Biomass Profiles Research Articles

Ocean primary production and available light: further algorithms for remote sensing

In the context of remote sensing of the ocean, the general problem of estimating water column production from surface irradiance and column chlorophyll concentration is examined, and some refinements are made to the linear theory presented by Platt (1986, Deep-Sea Research, 33, 149–163). Further empirical evidence is presented to show the stability of the relationship between surface light and biomass-normalized primary production of the ocean water column. A theoretical explanation is given for the non-zero intercept often obtained when these two variables are regressed. The systematic errors in the estimation of primary production by remote sensing, due to non-uniformity in the biomass profile, are examined through sensitivity analyses on a generalized biomass profile. The errors are shown to be functions of the parameters of the biomass profile, of the photosynthetic parameters and of the optical properties of the water. The probable random errors in the estimation of water column primary production using remotely sensed data are evaluated. Some general issues related to the collection and assimilation of data on ocean primary production are addressed.

Spatial/temporal variability of algal biomass and potential productivity in the Mauritanian upwelling zone, as estimated from CZCS data

The mesoscale distribution of phytoplankton in the Mauritanian coastal upwelling area has been mapped using a series of CZCS scenes covering more than one year. The spatial and temporal evolution of the algal biomass has been analysed. The CZCS images have been combined to establish “composite images” (ca. 840 km × 1260 Km) representing monthly averages of the surface pigment content. Satellite-derived pigment concentrations have been tentatively transformed into potential primary production per unit area. For this purpose, data concerning in situ primary production, vertical profiles of algal biomass and water optical properties, as previously obtained, were combined with mean values of available radiant energy taken from climatic atlases. An estimate of the daily integrated primary production in the different zones influenced by the seasonally fluctuating upwelling is proposed.

Vegetation and Soil-Landscape Relationships in the North Dakota Badlands

The objective of the study was to examine the interrelationships of soils, vegetation and position on the landscape in open geomorphic systems. The major landscape positions were the summit, backslope, footslope and toeslope. Beginning with the backslope, the thickness of the surface horizon, percent clay and moisture content increased downslope with obvious alluvial stratification at the toeslope. Geologic processes of erosion and sedimentation were primary factors influencing soil properties on the backslope, footslope and toeslope. Soils on the summit differed in that they were chronologically older and resulted from pedologic rather than sedimentation processes. Nonparametric analysis indicated a significant relationship (P<0.05) between cover of the major species and position on the landscape. Plant biomass, species composition and soil profiles varied with landscape position, which illustrated the concomitant development of soils and vegetation as influenced by topography. By appearances and moisture observations, the concave landscape positions that receive water from above, especially on the N aspect, were forested and the convex positions, especially on the S aspect, or in the backslope position, were covered by short and midgrasses.

Seasonal Patterns of Lowland Forest Floor Arthropod Abundance in Southeastern Peru

We conducted a 2-yr study with semi-monthly collections of forest floor arthropods and periodic monitoring of temperature, relative humidity, and soil moisture for three habitats of different soil drainage (terra firme, bamboo and flood plain) at a single site in southeastern Peru. Several diurnal and seasonal patterns of arthropod biomass occurred. All habitats followed parallel and coincident profiles of arthropod biomass through the four major seasons covered by this study (2 yr of wet and dry seasons). Biomass in wet seasons was greater than biomass in dry seasons. The strongest association between arthropod biomass and environmental measures occurred with the contemporary measurement of maximum temperature, but only two habitats, terra firme and bamboo, showed this association. The flood plain habitat showed no detectable associations between arthropod biomass and short term environmental measures. The total number of individual arthropods trapped over the 2 yr was highest for the bamboo habitat and lowest for the flood plain. The smallest overall mean individual mass was in the bamboo habitat. The highest was in the flood plain. The seasonal change in this mean individual mass value was regular for the flood plain, less regular for the bamboo habitat, and irregular for the terra firme forest. Of all the higher arthropod taxa trapped, the Coleoptera, and to a lesser extent the Collembola, exhibited consistent and distinct seasonal patterns. Other taxa such as ants, Diptera, and Orthoptera either showed seasonal patterns in one forest type or none at all.

