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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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Abundance and vertical distribution of calanoid copepods in the eastern tropical Atlantic.Copepod abundance is presented for four different station groups (SG1–4) and for four different depth layers related to the vertical extent of the OMZ. Four cells per species and depth layer represent its abundance in each station group in clockwise order: top left = SG1 (black), top right = SG2 (white), bottom right = SG3 (dark gray), bottom left = SG4 (light gray), as depicted in the top right corner. * = species identified as diel vertical migrants. C3–C5 = copepodid 3–5, C6 = adult, f = female, m = male, s.i. = single individual, OMZ = oxygen minimum zone. Blank cells indicate absence.
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pone-0077590-g004: Abundance and vertical distribution of calanoid copepods in the eastern tropical Atlantic.Copepod abundance is presented for four different station groups (SG1–4) and for four different depth layers related to the vertical extent of the OMZ. Four cells per species and depth layer represent its abundance in each station group in clockwise order: top left = SG1 (black), top right = SG2 (white), bottom right = SG3 (dark gray), bottom left = SG4 (light gray), as depicted in the top right corner. * = species identified as diel vertical migrants. C3–C5 = copepodid 3–5, C6 = adult, f = female, m = male, s.i. = single individual, OMZ = oxygen minimum zone. Blank cells indicate absence.

Mentions: Cluster analysis grouped the eight stations according to their similarity in copepod abundance and species composition into four station groups (SG1 to SG4, Figure 2), which is also reflected by geographic location and oceanographic features (see also Figure 1, Table 1). SG1 included the two northern equatorial stations (stns. 318, 319) with highest SST (>28°C) and only a weak OMZ (O2≥42.6 µmol kg−1). SG2 comprised the two stations located in the central Angola Basin (stns. 1, 2). The tropical stations of SG1 and SG2 were similar in total copepod abundance, but biodiversity was higher in the deep layer of SG2 (Figure 4). Stations grouped into SG3 were all located closer to the coast in the northeastern Angola Gyre (stns. 784, 787, 317) and had intermediate SST (23–29°C) and a moderate OMZ (17.6–39.8 µmol kg−1). Total copepod abundance was highest in almost every depth layer of SG3 compared to the other station groups (Figure 4). SG4 consisted of only one station (stn. 840) located in the southern Angola Gyre near the Angola-Benguela front and had lowest SST (18°C) and lowest O2 concentrations in the OMZ (16.4 µmol kg−1). SG4 was different from all other stations due to the lowest copepod abundance in every depth layer except within the OMZ, where copepod abundance was highest of all stations (Figure 4).


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)

Abundance and vertical distribution of calanoid copepods in the eastern tropical Atlantic.Copepod abundance is presented for four different station groups (SG1–4) and for four different depth layers related to the vertical extent of the OMZ. Four cells per species and depth layer represent its abundance in each station group in clockwise order: top left = SG1 (black), top right = SG2 (white), bottom right = SG3 (dark gray), bottom left = SG4 (light gray), as depicted in the top right corner. * = species identified as diel vertical migrants. C3–C5 = copepodid 3–5, C6 = adult, f = female, m = male, s.i. = single individual, OMZ = oxygen minimum zone. Blank cells indicate absence.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3818376&req=5

pone-0077590-g004: Abundance and vertical distribution of calanoid copepods in the eastern tropical Atlantic.Copepod abundance is presented for four different station groups (SG1–4) and for four different depth layers related to the vertical extent of the OMZ. Four cells per species and depth layer represent its abundance in each station group in clockwise order: top left = SG1 (black), top right = SG2 (white), bottom right = SG3 (dark gray), bottom left = SG4 (light gray), as depicted in the top right corner. * = species identified as diel vertical migrants. C3–C5 = copepodid 3–5, C6 = adult, f = female, m = male, s.i. = single individual, OMZ = oxygen minimum zone. Blank cells indicate absence.
Mentions: Cluster analysis grouped the eight stations according to their similarity in copepod abundance and species composition into four station groups (SG1 to SG4, Figure 2), which is also reflected by geographic location and oceanographic features (see also Figure 1, Table 1). SG1 included the two northern equatorial stations (stns. 318, 319) with highest SST (>28°C) and only a weak OMZ (O2≥42.6 µmol kg−1). SG2 comprised the two stations located in the central Angola Basin (stns. 1, 2). The tropical stations of SG1 and SG2 were similar in total copepod abundance, but biodiversity was higher in the deep layer of SG2 (Figure 4). Stations grouped into SG3 were all located closer to the coast in the northeastern Angola Gyre (stns. 784, 787, 317) and had intermediate SST (23–29°C) and a moderate OMZ (17.6–39.8 µmol kg−1). Total copepod abundance was highest in almost every depth layer of SG3 compared to the other station groups (Figure 4). SG4 consisted of only one station (stn. 840) located in the southern Angola Gyre near the Angola-Benguela front and had lowest SST (18°C) and lowest O2 concentrations in the OMZ (16.4 µmol kg−1). SG4 was different from all other stations due to the lowest copepod abundance in every depth layer except within the OMZ, where copepod abundance was highest of all stations (Figure 4).

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