Biogeochemical relationships between ultrafiltered dissolved organic matter and picoplankton activity in the Eastern Mediterranean Sea

Meador, Travis B.; Gogou, Alexandra; Spyres, G.; Herndl, Gerhard J.; Κρασακοπούλου, Ε.; Psarra, Stella; Yokokawa, Taichi; Corte, Daniele De; Zervakis, Vassilis; Repeta, Daniel J.

doi:10.1016/j.dsr2.2010.02.015

Cited by 50 publications

(20 citation statements)

References 81 publications

(58 reference statements)

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“…Also, Meador et al [27] reported similar ranges in the surface layer of the EM and suggested that PA and PB were related to DOC. In the present study, PB and DOC were significantly related (all data, n0145, r00.53, P<0.01), indicating that PB exerts a significant control on DOC cycling.…”

Section: Longitudinal Patterns Of Abundance and Biomassmentioning

confidence: 86%

Enzymatic Activities and Prokaryotic Abundance in Relation to Organic Matter along a West–East Mediterranean Transect (TRANSMED Cruise)

et al. 2012

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The distribution of extracellular enzymatic activities (EEA) [leucine aminopeptidase (LAP), ß-glucosidase (GLU), alkaline phosphatase (AP)], as well as that of prokaryotic abundance (PA) and biomass (PB), dissolved organic carbon (DOC), particulate organic carbon and particulate total nitrogen (POC, PTN), was determined in the epi-, meso-, and bathypelagic waters of the Mediterranean Sea along a West-East transect and at one Atlantic station located outside the Strait of Gibraltar. This study represents a synoptical evaluation of the microbial metabolism during early summer. Decreasing trends with depth were observed for most of the parameters (PA, PB, AP, DOC, POC, PTN). Significant differences between the western and eastern basins of the Mediterranean Sea were found, displaying higher rates of LAP and GLU and lower C/N ratios more in the eastern than in the western areas. Conversely, in the epipelagic layer, PA and PB were found to be higher in the western than in the eastern basins. PB was significantly related to DOC concentration (all data, n = 145, r = 0.53, P < 0.01), while significant correlations of EEA with POC and PTN were found in the epipelagic layer, indicating an active response of microbial metabolism to organic substrates. Specific enzyme activities normalized to cell abundance pointed out high values of LAP and GLU in the bathypelagic layer, especially in the eastern basin, while cell-specific AP was high in the epi- and bathypelagic zone of the eastern basin indicating a rapid regeneration of inorganic P for both prokaryotes and phytoplankton needs. Low activity and abundance characterized the Atlantic station, while opposite trends of these parameters were observed along the Mediterranean transect, showing the uncoupling between abundance and activity data. In the east Mediterranean Sea, decomposition processes increased probably in response to mesoscale structures which lead to organic matter downwelling.

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Section: Longitudinal Patterns Of Abundance and Biomassmentioning

confidence: 86%

Enzymatic Activities and Prokaryotic Abundance in Relation to Organic Matter along a West–East Mediterranean Transect (TRANSMED Cruise)

et al. 2012

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“…The water column of the EMS is well oxygenated. The oxygen minimum found at depths of about 1000 to 2000 m is equivalent to 70-75 % of saturation, while in deeper layers ventilation is enhanced by deep-water formation (Meador et al, 2010;Schlitzer et al, 1991).…”

Section: Oceanographic Settingmentioning

confidence: 99%

Occurrence, sources and transport pathways of natural and anthropogenic hydrocarbons in deep-sea sediments of the eastern Mediterranean Sea

