PRODUCTIVITY OF PODOSTEMUM CERATOPHYLLUM IN THE NEW RIVER,VIRGINIA

Productivity of Podostemum ceratophyllum, the dominant aquatic macrophyte in the New River, was measured at four sites representing soft- and hardwater reaches of the river. Available dissolved inorganic carbon (DIC) was 4–5 times greater in the hardwater reach. The difference in available DIC was reflected in standing crop and productivity of P. ceratophyllum. Maximum standing crops of P. ceratophyllum at the two hardwater sites (Sites 1 and 2) were 244.8 ± 30.7 g ash-free dry wt (AFDW) m^−-2 and 193.8 ± 18.7 g AFDW m^−-2 compared to 128.5 ± 14.9 g AFDW m^−-2 and 101.3 ± 6.9 g AFDW m^−-2 for the softwater sites (Sites 3 and 4). Productivity, based on differences in standing crops, was: Site 1, 1.08 ± 0.12 g C m^−-2 d^−-1; Site 2, 0.86 ± 0.08 g Cm^−-2d^−-1; Site 3,0.58 ± 0.06 g C m^−-2 d^−-1; Site 4,0.45 ± 0.03 g C m^−-2 d^−-1. Corresponding values for productivity as ¹⁴C uptake were: 2.77 ± 0.44 g C m^−-2 d^−-1; 2.10 ± 0.45 g C m^−-2 d^−-1; 0.34 ± 0.04 g C m^−-2 d^−-1; 0.28 ± 0.03 g C m^−-2 d^−-1. Productivity/biomass (P/B) based on ¹⁴C uptake and standing crop revealed that P. ceratophyllum productivity was inhibited at the softwater sites perhaps due to carbon limitation. Because of its abundance and its high productivity, P. ceratophyllum is hypothesized to contribute significantly to the New River organic matter budget.     

BIOMASS AND PRODUCTION OF PONTEDERIA CORDATA AND POTAMOGETON EPIHYDRUS IN THREE CONNECTICUT RIVERS

Above- and below-ground biomass of the emergent Pontederia cordata and the floating-leaved Potamogeton epihydrus was measured during the growing season in three interconnected rivers in Connecticut, U.S.A. Maximum biomass of Pontederia, averaging 1,212 g m^-2 dry weight (524 g m^-2 above-ground, 688 g m^-2 below-ground), occurred 100–150 days after major spring growth began. Peak biomass of Potamogeton averaged 94 g m^-2 (81 g m^-2 above-ground, 14 g m^-2 below-ground) and was attained in 45–85 days. New growth of Pontederia in spring arose from, and was heavily subsidized by, the large biomass of living overwintered rhizomes and roots, which averaged 497 g m^-2 in early June. This new growth appeared to have been produced in only one season, but in reality it contained energy fixed the current season, plus energy carried over from previous years. Net production of Pontederia calculated for only one growing season averaged 1,049 g m^-2. Potamogeton also perennated from rhizomes, but the biomass of these organs in spring was low, averaging 11 g m^-2 in late May. Biomass of Potamogeton in summer consisted primarily of tissue produced during the current season. Rhizomes and roots comprised a much greater proportion of the plant in Pontederia than in Potamogeton. The ratio of new living below-ground/above-ground biomass of Pontederia rose from zero in spring to an average of 1.71 in autumn. For Potamogeton, the below-ground/above-ground ratio averaged 0.37 in late spring, 0.20 in midsummer, and 0.41 in autumn. The overwintered below-ground biomass of Pontederia alive in spring was 42–79% of the new living below-ground biomass the previous autumn. Net photosynthetic efficiency during the period between initiation of major growth in spring and attainment of peak biomass averaged 1.3% for Pontederia and 0.3% for Potamogeton.     

Aspects of production and biomass of four seagrass species (Cymodoceoideae) from Papua New Guinea

