Fouling and stability of polymers and composites in marine environment

Effect of biofouling on various polymers and composites such as, Polyurethane (PU), Silicone rubber (SR), Polyester (PET), Glass Fiber Reinforced Polymer (GFRP), Carbon fibre Reinforced Plastic (CFRP) and Syntactic foams (SF) deployed for a period of one year in marine waters at a depth of 1 m was studied. These materials find wide marine applications. SR with lowest surface energy was the least fouled. Maximum barnacle attachment was seen on hard surface (GFRP) and minimum on flexible surface (SR). Attachment of barnacles and polychaetes are positively correlated with surface energy. Fouling load is positively correlated with Surface energy and hardness. The surface energy, hardness and tensile strength reduced while surface roughness considerably increased during this period. Maximum gravimetric weight loss was seen in PET (7.49%) followed by PU (4.25%) and minimum in CFRP (0.45%). Maximum thermogravimetric weight loss was observed in PET (73.5% at 400 °C) followed by PU (71.1%) and least in SR (2.4%). Fourier Transform infrared spectrum revealed that carbonyl/oxidation indices decreased for PET, GFRP, CFRP, and SR indicating biotic degradation. The same index increased for PU indicating abiotic oxidation.     

Nutrient optima and tolerances of benthic invertebrates,the effects of taxonomic resolution and testing of selected metrics in lakes using an extensive European data base

A large dataset from 1,077 lakes in Finland, Ireland, Sweden and the United Kingdom was collated to analyse the relationship between nutrient status and occurrence of different taxa, as well as between total phosphorus or chlorophyll and commonly used macroinvertebrate metrics developed for river assessment. We found that most taxa were associated with mesotrophic conditions (sensu OECD). Species associated with oligotrophic status included Baetis rhodani, Gammarus lacustris and plecopteran larvae, a group commonly associated with low nutrient status also in rivers. Species tolerant of eutrophic conditions were the chironomid larvae (Chironomus plumosus and Cryptochironomus defectus); and two species of tubificids (Psammoryctides barbatus and Potamothrix hammoniensis). For a number of taxa the associations of benthic invertebrates with nutrient state reported in the literature were not supported by analysis of the REBECCA data. The analysis indicated a variable response of littoral macroinvertebrates to eutrophication pressure when using common metrics developed for macroinvertebrates in rivers. Several metrics showed significantly different responses in lakes with different alkalinity, justifying the use of alkalinity for typing water bodies. These significant responses suggest that benthic invertebrates may be a useful component for classification of ecological status in lakes. The low amount of variance explained by the regressions (<30%), however, suggests that further harmonisation of sampling methods, as well as statistically more robust assessment tools are needed to increase the comparability of datasets and to improve the precision in the dose–response relationships.     

The effect of water temperature,current velocity and suspended solids on the distribution,growth and seasonality of Lemanea fluviatilis (C. Ag.), Rhodophyta,in the river Usk and other South Wales rivers

Two surveys of Lamanea in South Wales rivers have given details of its distribution, seasonality and range of tolerance to various environmental parameters, with particular reference to temperature, current velocity and suspended solids.Temperature, current velocity and suspended solids had most effect. Such findings were confirmed by principal component and correlation coefficient analysis.These investigations also suggest that abundant growths of Lemanea may be used in a limited manner as indicative of oligotrophic and metal free waters especially during Spring.In addition, transplants of Lemanea from the upper to the lower reaches of the River Usk and vice versa were studied to clarify the effect of suspended solids in nature.Using the ¹⁴C technique for primary production proved to be a successful method with Lamanea for comparison with chlorophyll a extraction and phycoerythrin. The importance of the latter in energy transfer for photosynthesis was revealed for this genus. A combination of various simple and cheap methods for the extraction of the pigment phycoerythrin was used successfully for the first time in red algal studies.Procedures for estimating percentage cover, standing crop and the presence/absence of the plant are given and the statistical reliability of the methods is evaluated.     

Crustacean zooplankton size structure in aquaculture lakes: is larger size structure always associated with higher grazing pressure?

