CALCIUM OXALATE CRYSTALS IN THE GREEN ALGA SPIROGYRA SP. (ZYGNEMATALES, CHLOROPHYTA)

Specimens of an unidentified species of the freshwater green alga Spirogyra were found to have abundant cruciate cellular inclusions up to 34 micrometers long. A crystalline nature was shown by birefringence in polarized light. Despite their large size and complex shape, these inclusions did not occur free in the large central vacuole. Instead, they were associated with cytoplasmic strands that spanned the space between gyres of the parietal spiral chloroplasts and with strands that suspended the nucleus in a cytoplasmic embayment of the central vacuole. Some crystals moved directionally along the cytoplasmic strands, and their movement was arrested by cytochalasin B, suggesting that actin microfilaments had a role in crystal movement. Solubility tests showed that the inclusions were composed of calcium oxalate; they dissolved rapidly in weak hydrochloric acid without effervescence, but they were not soluble in concentrated acetic acid or sodium hypochlorite. A colorimetric enzymatic test for oxalate was used to demonstrate microscopically the presence of oxalate and to quantify the amounts. The calcium oxalate crystals were surrounded by a water-soluble organic matrix that retained the shape of the crystal even after demineralization. Scanning electron microscopy was used to examine the morphology of isolated crystals.     

黑龙江省双星藻科新种

三江水绵图1 Spirogyra sanjingensis sp. nov. Celluis vegetativis 104-133μlatis, 142—295μlongis; dissepimentis planis; chromatophoris 9-10(11), anfractibus 1-1.5; conjugations scalari, tubo ex utroque cellula mascula et feminca emisso; cellulis fructiferis cylindricis, levi-     

FACULTATIVE PARASITISM OF SPIROGYRA SP. (CHLOROPHYTA) BY SAPROLEGNIA ASTEROPHORA AND PYTHIUM GRACILE (EUMYCOTA,OOMYCETES)1

Spirogyra sp. Link was found to be parasitized by filamentous fungi tentatively identified as Saprolegnia asterophora de Bary and Pythium gracile Schenk, in field samples and when maintained in unaltered pond water in an 18 h fluorescent light–6 h dark regime at 18 ± 2°C. Collections were made periodically between March 1978, and November 1979, from a pond in Mill Seek Sanctuary near Oyster Bay, Nassau Co., Long Island, New York. Initially, less than 1% of the total field population of Spirogyra sp. was infected by either fungal parasite with Saprolegnia asterophora being the dominant parasite present generally alone in most samples or present in 80–95% of the total number of infected algal filaments when occurring concurrently with P. gracile. However, in the laboratory, approximately 100% of the Spirogyra sp. filaments in any given sample became infected by Saprolegnia asterophora and/or P. gracile within a 1—2 wk and 3–4 wk period, respectively, with vegetative hyphae involved in the spread of infection to neighboring algal filaments. Infection of algal filaments occurred at random points with cell to cell hyphal extension within the filament causing disruption of host cells. Development of S. asterophora, and possibly P. gracile, sexual reproductive structures was common in relation with the host with asexual sporangial production not observed. Saprolegnia asterophora and P. gracile were cultured on glucose, yeast extract, malt extract (GYM) medium from infected Spirogyra sp. filaments, with infection of healthy algal filaments using these cultures by Saprolegnia asterophora, but not by P. gracile, induced in the laboratory. Growth responses and tropic responses of the fungi to the algal host could not be demonstrated.     

