Phytoplankton productivity and chlorophyll-A concentration of Oguta Lake in Southeastern Nigeria

The phytoplankton productivity and chlorphyll-a concentration of Oguta Lake, the largest natural lake in south-eastern Nigeria, are presented (Dec. 1983. Nov. 1984). The gross productivity ranged from 1.3 to 3.77 g C.m^–2.day^–1 for the water column, dropped during the period of heavy rainfall and varied with depth. The chlorophyll-a concentration had monthly means ranging from 2.31 to 4.00 mg.m^–3, with a drop during the rains, but little depth variation. Both productivity and chlorophyll-a showed non-significant correlation with the physico-chemical features of the water. The values of the biological parameters showed the lake as mesotrophic. The values are compared with those of other African lakes.     

The seasonality of monsoonal primary productivity in Sri Lanka

The relationship between phytoplankton primary production and seasonality of physico-chemical parameters were examined for five man-made lakes in the dry-zone of Sri Lanka. Sri Lanka experiences two monsoons dividing the year into four meteorological seasons: — the North East (October–December) and South West (April–June) monsoons and the two inter-monsoons. A significant log linear relationship was found between Secchi disc depth and the depth of the euphotic zone which was lowest during the NE monsoon. Maximum mean photosynthetic rate ranged from 0.935 ± 0.067 SE to 0.479 mg O₂l^–1 h^–1 ± 0.115. Gross primary productivity which ranged from 0.378 g O₂ m^–2 h^–1 in the NE monsoon to 0.980 g O₂ m^–2 h^–1 in the SW monsoon showed significant season variation. This is shown to be determined either directly or indirectly by the light regime.     

Net primary productivity of two mangrove forest stands on the northwestern coast of Sri Lanka

Productivity studies were carried out from September, 1985 to August, 1987 in two mangrove stands, i.e. estuarine and island fringing, in Dutch bay, a lagoon situated on the northwestern coast of Sri Lanka. Net above-ground primary productivity was measured by monitoring litterfall and above-ground biomass increment. The average annual rate of litterfall in the estuarine and island-fringing mangrove stands are 588.14 g m^–2 (approximately 6 t ha^–1) and 407.33 g m^–2 (approximately 4 t ha^–1) respectively. The average annual rates of above ground woody growth are 614.74 g m^–2 (approximately 6 t ha^–1) in the estuarine stands and 286.8 g m^–2 (approximately 3 t ha^–1) in the island-fringing mangrove stands. Hence estuarine mangrove stands record a higher annual rate of above-ground net primary production (NPP; 1207.88 g m^–2 or approximately 12 t ha^–1) than the fringing mangrove stands (694.22 g m^–2); approximately 7 t ha^–1). The annual rate of NPP in the water front zones of the stands (1300.47 g m^–2 in the estuarine stands and 874.56 g m^–2 in the fringing stands) are greater than those in the back-mangrove zones (115.28 g m^–2 in the estuarine stands and 513.88 g m^–2 in the island-fringing stands). These variations may be attributed to the differences in tidal flushing and influence of freshwater in the two localities.     

The physiological state of the phytoplankton community of three types of lakes as estimated by its adenylate energy charge

Variations in physiological state and biomass of the phytoplankton community were examined in three different types of lakes, namely Lake Barato, Lake Akan, and Lake Shikaribetu. When the physiological state of the phytoplankton community was estimated by its adenylate energy charge (AEC), low biomass and low physiological state co-appeared gradually in the metalimnion and hypolimnion during stratification. The physiological state of the phytoplankton as estimated by its AEC value did not always correspond to its biomass, estimated by chlorophyll-a and ATP in these three lakes. A high physiological state of the community was usually observed in the euphotic zone, but the low AEC value observed in the euphotic zone of Lake Barato was not identified in the euphotic zones of the other lakes. Thus, the relationship between the value of AEC, and biomass of phytoplankton is a complex variable, which is further discussed in this paper.     