Crustacean zooplankton size structure in 27 aquaculture lakes was studied to test the hypothesis that larger size structure is associated with higher grazing pressure. Mean body length of crustaceans was positively correlated with increasing Chl a (r ² = 0.40, P = 0.000) and TP (r ² = 0.38, P = 0.000), contrary to the empirical studies. However, the ratio of zooplankton to phytoplankton biomass decreased significantly with increasing TP (r ² = 0.27, P = 0.005) and mean body length (r ² = 0.46, P = 0.000). Meanwhile, size structure showed no significant effect in explaining residual variations of phosphorus–chlorophyll relationship (P = 0.231). These results indicate that larger size structure was not always associated with higher zooplankton grazing pressure. It is likely that in aquaculture lakes crustacean zooplankton size structure was of minor importance in control of phytoplankton biomass, and it was mainly regulated by fish predation. The results showed in our study and the empirical studies might be a reflection of two different stages of lake eutrophication and fish predation intensity. Handling editor: S. Dodson     

The activity of Triton X-100 soluble chlorophyllase in liposomes

Chlorophyllase (chlorophyll-chlorophyllidohydrolase, EC 3.1.1.14) was isolated and purified from Phaseolus vulgaris L. chloroplasts and etioplasts dissolved in 1% Triton X-100 and 10% glycerol. A 100 and 40-fold purification, respectively, was achieved. Enzyme preparations from both sources had similar affinities for chlorophyll a when assayed in a Triton X-100 medium. When electrophoresed in sodium dodecyl sulphate polyacrylamide gels the major band in both preparations migrated as a peptide of 30,000 daltons. Chlorophyll containing liposomes were also used as a substrate for chlorophyllase. The rate of hydrolysis did not follow Michaelis-Menten kinetics. When chlorophyllide a or methyl chlorophyllide a was incorporated in the liposomes, then in the presence of phytol dissolved in methanol, methylchlorophyllide a and chlorophyll a were shown to be synthesized. Apparently the purified enzyme in the presence of lipids, is endowed with both synthetic and hydrolytic activity.Abbreviations DEAE diethylaminoethyl - MeOH methanol - SDS sodium dodecyl sulphate     

Cyanobacterial blooms and water quality in Greek waterbodies

The cyanobacterial species composition of nine Greek waterbodies of different type and trophic status was examined during the warm period of the year (May–October). Cyanobacterial water blooms were observed in all waterbodies. Forty-six cyanobacterial taxa were identified, 11 of which are known to be toxic. Eighteen species are reported for the first time in these waterbodies, 8 of which are known to produce toxins. Toxin producing species were found in all of the waterbodies and were primarily dominant in bloom formations (e.g., Microcystis aeruginosa, Anabaena flos-aquae, Aphanizomenon flos-aquae and Cylindrospermopsis raciborskii). Cosmopolitan species (e.g., M. aeruginosa), pantropic (e.g., Anabaenopsis tanganyikae) and holarctic species (e.g., Anabaena flos-aquae) were encountered. Shallow, eutrophic waterbodies had blooms dominated by Microcystis species and were characterized by phytoplankton association M. Anabaena and Aphanizomenon species of association H were dominant in waterbodies with low dissolved inorganic nitrogen and thermal stratification in the summer. Total cyanobacterial biovolumes (CBV) ranged from 7 to 9,507 cm³ m⁻³ and were higher than Alert Level 2 and Guidance Level 2 (10 cm³ m⁻³; World Health Organization; WHO) in seven of the waterbodies. Chlorophyll a concentrations ranged from 6 to 90,000 mg m⁻³ and were higher than Alert Level 2 and Guidance Level 2 (50 mg m⁻³; WHO) in eight of the waterbodies. There is also an elevated risk of acute toxicosis (Guidance Level 3; WHO) in five waterbodies. Water of an undesirable quality, hazardous to humans and animals occurs in several Greek waterbodies.     

Phosphorus inputs to Lake Naivasha,Kenya, from its catchment and the trophic state of the lake

The main river supplying Lake Naivasha, Kenya, the Malewa, drains a catchment given over to largely subsistence cultivation and animal husbandry. The lake itself is the focus for an intensive horticultural industry based upon irrigation from the lake. The Malewa, however, is relatively independent of the impact of industry, and so its contribution to eutrophication of the lake was evaluated. Two periods of study, a very wet-dry and a `normal' wet-dry season showed that the river contribution of phosphorus led to a total phosphorus loading of 1.4 g m<sup>–2</sup> lake surface ann<sup>–1</sup> in the very wet period compared to 0.2 in the `normal'. Chlorophyll `a' in the open water of the lake was significantly related to soluble reactive phosphorus. The lake is now eutrophic by normal limnological criteria.     

