The structure of the pelagic food web in relation to water column structure in the Skagerrak

Kiørboe, Thomas; Kaas, Hanne; Kruse, Bo Mammen; Møhlenberg, Flemming; Tiselius, Peter; Ertebjerg, G.

doi:10.3354/meps059019

Cited by 70 publications

(27 citation statements)

References 26 publications

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“…2B) would support our conclusion of a relatively higher flux of organic matter to bacteria in stratified than in mixed waters. Therefore, our results are consistent with the earlier notions that traditional food chains dominate in turbulent or mixed waters, whereas microbial food chains dominate in strongly stratified waters (Azam et al 1983, Hagström et al 1988, Kiørboe et al 1990, Legendre & Le Fèvre 1995.If physical forces such as turbulent mixing and temperature can be considered as influential regulating factors in plankton ecology (White et al 1991, Kirchman et al 1995, Peters et al 1998, Petersen et al 1998, we would expect to find trends similar to the BP/PP versus SST relationship observed in the Yellow Sea in other regions. Temporally independent (i.e.…”

supporting

confidence: 92%

Sea-surface temperature and f-ratio explain large variability in the ratio of bacterial production to primary production in the Yellow Sea

Cho¹,

Park²,

Shim³

et al. 2001

Mar. Ecol. Prog. Ser.

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To determine whether parameters related to hydrography and phytoplankton utilization of nitrogenous nutrients are responsible for the variability in ratios of euphotic zone-integrated bacterial production (BP) to primary production (PP), we measured bacterial production, primary production, new production, regenerated production and environmental variables in the euphotic zone in May 1995 and June 1996 at a frontal region in the Yellow Sea. The BP/PP ratios were highly variable with different hydrodynamic conditions, ranging from 0.03 for mixed waters to 0.40 for stratified waters. The BP/PP ratios were significantly correlated (r 2 = 0.64, p < 0.01) with water-column stability of the euphotic zone and, to a greater degree, with sea-surface temperature (SST; r 2 = 0.74, p < 0.001). SST was also closely correlated with water-column stability (r 2 = 0.91, p < 0.0001). An inverse relationship was found (r 2 = 0.61, p < 0.01) between BP/PP and ƒ-ratios, indicating close association of the variability of the BP/PP ratios with the relative utilization of nitrogen by phytoplankton. High BP/PP values were found when the euphotic zone was stratified and phytoplankton mostly depended on ammonium for nitrogen source, and low BP/PP values were found when the euphotic zone was completely mixed and phytoplankton mostly depended on nitrate. Our results suggest that both turbulent mixing and water temperature were underlying physical forces regulating variations in BP/PP ratios in the Yellow Sea. It might be possible to predict energy pathways in the Yellow Sea and, presumably, in other marine environments by remote-sensing of SST and ocean color.KEY WORDS: Bacterial production/primary production ratio · Water-column stability · Sea-surface temperature · ƒ-ratio · Yellow Sea Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 216: [31][32][33][34][35][36][37][38][39][40][41] 2001 Currently, it is thought that hydrodynamic conditions are responsible for the structures of the pelagic food web (i.e. traditional grazing food chains or microbial loops: Cushing 1989, Legendre & Le Fèvre 1989, Kiørboe 1993. The emerging paradigm is that in turbulent or mixed environments where large phytoplankton are abundant, traditional food chains dominate, whereas in strongly stratified oligotrophic environments where small phytoplankton are abundant, microbial food chains dominate (Azam et al. 1983, Hagström et al. 1988, Kiørboe et al. 1990, Legendre & Le Fèvre 1995. Thus, the relative flux of organic matter from PP to bacteria can be expected to vary in relation to hydrography. Further, in stratified waters, most of PP is based on regenerated nitrogen (low ƒ-ratio), whereas in mixed waters PP is increasingly dependent on new nitrogen (high ƒ-ratio) (Kiørboe et al. 1990, Taylor & Joint 1990. We hypothesized that information on hydrography and the ƒ-ratio would provide clues to the explanation of the variability of BP/PP ratios in marine systems. We tested our hypothesis at a tidal front re...

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supporting

confidence: 92%

Sea-surface temperature and f-ratio explain large variability in the ratio of bacterial production to primary production in the Yellow Sea

Cho¹,

Park²,

Shim³

et al. 2001

Mar. Ecol. Prog. Ser.