Analysis of the deep chlorophyll maximum across the Azores Front

Physical, chemical and biological observations made in late July and August 1997 across the Azores Front (37° N, 32°W to 32° N, 29°W) are presented. The objectives of the study were: (1) to analyse horizontal and vertical profiles of temperature, salinity, density, nutrients and chlorophyll-a (Chl a) of the top 350 m; (2) to identify the main differences in the deep Chl a Maximum (DCM) and hydrographic structure between the water masses that pass north and south of the Azores Front; and (3) to estimate phytoplankton primary production in these water masses. Horizontal and vertical profiles of salinity, temperature, density, nutrients and phytoplankton pigments in the top 350 m were analysed. The Front separates two distinct water types: the 18°C Mode Water (18 MW) of sub-tropical origin, and the 15°C Mode Water (15 MW) of sub-polar origin. Differences in the DCM and hydrographic structure between 18 MW and 15 MW were observed in the contour plots of each section. The average Chl a concentration between 5 and 200 m depth decreased significantly from 15 MW to 18 MW. The same pattern was observed for the Chl a concentration at the DCM depth. A vertical one-dimensional model was used to estimate the phytoplankton primary production in the 15 MW and 18 MW and led to an estimated water column average gross primary productivity (GPP) between 1.08 and 2.71 mg C m^–3 d^–1 for the 15 MW and about half of these values for the 18 MW. These results indicate that the typical south–north positive slope on DCM depth parallels a latitudinal increase on GPP, suggesting that the location of the Azores Front may have a significant regional impact on GPP.     

Benthic algal biomass and productivity in high subarctic streams,Alaska

Year-round measurements of the standing crop of epilithic algae (as chlorophyll a concentration) in two streams — one second and one fourth order (map scale 1:63 360) — in interior Alaska (64°–65° N) were only about one tenth that reported from streams of temperate North America. Cell densities in these streams, however, were similar to those in comparable temperate streams. Year-round domination of the benthic flora by very tiny diatoms (Achnanthes spp.) may explain the apparent disparity between low chlorophyll a content and nearly average cell densities. Chlorophyll a standing crop in a more alkaline groundwater-fed stream, however, was higher and within the range of similarly sized temperate streams. Maximum chlorophyll a standing crop varied positively with alkalinity in 5 clear-water streams where standing crop was measured on natural or artificial substrates. Seasonal mean concentrations of sestonic chlorophyll a (used as estimates of benthic algal chlorophyll a standing crop) varied directly and significantly with alkalinity among ten clear-water streams; and, with total phosphorus among 8 of 10 clear-water and 5 brown-water streams studied. During the summer, when there is little darkness, gross primary productivity (as estimated by the diurnal dissolved-oxygen method) was similar to that of northern temperate streams. Gross primary productivity was also seen to vary directly with alkalinity in 5 clear-water streams of this region.U.S. Fish and Wildlife Service     

青藏高原两种植被类型净初级生产力与气候因素的关系及周转值分析

基于2008—2016年青海海北站9年净初级生产力及气候因子监测数据,分析了青藏高原高寒小嵩草草甸和高寒金露梅灌丛两种植被净初级生产力年际动态,并探讨了气候因子对其影响及其不同土层深度根系周转值特征。结果表明:(1)年际尺度上,小嵩草草甸地上净初级生产力表现为显著增加趋势,增幅为7.02 g m~(-2) a~(-1),而金露梅灌丛地上净初级生产力相对较为稳定;对于其地下净初级生产力和总生产力,小嵩草草甸和金露梅灌丛均表现为增加趋势(P0.05),9年间小嵩草草甸地上、地下和总净初级生产力平均值分别为(217.55±9.95)、(1882.75±161.33) g m~(-2) a~(-1)和(2100.30±163.38) g m~(-2) a~(-1),金露梅灌丛地上、地下和总净初级生产力9年间平均值分别为(256.27±11.4)、(1614.31±173.03) g m~(-2) a~(-1)和(1870.58±177.93) g m~(-2) a~(-1)。(2)不同植被类型地上净初级生产力对气候因素响应不同,金露梅灌丛地上净初级生产力主要受温度影响,而温度对小嵩草草甸地上净初级生产力无显著影响。此外,降水不是限制高寒生态系统草地地上净初级生产力主要因子,相比于降水影响,高寒生态系统地上净初级生产力更受温度调控。(3)年均温和年降水对金露梅灌丛和小嵩草草甸地下净初级生产力均无显著影响(P0.05),表明高寒生态系统,其地下生产力受外界气候条件变化影响微弱,是一个稳定的碳库。(4)两种植被类型其根系周转值均随着土壤深度的增加呈逐渐增加趋势,且高寒灌丛根系周转值明显高于高寒草甸根系周转值。研究表明,在全球气候变暖背景下将会增加金露梅灌丛地上净初级生产力,而对小嵩草草甸地上净初级生产力无显著影响。     