Selection and stability of synthetic varieties of Lolium perenne

Summary The performance of three experimental cultivars of Lolium perenne selected for yield or water soluble carbohydrate content was monitored over four generations of seed multiplication under relaxed selection. In each variety the selected trait regressed towards that of the base population from which the selection line derived. This could be accounted for by residual genetic variation within the lines for the selected trait, and in some instances, by association of this variation with the fitness character, seed numbers produced. These results emphasize the need for practical breeding programmes to consider the nature of the gene action controlling the selected trait, if additive, directional selection should be effective in increasing the expression of the character. Where ambidirectional dominance and epistasis are important, consideration should be given to means of achieving reassortment of the controlling genes prior to selection.     

Seasonality and controls of phytoplankton productivity in the middle Cape Fear River, USA

Our 1 year study was aimed at assessing seasonal patterns and controls on phytoplankton primary production (PPR) and biomass (chlorophyll a) in a fourth order section of the middle Cape Fear River in North Carolina, USA, and to determine the impact of three low-head lock and dam (LD) structures on these variables within the 70 km study reach of this coastal river. Mean concentrations of NO₃ ⁻–N, NH₄ ⁺–N and soluble reactive phosphorus (SRP) averaged 52.9, 6.0, and 3.6 μmol l⁻¹ in monthly sampling, while the average light attenuation coefficient was 2.4 m⁻¹. The average euphotic depth was 2.1 m. Nutrient concentrations and attenuation coefficients were not significantly different above versus below each LD, or along the entire study reach. Significantly higher concentrations of dissolved O₂ below versus above each LD were attributed to re-aeration during spillway transit. No seasonal pattern in physicochemical properties was apparent. Phytoplankton chlorophyll a concentrations ranged from <1 to 36 μg l⁻¹, while rates of primary production ranged from 18 to 2,580 mg C m⁻² day⁻¹, with values for both variables peaking in the spring and early summer. Chlorophyll a and primary productivity values were consistently higher above versus below each LD in May and June suggesting a seasonal effect, but values were otherwise similar such that overall means were not significantly different. Several factors point to light as the primary control on phytoplankton in the middle Cape Fear River: high nutrient concentrations; a low ratio of euphotic : mixing depth (0.46); progressive increases in chlorophyll a and radiocarbon uptake in all treatments in quarterly nutrient enrichment bioassays conducted at levels of irradiance elevated relative to in situ river values; and consistently low quarterly values of (maximum rate of chlorophyll-normalized C uptake; ≤3.7 mg C mg chl a⁻¹ h⁻¹) and I _k (light saturation parameter; ≤104 μmol photons m⁻² s⁻¹) for photosynthetic light–response (P–I) curves. Handling editor: L. Naselli-Flores     

An evaluation of Secchi disk visibility for estimating plankton density in Fish ponds

Correlation coefficients between Secchi disk visibility (X) in fish ponds and concentrations of chlorophyll a and particulate organic matter were –0.79 (P< 0.01) and –0.83 (P< 0.01), respectively. Different observers may obtain different values for Secchi disk visibility and measurements by the same observer differ with the time of day. Nevertheless, Secchi disk visibility provides a suitable estimate of plankton density for management purposes in ponds were plankton is the primary source of turbidityResearch supported by Hatch Project Alabama 398 and by the Office of Water research and Technology of the Department of the Interior through the Water Resources Research Institute of Auburn, University under provisions of the Water Research Act of 1964.     

Recent advances in chlorophyll biosynthesis

The importance of chlorophyll (Chl) to the process of photosynthesis is obvious, and there is clear evidence that the regulation of Chl biosynthesis has a significant role in the regulation of assembly of the photosynthetic apparatus. The understanding of Chl biosynthesis has rapidly advanced in recent years. The identification of genetic loci associated with each of the biochemical steps has been accompanied by a greater appreciation of the role of Chl biosynthesis intermediates in intracellular signaling. The purpose of this review is to provide a source of information for all the steps in Chl and bacteriochlorophyll a biosynthesis, with an emphasis on steps that are believed to be key regulation points.     