A POLYPLOID SPECIES COMPLEX OF SPIROGYRA COMMUNIS (CHLOROPHYTA) OCCURRING IN NATURE 1

Investigations were conducted to determine whether ploidal changes found in laboratory cultures of Spirogyra also occur in nature. In an earlier study filament types identifiable as three different species (Spirogyra singu-laris Nordstedt, S. communis (Hassall)Kütz., S. fragilis Jao) arose from an original clonal culture through vegetative growth and sexual reproduction. These three “species” or filament groups differed in filament width, chloroplast number, zygospore size, and chromosome number. The differences in chromosome number represented a polyploid series of diploid (S. communis), triploid (S. fragilis), and tetraploid (S. singularis) forms in which width increased with ploidal level. The three width groups constituted a “species complex.” Five years after isolation of the original strain in this species complex, filaments corresponding to two of the width groups (S. singularis and S. communis) were found at the original collection site in the Santa Catalina Mountains in southern Arizona. The two field-collected groups were indistinguishable from the laboratory species complex in morphology and chromosome number. Homothallic conjugation within the two field width groups yielded progeny similar to those from homothallic conjugation of groups in the laboratory species complex. Filament widths of progeny were generally within the width limits of respective parental groups. The four possible intergroup crosses between the two laboratory and two field width groups yielded progeny similar to the wider parent (S. singularis) or the parent of intermediate width (S. fragilis). Progeny characteristics were determined by the width groups of parents, regardless of whether parents came from the laboratory or field. The similarities in morphology, chromosome numbers, and reproductive behavior of laboratory and field width groups imply that the laboratory species complex of S. communis has a natural counterpart in the field.     

A MOVING MAT: PHOTOTAXIS IN THE FILAMENTOUS GREEN ALGAE SPIROGYRA (CHLOROPHYTA,ZYGNEMATACEAE)1

A blue light– (peak at 470 nm) induced photomovement was observed in the filamentous eukaryotic algae, Spirogyra spp. When Spirogyra filaments were scattered in a water chamber under a unilateral light source, they rapidly aligned toward the light source in 1 h and bound with neighboring filaments to form thicker parallel bundles of filaments. The filaments in the anterior of the bundles curved toward the light first and then those in the posterior began to roll up toward the light, forming an open‐hoop shape. The bundle of filaments then moved toward the light source by repeated rolling and stretching of filaments. When the moving bundle met other filaments, they joined and formed a bigger mat. The coordination of filaments was essential for the photomovement. The average speed of movement ranged between 7.8 and 13.2 μm·s^?1. The movement was induced in irradiance level from 1 to 50 μmol photons·m^?2·s^?1. The filaments of Spirogyra showed random bending and stretching movement under red or far‐red light, but the bundles did not move toward the light source. There was no distinct diurnal rhythm in the photomovement of Spirogyra spp.     

TEMPERATURE AND IRRADIANCE EFFECTS ON GROWTH OF PITHOPHORA OEDOGONIA (CHLOROPHYCEAE) AND SPIROGYRA SP. (CHAROPHYCEAE)1

Growth responses of Pithophora oedogonia (Mont.) Wittr. and Spirogyra sp. to nine combinations of temperature (15°, 25°, and 35°C) and photon flux rate (50, 100, and 500 μmol·m^?2·s^?1) were determined using a three-factorial design. Maximum growth rates were measured at 35°C and 500 pmol·m^?2·s^?1 for P. oedogonia (0.247 d^?1) and 25°C and 500 μmol·m^?2·s^?1 for Spirogyra sp. (0.224 d^?1). Growth rates of P. oedogonia were strongly inhibited at 15°C (average decrease= 89%of maximum rate), indicating that this species is warm stenothermal. Growth rates of Spirogyra sp. were only moderately inhibited at 15° and 35°C (average decrease = 36 and 30%, respectively), suggesting that this species is eurythermal over the temperature range employed. Photon flux rate had a greater influence on growth of Spirogyra sp. (31% reduction at 50 pmol·m^?2·s^?1 and 25°C) than it did on growth of P. oedogonia (16% reduction at 50 μmol·m^?2·s^?1 and 35°C). Spirogyra sp. also exhibited much greater adjustments to its content of chlorophyll a (0.22–3.34 μg·mg fwt^?1) than did P. oedogonia (1.35–3.08 μg·mg fwt^?1). The chlorophyll a content of Spirogyra sp. increased in response to both reductions in photon flux rate and high temperatures (35°C). Observed species differences are discussed with respect to in situ patterns of seasonal abundance in Surrey Lake, Indiana, the effect of algal mat anatomy on the internal light environment, and the process of acclimation to changes in temperature and irradiance conditions.     