et al. 2013

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Abstract. Surface sediments collected from deep basins (1018-4087 m depth) of the eastern Mediterranean Sea (Ionian Sea, southern Aegean Sea and northwestern Levantine Sea) were analyzed for aliphatic and polycyclic aromatic hydrocarbons as tracers of natural and anthropogenic inputs. Concentrations of total aliphatic hydrocarbons, n-alkanes and the unresolved complex mixture (UCM) of aliphatic hydrocarbons varied significantly, ranging from 1.34 to 49.2 µg g −1 , 145 to 4810 ng g −1 and 0.73 to 36.7 µg g −1 , respectively, while concentrations of total polycyclic aromatic hydrocarbons (PAHs) ranged between 11.6 and 223 ng g −1 . Molecular profiles of determined hydrocarbons reflect a mixed contribution from both natural and anthropogenic sources in deep-sea sediments of the eastern Mediterranean Sea, i.e., terrestrial plant waxes, degraded petroleum products, unburned fossil fuels and combustion of grass, wood and coal. Hydrocarbon mixtures display significant variability amongst sub-regions, reflecting differences in the relative importance of inputs from various sources and phase associations/transport pathways of individual hydrocarbons that impact on their overall distribution and fate. Hydrocarbon concentrations correlated significantly with the organic carbon content of sediments, indicating that the latter exerts an important control on their transport and ultimate accumulation in deep basins. Additionally, water masses' circulation characteristics also seem to influence the regional features and distribution patterns of hydrocarbons. Our findings highlight the role of deep basins/canyons as repositories of both natural and anthropogenic chemical species.

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“…By contrast, very little information is available on DOC dynamics at the surface in open-seawater [Avril, 2002;Santinelli et al, 2008]. In addition, only a few papers report DOC data combined with microbiological information and these are limited to narrow areas [Yoro et al, 1997;Gasol et al, 1998Sempéré et al, 2002Sempéré et al, , 2003Van Wambeke et al, 2004;La Ferla et al, 2005;Meador et al, 2010].…”

Section: Introductionmentioning

confidence: 99%

Organic carbon dynamics in the Mediterranean Sea: An integrated study

Santinelli

Sempéré

Wambeke

et al. 2012

Global Biogeochemical Cycles

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[1] Total (TOC) and dissolved (DOC) organic carbon vertical profiles were analyzed from 11 stations located in various regions of the Mediterranean Sea, together with the distribution of other physical, chemical and biological parameters. TOC showed the highest concentrations (68-83 mM) above the pycnocline, followed by a marked decrease to values of 45-48 mM at 100-200 m. Below 200 m, values of 40-45 mM were observed. The excess TOC and DOC occurring at each station was calculated by subtracting 48 mM from the observed concentrations. The stock of the excess TOC and DOC increased eastward; while surface DOC mineralization rates decreased from 1.The integrated average of the biological parameters in the above-pycnocline layer showed a bacterial production versus particulate primary production (BP/PPP) ratio ranging from 22% in the Ionian Sea (MIO station) to 31% in the Ligurian Sea (Dyfamed station), while bacterial carbon demand versus PPP was higher than 100%, considering a bacterial growth efficiency of both 15% and 30%. The data here reported indicate various scenarios of carbon dynamics. At the stations west of the Sardinian Channel, the microbial loop was very active, and a high flux of carbon to the microbial loop (large bacterial and protist abundance) may be hypothesized, which would result in a low DOC concentration. At the stations east of the Sardinian Channel, no significant longitudinal variation was found in DOC and BP. DOC accumulated at these stations, possibly due to bacteria P-limitation, to DOC chemical composition and/or to the occurrence of different prokaryotic populations with a different ability to consume the available DOC.

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Biogeochemical relationships between ultrafiltered dissolved organic matter and picoplankton activity in the Eastern Mediterranean Sea

Cited by 50 publications

References 81 publications

Enzymatic Activities and Prokaryotic Abundance in Relation to Organic Matter along a West–East Mediterranean Transect (TRANSMED Cruise)

Enzymatic Activities and Prokaryotic Abundance in Relation to Organic Matter along a West–East Mediterranean Transect (TRANSMED Cruise)

Occurrence, sources and transport pathways of natural and anthropogenic hydrocarbons in deep-sea sediments of the eastern Mediterranean Sea

Organic carbon dynamics in the Mediterranean Sea: An integrated study

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