Recent advances in chlorophyll biosynthesis

The importance of chlorophyll (Chl) to the process of photosynthesis is obvious, and there is clear evidence that the regulation of Chl biosynthesis has a significant role in the regulation of assembly of the photosynthetic apparatus. The understanding of Chl biosynthesis has rapidly advanced in recent years. The identification of genetic loci associated with each of the biochemical steps has been accompanied by a greater appreciation of the role of Chl biosynthesis intermediates in intracellular signaling. The purpose of this review is to provide a source of information for all the steps in Chl and bacteriochlorophyll a biosynthesis, with an emphasis on steps that are believed to be key regulation points.     

Spatio-temporal variation of periphyton biomass and accumulation in a temperate spring-fed stream

Spatio-temporal variation of plant populations often can demonstrate synchronous patterns, particularly within highly connected landscapes. Periphyton biomass (chlorophyll a) and net accumulation were measured at five sites in a spring-fed fourth-order stream located in central Pennsylvania with a mixed land-uses watershed (Spring Creek, USA) to characterize longitudinal variation within the stream. Samples were collected at three-week intervals over one year to describe seasonal patterns of periphyton biomass and net production (n = 17 per site). Spring Creek periphyton biomass and net accumulation increased dramatically from the headwaters to downstream (range 10–1,000 mg/m²). The downstream reaches had exceptionally large algal biomass (chlorophyll a > 300 mg/m²) and potential for rapid turnover. Varying degrees of seasonality were observed among the sites, with upstream sites showing more temporal variation but no distinct seasonal pattern. Despite this, large-scale disturbances within the watershed seem to promote synchrony among sites throughout the stream as reflected by close correlations in chlorophyll values (Pearson correlation coefficient r > 0.50).     

Consistent Sets of Spectrophotometric Chlorophyll Equations for Acetone, Methanol and Ethanol Solvents

A set of equations for determining chlorophyll a (Chl a) and accessory chlorophylls b, c ₂ , c ₁ + c ₂ and the special case of Acaryochloris marina, which uses Chl d as its primary photosynthetic pigment and also has Chl a, have been developed for 90% acetone, methanol and ethanol solvents. These equations for different solvents give chlorophyll assays that are consistent with each other. No algorithms for Chl c compounds (c ₂ , c ₁ + c ₂) in the presence of Chl a have previously been published for methanol or ethanol. The limits of detection (and inherent error, ± 95% confidence limit), for chlorophylls in all organisms tested, was generally less than 0.1 μg/ml. The Chl a and b algorithms for green algae and land plants have very small inherent errors (< 0.01 μg/ml). Chl a and d algorithms for Acaryochloris marina are consistent with each other, giving estimates of Chl d/a ratios which are consistent with previously published estimates using HPLC and a rarely used algorithm originally published for diethyl ether in 1955. The statistical error structure of chlorophyll algorithms is discussed. The relative error of measurements of chlorophylls increases hyperbolically in diluted chlorophyll extracts because the inherent errors of the chlorophyll algorithms are constants independent of the magnitude of absorbance readings. For safety reasons, efficient extraction of chlorophylls and the convenience of being able to use polystyrene cuvettes, the algorithms for ethanol are recommended for routine assays of chlorophylls. The methanol algorithms would be convenient for assays associated with HPLC work.     

The effects of rain on the erosion threshold of intertidal cohesive sediments

Intertidal sedimentary environments are complex systems governed by interactions between physical, chemical and biological processes and parameters. Tidally induced flow and wave action are known to be an integral driving force behind the erosion, transport, deposition and consolidation cycle (ETDC) of intertidal sediments. Whilst considerable advances have been made in understanding both the physical and biological processes and their interactions in these systems, it is clear that there are gaps in our understanding. One factor that has been largely ignored to date is that of rain. Visual observations in the field and associated data indicated that rain showers during low tide are correlated with a reduction in the erosion threshold of intertidal cohesive sediments. This paper presents preliminary field and laboratory data showing the importance of rain in reducing the erosion threshold of cohesive intertidal sediments. The implications for our knowledge of, and modelling of the ETDC cycle of cohesive intertidal sediments are discussed.     