Light-harvesting properties of zinc complex of chlorophyll-<Emphasis Type="Italic">a</Emphasis> from <Emphasis Type="Italic">spirulina</Emphasis> in surfactant micellar media

Zn chlorophyll-a was prepareted from Mg chlorophyll-a from spirulina and the optical properties of the ground state and the photoexited state of Zn chlorophyll-a in aqueous surfactant micellar media were studied using UV-vis absorption, fluorescence emission spectra, electrochemical and fluorescence lifetime measurements. In comparison of the UV-vis absorption and fluorescence emission spectra of Zn chlorophyll-a and Mg chlorophyll-a, the blue-shift in the absorption bands and emission peak of Zn chlorophyll-a was observed. The energies of the first excited singlet state of Zn chlorophyll-a was 1.87eV. The first oxidation and reduction potentials of the photoexcited singlet state of Zn chlorophyll-a were −0.67 and 0.60V, respectively. Fluorescence lifetime of Zn chlorophyll-a was 9.0 ns in CTAB micellar solution. The fluorescence lifetime of Zn chlorophyll-a is shorter than that of Mg chlorophyll-a (9.8 ns). The photositability of Zn chlorophyll-a was superior to that of Mg chlorophyll-a in various pH conditions. Published online December 2004     

Primary production in a tropical reservoir in Sri Lanka*

Primary production was measured every 2 weeks during 16 months (N = 33) in Tissawewa, a tropical shallow reservoir in the lowlands of south-east Sri Lanka. Results are interpreted in relation to selected environmental conditions such as oxygen concentrations, water temperature, Secchi-disc depth, wind force, conductivity, and morphoedaphic index and water level fluctuations. Because of regularly reoccurring high wind speeds the water column is well mixed. Daily gross primary production per unit area was plotted as a function of the algal biomass per unit area over the euphotic zone. Chlorophyll-a concentration in the euphotic zone was taken as measure for the algal biomass. The literature comparisons showed that the primary productivity in Tissawewa was in the same range as in 29 tropical lakes and reservoirs, of which 27 were from Africa. The productivity of these 30 tropical lakes and reservoirs was compared with: (a) 27 lakes of which 25 were temperate lakes, and (b) 49 North American temperate lakes. Firstly, comparisons were made on an annual basis for the tropical water bodies, but restricted to May–September, the growing season, for temperate water bodies. The gross primary productivity of tropical water bodies was ca. three times higher than that of temperate water bodies. These differences were even more dramatic if the two geographical regions are compared on an annual basis, i.e. the tropical systems are ca. six times more productive than their temperate counterpart.     

Primary productivity and nutrients in the sediment retention basin of Lake Monroe

Lake Monroe is the largest body of water in Indiana with a daily mean productivity of 220 mg · C · m⁻² · day⁻¹ in an observed range from 26 to 714 m · C · M⁻² day⁻¹. It is a medium soft reservoir; the acid combining capacity varies from 0.28 to 0.71 meq · l⁻¹ with a mean slightly above 0.5 meq · l⁻¹. The results of diurnal changes in major nutrients, the C, N, and P ratios, and bioassay experiments indicated that phosphorus is the major limiting nutrient on algal photosynthesis in this lake. Surface photo-inhibition may be used to indicate the sufficiency of light for the species of algae in the water. The low productivity in December, January, February, and early March can be attributed to light limitation due to low water transparency. Contribution no. 312 of the Great Lakes Research Division, University of Michigan. Contribution no. 312 of the Great Lakes Research Division, University of Michigan.     

Primary productivity is weakly related to floristic alpha and beta diversity across Australia

