Effects of the gastropod Rhinoclavis aspera (Linnaeus, 1758) on microbial biomass and productivity in coral-reef-flat sediments

1994 ◽  
Vol 45 (4) ◽  
pp. 569 ◽  
Author(s):  
JA Hansen ◽  
GA Skilleter
Keyword(s):  
Coral Reef ◽  
Primary Production ◽  
Bacterial Growth ◽  
Bacterial Production ◽  
Reef Flat ◽  
Gross Primary Production ◽  
Bacterial Activity ◽  
Physical Disturbance ◽  
Deposit Feeding ◽  
Number Of Bacteria

Abundance of the deposit-feeding gastropod Rhinoclavis aspera in coral-reef-flat sediments was estimated along with numbers of bacteria, rate of bacterial production, biomass of microalgae (measured as concentration of chlorophyll a) and rates of gross primary production at two different times of the year. Standing stocks of bacteria and microalgae were greater in June 1986 (winter) than in January 1987 (summer), but rates of bacterial production and gross primary production were slower in June. Significant correlations between the abundance of R. aspera and the rates of bacterial production indicated that grazing by the gastropods may affect bacterial activity. Densities of R. aspera were manipulated in enclosures in the field to determine their effects on the number of bacteria, the rates of bacterial production and the biomass of microalgae. There were no consistent effects of gastropods on either the biomass of microalgae or rates of bacterial growth. Numbers of bacteria were, however, significantly less in enclosures with greater densities of gastropods. Physical disturbance of the sediments (to simulate the movements of the gastropods) also caused a significant decrease in the numbers of bacteria. The decrease in numbers of bacteria was not the result of slower rates of bacterial growth, indicating that cell removal was a more probable fate. It may be that disruption of sediments by the gastropods increased the abundance of other grazers, such as meiofauna, which then consumed the bacteria.

scholarly journals Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon

2016 ◽  
Vol 13 (11) ◽  
pp. 3187-3202 ◽  
Author(s):  
France Van Wambeke ◽  
Ulrike Pfreundt ◽  
Aude Barani ◽  
Hugo Berthelot ◽  
Thierry Moutin ◽  
...  
Keyword(s):  
Primary Production ◽  
Bacterial Growth ◽  
N2 Fixation ◽  
Bacterial Production ◽  
Heterotrophic Bacteria ◽  
New Caledonia ◽  
Gross Primary Production ◽  
Growth Efficiency ◽  
Bacterial Growth Efficiency ◽  
Second Phase

Abstract. Studies investigating the fate of diazotrophs through the microbial food web are lacking, although N2 fixation can fuel up to 50 % of new production in some oligotrophic oceans. In particular, the role played by heterotrophic prokaryotes in this transfer is largely unknown. In the frame of the VAHINE (VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific) experiment, three replicate large-volume (∼ 50 m3) mesocosms were deployed for 23 days in the new Caledonia lagoon and were intentionally fertilized on day 4 with dissolved inorganic phosphorus (DIP) to stimulate N2 fixation. We specifically examined relationships between heterotrophic bacterial production (BP) and N2 fixation or primary production, determined bacterial growth efficiency and established carbon budgets. BP was statistically higher during the second phase of the experiment (P2: days 15–23), when chlorophyll biomass started to increase compared to the first phase (P1: days 5–14). Phosphatase alkaline activity increased drastically during the second phase of the experiment, showing adaptations of microbial populations after utilization of the added DIP. Notably, among autotrophs, Synechococcus abundances increased during P2, possibly related to its capacity to assimilate leucine and to produce alkaline phosphatase. Bacterial growth efficiency based on the carbon budget (27–43 %), was notably higher than generally cited for oligotrophic environments and discussed in links with the presence of abundant species of bacteria expressing proteorhodopsin. The main fates of gross primary production (particulate + dissolved) were respiration (67 %) and export through sedimentation (17 %). BP was highly correlated with particulate primary production and chlorophyll biomass during both phases of the experiment but was slightly correlated, and only during P2 phase, with N2 fixation rates. Heterotrophic bacterial production was strongly stimulated after mineral N enrichment experiments, suggesting N-limitation of heterotrophic bacteria across the experiment. N2 fixation rates corresponded to 17–37 % of the nitrogen demand of heterotrophic bacteria. Our results suggest that most of the diazotroph-derived nitrogen fuelled the heterotrophic bacterial community through indirect processes generating dissolved organic matter and detritus, like mortality, lysis and grazing of both diazotrophs and non-diazotrophs.