Chlorophylls, ligands and assembly of light-harvesting complexes in chloroplasts

Chlorophyll (Chl) b serves an essential function in accumulation of light-harvesting complexes (LHCs) in plants. In this article, this role of Chl b is explored by considering the properties of Chls and the ligands with which they interact in the complexes. The overall properties of the Chls, not only their spectral features, are altered as consequences of chemical modifications on the periphery of the molecules. Important modifications are introduction of oxygen atoms at specific locations and reduction or desaturation of sidechains. These modifications influence formation of coordination bonds by which the central Mg atom, the Lewis acid, of Chl molecules interacts with amino acid sidechains, as the Lewis base, in proteins. Chl a is a versatile Lewis acid and interacts principally with imidazole groups but also with sidechain amides and water. The 7-formyl group on Chl b withdraws electron density toward the periphery of the molecule and consequently the positive Mg is less shielded by the molecular electron cloud than in Chl a. Chl b thus tends to form electrostatic bonds with Lewis bases with a fixed dipole, such as water and, in particular, peptide backbone carbonyl groups. The coordination bonds are enhanced by H-bonds between the protein and the 7-formyl group. These additional strong interactions with Chl b are necessary to achieve assembly of stable LHCs.     

The Planktonic Index of Biotic Integrity (P-IBI): An approach for assessing lake ecosystem health

Using historical (1970) and more recent (1996) Lake Erie plankton and trophic status data, we developed a Planktonic Index of Biotic Integrity (P-IBI) to measure changes in lake ecosystem health. We used discriminant analysis to determine phytoplankton and zooplankton community characteristics (metrics) that distinguished among levels of impairment. Traditional measures of lake trophic status classes (i.e., oligotrophic, mesotrophic, eutrophic), such as chlorophyll a and total phosphorus concentrations, were used to classify sites on a gradient of impairment. We then judged the ability of plankton metrics to distinguish among trophic status classes. Because of the temporal variability found in plankton communities, we conducted analyses on a monthly basis (May–September). For June, July and August we found five unique metrics that could distinguish among trophic status classes. The P-IBI showed an increase in water quality in Lake Erie between 1970 (<3 = eutrophic) and the mid-1990s (1996 and 1997) (3–4 = mesotrophic) (which reflected mean (±standard error) total phosphorus concentrations (μg/L) 1970 > 1996; western basin (41.53 ± 2.68 > 29.75 ± 1.39), eastern basin (14.84 ± 0.82 > 7.74 ± 0.28) and mean (±standard error) chlorophyll a concentrations (μg/L) uncorrected for pheophytin 1970 > 1996; western basin (12.58 ± 1.82 > 5.40 ± 0.22), central basin (5.90 ± 0.36 > 3.17 ± 0.54), and eastern basin (5.17 ± 0.38 > 1.67 ± 0.18)), with declining water quality in the late 1990s (1998 and 1999) (3) and 2002 (<3). We recommend that the techniques used in creating the P-IBI be investigated for determining ecosystem health of other lakes.     

In situ photosynthetic differentiation of the green algal and the cyanobacterial photobiont in the crustose lichen Placopsis contortuplicata

In situ photosynthetic activity in the green algal and the cyanobacterial photobionts of Placopsis contortuplicata was monitored within the same thallus using chlorophyll a fluorescence methods. It proved possible to show that the response to hydration of the green algal and the cyanobacterial photobionts is different within the same thallus. Measurements of the photochemical efficiency of PS II, Fv/Fm, reveal that in the dry lichen thallus photosynthetic activity could be induced in the green algal photobiont by water vapour uptake, in the cyanobacterial photobiont only if it was hydrated with liquid water. However, rates of apparent electron flow through PS II as well as rates of CO₂ gas exchange were suboptimal after hydration with water vapour alone and maximum rates could only be observed when the thallus was saturated with liquid water. The differences in the waterrelated photosynthetic performance and different light response curves of apparent electron transport rate through PS II indicate that the two photobionts act highly independently of each other. It was shown that the cyanobacteria from the cephalodia in P. contortuplicata act as photobiont. The rate of electron flow through PS II was found to be saturated at 1500 mol photon m^–2 s^–1, despite a considerable increase of non-photochemical quenching in the green algal photobiont which is lacking in the cyanobacterial photobiont. No evidence of photoinhibition could be found in either photobiont. Pronounced competition between the green algal and the cyanobacterial thallus can be observed in the natural habitat, indicating that the symbiosis in P. contortuplicata should be regarded as a very variable adaptation to the extreme environmental conditions in the maritime Antarctic.Abbreviations DR dark respiration - ETR apparent rate of electron flow of PS II (=F/Fm×PFD) - F difference in yield of fluorescence and maximal Fm and steady state Fs under ambient light - Fo minimum level of fluorescence yield in dark-adapted state - Fo minimum level of fluorescence yield after transient darkening and far-red illumination - Fm maximum level of dark-adapted fluorescence yield - Fm maximum yield of fluorescence under ambient light - Fs yield of fluorescence at steady state - Fv difference in minimum fluorescence and maximum fluorescence in dark-adapted state - NP net photosynthesis - NPQ coefficient for non-photochemical quenching - PAR photosynthetically active radiation (400–700 nm) - PFD photon flux density in PAR - PS II photosystem II - qN coefficient for non-photochemical quenching - qP coefficient for photochemical quenching     