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“…Anon., 1993;Rosenberg et al, 1996;Miskov-Nodland et al, 1999) and some papers on crustacean mesozooplankton (e.g. Båmstedt, 1983;Kiørboe et al, 1990;Tiselius et al, 1991) and euphausids (e.g. Buchholz and Boysen-Ennen, 1988;Bøhle and Moksness, MS 1991).…”

Section: Discussionmentioning

confidence: 99%

“…This often results in a summer "dome" or "ridge" of the pycnocline in the central area of the Skagerrak (Fonselius, 1996, Danielssen et al, 1997 that also influences the structure of the near-surface phyto-and zooplankton community (e.g. Kiørboe et al, 1990;Kahru and Leeben, 1991). The third feature, of particular significance for the deep-water community, is the sub-surface inflow of saline Atlantic Water along the southern slope of the deep-water basin (Rohde, 1996).…”

Section: Discussionmentioning

confidence: 99%

Predator-Prey Relationships and Food Sources of the Skagerrak Deep-water Fish Assemblage

Bergstad¹,

Wik²,

Hildre³

2003

J. Northw. Atl. Fish. Sci.

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The feeding ecology of fishes inhabiting the 300700 m deep shelf trough of the central Skagerrak (northeastern North Sea) was investigated to identify major trophic pathways and analyse the relative significance of epipelagic, mesopelagic and benthic food sources. Two benthopelagic fish species, roundnose grenadier, Coryphaenoides rupestris, and greater silver smelt, Argentina silus, were highly dominant in this area, but the squalid shark Etmopterus spinax, the chimaera, Chimaera monstrosa, and the witch flounder, Glyptocephalus cynoglossus were also characteristic members of the deep fish assemblage.Vertically migrating euphausids, shrimps (i.e. Pasiphaea sp.), copepods and hyperid amphipods were found to provide direct links between the epipelagic production and the deep-living roundnose grenadier. Prominent benthopelagic prey included the omnivorous Pandalus borealis and Sabinea sarsi. The trophic position of the greater silver smelt was uncertain because a high fraction of the stomach contents were unidentifiable, but a probable food source was thought to be mesopelagic and benthopelagic gelatinous plankton. Etmopterus spinax fed mostly on micronektonic crustaceans such as euphausids, but may have also scavenged on fish carcasses. Both the witch flounder and Chimaera monstrosa were benthophages feeding on a great variety of polychaetes, bivalves, gammarid amphipods and other medium-sized benthic prey.Trophic transfer patterns observed in the Skagerrak were compared with results from slope waters and deep fjords.

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“…In various aquatic environments, protozoan grazing (Rassoulzadegan & Sheldon 1986, Sherr et al 1992) and viral lysis (Proctor & Fuhrman 1992, Suttle 1994 have been related to the variations in bacterial abundance. Meanwhile, other research concluded that the physical stability of the water column, which largely controls the trophic conditions, determines bacterial distribution and production and their quantitative role in microbial food-web processes (Cushing 1989, Kiørboe et al 1990, Cho et al 2001, Shiah et al 2001. In combination, these results suggest that the factors controlling bacterial populations are system-dependent.…”

Section: Introductionmentioning

confidence: 60%

Bacterial abundance and production during the unique spring phytoplankton bloom in the central Yellow Sea

Hyun¹,

Kim²

2003

Mar. Ecol. Prog. Ser.

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To elucidate the factors responsible for the resulting bacterial properties during the spring phytoplankton bloom in the central Yellow Sea, we investigated bacterial abundance and production together with physico-chemical and biological parameters. In spring, the central Yellow Sea is characterized by the horizontal intrusion of high-temperature and high-salinity Yellow Sea Warm Current (YSWC), which forms a thermohaline front between the central Yellow Sea and cold coastal waters, and by the vertical mixing of high-nutrient Yellow Sea Cold Water (YSCW) over the previous winter. The combination of high nutrient conditions with weak vertical density gradients because of increased irradiance, which increases the residence time of phytoplankton within the euphotic layer, seems to trigger the spring phytoplankton bloom. Enhanced bacterial biomass, production, and turnover rates were observed in the bloom area. Bacterial variables were significantly correlated with chl a concentration, but not with temperature. These results indicated that resource supply from phytoplankton primarily stimulated bacterial growth. Despite the enhanced bacterial growth in the bloom area, abundant heterotrophic nanoflagellates and their grazing on bacteria were responsible for the relatively smaller increase in bacterial biomass in the bloom area. Higher bacterial growth but smaller increases in bacterial biomass indicated that bacterial growth and biomass are independently controlled during the spring bloom in the central Yellow Sea, in which bacterial growth is primarily stimulated by organic material produced from the phytoplankton bloom, but the enhanced biomass is more tightly controlled by grazing.

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The structure of the pelagic food web in relation to water column structure in the Skagerrak

Cited by 70 publications

References 26 publications

Sea-surface temperature and f-ratio explain large variability in the ratio of bacterial production to primary production in the Yellow Sea

Sea-surface temperature and f-ratio explain large variability in the ratio of bacterial production to primary production in the Yellow Sea

Predator-Prey Relationships and Food Sources of the Skagerrak Deep-water Fish Assemblage

Bacterial abundance and production during the unique spring phytoplankton bloom in the central Yellow Sea

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