Biomass and production data of the seagrasses Cymodocea serrulata (R. Brown) Aschers. and Magnus, Cymodocea rotundata Ehrenb. et Hempr. ex Aschers., Halodule uninervis (Forssk.) Aschers. and Syringodium iksoetifolium (aschers.) Dandy were collectede in monospecific stands in Bootless Inlet, Papua New Guinea. Cymodocea serrulata and Cymodocea rotundata were studied from November 1980 to November 1981. Total annual mean biomass was 354 and 201 g ADW m⁻², respectively. The largest proportion of these biomass values was contributed by the rhizomes (49 and 36%, respectively) and leaf biomass was ± 30% for both species. Halodule uninervis was studied at an intertidal and a subtidal site. The highest total annual mean biomass (600 g ADW m⁻²) was recorded at the intertidal site, of which 85% was found below ground. The largest proportion of the biomass, at both sites, was contributed by the below-ground vertical axes of the shoots. The biomass of the rhizomes was relatively low (9–12%) for Halodule uninervis. Proportionally, the largest above-ground biomass (40%) was recorded for Syringodium isoetifolium, of which the annual mean biomass was 481 g ADW m⁻².Total production (above and below ground) was 4.9 and 3.0 g ADW m⁻² day⁻¹ for Cymodocea serrulata and Cymodocea rotundata, respectively. Approximately 70% was production of leaves. Total production amounted to 6.0 and 4.0 g ADW m⁻² day⁻¹ for Halodule uninervis at the intertidal and subtidal sites, respectively. The maximum production was recorded for Syringodium isoetifolium, 60% of the 9.0 g ADW m⁻² day⁻¹ was contributed by the leaves. All species reached the maximum production during February and March, when the water temperatures were highest and water was retained above all sites, at all times. The increase of leaf production was mainly due to the increase in biomass of the mature leaves. Significant changes in the plastochrone interval of the leaves were not observed during this period.     

The productivity and composition of mangrove forests,Laguna de Términos,Mexico

The composition and productivity of two mangrove sites surrounding the Laguna de Términos, Mexico, were studied from March 1979 to January 1984. Measurements were made of the tree composition, above-ground woody biomass changes, and litterfall production at a high-salinity fringing site and a low-salinity riverine site. Rhizophora mangle L. was the dominant tree at the fringing site, but occurred only at the water's edge at the riverine site. Avicennia germinans L. dominated the inland area of the riverine site. Laguncularia racemosa Gaertn. f. had a more even distribution from shore to inland and from site to site. Average diameter at breast height (DBH) was greater at the riverine site for each of the three species; however, tree density (trees > 2.5 cm DBH) was more than twice as high at the fringing site (7510 ha⁻¹) than at the riverine site (3360 ha⁻¹). Wood production (1206 g m⁻² year⁻¹ vs. 772 g m⁻² year⁻¹) and litterfall (1252 g m⁻² year⁻¹ vs. 835 g m⁻²) were higher at the riverine site than at the fringing site. Total estimated above-ground net production was 2458 g m⁻² year⁻¹ at the riverine site and 1607 g m⁻² year⁻¹ at the fringing site.     

Cultivation of Lemna gibba under desert conditions. I: Twelve months of continuous cultivation in open ponds

Duckweed, Lemna gibba, was grown in 12 m² shallow ponds in the Negev desert, during 12 months of continuous cultivation, beginning April 1984. Average monthly growth rates varied with the season of the year. The lowest daily yield, 2·6±0·4 g dry weight m⁻² day⁻¹, was obtained during January. Highest daily yields, 7·9±2·6 g dry weight m⁻² day⁻¹ and 7·0±1·2 g dry weight m⁻² day⁻¹, were obtained during September and May. A 35% decline of the yield was seen during midsummer (July), 4·8±1·2 g dry weight m⁻² day⁻¹. The average rate for the year was 5·15±1·7 g dry weight m⁻² day⁻¹. The protein content of the plants ranged from 30 to 38% per unit dry weight.Growth performance is discussed in relation to the prevailing climatic conditions.     

黄河源园区高寒草地碳储量估算及其影响因素

高寒草地碳储量及其影响因素研究是认识青藏高原草地生态系统乃至陆地生态系统碳循环和气候变化的关键之一。利用2021年8月上旬地面调查数据与同期高分6号遥感数据建立回归关系,在反演研究区植被地上、地下生物量碳密度和0—40cm土壤层有机碳密度基础上,估算了黄河源园区高寒草地有机碳储量,并通过路径分析探讨了土壤理化性质对碳密度的影响驱动机制。结果表明：(1)2021年黄河源园区地上生物量、地下生物量、0—40cm土壤层碳密度分别为37.65g/m²、1305.28g/m²、4769.11g/m²;总碳储量为100.44Tg(1Tg=10¹²g),植被层和土壤层碳储量分别分为22.06Tg、78.38Tg,占总碳密度的21.96%、78.04%。(2)黄河源园区高寒草甸和高寒草原两种草地类型地上生物量碳密度分别为41.27g/m²、30.76g/m²;地下生物量碳密度分别为1661.41g/m²、618.74g/m²;0...     

