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Distribution and ecophysiology of calanoid copepods in relation to the oxygen minimum zone in the eastern tropical atlantic.

Teuber L, Schukat A, Hagen W, Auel H - PLoS ONE (2013)

Bottom Line: Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology.Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth.Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature.

View Article: PubMed Central - PubMed

Affiliation: Bremen Marine Ecology, University of Bremen, Bremen, Germany.

ABSTRACT
Oxygen minimum zones (OMZs) affect distribution patterns, community structure and metabolic processes of marine organisms. Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology. For this study, calanoid copepods were sampled from different depths (0-1800 m) at eight stations in the eastern tropical Atlantic (3 °47'N to 18 °S) during three expeditions in 2010 and 2011. Their horizontal and vertical distribution was determined and related to the extent and intensity of the OMZ, which increased from north to south with minimum O2 concentrations (12.7 µmol kg(-1)) in the southern Angola Gyre. Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth. Maximum copepod biodiversity was observed in the deep waters of the central Angola Basin. Respiration rates and enzyme activities were measured to reveal species-specific physiological adaptations. Enzyme activities of the electron transport system (ETS) and lactate dehydrogenase (LDH) served as proxies for aerobic and anaerobic metabolic activity, respectively. Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature. Copepods of the families Eucalanidae and Metridinidae dominated within the OMZ. Several of these species showed adaptive characteristics such as lower metabolic rates, additional anaerobic activity and diel vertical migration that enable them to successfully inhabit hypoxic zones.

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CTD profiles from stations analysed for copepod abundance.A, temperature. B, dissolved oxygen concentration. C, fluorescence (in relative units as proxy for chlorophyll a concentration). Shades of gray correspond to different station groups (SG1, 3, and 4) according to species composition derived from cluster analysis; SG1 = black, SG3 = dark gray, SG4 = light gray. CTD data for SG2 were not available. Note the different scaling of the y-axes.
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pone-0077590-g003: CTD profiles from stations analysed for copepod abundance.A, temperature. B, dissolved oxygen concentration. C, fluorescence (in relative units as proxy for chlorophyll a concentration). Shades of gray correspond to different station groups (SG1, 3, and 4) according to species composition derived from cluster analysis; SG1 = black, SG3 = dark gray, SG4 = light gray. CTD data for SG2 were not available. Note the different scaling of the y-axes.

Mentions: Sea surface temperature (SST) ranged from 17.8 to 29.6°C (Table 1, Figure 3A). SST was highest at stns. 318 and 319 near the equator (SG1, black curves) and at stn. 317 (SG3, dark gray curves), while the lowest SST was recorded at stn. 840 (SG4, light gray curve) in the southern Angola Gyre. The depth of the mixed layer extended from 10 m at stn. 784 in the northeastern Angola Gyre to 86 m at stn. 840. Differences between temperature profiles were most pronounced within the upper few hundred meters, therefore, temperature profiles are only plotted down to 400 m depth.


Distribution and ecophysiology of calanoid copepods in relation to the oxygen minimum zone in the eastern tropical atlantic.

Teuber L, Schukat A, Hagen W, Auel H - PLoS ONE (2013)

CTD profiles from stations analysed for copepod abundance.A, temperature. B, dissolved oxygen concentration. C, fluorescence (in relative units as proxy for chlorophyll a concentration). Shades of gray correspond to different station groups (SG1, 3, and 4) according to species composition derived from cluster analysis; SG1 = black, SG3 = dark gray, SG4 = light gray. CTD data for SG2 were not available. Note the different scaling of the y-axes.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818376&req=5

pone-0077590-g003: CTD profiles from stations analysed for copepod abundance.A, temperature. B, dissolved oxygen concentration. C, fluorescence (in relative units as proxy for chlorophyll a concentration). Shades of gray correspond to different station groups (SG1, 3, and 4) according to species composition derived from cluster analysis; SG1 = black, SG3 = dark gray, SG4 = light gray. CTD data for SG2 were not available. Note the different scaling of the y-axes.
Mentions: Sea surface temperature (SST) ranged from 17.8 to 29.6°C (Table 1, Figure 3A). SST was highest at stns. 318 and 319 near the equator (SG1, black curves) and at stn. 317 (SG3, dark gray curves), while the lowest SST was recorded at stn. 840 (SG4, light gray curve) in the southern Angola Gyre. The depth of the mixed layer extended from 10 m at stn. 784 in the northeastern Angola Gyre to 86 m at stn. 840. Differences between temperature profiles were most pronounced within the upper few hundred meters, therefore, temperature profiles are only plotted down to 400 m depth.

Bottom Line: Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology.Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth.Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature.

View Article: PubMed Central - PubMed

Affiliation: Bremen Marine Ecology, University of Bremen, Bremen, Germany.

ABSTRACT
Oxygen minimum zones (OMZs) affect distribution patterns, community structure and metabolic processes of marine organisms. Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology. For this study, calanoid copepods were sampled from different depths (0-1800 m) at eight stations in the eastern tropical Atlantic (3 °47'N to 18 °S) during three expeditions in 2010 and 2011. Their horizontal and vertical distribution was determined and related to the extent and intensity of the OMZ, which increased from north to south with minimum O2 concentrations (12.7 µmol kg(-1)) in the southern Angola Gyre. Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth. Maximum copepod biodiversity was observed in the deep waters of the central Angola Basin. Respiration rates and enzyme activities were measured to reveal species-specific physiological adaptations. Enzyme activities of the electron transport system (ETS) and lactate dehydrogenase (LDH) served as proxies for aerobic and anaerobic metabolic activity, respectively. Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature. Copepods of the families Eucalanidae and Metridinidae dominated within the OMZ. Several of these species showed adaptive characteristics such as lower metabolic rates, additional anaerobic activity and diel vertical migration that enable them to successfully inhabit hypoxic zones.

Show MeSH
Related in: MedlinePlus