Heterotrophic Bacterial Production and Its Dependence on Autotrophic Production in a Hypertrophic African Reservoir

1990 ◽  
Vol 47 (5) ◽  
pp. 1027-1037 ◽  
Author(s):  
Richard D. Robarts ◽  
Richard J. Wicks
Keyword(s):  
South Africa ◽  
Primary Production ◽  
Water Temperature ◽  
Water Column ◽  
Bacterial Growth ◽  
Bacterial Production ◽  
Doubling Time ◽  
Limiting Factor ◽  
Close Coupling ◽  
Bacterial Dna

The incorporation of [methyl-3H]thymidine (TdR) into bacterial DNA in Hartbeespoort Dam, South Africa was measured over 16 mo and at nine depths. Bacterial numbers at the surface ranged between 2.45 and 32.20 × 106 cells∙mL−1[Formula: see text] while bacterial production varied between 1.0 and 251 pmol TdR∙L−1∙h−1 (0.01 to 1.9 mg C∙m−3∙h−1). At the bottom, production ranged between 0 and 26.7 pmol TdR∙L−1∙h−1 (0–0.2 mg C∙m−3∙h−1). The fastest bacterial doubling time was 59 h. At the surface, bacterial production was dominantly correlated to chlorophyll a (6.6–6530 mg∙m−3) and phaeopigments (0.9–378 mg∙m−3) (r = 0.81) followed by primary production (26.6–8886 mg C∙m−3∙h−1) (r = 0.77) (n = 30–34, p < 0.001). However, below 5 m, water temperature and bacterial numbers were the dominant correlates. Bacterial production for the water column averaged 2% of daily, areal primary production. The data demonstrated a close coupling between autotrophic production and heterotrophic bacterial production. However, the low bacterial production compared with primary production, together with the small size of the bacteria (usually 0.09–0.25 μm width), suggest substrate supply was a major limiting factor of bacterial growth.

Short-term coherency between gross primary production and community respiration in an algal-dominated reef flat

Coral Reefs ◽  
2010 ◽  
Vol 30 (1) ◽  
pp. 53-58 ◽  
Author(s):  
J. L. Falter ◽  
M. J. Atkinson ◽  
D. W. Schar ◽  
R. J. Lowe ◽  
S. G. Monismith
Keyword(s):  
Primary Production ◽  
Reef Flat ◽  
Gross Primary Production ◽  
Community Respiration ◽  
Short Term

scholarly journals Light and Primary Production Shape Bacterial Activity and Community Composition of Aerobic Anoxygenic Phototrophic Bacteria in a Microcosm Experiment

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Kasia Piwosz ◽  
Ana Vrdoljak ◽  
Thijs Frenken ◽  
Juan Manuel González-Olalla ◽  
Danijela Šantić ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Light Intensity ◽  
Bacterial Community ◽  
Primary Production ◽  
Community Composition ◽  
Bacterial Production ◽  
Bacterial Community Composition ◽  
Bacterial Activity ◽  
Bacterial Respiration ◽  
Metabolic Coupling

ABSTRACT Phytoplankton is a key component of aquatic microbial communities, and metabolic coupling between phytoplankton and bacteria determines the fate of dissolved organic carbon (DOC). Yet, the impact of primary production on bacterial activity and community composition remains largely unknown, as, for example, in the case of aerobic anoxygenic phototrophic (AAP) bacteria that utilize both phytoplankton-derived DOC and light as energy sources. Here, we studied how reduction of primary production in a natural freshwater community affects the bacterial community composition and its activity, focusing primarily on AAP bacteria. The bacterial respiration rate was the lowest when photosynthesis was reduced by direct inhibition of photosystem II and the highest in ambient light condition with no photosynthesis inhibition, suggesting that it was limited by carbon availability. However, bacterial assimilation rates of leucine and glucose were unaffected, indicating that increased bacterial growth efficiency (e.g., due to photoheterotrophy) can help to maintain overall bacterial production when low primary production limits DOC availability. Bacterial community composition was tightly linked to light intensity, mainly due to the increased relative abundance of light-dependent AAP bacteria. This notion shows that changes in bacterial community composition are not necessarily reflected by changes in bacterial production or growth and vice versa. Moreover, we demonstrated for the first time that light can directly affect bacterial community composition, a topic which has been neglected in studies of phytoplankton-bacteria interactions. IMPORTANCE Metabolic coupling between phytoplankton and bacteria determines the fate of dissolved organic carbon in aquatic environments, and yet how changes in the rate of primary production affect the bacterial activity and community composition remains understudied. Here, we experimentally limited the rate of primary production either by lowering light intensity or by adding a photosynthesis inhibitor. The induced decrease had a greater influence on bacterial respiration than on bacterial production and growth rate, especially at an optimal light intensity. This suggests that changes in primary production drive bacterial activity, but the effect on carbon flow may be mitigated by increased bacterial growth efficiencies, especially of light-dependent AAP bacteria. Bacterial activities were independent of changes in bacterial community composition, which were driven by light availability and AAP bacteria. This direct effect of light on composition of bacterial communities has not been documented previously.

