scholarly journals Metabolic balance of gross primary production and community respiration in Sagami Bay, Japan

2006 ◽  
Vol 321 ◽  
pp. 31-40 ◽  
Author(s):  
S Hashimoto ◽  
N Horimoto ◽  
T Ishimaru ◽  
T Saino
Keyword(s):  
Primary Production ◽  
Gross Primary Production ◽  
Community Respiration ◽  
Sagami Bay ◽  
Metabolic Balance

scholarly journals Consequences of respiration in the light on the determination of production in pelagic systems

2007 ◽  
Vol 4 (1) ◽  
pp. 105-114 ◽  
Author(s):  
O. Pringault ◽  
V. Tassas ◽  
E. Rochelle-Newall
Keyword(s):  
Primary Production ◽  
Dark Respiration ◽  
Gross Primary Production ◽  
Community Respiration ◽  
Metabolic Balance ◽  
Net Community Production ◽  
Respiration Rates ◽  
Seawater Samples ◽  
Community Production

Abstract. Oxygen microprobes were used to estimate Community Respiration (R), Net Community Production (NCP) and Gross Primary Production (GPP) in coastal seawater samples. Using this highly stable and reproducible technique to measure oxygen change during alternating dark and light periods, we show that respiration in the light could account for up to 640% of respiration in the dark. The light enhanced dark respiration can remain elevated for several hours following a 12 h period of illumination. Not including Rlight into calculations of production leads to an underestimation of GPP, which can reach up to 650% in net heterotrophic systems. The production: respiration (P:R) ratio is in turn affected by the higher respiration rates and by the underestimation of GPP. While the integration of Rlight into the calculation of P:R ratio does not change the metabolic balance of the system, it decreases the observed tendency, thus net autotrophic systems become less autotrophic and net heterotrophic systems become less heterotrophic. As a consequence, we propose that efforts have to be focused on the estimation and the integration of Rlight into the determination of GPP and R for a better understanding of the aquatic carbon cycle.

scholarly journals Annual plankton community metabolism in estuarine and coastal waters in Perth (Western Australia)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5081 ◽  
Author(s):  
Susana Agusti ◽  
Lorena Vigoya ◽  
Carlos Manuel Duarte
Keyword(s):  
Organic Matter ◽  
Western Australia ◽  
Environmental Variability ◽  
Gross Primary Production ◽  
Marine Ecosystem ◽  
Community Respiration ◽  
Metabolic Rates ◽  
Metabolic Balance ◽  
Net Community Production ◽  
R Ratio

The planktonic metabolic balance that is the balance between gross primary production (GPP) and community respiration (CR) was determined in Matilda Bay (estuarine) and Woodman Point (coastal) in Perth, Western Australia. The rates of net community production (NCP = GPP – CR) and the ratio between GPP and CR (P/R) were assessed to evaluate whether the metabolic balance in the two coastal locations tends to be net autotrophic (production exceeding community respiration) or net heterotrophic (respiration exceeding production). We also analyzed environmental variability by measuring temperature, salinity, and nutrients and chlorophyll a concentration. Samples were collected biweekly from March 2014 to March 2015. During the study period the metabolic rates were three times higher in Matilda Bay than in Woodman Point. The predominant metabolism was net autotrophic at both sites with P/R ratios >1 in the majority of the sampling dates. In Matilda Bay, the metabolic rates were negatively correlated with salinity denoting river dynamics influence, and positively with chlorophyll a. In Woodman Point only the GPP was positively correlated with chlorophyll a. The positive correlation between P/R ratio and GPP in Matilda Bay and the positive correlations between the metabolic rates and chlorophyll a suggest that factors controlling autotrophic processes are modulating the planktonic metabolic balance in the coastal marine ecosystem in Perth. Significant correlations were found between CR and GPP-standardized to chlorophyll a and water temperature. The net autotrophic metabolic balance indicates that in both ecosystems planktonic communities are acting as a sink of CO2 and as a source of organic matter and oxygen to the system and are able to export organic matter to other ecosystems.

scholarly journals Relationship between net and gross primary production in the Sagami Bay, Japan

2005 ◽  
Vol 50 (6) ◽  
pp. 1830-1835 ◽  
Author(s):  
S. Hashimoto ◽  
N. Horimoto ◽  
Y. Yamaguchi ◽  
T. Ishimaru ◽  
T. Saino
Keyword(s):  
Primary Production ◽  
Gross Primary Production ◽  
Sagami Bay

Evaluation of a Toxicant on the Metabolism of Model Stream Communities

1976 ◽  
Vol 33 (12) ◽  
pp. 2740-2746 ◽  
Author(s):  
Alan W. Maki ◽  
Howard E. Johnson
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Benthic Communities ◽  
Exposure Period ◽  
Community Respiration ◽  
Metabolic Rates ◽  
Stream Communities ◽  
Time Period

