A Comparison of Benthic Microalgal Production Measured by C14 and Oxygen Methods

1973 ◽  
Vol 30 (2) ◽  
pp. 309-312 ◽  
Author(s):  
C. Hunding ◽  
B. T. Hargrave
Keyword(s):  
Dissolved Oxygen ◽  
Primary Production ◽  
Sandy Beach ◽  
Sediment Cores ◽  
Benthic Primary Production ◽  
Sources Of Error ◽  
Undisturbed Sediment

A comparison of estimates of benthic primary production on a sandy beach measured by in situ oxygen and laboratory C14 methods showed that both methods gave similar measures of the magnitude of production. Sources of error in each method are discussed. Measures of C14 uptake offer sensitivity when production is low, but when undisturbed sediment cores can be obtained, production is most easily measured by following changes in dissolved oxygen.

scholarly journals Characterizing the Preservation Potential of Buried Marine Archaeological Sites

Heritage ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 838-857
Author(s):  
David Gregory
Keyword(s):  
Dissolved Oxygen ◽  
Sediment Cores ◽  
Organic Content ◽  
Archaeological Sites ◽  
High Porosity ◽  
Geochemical Processes ◽  
Sediment Types ◽  
Preservation Potential ◽  
Mesocosm Experiments

The preservation potential of sediments from a submerged prehistoric site buried in a full marine environment was assessed using a combination of direct in situ measurements, measurements on extracted sediment cores and laboratory mesocosm experiments. The results show that first and foremost it is paramount to ascertain the state of preservation of the materials in the seabed—in this case wooden artifacts—that are to be preserved in situ. The results suggest that dissolved oxygen and sulfide are good parameters to measure in situ to assess the general oxidizing or reducing nature of the environment. If it is possible to take sediment core samples, it is similarly important to measure dissolved oxygen and hydrogen sulfide in the core and extract pore water to assess for sulfate content. Sediments should be characterized for particle size, water content (porosity) and organic content. In this way, we show that dissolved oxygen was rapidly depleted in the first few centimeters of sediment, thereafter sulfate reduction dominated the geochemical processes. Coarser sediment types with high porosity and low organic content have lower rates of organic material turnover, indicating better preservation conditions.

scholarly journals In situ measurements of benthic primary production, respiration and nutrient fluxes in a hypersaline coastal lagoon of SE Brazil

1996 ◽  
Vol 44 (2) ◽  
Author(s):  
Bastiaan Knoppers ◽  
Weber Friederichs Landim de Souza ◽  
Marcelo Friederichs Landim de Souza ◽  
Eliane Gonzalez Rodriguez ◽  
Elisa de Fátima da Cunha Vianna Landim ◽  
...  
Keyword(s):  
Primary Production ◽  
Coastal Lagoon ◽  
In Situ Measurements ◽  
Nutrient Fluxes ◽  
Benthic Primary Production ◽  
Se Brazil ◽  
Hypersaline Coastal Lagoon

Epibenthic Algal Production and Community Respiration in the Sediments of Marion Lake

1969 ◽  
Vol 26 (8) ◽  
pp. 2003-2026 ◽  
Author(s):  
Barry T. Hargrave
Keyword(s):  
Oxygen Consumption ◽  
Particulate Matter ◽  
Oxygen Concentration ◽  
Sediment Cores ◽  
Day Length ◽  
Community Respiration ◽  
Oxygen Production ◽  
Algal Production ◽  
Undisturbed Sediment

Gross epibenthic algal production and benthic community respiration in Marion Lake, British Columbia, were measured during 1968 by following changes in dissolved oxygen over undisturbed sediment cores. No measurable chemical uptake of oxygen occurred during short-term experiments. Multiple regression analyses showed that in situ oxygen production by epibenthic algae was directly related to temperature, light, and community respiration and inversely related to day length. Mean weekly values of these variables were substituted into the regression to estimate annual gross algal production on sediment at various depths in Marion Lake. Photosynthetic efficiency ranged from 0.4 to 3.1% and increased with depth of water over the sediment. Sedimentary chlorophyll was stratified with highest concentrations in the upper few centimeters of sediment which corresponded to the depth of oxygen penetration.Measurements of in situ oxygen consumption showed that community respiration was related to temperature, oxygen concentration, and day length in a curvilinear manner. Oxygen uptake was minimal at midday and increased during the night. A multiple linear regression was derived, after suitable transformations, and mean weekly values of variables substituted to estimate annual community respiration.Bacterial respiration was measured as the difference in total community respiration when antibiotics were added to water over undisturbed sediment cores. Less than 30% of community oxygen consumption was inhibited by antibiotic treatment during the summer, whereas over 45% reduction occurred during the winter. Bacterial respiration was directly related to temperature and showed no significant correlation with oxygen concentration or other variables shown to affect community respiration. Macrofauna respired 33% of the total oxygen consumed by sediment cores during June, and epibenthic algae were estimated to account for 23% of community respiration. Net epibenthic algal production, calculated by correcting gross oxygen production for estimated algal respiration, was 85% of gross production during the summer.Annual carbon flux across the sediment in Marion Lake was estimated by comparing processes of carbon addition and removal. From previous studies, phytoplankton and macrophytes added 0.8 and 18 g C m−2 year−1. Organic particulate matter from the inlet stream, other than macroscopic debris, contributed 143 g C m−2 year−1 and average gross epibenthic algal production was 40 g C m−2 year−1. Community respiration consumed 57 g C m−2 year−1. An additional 143 g C m−2 year−1 was lost as particulate matter in the outlet stream and emerging insects could remove 1.3 g C m−2 year−1. Only 8 g C m−2 was estimated to accumulate below the aerobic surface–sediment layer annually.

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