scholarly journals Ecosystem metabolism in a dryland river waterhole

2007 ◽  
Vol 58 (3) ◽  
pp. 250 ◽  
Author(s):  
C. S. Fellows ◽  
M. L. Wos ◽  
P. C. Pollard ◽  
S. E. Bunn
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Bacterial Production ◽  
Gross Primary Production ◽  
Eutrophic Lakes ◽  
Metabolic Balance ◽  
Lake Metabolism ◽  
Allochthonous Inputs ◽  
Carbon Demand ◽  
Dryland River

Little is known about ecosystem processes in dryland rivers, despite the global distribution of these systems. Those in Australia are characterised by long periods of no flow in which they persist for many months as series of isolated, often turbid, waterholes. We assessed benthic and pelagic primary production, respiration, and bacterial production in one of these waterholes to determine the metabolic balance of the waterhole and resolve the relative importance of autochthonous and allochthonous sources of organic carbon. Despite a photic zone depth of only 0.25 m, three lines of evidence suggested that autochthonous sources of organic carbon were important for fuelling bacterial production under no-flow conditions: the metabolic balance of the waterhole was not indicative of large allochthonous inputs; rates of gross primary production were great enough to meet a substantial fraction of estimated bacterial carbon demand; and pathways for allochthonous carbon to enter the waterhole were limited. These results suggest that models of lake metabolism based on temperate ecosystems can be expanded to include dryland river waterholes, which group with eutrophic lakes owing to their high levels of inorganic nutrients, low allochthonous inputs and autotrophic metabolic balance.

scholarly journals Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon

2015 ◽  
Vol 12 (23) ◽  
pp. 19861-19900 ◽  
Author(s):  
F. Van Wambeke ◽  
U. Pfreundt ◽  
A. Barani ◽  
H. Berthelot ◽  
T. Moutin ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Primary Production ◽  
Bacterial Growth ◽  
N2 Fixation ◽  
Bacterial Production ◽  
Carbon Budget ◽  
New Caledonia ◽  
Growth Efficiency ◽  
Mesocosm Experiment ◽  
Bacterial Growth Efficiency

Abstract. N2 fixation fuels ~ 50 % of new primary production in the oligotrophic South Pacific Ocean. The VAHINE mesocosm experiment designed to track the fate of diazotroph derived nitrogen (DDN) in the New Caledonia lagoon. Here, we examined the temporal dynamics of heterotrophic bacterial production during this experiment. Three replicate large-volume (~ 50 m3) mesocosms were deployed and were intentionally fertilized with dissolved inorganic phosphorus (DIP) to stimulate N2 fixation. We specifically examined relationships between N2 fixation rates and primary production, determined bacterial growth efficiency and established carbon budgets of the system from the DIP fertilization to the end of the experiment (days 5–23). Heterotrophic bacterioplankton production (BP) and alkaline phosphatase activity (APA) were statistically higher during the second phase of the experiment (P2: days 15–23), when chlorophyll biomass started to increase compared to the first phase (P1: days 5–14). Among autotrophs, Synechococcus abundances increased during P2, possibly related to its capacity to assimilate leucine and to produce alkaline phosphatase. Bacterial growth efficiency based on the carbon budget was notably higher than generally cited for oligotrophic environments (27–43 %), possibly due to a high representation of proteorhodopsin-containing organisms within the picoplanctonic community. The carbon budget showed that the main fate of gross primary production (particulate + dissolved) was respiration (67 %), and export through sedimentation (17 %). BP was highly correlated with particulate primary production and chlorophyll biomass during both phases of the experiment but slightly correlated, and only during P2 phase, with N2 fixation rates. Our results suggest that most of the DDN reached the heterotrophic bacterial community through indirect processes, like mortality, lysis and grazing.

scholarly journals Estimation of crop gross primary production (GPP): fAPARchl versus MOD15A2 FPAR

2014 ◽  
Vol 153 ◽  
pp. 1-6 ◽  
Author(s):  
Qingyuan Zhang ◽  
Yen-Ben Cheng ◽  
Alexei I. Lyapustin ◽  
Yujie Wang ◽  
Feng Gao ◽  
...  
Keyword(s):  
Primary Production ◽  
Gross Primary Production

scholarly journals Soil drying weakens the positive effect of climate factors on global gross primary production

2021 ◽  
Vol 129 ◽  
pp. 107953
Author(s):  
Huan Chen ◽  
Xiaoyong Bai ◽  
Yangbing Li ◽  
Qin Li ◽  
Luhua Wu ◽  
...  
Keyword(s):  
Primary Production ◽  
Gross Primary Production ◽  
Soil Drying ◽  
Climate Factors ◽  
Positive Effect
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