The effects of a toxicant, the lampricide TFM (3-trifluoromethyl-4-nitrophenol), on the metabolism of benthic communities were studied in a series of six indoor model streams resembling typical woodland streams. Each artificially illuminated stream consisted of a 4-m pool section and a 4-m riffle section.A specially developed in situ stream respirometer was used for measurements of net primary production and community respiration in pool and riffle communities. Pretreatment levels of gross primary production ranged during summer, fall, and early winter from 10.7 to 79.0 mg O2∙m−2∙h−1 and were suppressed by 25–50% during exposure to 9.0 mg/liter TFM. Community respiration ranged from 10.5 to 36.2 mg O2∙m−2∙h−1 during the same time period and was increased 3–50% by the 9.0 mg/liter lampricide treatment. Calculated photosynthesis to respiration (P:R) ratios proved to be sensitive indicators of the influence of the toxicant. The stream communities demonstrated a capacity to adjust to the toxicant influence as evidenced by the rapid return of metabolic rates to pretreatment levels following the exposure period.

scholarly journals Seasonal and latitudinal patterns of pelagic community metabolism in surface waters of the Atlantic Ocean

2012 ◽  
Vol 9 (1) ◽  
pp. 507-525 ◽  
Author(s):  
S. Agusti
Keyword(s):  
Atlantic Ocean ◽  
Spatial Patterns ◽  
Gross Primary Production ◽  
Community Respiration ◽  
Metabolic Balance ◽  
Tropical Zone ◽  
Large Variability ◽  
Temporal And Spatial Patterns ◽  
Temporal And Spatial ◽  
North And South

Abstract. Temporal and spatial patterns in the variability of the pelagic metabolism at the surface of the Atlantic Ocean were analyzed in a series of four oceanographic cruises (LATITUDE 1, 2, 3 and 4). The cruises crossed the oligotrophic waters of North and South subtropical gyres and this explained the low values of both gross primary production (GPP) and community respiration (R) found. Net community production (NCP), the balance between production and consumption, was strongly related to the variability in R rates (R2=0.72, P<0.0001). NCP was net heterotrophic in 83 % of the data, but showed strong temporal and spatial patterns. At the inter-tropical zone, around 10°–12° N and 10°–12° S, a large variability was observed with values of NCP oscillating from net heterotrophic to net autotrophic seasonally. This variability implied NCP to be net autotrophic in boreal fall and austral spring, and net heterotrophic in boreal spring and austral fall, in the areas around the boundaries of the inter-tropical zone. The variability observed concur with the seasonal climatic and oceanographic regimes of the inter-tropical area, whith documented seasonal changes of the North and South Atlantic equatorial currents system, the Guinea Dome, and the Benguela current. When considering the season of the data obtained, significant differences between spring and fall were found for the surface Atlantic, with water temperature and respiration increasing in autumn, showing a net heterotrophic metabolism, and with temperature and respiration decreasing in spring, where NCP were closer to the metabolic balance. In contrast, no seasonal differences were found for GPP and chlorophyll-a concentration. The results showed new spatial and temporal patterns in the pelagic metabolic balance of the surface Atlantic Ocean with consequences for the carbon flux.

Pharmaceuticals and personal care products alter growth and function in lentic biofilms

2015 ◽  
Vol 12 (3) ◽  
pp. 301 ◽  
Author(s):  
Lawton Shaw ◽  
Chuyen Phung ◽  
Michael Grace
Keyword(s):  
Primary Production ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Personal Care Products ◽  
Algal Growth ◽  
Biologically Active ◽  
Community Respiration ◽  
Personal Care ◽  
Ecological Processes ◽  
And Function

Environmental context Pharmaceuticals and personal care products are routinely found in waters discharged from treatment plants and in surrounding aquatic ecosystems. Despite the widespread occurrence of these biologically active agents, there is limited understanding of their potential effects on key ecosystem processes such as primary production, ecosystem respiration and algal growth. This paper examines the effects of five common pharmaceuticals on the rates of these fundamental processes. Abstract Pharmaceutical diffusing substrates were used to study in situ responses of aquatic biofilms in an urbanised lentic ecosystem to five pharmaceutical and personal care products (PPCPs; caffeine, cimetidine, ciprofloxacin, diphenhydramine and metformin). The pharmaceutical diffusing substrates consisted of porous biofilm substrates placed atop a mass of agar amended with 2.5mM of the PPCP compound of interest. Over 21 days, biofilms growing on the substrata were exposed to slow diffusion of the PPCP through the agar and porous substrate. Algal biomass was suppressed by exposure to diphenhydramine (–81%) and ciprofloxacin (–50%). Gross primary production was completely suppressed by diphenhydramine exposure but stimulated by caffeine (+39%) and cimetidine (+46%). For heterotroph biofilms, community respiration was suppressed by exposure to diphenhydramine (–24%). To characterise PPCP exposure, rates of diffusion from the pharmaceutical diffusing substrates were measured at 10, 20 and 30°C. Diffusion was Fickian for all compounds and all temperatures. Diffusion coefficients, D, were in the range 1.5×10–10 to 1.1×10–9m2s–1. From diffusion data, average release rates over 21 days were typically 30–50ngmin–1cm–2 at 20°C. The results show that PPCPs can dramatically affect rates of key ecological processes, and the relationship between release rate and ambient concentration of PPCPs is discussed.

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