A POLYPLOID SPECIES COMPLEX IN SPIROGYRA MAXIMA (CHLOROPHYTA,ZYGNEMATACEAE), A SPECIES WITH LARGE CHROMOSOMES1

A species complex in Spirogyra consists of the series of filament morphotypes of various ploidal levels arising from an original morphotype within a clonal culture or in nature. A clonal culture of filaments identified as Spirogyra maxima (Hassall) Kützing produced several morphotypes, i.e. filament types of distinctly different widths and ploidal levels. Banding patterns and satellites were visible on chromosomes stained at mitotic prophase and metaphase. The original culture of S. maxima contained filaments averaging 127 μ wide. Vegetative cells of the original culture contained six large chromosomes (>4 μ long), identifiable as three distinct pairs based on banding patterns and presence of satellites: (1) one pair of short chromosomes (ca. 5.0 μ); (2) one pair of long chromosomes (ca. 8.0 μm); and (3) a second pair of long chromosomes (ca. 9.0 μm) including a nucleolar organizing region and satellite. A larger morphotype averaging 175 μm in width contained 12 chromosomes, with two pairs of short chromosomes and four pairs of long chromosomes (satellites were usually indistinct). Aneuploid chromosome numbers ranging from 5 to 13 were observed in a few cells. Binucleate and trinucleate cells were also observed. A twobanded chromosome fragment was observed in a few cells with 6 chromosomes and a few cells with 12 chromosomes. The variety of morphotypes derived in this study could be identified as four different species of Spirogyra by conventional taxonomic criteria. The banding patterns and satellites on chromosomes suggest that three pairs of homologous chromosomes are present in filaments of the original clonal culture and that these filaments are themselves autopolyploid (diploid) descendants of ancestral form with a base chromosome number of x = 3.     

EFFECTS OF TEMPERATURE AND IRRADIANCE ON THE SEASONAL VARIATION OF A SPIROGYRA (CHLOROPHYTA) POPULATION IN A MIDWESTERN LAKE (U.S.A.)

Although Spirogyra Link (1820) is a common mat‐forming filamentous alga in fresh waters, little is known of its ecology. A 2‐year field study in Surrey Lake, Indiana, showed that it grew primarily in the spring of each year. The population consisted of four morphologically distinct filamentous forms, each exhibiting its own seasonal distribution. A 45‐μm‐wide filament was present from February to late April or early May, a 70‐μm‐wide form was present from late April to mid‐June, a 100‐μm‐wide form was present from February to mid‐June, and a 130‐μm‐wide form appeared only in February of 1 of 2 study years. The 70‐ and 100‐μm‐wide forms contributed to the peak amount of biomass observed in late May and early June. Multiple regression analysis indicated that the presence of the 45‐, 70‐, and 100‐μm‐wide forms was negatively correlated with temperature. Presence of the 130‐μm‐wide form was negatively correlated with irradiance. Isolates of these filament forms were exposed to temperature (15, 25, and 35° C)/irradiance (0, 60, 200, 400, 900, and 1500 μmol·m^?2·s^?1) combinations in the laboratory. Growth rates of the 45‐μm‐wide form were negative at all irradiances at 35° C, suggesting that this form is susceptible to high water temperatures. However, growth rates of the other forms did not vary at the different temperatures or at irradiances of 60 μmol·m^?2·s^?1 or above. Net photosynthesis was negative at 35° C and 1500 μmol·m^?2·s^?1 for the 100‐ and 130‐μm‐wide forms but positive for the 70‐μm‐wide form. All forms lost mat cohesiveness in the dark, and the 100‐ and 130‐μm‐wide forms lost mat cohesiveness under high irradiances and temperature. Thus, the morphological forms differed in their responses to irradiance and temperature. We hypothesize that the rapid disappearance of Spirogyra populations in the field is due to loss of mat cohesiveness under conditions of reduced net photosynthesis, for example, at no to low light for all forms or at high light and high temperatures for the 100‐ and 130‐μm‐wide forms. Low light conditions can occur in the interior of mats as they grow and thicken or under shade produced by other algae.     