Effects of dwarf bamboo (Fargesia denudata) density on biomass, carbon and nutrient distribution pattern

Dense dwarf bamboo population is a structurally and functionally important component in many subalpine forest systems. To characterize the effects of stem density on biomass, carbon and majority nutrients (N, P, K, Ca and Mg) distribution pattern, three dwarf bamboo (Fargesia denudata) populations with different stem densities (Dh with 220 ± 11 stems m^?2, Dm with 140 ± 7 stems m^?2, and Dl with 80 ± 4 stems m^?2, respectively) were selected beneath a bamboo-fir (Picea purpurea) forest in Wanglang National Nature Reserve, Sichuan, China. Leaf, branch, rhizome, root and total biomass of dwarf bamboo increased with the increase of stem density, while carbon and nutrient concentrations in bamboo components decreased. Percentages of below-ground biomass and element stocks to total biomass and stocks decreased with the increase of stem density, whereas above-ground biomass and element stocks exhibited the opposite tendency. Moreover, more above-ground biomass and elements were allocated to higher part in the higher density population. In addition, percentages of culm biomass, above-ground biomass and element stocks below 100 cm culm height (H₁₀₀) increased with the increase of stem density, while percentages of branch and leaf biomass below H₁₀₀ decreased. Pearson’s correlation analyses revealed that root biomass, above-ground biomass, below-ground biomass and total biomass significantly correlated to leaf biomass in H_100?200 and total leaf biomass within high density population, while they significantly correlated to leaf biomass in H_50?150 within low density population. The results suggested that dwarf bamboo performed an efficient adaptive strategy to favor limited resources by altering biomass, carbon and nutrients distribution pattern in the dense population.     

Primary productivity of papyrus (Cyperus papyrus) in a tropical swamp; Lake Naivasha,Kenya

Papyrus (Cyperus papyrus) standing biomass and the primary productivity of undisturbed and previously harvested areas of papyrus was measured in Lake Naivasha swamp, Kenya. Papyrus culm density in undisturbed swamp was estimated to be 13·1±1·9 culms m⁻² and aerial biomass was 3602 g m⁻². In undisturbed swamp the aerial productivity was 14·1 g m⁻² day⁻¹ while the previously harvested swamp reached a peak of 21·0 g m⁻² after 6 months. The annual aerial production rate of papyrus in Lake Naivasha was estimated to be 5150 g m⁻² year⁻¹. To sustain yields of regularly harvested papyrus swamps, the harvest intervals should exceed 1 year.     

Littoral benthos of the Northern Baltic Sea. IV. Pattern and dynamics of macrobenthos in a sandy-bottom Zostera marina community in Tvärminne

The composition and abundance of the macroscopic biota of a sandy-bottom Zostera marina community at a depth of 3–5 m were studied in Tvärminne, S Finland, in 1968–1971. Zostera occurred contagiously and very sparsely, 6 ± 2 shoots · m⁻², ash-free dry weight (AFDW) 2 ± 1 g · m⁻² (95% confidence interval). Totals of 45 plant and 70 animal taxa were found. Fucus vesiculosus (80%) and Zostera marina (11%) dominated the plant biomass, 16.5 ± 17.8 g · m⁻² in June 1971. At this time animal density was 8540 ± 830 ind. · m⁻² (0.6-mm mesh) and AFDW 17.3 ± 5.0 g · m⁻², 80–90% of the latter consisting of Macoma baltica, Mya arenaria, Corophium volutator, Nereis diversicolor and Hydrobia spp. The same percentage of animal density was made up by Hydrobia spp., M. baltica, C. volutator and Pygospio elegans. Normal analysis by classification of the samples suggested that the community was spatially rather homogeneous in 1971. Inverse analysis, based on interspecific correlations, revealed three distributional groups of species. These groups corresponded to the compositional subdivisions suggested by normal analysis. The community was subdivided into strata characterized by (D) deposit feeders, (Z) Zostera marina and (F) Fucus vesiculosus. The periodicity of the biota in the Zostera-characterized stratum was investigated. The principal dominants, especially Fucus, Zostera and Macoma, showed no distinct seasonal or interannual differences in 1968–1971, which made the community seem very stable. Yet, the species diversity of plants varied with the abundance of filamentous algae. Animal species diversity and mean animal density reached their seasonal minima in late summer, when the parental stocks of many invertebrates were dying and the summer's offspring were often still too small to be obtained by our methods. The recruitment of many important animal species failed in 1968 as compared with the other years.     