Aim Ecosystem functions such as productivity may be influenced not only by the biological diversity at each location (α‐diversity) but also by the biological turnover between locations (β‐diversity). We perform a continental‐scale test of the strength and direction of relationships between gross primary productivity (GPP) and both α‐ and β‐diversity. Location Continental Australia. Methods Species occurrence records were used to quantify the taxonomic α‐diversity of vascular plants in approximately 11,000 1 km × 1 km grid cells across Australia, and to calculate the average β‐diversity within a 10‐km radius around each cell. The magnitude and variability of monthly, MODIS‐derived remotely sensed GPP (2001–12) were summarized for continental Australia, as were rainfall and temperature over the same period. Generalized additive models were then used to test whether the magnitude or variability of GPP were distinctly influenced by either biodiversity measure, over and above the influence of environmental conditions. Results Precipitation and temperature explained large proportions of deviance in the magnitude (75.6%) and variability (38.3%) of GPP across the Australian continent. GPP was marginally more strongly related to species richness than it was to species turnover. However, neither diversity measure provided substantial increases in the explanatory power of GPP models over and above that of environment‐only models (always < 1%). Main conclusions The relationship between primary productivity and taxonomic α‐ and β‐diversity was weak for the Australian flora. Our findings question the generality of key assumptions, predictions and results in the literature regarding the strength of empirical relationships between productivity and biodiversity across multiple biological levels (α‐, β‐ and γ‐diversity) at macroecological scales.     

Primary productivity of natural grass ecosystems of the tropics: A reappraisal

Studies of net primary production in four contrasting tropical grasslands show that when full account is taken of losses of plant organs above- and below-ground these ecosystems are far more productive than earlier suggested. Previous values have mainly been provided by the International Biological Programme (IBP), where estimates of production were based on a change in vegetation mass alone and would not necessarily have taken full account of organ losses and turnover. Calculation at three of our sites based on estblished methodology using changes in plant mass alone (i.e. that used by the International Biological Programme, IBP) proved to be serious underestimates of when acount was taken of losses simultaneously with measurement of change in plant mass. Accounting for the turnover of material at these three sites resulted in productivities up to five times higher than were obtained using the standard IBP procedure. An emergent C₄ grass stand at a fourth site in the Amazon achieved a productivity which approached the maximum recorded for agricultural crops. In this case, productivity values, when organ losses were taken into account, only slightly exceeded that obtained with IBP methods. The findings reported here have wider implications, in prediction of global carbon cycling, remote sensing of plant productivity and impact assessment of conversion to arable cropping systems.     

Changes in Phytoplankton Biomass and Nutrient Quantities in Sea Ice as Responses to Light/Dark Manipulations during different Phases of the Baltic Winter 2003

The response of Baltic Sea ice communities to changing light climate was studied in three subsequent 3 week in situ experiments on the SW coast of Finland. The investigation covered three different winter periods, short day with low solar angles leading to limited light in the ice, late winter with deep snow cover and early spring with melting snow and increasing light availability. The experimental setup consisted of transparent (no snow) and completely darkened (heavy snow cover) plexiglass tubes in which the ice cores were incubated in situ from 1 to 2 weeks. Changes in the concentrations of inorganic nutrients (NO₃⁻-–N, PO₄³⁻-–P, SiO₄⁻-–Si) and chlorophyll-a concentration in the phytoplankton community composition were recorded as responses to different light manipulations. Changes in inner ice light intensity in untreated ice as well as the temperature both in air and ice were recorded over the entire study period. Increased irradiance in late winter/early spring and during meltdown affected the chlorophyll-a amount in the sea ice. During these periods the phytoplankton community in the top layers decreased possibly as a consequence of photo-acclimation. Closer to the bottom of the ice, however, the increased inner ice light intensity induced algal growth. Complete exclusion of light stopped the algal growth in the whole ice column. Darkening the ice cores also slowed down the ice melting opposite to accelerated melting caused by increased light. The significant differences found in nutrient concentrations between the light and dark treatments were mostly explicable by changes in algal biomass. No obvious changes were observed in the phytoplankton community composition due to light manipulation, diatoms and heterotrophic flagellates dominating throughout the study period.     

Influence of gizzard shad on phytoplankton size and primary productivity in mesocosms and earthen ponds in the southeastern U.S.

