Modelling kelp forest primary production using in situ photosynthesis, biomass and light measurements

2016 ◽  
Vol 553 ◽  
pp. 67-79 ◽  
Author(s):  
KL Rodgers ◽  
NT Shears
Keyword(s):  
Primary Production ◽  
Kelp Forest

In situ assessment of the daily primary production of the temperate symbiotic coral Cladocora caespitosa

2013 ◽  
Vol 58 (4) ◽  
pp. 1409-1418 ◽  
Author(s):  
C. Ferrier-Pagès ◽  
F. Gevaert ◽  
S. Reynaud ◽  
E. Beraud ◽  
D. Menu ◽  
...  
Keyword(s):  
Primary Production ◽  
Cladocora Caespitosa ◽  
In Situ Assessment

The Simulated in situ Measurements of Oceanic Primary Production

1963 ◽  
Vol 14 (2) ◽  
pp. 139 ◽  
Author(s):  
HR Jitts
Keyword(s):  
Primary Production ◽  
In Situ Measurements ◽  
Light Conditions ◽  
Significant Relation ◽  
Blue Glass ◽  
Simultaneous Measurements ◽  
Reflected Light

Simultaneous measurements with two types of incubators were made on replicate samples both in the incubators and in situ in the ocean. Both incubators used sunlight and blue glass filters to simulate light conditions at depths in the ocean. The first gave measurements of column production 1.58 times those in situ. This was due to the fact that at depths greater than 20 m the incubator gave much higher results with no significant relation to those measured in situ. In the second incubator the accuracy of reproduction of oceanic light conditions was improved by reducing reflected light and using a balance-by-depth twin photometer system for determining the depths of sampling. The measurements of column production in the second incubator were 1.03 times the in situ values.

The relation of oceanic primary production to available photosynthetic irradiance

1976 ◽  
Vol 27 (3) ◽  
pp. 441 ◽  
Author(s):  
HR Jitts ◽  
A Morel ◽  
Y Saijo
Keyword(s):  
Primary Production ◽  
Surface Ocean ◽  
Surface Samples ◽  
In Situ Method ◽  
Wide Range ◽  
Total Irradiance ◽  
Highly Correlated ◽  
Bodies Of Water ◽  
High Degree

Primary production was measured at 14 stations covering a wide range of oceanic waters. Measurements were made by both the in situ method (Pi) and the simulated in situ method (Ps) Production v. constant irradiance (P v. I) was also measured. Available photosynthetic irradiance [Eq(350-700) in quanta m-2 s-1] was calculated from continuous records of total irradiance and measurements of the percentage submarine transmission of irradiance were made with a quantum meter. Using the P v. I curves and Eq(350-700), primary production at several depths at each station was calculated (P,). Pc was shown to be a precise estimate of Ps at all depths. Pc was also highly correlated with Pi, but both Pc and Pi overestimated Pi at the surface by 40 %. Some experiments at three stations showed that a 2-mm thickness of clear glass placed over surface samples in the measurement of Ps could increase Ps by about 50%. This suggested that U.V. irradiance in surface ocean waters decreased Pi and could explain the overestimates by Pc and Ps. The results showed the need for precise information of spectrai composition of irradiance in studies of primary production but demonstrated the kalidity of Eq(350-700) as an estimate of available photosynthetic irradiance. They also showed that Pc could estimate Pi with a high degree of precision, and that such a calculative method could provide a useful way of continuously monitoring the primary production of large bodies of water for extended periods.

Coexistence in a subtidal habitat in southern Chile: the effects of giant kelp Macrocystis pyrifera overgrowth on the slipper limpet Crepipatella fecunda

2014 ◽  
Vol 95 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Francisco J. Díaz ◽  
Sandra V. Pereda ◽  
Alejandro H. Buschmann
Keyword(s):  
Annual Cycle ◽  
Kelp Forest ◽  
Population Level ◽  
Macrocystis Pyrifera ◽  
Ecological Interactions ◽  
Southern Chile ◽  
Positive Effect ◽  
Neutral Effect ◽  
Slipper Limpet

In many coastal areas substrate is the limiting resource for benthic organisms. Some sessile species can be used as secondary substrate, reducing competition and increasing coexistence. In southern Chile, annual populations of Macrocystis pyrifera recruit and grow on the shells of Crepipatella fecunda. This study describes ecological interactions between the kelp and the slipper limpet over an annual cycle. The degree of kelp overgrowth was established by collecting sporophytes and through in situ submarine photography over a 10 month period (starting when kelp recruits became visible and ending when sporophytes were no longer present). Changes in the biochemical composition of the limpet tissue were also recorded by chemical analyses, to evaluate the potential effects (positive/neutral/negative) of kelp on C. fecunda nutritional condition. The results indicate that both species coexist, although kelp overgrowth may cause a decrease in carbohydrates in C. fecunda tissues, restricted to the period when the kelp forest reaches its maximum biomass. Individually, the short duration of the maximum overgrowth period and the size reached by C. fecunda females (up to 65 mm shell length) may enable rapid limpet recovery, avoiding competitive exclusion. On a population level, the M. pyrifera annual cycle generates the needed ‘break’ for C. fecunda populations, reducing the effects of kelp overgrowth. Thus, in the view of the neutral effect of kelp overgrowth, together with the positive effect of C. fecunda on M. pyrifera recruitment described somewhere else, this ecological interaction can be categorized as commensalism.

Modelling Primary Production in Water Bodies: A Numerical Approach that Allows Vertical Inhomogeneities

1973 ◽  
Vol 30 (10) ◽  
pp. 1469-1473 ◽  
Author(s):  
Everett J. Fee
Keyword(s):  
Primary Production ◽  
Algal Biomass ◽  
Numerical Approach ◽  
Light Responses ◽  
Phytoplankton Primary Production ◽  
Basic Approach ◽  
Mathematical Solution ◽  
Model Predictions ◽  
Vertical Variations

A new model for computing integral daily phytoplankton primary production is described. The model incorporates vertical variations of algal biomass, complex photosynthesis vs. light responses, nonexponential extinction of light vs. depth, and any distribution of surface light over a day. The basic approach is to combine measured relations for photosynthetic rate vs. light, light vs. depth, and light vs. time in an interpolative scheme rather than attempting to fit equations to the data and using the resulting equations to obtain a mathematical solution. The model is general and should have wide applicability. Model predictions agreed well with in situ measurements of production.

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