COMPARISON OF TWO METHODS OF SELECTING SMOOTHING SPLINE FUNCTIONS FOR ESTIMATION OF SPECIFIC RATES IN FERMENTATIONS

Abstract A new method of selecting smoothing spline functions is presented and used to curve fit experimental fermentation data. From the curves generated, estimates for the specific growth rate, the specific rate of substrate utilization and the biomass energetic yield are made. Selection of the smoothness parameters is based on minimization of a response surface fit to the smoothness parameters used to generate the time profiles of biomass and substrate concentration. The response modelled is the extent of closure of the carbon balance and the available electron balance. Results obtained using cross validation for selection of the smoothness parameter are also presented, and compared to the results calculated using the response surface technique. Estimates made for specific growth rate and biomass energetic yield are used with the covariate adjustment procedure to calculate point and 95% confidence interval estimates for the true biomass energetic yield, ηmax, and the maintenance coefficient, me. The results show that the spline fit has an effect on the parameter estimates. The newly developed response surface method compares favorably with the cross validation method.

Biological oceanography of the red oceanic system

Biological oceanography of the red oceanic system

Vertical distribution of the standing crop of plankton and micronekton at three stations in the northeast Atlantic

AbstractThe vertical profiles of planktonic and micronektonic biomass have been observed at three positions in the northeastern Atlantic. There were exponential decreases in biomass with depth that were similar at all three positions. Differences in the total integrated standing stocks were largely accounted for by the much larger quantities of gelatinous organisms occurring at the higher latitude positions. Micronekton total standing crops were about a third those of the plankton.

Vertical profiles of primary productivity, biomass and physico-chemical properties in meromictic Big Soda Lake, Nevada, U.S.A.

The contribution of bacteria to total primary production was estimated in Big Soda Lake and related to vertical profiles of biomass and various physical and chemical properties. The purple sulfur bacteriaThiocapsa sp. was responsible for 25% of the total primary production. Bacteriochlorophyll (BChl) distribution and DCMU sensitivity experiments confirmed this bacterial activity. High concentrations of photosynthetically inactive phytoplankton were detected in anaerobic-low redox water and were attributed to an early season algal bloom that had settled into a zone of maximal viscosity. Nutrient enrichment bioassay experiments indicated that iron was the most important nutrient controlling early season algal growth.

A study of the benthic communities of twenty lakes in the South Island, New Zealand

SUMMARY. The benthos of a heterogeneous series of lakes was sampled in late winter‐spring (before insect emergence) to determine species composition, community structure and standing crops. Nearly 50 species were found, with an average of only 12.4 per lake. Fifteen species occurred widely, with the same few species(Limnodrilus hoffmeisteri, Potamopyrgus antipodarum and sometimes Chironomus and Macropelopia spp.) often dominant. All taxonomic groups were of limited diversity; for instance, the maximum number of chironomids per lake was 8, with an average of 4.7 species. There were no chaoborids or mayflies, and very few isopods, amphipods, ceralopogonids and water mites. Niches of common species were broad.Species composition and dominance were not related to lake trophic status; hence there were no indicator organisms. Standing crops varied only broadly with lake trophic status, probably because of the differential influence of extraneous factors such as relative depth and input of allochthonous organic matter and silt. Depth: biomass profiles were also variable and only partly correlated with trophic status. Instead, many lakes were grouped on the basis of geographical area and the influence of extraneous factors; species were grouped according to the relative extent of their distribution.

Testing a simulation model for reconstruction of prehistoric forest-stand dynamics

Three characteristics of the output of a forest-stand simulation model were matched to pollen records of actual vegetation in central Tennessee. Temporal shifts of individual pollen taxon frequencies were compared to shifts of individual plant species frequencies in simulated biomass for the last 16,000 yr. Individual pollen profiles (temporally ordered species frequencies) were also compared to simulated biomass profiles during that period. Modern ratios of pollen to vegetation composition ( R values) were compared with those calculated from simulated biomass percentages and fossil pollen percentages. The model output was similar to the comparable characteristics of the pollen record. The model output is therefore a plausible description of vegetation characteristics at the site of pollen deposition in central Tennessee. The model produced information unavailable from other sets of prehistoric data. This information describes the invasion and growth of the yellow-poplar which produces no windborne pollen, and of palynologically indistinguishable oak and pine species. These results suggest that many paleoecological questions can be answered through appropriate simulation modeling studies.