Primary production in papyrus (<Emphasis Type="Italic">Cyperus papyrus</Emphasis> L.) of Rubondo Island,Lake Victoria,Tanzania

Above- and below-ground production and morphological characteristics of papyrus wetlands were measured at monthly intervals from July 2005 to June 2006 at Rubondo Island, Lake Victoria, Tanzania. The average value of live culm biomass (5,789 ± 435 g DW m⁻²) was higher than that of umbel biomass (2,902 ± 327 g DW m⁻²) by 50%. Root to rhizome means biomass value ratio was 1:1.8, rhizome biomass (4,144 ± 452 g DW m⁻²) being higher than roots biomass (2,254 ± 314 g DW m⁻²) by 45%. Direct proportion was observed between shoot density and culm–unit (culms and umbels) biomass. The average value of detritus/litter biomass (1,306 ± 315 g DW m⁻²) was less than total aerial biomass by 86%. The values of biomass are average of 12 sampling months from July 2005 to June 2006.     

CO2 flux in alpine wetland ecosystem on the Qinghai-Tibetan Plateau, China

Using the CO₂ flux data measured by the eddy covariance method in the northeast of Qinghai-Tibetan Plateau in 2005, we analyzed the carbon flux dynamics in relation to meteorological and biotic factors. The results showed that the alpine wetland ecosystem was the carbon source, and it emitted 316.02 gCO₂ · m⁻² to atmosphere in 2005 with 230.16 gCO₂ · m⁻² absorbed in the growing season from May to September and 546.18 gCO₂ · m⁻² released in the non-growing season from January to April and from October to December. The maximum of the averaged daily CO₂ uptake rates and release rates was (0.45 ± 0.0012) mgCO₂ · m⁻² · s⁻¹ (Mean ± SE) in July and (0.22 ± 0.0090) mgCO₂ · m⁻² · s⁻¹ in August, respectively. The averaged diurnal variation showed a single-peaked pattern in the growing season, but exhibited very small fluctuation in the non-growing season. Net ecosystem exchange (NEE) and gross primary production (GPP) were all correlated with some meteorological factors, and they showed a negatively linear correlation with aboveground biomass, while a positive correlation existed between the ecosystem respiration (R_es) and those factors.     

基于树木起源、立地分级和龄组的单木生物量模型

以马尾松(Pinus massoniana)和落叶松(Larix)的大样本实测资料为建模样本,以独立抽取的样本为验证样本,把样本按起源、立地和龄组进行分级,采用与材积相容的两种相对生长方程,分普通最小二乘和两种加权最小二乘,对地上部分总生物量、地上各部分生物量和地下生物量进行模型拟合和验证,使用决定系数、均方根误差、总相对误差和估计精度等8项统计量对结果进行分析。结果表明:两个树种地上部分总生物量,立地分类方法,模型的拟合结果和适用性都最优;马尾松VAR模型较优,而落叶松CAR模型较好;两种加权最小二乘方法,在建模样本和验证样本中表现得不一致。在建模样本中,加权回归2(权重函数1/f^0.5)略优于加权回归1(权重函数1/y^0.5),但在验证样本中,加权回归1却明显优于加权回归2。而同时满足建模样本拟合结果最优和验证样本检验结果最优的组合中,只有加权回归1。两个树种地上部分各分量生物量,模型拟合结果和适用性,均为干材最优,树叶最差、树枝和树皮居中,样本分类、模型类型和加权最小二乘方法对干材生物量的影响,规律和地上部分总生物量相同;样本分类、模型类型和加权最小二乘方法的最优组合,用验证样本检验的结果,总相对误差树枝不超过±10.0%,树皮不超过±5.0%,树叶马尾松不超过±30.0%,落叶松不超过±20.0%。两个树种地下部分(根)生物量,样本按龄组分类方法,模型拟合结果最优,与材积相容的模型总体上优于与地上部分总生物量相容模型。     

Stable musselMytilus edulis beds in the Wadden Sea—They’re just for the birds

Predation by eiders, oystercatchers and herring gulls on natural mussel bedsMytilus edulis was studied in the Königshafen, a sheltered bay in the Wadden Sea. About 15 ha (2.5%) of the Königshafen were covered with mussel patches of a biomass of about 1300 g AFDW m^?2. The biomass on the mussel beds was dominated by old mussels and found to be constant over several years. Birds annually removed 30% of the standing stock. Eiders were by far the most important predators and consumed 346 g AFDW m^?2, followed by oystercatchers with 28 g AFDW m^?2 and herring gulls with 3.6 g AFDW m^?2. Birds consumed a substantial part of the annual production of the mussel beds which was estimated from literature data to be approx. 500 to 600 g AFDW m^?2. As other predators were absent, the production of the mussels was sufficient to sustain the high predation rate by birds. Stable mussel beds form a short and efficient link between primary production and bird predation which is unusual for the Wadden Sea, where the main part of primary food supply is thought to be unavailable for higher trophic levels.     

