C m − 2 d − 1 (150 m) NW Mediterranean May and June 3.6–9.6
1.2–7.2 µg C l − 1 d − 1 (5 and 40 m) 0.8–2.2
Christaki et al. (1996, 1998) current
1.0–2.1 pmol TdR l − 1 h − 1 Barcelona: June
1.5–6.0 0.5–3.0 pmol l − 1
− 1 Gasol et al. (1998) In-Offshore transect 20–360 mg C m − 2
− 1 (60–80 m) Barcelona Stratification 3.1–5.4 0.02–2.5 µg C l − 1 d − 1 Pedr´os-Ali´o et al. (1999) Balearic islands period (3 yr) 1–104 mg C m − 2 d − 1 (200 m) Algerian current October 6.6–9.0
0.3–4.5 µg C l − 1 d − 1 Moran et al. (2001) 33–384 mg C m − 2
− 1 (120 m) NW Mediterranean: March
1.5–8.9 0.09–5.9 µg C l − 1
− 1 0.3–3.0 Vaqu´e et al. (2001) transects off-shore (HDNA 25-87%) NW Mediterranean: Monthly 1.4–11.0
undetectable–4.8 µg C l − 1 d − 1 Lem´ee et al. (2002) station off-Nice (one year) 60–468 mg C m − 2
− 1 (130 m) Almeria-Oran front November, 5.0–15.0 0.1–5.5 µg C l − 1
− 1 Van Wambeke et al. (2004) (Alboran Sea) January
68–215 mg C m − 2 d − 1 (200 m) Atl. jet 52–70 mg C m − 2
− 1 (200 m) Med water East Levantine Basin, Cyprus September 2.8–4.9
0.2–0.4 pmol TdR l − 1 h − 1 0.4–0.9 eddy, core and boundary 0.2–0.48 10 6 cells l − 1 h − 1 Zohary and Robarts (1992) Levantine basin October–November 0.4–3.9 0.04–0.2 µg C l − 1 d − 1 Robarts et al. (1996) 0–3.9, avg: 0.3 pmol TdR l − 1 h − 1 8–43, avg 24 mg C m − 2 d − 1 (200 m) Cyprus eddy March 2.5–3.5
0.0–0.2 average 0.1 pmol TdR l − 1 h − 1 Zohary et al. (1998) S. Aegean Sea September, 3.0–5.0
0.45–1.96 µg C l − 1 d − 1 Van Wambeke et al. (2000) (transect off-shore) March 7–131, avg 45 mg C m − 2 d − 1 (100 m) North and South September, 2.3–15.2 0.22–0.94 µg C l − 1
− 1 0.3–3.1 Christaki et al. (2003), Aegean
March 48–110 mg C m − 2
− 1 (10 m) 35–100% Siokou-Frangou et al. (2002) east-west transect June–July 2.9–5.0 0.0048–1.3 µg C l − 1 d − 1 0.5–1.2 Christaki et al. (2001), 13–75 mg C m − 2
− 1 (200 m) 45–85% Van Wambeke et al. (2002) chl a concentration and an increase in bacterial production. It was suggested that while phytoplankton was concurrently N and P limited, bacterial growth was mainly limited by phos- phorous (Pitta et al., 2005; Thingstad et al., 2005; Zohary et al., 2005). However, while phosphorus is usually the lim- iting nutrient, nitrogen and carbon limitation or co-limitation also occurs, and the type of limitation can vary with depth (Sala et al., 2002; Van Wambeke et al., 2000, 2009). It seems that the bacterioplankton of the oligotrophic MS lives in a dynamic equilibrium in which slight changes in grazing pressure, competition and nutrient concentrations can shift the communities from limitation by one nutrient to another (Sala et al., 2002). Indeed, over time scales of just a few hours, large shifts in abundance, production, and portions of particle-attached or free-living bacteria have been docu- mented (M´evel et al., 2008). The metabolism of natural communities of bacterioplank- ton has been studied in terms of enzymatic activity and dis- solved amino-acid (DFAA) uptake; these parameters are in- dicators of the uptake of dissolved organic matter by bacteria and the factors possibly influencing uptake (Karner and Ras- soulzadegan, 1995; Van Wambeke et al., 2000, 2004; Chris- taki et al., 2003; Misic and Fabiano, 2006). For example, in a longitudinal study across the MS, alkaline phosphatase activity was used as an indicator of bacterial P-limitation (Van Wambeke et al., 2002). Alkaline phosphatase turnover times of less than 100 h were documented and corresponded to situations of P limitation on bacterial production. In a study conducted in the Aegean Sea, ectoaminopeptidase ac- tivity was weakly related to bacterial production, but tightly coupled with respiration rates of amino acids; moreover, the percentage of respiration of DFAA was relatively high (50±18%) (Christaki et al., 2003). The authors hypothesized Biogeosciences, 7, 1543–1586, 2010 www.biogeosciences.net/7/1543/2010/ Yüklə 0,96 Mb. Dostları ilə paylaş:
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