PHOSPHORUS UPTAKE KINETICS OF SPIROGYRA FLUVIATILIS (CHAROPHYCEAE) IN FLOWING WATER1,2

The inorganic phosphorus (P_i) uptake kinetics of Spirogyra fluviatilis Hilse were examined as a function of phosphorus cell quota (Q^P) and flow velocity in a laboratory stream apparatus. Short-term uptake and the acclimation of the uptake mechanism to flow were measured by the disappearance of P_i pulses in a recirculating flow cell. Short-term P_i uptake was biphasic. When the alga was P-deficient, Phase 1 and 2 half-saturation constants and maximum uptake rates were 11.0 and 47.2 μg P·L^?1 and 473 and 803 μg P·g dry wt^?1 h^?1, respectively. Flowing water altered short-term uptake when the alga was P-deficient, but not when it was P-replete. When Q^P was less than 0.21%, increases in flow velocity from 3 to 15 cm·s^?1 enhanced uptake with maximum uptake for any P_i pulse at 12 and 15 cm·s^?1. At 22 and 30 cm·s^?1, uptake was reduced by 12% or more relative to the maxima. If, however, the alga was cultivated at 22 and 30 cm·s^?1 and short-term P_i uptake was measured at 12 cm·s^?1, uptake was on average 33% greater than when the alga was cultivated at the latter velocity. Apparently, the alga could adjust short-term uptake to compensate for the suboptimal conditions of the faster velocities. Long-term P_i uptake and net phosphorus efflux were estimated by a non-steady state application of the Droop equation. Long-term uptake of very low P_i concentrations was not reduced by fast flowing water. Instead, uptake increased proportionately with flow velocity. Maximum phosphorus efflux from S. fluviatilis was 3% of cellular P per hour and occurred when Q^P was greater than 0.2%. At lower Q^P, the hourly efflux rate was typically less than 1%. Flowing water did not greatly enhance efflux, although when P_i was undetectable, efflux did tend to increase slightly with velocity. The data show that the effects of flowing water on P_i uptake were varied and not always beneficial. If the effects of flowing water on nutrient acquisition by other lotic algae are similarly varied and complex, flow may be an important determinant of nutrient partitioning among benthic algae in streams.     

几种生物CaCO_3霰石结晶的取向性

ＣａＣＯ３结晶广泛分布于生物界,其主要结晶形式为方解石、霰石及球霰石。用Ｘ－射线衍射法对三角帆蚌及合浦珍珠母贝的珍珠层、墨鱼骨和大黄鱼耳石的ＣａＣＯ３结晶进行测定,发现各样品均有一定取向性,以三角帆蚌和合浦珍珠母贝珍珠层的取向性为最强,墨鱼骨的取向性次之,大黄鱼耳石的取向性最小,以上材料粉末样的衍射分析表明,各样品对应ｄ值间差异极小,均为Ｘ射线衍射卡（５—０４５３）所表征的ＣａＣＯ３霰石结构。     

几种生物CaCO3霰石结晶的取向性

CaCO3结晶广泛分布于生物界,其主要结晶形式为方解石、霰石及球霰石。用X－射线衍射法对三角帆蚌及合浦珍珠母贝的珍珠层、墨鱼骨和大黄鱼耳石的CaCO3结晶进行测定,发现各样品均有一定取向性,以三角帆蚌和合浦珍珠母贝珍珠层的取向性为最强,墨鱼骨的取向性次之,大黄鱼耳石的取向性最小,以上材料粉末样的衍射分析表明,各样品对应d值间差异极小,均为X射线衍射卡（5－0453）所表征的CaCO3霰石结构。     

PHYSIOLOGICAL RESPONSES TO TEMPERATURE AND IRRADIANCE IN SPIROGYRA (ZYGNEMATALES, CHAROPHYCEAE)1

Spirogyra Link (1820) is an anabranched filamentous green alga that forms free-floating mats in shallow waters. It occurs widely in static waters such as ponds and ditches, sheltered littoral areas of lakes, and stow-flowing streams. Field observations of its seasonal distribution suggest that the 70-μm-wide filament form of Spirogyra should have a cool temperature and high irradiance optimum for net photosynthesis. Measurements of net photosynthesis and respiration were marie at 58 combinations of tight and temperature in a controlled environment facility. Optimum conditions were 25°C and 1500 μmol photons m⁻² s⁻¹, at which net photosynthesis averaged 75.7 mg O₂ gdm⁻¹ h⁻¹. Net photosynthesis was positive at temperatures from 5° to 35°C at most irradiances except at combinations of extremely low irradiances and high temperatures (7 and 23 μmol photons m⁻² s⁻¹ at 30°C and 7, 23, and 35 μmol photons m⁻² s⁻¹ at 35°C). Respiration rates increased with both temperature and prior irradiance. Light-enhanced respiration rates were significantly greater than dark respiration rates following irradiances of 750 μmol photons m⁻² s⁻¹ or greater. Polynomials were fitted to the data to generate response surfaces; such response surfaces can be used to represent net photosynthesis and respiration in ecological models. The data indicate that the alga can tolerate the cool water and high irradiances characteristic of early spring but cannot maintain positive net photosynthesis under conditions of high temperature and low light (e.g. when exposed to self-shading ).     