Gizzard shad (Dorosoma cepedianum), a filter feeding omnivore, can consume phytoplankton, zooplankton and detritus and is a common prey fish in U.S. water bodies. Because of their feeding habits and abundance, shad have the potential to affect primary productivity (and hence water quality) directly through phytoplankton grazing and indirectly through zooplankton grazing and nutrient recycling. To test the ability of shad to influence primary productivity, we conducted a 16-day enclosure study (in 2.36-m³ mesocosms) and a 3-year whole-pond manipulation in 2–5 ha earthen ponds. In the mesocosm experiment, shad reduced zooplankton density and indirectly enhanced chlorophyll a concentration, primary productivity, and photosynthetic efficiency (assimilation number). While shad did not affect total phytoplankton density in the mesocosms, the density of large phytoplankton was directly reduced with shad. Results from the pond study were not consistent as predicted. There were few changes in the zooplankton and phytoplankton communities in ponds with versus ponds without gizzard shad. One apparent difference from systems in which previous work had been conducted was the presence of high densities of a potential competitor (i.e., larval bluegill) in our ponds. We suggest that the presence of these extremely high larval bluegill densities (20–350 larval bluegill m^–3; 3–700 times higher density than that of larval gizzard shad) led to the lack of differences between ponds with versus ponds without gizzard shad. That is, the influence of gizzard shad on zooplankton or phytoplankton was less than the influence of abundant bluegill larvae. Differences in systems across regions must be incorporated into our understanding of factors affecting trophic interactions in aquatic systems if we are to be able to manage these systems for both water quality and fisheries.     

不同放养和管理模式下三角帆蚌养殖水体中的浮游生物和初级生产力

通过围隔实验研究了3种放养(单养三角帆蚌,蚌与鲢、鳙混养,蚌与银鲫混养)和2种管理(施肥、投饵兼施肥)模式下养殖水体的浮游生物和初级生产力.结果表明:围隔内浮游植物主要为＜20 μm粒级的种类,其中蓝藻、绿藻和裸藻占优势,硅藻、隐藻、黄藻和甲藻的数量和质量较低;实验期间,围隔内浮游植物数量和质量平均值分别为0.35×109～1.26×109 ind·L-1和32～86 mg·L-1,其中三角帆蚌与鲢、鳙混养的围隔内浮游植物数量和质量较高,蓝藻和硅藻数量和质量明显高于其它围隔;围隔内浮游动物数量以原生动物最多,其质量则以轮虫占优势,枝角类和桡足类等大型浮游动物的数量较少;单养蚌的围隔内浮游动物质量最高;与混养围隔相比,单养蚌的围隔内轮虫质量在浮游动物中的比例较低,桡足类的比例相对较高;蚌与鲢、鳙混养围隔内浮游动物数量最多,原生动物数量在浮游动物中的比例分别高于单养蚌和蚌、银鲫混养的围隔,而轮虫的比例低于后者;实验期间,围隔内初级生产力平均值为4.11～5.45 g O2·m-2·d-1,水呼吸为2.39～4.12 g O2·m-2·d-1,初级生产力与水呼吸的比值为1.25～1.99;单养蚌的围隔内初级生产力最高,蚌、银鲫混养的围隔内初级生产力最低.结果表明:三角帆蚌养殖水体内浮游植物和浮游动物均表现出小型化的趋势;较高的浮游植物数量和质量,特别是较高的硅藻数量和质量,可能是三角帆蚌与鲢、鳙混养围隔内二龄蚌生长较好的原因之一;浮游植物种类组成较初级生产力对蚌生长的影响更大.     

Colletotrichum acutatum is the main cause of Colletotrichum leaf disease of rubber in Sri Lanka

Colletotrichum gloeosporoides has been described as the causal agent of Colletotrichum leaf disease of rubber in Sri Lanka and other parts of the world since 1905. A study carried out on vegetative and reproductive characteristics of 52 isolates from Colletotrichum leaf disease lesions on Hevea brasiliensis in Sri Lanka revealed that only 18 isolates belong to Colletotrichum gloeosporioides. The remaining 34 isolates represented C. aculatum indicating that C. acutatum is the main cause of Colletotrichum leaf disease in Sri Lanka.This revised version was published online in October 2005 with corrections to the Cover Date.     

我国3个桉树人工林种植区生产力影响因素

研究影响桉树人工林生产力的主要因素,对于提高桉树人工林生产力以及经营水平和合理利用树种都具有重要的意义。收集我国3个桉树人工林种植区(广东省、广西壮族自治区、云南省)关于生物量与生产力研究中的相关数据,对海拔、林分密度、林龄、年均温和年降水量与乔木层生物量进行了主成分分析与混合模型分析,探究各因素对我国桉树人工林生物量与生产力的影响。结果显示:年均温、年降水量、林龄、海拔和林分密度均是影响广东、广西、云南这3个省(区)桉树人工林生物量的主要因素,其中年降水量对这3个地区桉树人工林的生物量影响极其显著(P0.01),林龄和林分密度对桉树人工林的生物量影响显著(P0.05)。这是因为这3个地区都位于亚热带,温度都属于桉树生长的适宜温度,而这3个地区存在明显的干湿季,降水量在季节和地域上分布不均匀,导致这3个地区年降水量存在较明显的差异。因此,年降水量成为影响这3个地区桉树人工林生物量的关键因素。     