Distributed parameter model of an airlift fermentor

AbstractA distributed parameter model for an airlift fermentor is presented. A riser represents the airlift fermentor, with plug flow in both gas and liquid phases, a well‐mixed section that acts as gas separator, and a downcomer with plug flow. The set of equations proposed makes possible both the understanding and design of the system. Macroscopic balances shows a behavior that is very close to conventional continuous stirred tank fermentor from the viewpoint of biomass production. In addition, the model predicts concentration profiles of biomass, substrate and oxygen in the liquid, and oxygen in the gas phase. This allows estimation of optimal gas flow rate for sufficient oxygen transfer with minimum energy input.

UNDERGROUND BIOMASS PROFILES AND PRODUCTIVITY IN ATLANTIC COASTAL MARSHES

An underground biomass profile and productivity study involved year‐long sampling programs in 18 stands of salt marsh plants in Georgia, Delaware, and Maine. As the result of the monthly or bimonthly marsh coring program three types of underground biomass profiles were found. In the first, the concentration of macro‐organic matter (MOM) was uniform with depth; the notable example of this type was creekbank Spartina alterniflora in the southern part of the coast. A second type had a high MOM concentration at the surface which decreased with depth. This, the most common type of profile, was exemplified by Spartina patens, S. alterniflora from the high marsh along the southern coast (Georgia), and creekbank S. alterniflora from the northern part of its range (Maine). The third type of profile was seen where a large rhizome mat developed 15–20 cm below the surface. Spartina cynosuroides and Phragmites communis were typical examples of this type of profile, resulting in a low biomass at the surface, a higher biomass somewhat below the surface, and a low concentration at depth. The annual maxima and minima of MOM biomass were used to calculate annual increments, which can be considered minimum annual production values. These productivity values ranged from a low of 80 g C/m2 for creekhead S. alterniflora in Maine to a high of 1690 g C/m2 for Juncus gerardi in Maine. The mean for all plant stands was 650 g C/m2. Since the average carbon content of the MOM was 35.3%, this corresponds to 1850 g dry weight/m2 per year. As a measure of the relative activity of the total pool of macro‐organic material in the soil, turnover times were calculated by dividing the total macro‐organic matter by the annual increments. Within the MOM pool there are several components with turnover times varying from days to years. The turnover time for the entire pool ranged from 18 months in two Georgia salt marsh plant stands to 224 months for one in Maine. In the two instances where values for a species could be compared between Maine and Georgia, the turnover time was shorter at the more southerly site. These results can probably be attributed to slower microbial decay rates in the cooler climate. In Georgia and Maine where the turnover values for a species were determined for two elevations, the time was shorter at the lower elevation.

Underground Biomass Profiles and Productivity in Atlantic Coastal Marshes

An underground biomass profile and productivity study involved year-long sampling programs in 18 stands of salt marsh plants in Georgia, Delaware, and Maine. As the result of the monthly or bimonthly marsh coring program three types of underground biomass profiles were found. In the first, the concentration of macro-organic matter (MOM) was uniform with depth; the notable example of this type was creekbank Spartina alterniflora in the southern part of the coast. A second type had a high MOM concentration at the surface which decreased with depth. This, the most common type of profile, was exemplified by Spartina patens, S. alterniflora from the high marsh along the southern coast (Georgia), and creekbank S. alterniflora from the northern part of its range (Maine). The third type of profile was seen where a large rhizome mat developed 15–20 cm below the surface. Spartina cynosuroides and Phragmites communis were typical examples of this type of profile, resulting in a low biomass at the surface, a higher biomass somewhat below the surface, and a low concentration at depth. The annual maxima and minima of MOM biomass were used to calculate annual increments, which can be considered minimum annual production values. These productivity values ranged from a low of 80 g C/m2 for creekhead S. alterniflora in Maine to a high of 1690 g C/m2 for Juncus gerardi in Maine. The mean for all plant stands was 650 g C/m2. Since the average carbon content of the MOM was 35.3%, this corresponds to 1850 g dry weight/m2 per year. As a measure of the relative activity of the total pool of macro-organic material in the soil, turnover times were calculated by dividing the total macro-organic matter by the annual increments. Within the MOM pool there are several components with turnover times varying from days to years. The turnover time for the entire pool ranged from 18 months in two Georgia salt marsh plant stands to 224 months for one in Maine. In the two instances where values for a species could be compared between Maine and Georgia, the turnover time was shorter at the more southerly site. These results can probably be attributed to slower microbial decay rates in the cooler climate. In Georgia and Maine where the turnover values for a species were determined for two elevations, the time was shorter at the lower elevation.