THE RPS12 GENE IN SPROGYRA MAXIMA (CHLOROPHYTA) AND ITS EVOLUTIONARY SINGNIFICANCE1

The str operon consists fo four genes in eubacteria. Portions of his operon are conserved in the chloroplast genomes of green algae and land plants. In land plant chloroplasts, the str operon comprises only two genes, rps12 and rps7, and is arranged in a trans-spliced state. Since no other previously studied chloroplast genome contains this arrangement, and because the charophyte lineage is the sister group of land plants, we chose to look for this arrangement in the Charophyceae. The two str genes, rps12 and rps7, present in the chloroplasts of Spirogyra maxima Hanssall, were identified by hybridization of a Southern blot and requenced. The results indicate that Spirogyra contains a str operon almost identical to that of land plant chloroplasts. Based upon the structure of the operon in other chloroplasts and eubacterial genomes, the trans-spliced state most likely evolved early within the charophyte lineage.     

ISOLATION OF A NUCLEUS-ASSOCIATED MICROTUBULE SCAFFOLD FROM SPIROGYRA (ZYGNEMATALES, CHAROPHYCEAE)

A phragmosome-like perinuclear scaffold attaches to helical chloroplast bands in the peripheral cytoplasm of Spirogyra crassa Kützing by rigid, stalk-like cytoplasmic strands. Balanced integration of forces within this scaffold by microfilament-based tension conveyed along stabilized microtubules (MTs) within the stalks controls transverse centering of the lenticular nucleus in the cylindrical cell prior to mitosis. Nuclei with their associated scaffolds were released from rapidly frozen, shattered cells upon thawing in a MT-stabilizing buffer and could be purified by a procedure combining filtration, differential centrifugation, and isopyknic centrifugation in a linear density gradient. In the osmotically indifferent gradient medium Nycodenz™, nuclei with adhering scaffolds attained a buoyant density of 1.26–1.27 g·cm⁻³. The nuclei maintained their energetically unfavorable, lenticular shape in vitro and appeared structurally preserved as judged by video-enhanced differential interference contrast and by fluorescent staining of DNA with 4'-6'-diamidino-2-phenylindole. The stalks of the scaffold, though still radiating from the nuclear rim, lost their straightness and were often severed during the isolation process. The distal ends of many unsevered stalks and of stalk fragments were still associated with chloroplast fragments. Persistent flexural rigidity of the scaffold stalks and indirect immunofluorescence indicated preservation of MTs. In addition to tubulin, both actin and an intermediate filament antigen of M _r ≈ 68 kDa were detected in the isolated nuclei with associated scaffolds by immunoblot with monoclonal antibodies.     

DISTRIBUTION,MORPHOLOGICAL DIVERSITY AND EVIDENCE FOR POLYPLOIDY IN NORTH AMERICAN ZYGNEMATACEAE (CHLOROPHYTA)1

Large-scale collections of Zygnemataceae in the continental United States of America were made between March and August in 1982, 1983, and 1984. Collections were made on a 31000-km transect through 35 states. Zygnemataceae were found at 318 sites was inspected. Temperature average 19°C and p^H averaged 6.1 over all sites. Algal strains in collections were identified to genus, characterized for filament width, chloroplast number, and end wall type, then photographed and isolated into unialgal culture. Spirogyra was the most common genus collected(632 strains), followed in abundance by Zygnema (174 Strains) and Mougeotia (135 strains). These three genera contained 95% of the strains collected and were equally widely distributed. Strains of the three genera frequently occurred together; no genus displayed evidence of habitat specialization among the three habitat types: flowing water, permanent ponds or lakes, and temporary pools. In Spirogyra, strains with plane (flat) end walls were four times more abundant than those with replicate (interlocking) end walls. Spirogyra with plane end walls showed more variation in filament width than Zygnema, Mougeotia, or Spirogyra with replicate end walls. In Spirogyra with plane end walls, filament width was correlted with nuclear DNA content and number of strains found per collection site was twice that of other genera or Spirogyra, with replicate end walls. Spirogyra strains wider than 70 μm were more frequent on the northern part of the transect. It is proposed that polyploidy may be of widespread occurrence in Spirogyra with plane end walls and that associated morphological plasticity may account for the high apparent specied diversity and survival of the genus in a wider variety of microhabitats than occupied by other Zygnemataceae.     