Reproductive tactics of the Asian cichlids of the genusEtroplus in Sri Lanka

Synopsis The Asian cichlids,Etroplus maculatus (the orange chromide) and E. suratensis (the green chromide) in Sri Lanka reproduce twice during the year when water conditions are favorable for nest construction and maintaining visual contact with offspring. These are the drier premonsoonal and monsoonal seasons when water turbidity decreased and salinity increased. When breeding in isolation orange chromide pairs selected dense vegetation where nests were camouflaged. During the peak breeding cycle (July) orange chromide pairs selected sparse vegetation for nesting as a compromise between survival of young and availability of adult food. These areas were also occupied by foraging non-breeding conspecifics which increased the threat of cannibalism of offspring. Under these pressures most orange chromides nested in colonies which helped decrease both actual and attempted cannibalism. The sympatric green chromide does not forage during nesting and nest site selection was determined mainly by factors favoring offspring survival. Biparental care is exhibited by both species. One member of an orange chromide pair stands guard over offspring while the other leaves the territory to forage — their roles are reversed every few minutes. The total parental investment is equivalent to the full investment of a single parent. Monogamy appears to be maintained by their metabolic constraints. In the green chromide both parents are vigilant over offspring and neither forages thus spending twice as much time in parental investment.     

Some aspects of photosynthetic characteristics in a set of perennial irrigation reservoirs located in five river basins in Sri Lanka

Phytoplankton primary productivity of eleven irrigation reservoirs located in five river basins in Sri Lanka was determined on a single occasion together with light climate and nutrient concentrations. Although area-based gross primary productivity (1.43–11.65 g O₂ m^–2 d^–1) falls within the range already established for tropical water bodies, net daily rate was negative in three water bodies. Light-saturated optimum rates were found in water bodies, with relatively high algal biomass, but photosynthetic efficiency or specific rates were higher in water bodies with low algal biomass, indicating nutrient limitation or physiological adaptation of phytoplankton. Concentrations of micronutrients and algal biomass in the reservoirs are largely altered by high flushing rate resulting from irrigation release. Underwater light climate and nutrient availability control the rate of photosynthesis and subsequent area-based primary production to a great extent. However, morpho-edephic index or euphotic algal biomass in the most productive stratum of the water column is not a good predictor of photosynthetic capacity or daily rate of primary production of these shallow tropical irrigation reservoirs.     

中国南方3种主要人工林生物量和生产力的动态变化

基于中国南方杉木、马尾松、桉树3种主要人工林的幼龄林、中龄林、近熟林、成熟林、过熟林5个不同年龄各3块1000 m2样地(共计45块)的建立和调查,采用样木回归分析法(乔木层)和样方收获法(灌木层、草本层、地上凋落物)获取不同林型不同林龄径级样木和其它基本数据,探讨了3种人工林各组分各层次林分生物量和生产力的分配特征及随林龄的变化规律,结果表明,林分生物量和生产力与林龄密切相关,增长模型的拟合度均较高,相关显著;杉木、马尾松、桉树人工林的生物量随林龄的增长呈增加趋势,成熟林的生物量分别为192.30、191.53、105.77 Mg/hm2,其中活体植物分别占95.76%—98.39%、75.01%—99.14%、85.60%—97.61%;生物量的层次分配乔木层占绝对优势,并随年龄而增加,其它层次所占比例较小,总体趋势为凋落物草本层灌木层;乔木层的器官分配以干所占比例最高,杉木、马尾松、桉树分别占54.89%—75.97%、49.93%—83.10%、51.07%—98.48%,随年龄的增加而增加,根的比例次之,枝叶所占比例较小,随林龄而下降;灌木层器官分配以枝的相对生物量较大,草本层的地上和地下分配规律不明显;与其它森林类型相比,杉木和马尾松的生物量处于中上游水平,桉树的生物量较低,但3种人工林的生产力均很高,分别为12.37、8.98、21.10 Mg hm-2a-1,均是光合效率高、固碳潜力大的中国南方速生丰产优良造林树种。