Population Dynamics,Growth and Productivity of Abra ovata (Mollusca,Bivalvia) in the Evros Delta (North Aegean Sea)

Monthly samples of Abra ovata were collected during February 1983-January 1984 in the Evros Delta (N. Aegean Sea). Population density (mean annual value = 2407.5 ind · m⁻²) was characterized by seasonal variation. An analysis of the length frequency distributions shows that one annual recruitment of juveniles (> 2 mm) occurred in October-January; and also that, throughout the year, two age groups existed in the population. One growth ring was formed on the shells of the oldest age group during July-August. Mean growth in shell length can be described by Bertalanffy function. A positive correlation existed between shell length and decalcified dry weight. Secondary production in A. ovata, calculated by the instantaneous growth method, showed a mean biomass of 29.221 g dry weight m⁻²yr⁻¹, a productivity of 17.086 g dry weight m⁻²yr⁻¹ and an annual turnover ratio of 0.59.     

Biomass production by irrigated and fertilized Salix clones

In an attempt to assess maximum biomass production of willows, field experiments with irrigation and fertilization (through the same system) were carried out in the south of Sweden (57°N). The site was near the coast on a sandy soil (pH 5) on which the populations of herbivores (moose and voles) were small. Different irrigation systems were tested on a 1-ha experimental area: drip-, sprinkler, and a subsurface system. Fertilization was carried out from the last week of May until early September. A liquid fertilizer, complete except for calcium and magnesium, was given in an amount corresponding to an addition of 10 kg. ha⁻¹. week⁻¹, with the other nutrients in optimum proportions. Irrigation started during the first week of May 1985, and continued twice a week throughout the month with 30 mm on each occasion. The rest of the growing season was very wet, and consequently irrigation was limited to 10 mm a week in June, July, and August. The total amount of irrigation given to the crop during the growing season was 330 mm and precipitation was 271 mm. The crop was fertilized with 150 kg. ha⁻¹ of nitrogen with other nutrients in optimal proportions. Leaves were analysed for macronutrients and the ground-water for nitrate and ammonium.The above-ground production of woody biomass for a Salix dasyclados Vimm. clone during its third year on 4-year-old roots was 3·6 kg. m⁻² dry matter for a drip irrigated plot. The comparable result for the subsurface system was 2·8 kg. Two-year-old shoots on 4-year-old roots of the same clone for a drip system plot produced 3·0 kg m⁻². Production of 1 kg. m⁻² corresponds to 10 tonne or 25 m³. ha⁻¹. Annual production in clones of Salix viminalis L. was only 1·2–1·8 kg.m⁻² during the second and third years. Tests using N¹⁵-labelled fertilizer have so far shown no leakage in the groundwater. The capacity of some of the Salix clones to convert solar energy into biomass is higher than for any other crop in Sweden, whether in forestry or agriculture.     

Effects of Elevated CO2 and Temperature on Biomass Growth and Allocation in a Boreal Bioenergy Crop (Phalaris arundinacea L.) from Young and Old Cultivations

An auto-controlled climate system was used to study how a boreal bioenergy crop (reed canary grass, Phalaris arundinacea L., hereafter RCG) responded to a warming climate and elevated CO₂. Over one growing season (April–September of 2009), RCG from young and old cultivations (3 years [3-year] and 10 years [10-year]) was grown in closed chambers under ambient conditions (CON), elevated CO₂ (EC, approximately 700 μmol?mol^?1), elevated temperature (ET, ambient + approximately 3 °C) and elevated temperature and CO₂ (ETC). The treatments were replicated four times. Throughout the growing season, the above-ground (leaf and stem biomass) and below-ground biomasses were measured six times, representing various developmental stages (early stages: the first three stages, and late stages: the last three stages). Compared to the growth observed under CON, EC enhanced RCG biomass growth over the whole growing season (p?<?0.05), whereas ET increased RCG biomass growth in early stages but decreased growth in late stages, regardless of the cultivation age. However, the negative effect of ET later in the growing season was partially mitigated by CO₂ enrichment. Compared to CON plants, the final total biomass was 18 % higher for 3-year plants and 8 % higher for 10-year plants grown under EC. In comparison, for 3-year and 10-year plants, the biomass was 5 and 3 % lower under ET and 7 and 4 % greater under ETC, respectively. Under EC, the below-ground growth contributed more to the total biomass growth compared to the above-ground portion. The opposite situation was observed under ET and ETC. The climate-related changes in biomass growth were smaller in the old cultivation than in the young cultivation due to the lower net assimilation rate and lower specific leaf area in the old cultivation plants.     