Water chemistry variability in the lower intertidal zone [-2pt] of an estuary in the Seto Inland Sea,Japan: seasonal patterns of nutrients and particulate compounds

From April 1994 to April 1996, we carried out monthly surveys on the physical and chemical variability of ebbing water at two intertidal stations near the emerged tidal flat and surface water at a nearby subtidal station, in a tidal estuary of the Seto Inland Sea, Japan. The fresh water runoff was a major source of new nitrogen (nitrate+nitrite = –2.1 × salinity + 74.3, r ² = 0.76, p < 0.001, at the inner intertidal station). In contrast, the absence or weak correlation of ammonium, phosphate and silicate with salinity in ebbing water highlighted the importance of in situ biologically-mediated processes, including the excretory activity of intertidal dominant bivalves (Ruditapes philippinarum and Musculista senhousia) and primary producer nutrient uptake. Among suspended particulate matter (SPM), the negative correlation of Chl a with salinity (p< 0.001) suggested that an upper intertidal zone, where high microphytobenthic assemblages occur, may represent a considerable source of microalgal biomass. Whereas, a stronger correlation of POC with pheo-pigments (r ² 0.92) than with Chl a (r ² 0.44), a low fraction of living phyto-Carbon (ca. 5%) and a high pheo-pigment/Chl a ratio (ca. 3) indicated a high portion of refractory algal material and a close water–sediment coupling on the flat, in which abundant macrozoobenthos is likely to play an important role. In spite of the strong variability of this ecosystems, this study also demonstrated that highly significant seasonal patterns can be recognized in our study area. However, patterns varied depending on the different nutrient species, SPM and sites. In ebbing water, ammonium concentrations were significantly higher in the cold period (i.e. November–April: water temperature 10.0 ± 4.4 °C), when primary producer biomass decreases, while Chl a and pheo-pigment content were 4.3 and 4.8 higher in the warm period (May–October: water temperature 23.5 ± 4.2 °C), respectively. At the subtidal site, nutrients were 1.9 (silicate)–2.9 (phosphate) and SPM was 1.8 (POC)–2.1 (pheo-pigments) times higher in the warm period. On an annual basis, mean pheo-pigment and POC content was 12–25 times and 4–8 times higher on the intertidal zone than on the subtidal zone, respectively, while nutrient concentrations were within the same order of magnitude. Such a qualitative difference (i.e. nutrients vs. SPM) between sites suggests that particle deposition and/or removal is likely to occur along the estuary, resulting in a limited SPM content at the surface layer of the subtidal site, while nutrients are more directly transported into the surface layer of the subtidal zone by lower salinity water mass intrusion from the intertidal zone, most importantly during the warm period.     

Measurement of serum levels of natalizumab, an immunoglobulin G4 therapeutic monoclonal antibody

Chlorophyllide a is a metabolite late in the biosynthesis of chlorophylls and bacteriochlorophylls. Isolation procedures for chlorophyllide a from Rhodobacter capsulatus CB1200 and barley (Hordeum vulgare L.) are described and compared. R. capsulatus CB1200 is a double mutant in the bacteriochlorophyllide a biosynthetic pathway, and chlorophyllide a is excreted by the cells when grown in Tween 80-containing liquid medium. It was purified by liquid or solid phase extraction, yielding 7 mg of chlorophyllide a from 1 L of culture. In a second approach, intrinsic chlorophyllase activity was used to dephytylate chlorophyll in an acetonic preparation of leaves of wild-type or chlorophyll b-deficient barley. Purification was achieved by liquid phase extraction, yielding 14 μg of chlorophyllide a per gram of barley leaves. Chlorophyllide a was identified by thin layer chromatography, absorption spectroscopy, and mass spectrometry.