Wetland vegetation ecology on a reclaimed coal surface mine in southern Illinois,USA

An early successional wetland complex on a reclaimed surface coal mine in southern Illinois was studied 1985–1987. Seasonally, biomass was low, with above-ground values of 10–210g m^–2 and below-ground biomass of 1.5–2435 g m^–2. Biomass peaked in spring and did not vary much throughout the remainder of the growing season. Stem densities were high (179–1467 m^–2) because large numbers of seedlings became established as falling water levels exposed large areas of mudflats. Fluctuating water levels led to a lack of community zonation. Species diversity (H) was low to moderate over all sites with diversity values ranging between 1.86 and 3.27.     

Dynamics,biomass and total rhizome length of the seagrass Thalassodendron ciliatum at Inhaca Island,Mozambique

Dynamic and structural aspects of Thalassodendron ciliatum were studied in the intertidal zones around Inhaca Island during the rainy seasons 1991 to 1993. Measurements comprised leaf growth rate, leaf detachment rate, biomass, above-ground to below-ground biomass ratios and total rhizome length. On average, three leaves were, at the same time, formed and detached from a shoot during 15 day periods and five leaves from a shoot during 30 day periods. Mean leaf growth rate varied from 101.2 to 159.5 mm, 313.2 to 366.9 mm and 540 to 583.0 mm for 15, 30 and 45 days of measurements respectively. Differences between locations (Banco Sidzanye, Barreira Vermelha and Portinho-EBM/BV) were not statistically significant for the 30 and the 45 day period, but significant for the 15-day period. The average leaf growth rate per day was between 14.1 to 18.3 mm day^-1 shoot^-1, and the average time for leaf turnover (6 to 9 leaves) on one shoot was four successive spring tides (around 45 days). The average above-ground to below-ground biomass ratio was 1: 1.5 (61% in below-ground biomass) and leaf biomass varied between 45.1 and 211.7 g DW m^-2. Total rhizome length varied between 960.0 to 6641.6 cm m^-2. A positive correlation was observed between this variable with rhizomes and roots and between rhizomes and roots.     

Effects of fire,mowing and nitrogen addition on root characteristics in tall-grass prairie

Abstract. Root harvests and root windows were used to study the influence of fire, mowing and nitrogen additions on root lengths, biomass, and nitrogen content in tall-grass prairie. Four years of nitrogen additions (10 g m² yr^?1) increased below-ground mass by 15 % and nitrogen concentration in that mass by 77 %. In general, live roots and rhizomes exhibited greater increases in nitrogen concentrations than detrital roots and rhizomes. After four years of treatment, live roots and rhizomes immobilized an additional 1.5 to 5 g/m² of nitrogen, depending upon specific treatment, while dead roots and rhizomes immobilized an additional 3 to 3.5 g/m². Average root growth parameters, as measured with root windows, were positively correlated with above-ground peak foliage biomass; however, the only significant correlation was between average new root growth and above-ground peak foliage biomass (r = 0.73, p ≤ 0.04). Root growth and decay, as measured by annual mean values for eight root windows over a four year interval, were insensitive to climatic and treatment effects.     

The growth dynamics of Halophila hawaiiana

A functional growth model was developed for Halophila hawaiiana Doty and Stone, based on its regular plastochrone interval, and the relationship between leaf area and plant biomass. The model allows estimates of biomass, productivity and turnover from easily collected field samples. From these samples, the number of actively growing apical buds, total leaf number and total leaf area for a unit area were determined. This model was applied to a meadow in Kaneohe Bay, Oahu. The mean biomass was 104.25 g dry wt. m⁻² and the productivity 7.11 g dry wt. m⁻² day⁻¹. The turnover time was 14.7 days.