PHYLOGENY OF SPIROGYRA AND SIROGONIUM (ZYGNEMATOPHYCEAE) BASED ON RBCL SEQUENCE DATA1

DNA sequence data were obtained for the gene encoding the large subunit of RUBISCO (rbcL) from 26 strains of Spirogyra and seven of Sirogonium, using as outgroups 10 genera in the Zygnematales and Desmidiales (Closterium, Cosmarium, Cylindrocystis, Gonatozygon, Mesotaenium, Netrium, Penium, Zygnema, Zygnemopsis, Zygogonium). Sequence data were analyzed using maximum parsimony (MP), maximum likelihood (ML), and Bayesian inference (BI), with bootstrap replication (MP, ML) and posterior probabilities (BI) as measures of support. MP, ML, and BI analyses of the rbcL data strongly support a single clade containing Spirogyra and Sirogonium. The Spirogyra taxa are monophyletic, with the exception of Spirogyra maxima (Hassall) Wittrock, which is nested within a clade with Sirogonium and shares with them the characters of loosely spiraled chloroplasts (<1 complete turn per cell) and anisogamy of gametangial cells; S. maxima differs from Sirogonium in displaying well‐defined conjugation tubes rather than a tubeless connection involving bending (genuflection) of filaments. The ML and BI analyses place this Sirogonium/Spirogyra maxima clade sister to the remaining Spirogyra. Morphological differences among strains of Spirogyra grouped together on the basis of rbcL data, including laboratory strains derived from clonal cultures (Spirogyra communis, S. pratensis), indicate that some characters (filament width, chloroplast number) used in the traditional taxonomy of this group are poor measures of species identity. However, some characters such as replicate end walls and loose spiraling of chloroplasts may be synapomorphies for Spirogyra clades.     

MULTIMINERAL CALCAREOUS DEPOSITS IN THE MARINE ALGA ACETABULARIA ACETABULUM (CHLOROPHYTA; DASYCLADACEAE)

The ultrastructure and mineralogy of cultured and wild specimens of the green algae Acetabularia acetabulum were studied. Sites of calcification were clarified using TEM and SEM. Minerology was determined via electron diffraction, energy-dispersive x-ray microanalysis, and Fourier transform infrared spectral analyses of the calcareous deposits. These deposits were found covering the surface and within the cell wall of the cultured juveniles and adult wild specimens of A. acetabulum. Deposits within and directly over the wall were amorphous calcium carbonate (ACC) in granular form. In-wall and outer cell wall ACC appear to develop independently from each other. The formation of the in-wall ACC may be mediated by the wall structure and/or chemistry, whereas mucin may be the factor mediating formation of outer cell wall ACC. In contrast to the stable in-wall ACC, outer cell wall ACC could be transitory, transforming into aragonite. In cultured cells, a small amount of monohydrocalcite crystals and calcite were found. It is possible that these were transformation products of ACC. In wild specimens, whewellite (calcium oxalate monohydrate) was present inside and outside of the cap wall. It is unclear if whewellite is present within the cytoplasm. Local and temporal differences in the microenvironments for the multiphase mineralization are suggested.     

高CO_2和UVR对叉节藻和刚毛藻生长及光化学效率的影响

为研究高CO2及UVR对大型海藻耦合效应的影响,实验选择红藻门可进行钙化的叉节藻(Amphiroa sp.)与绿藻门不具钙化能力的刚毛藻(Cladophora sp.)进行对比,探讨了高CO2与UVR对这两种藻生长及光化学效率的影响,并分析高CO2和UVR的耦合效应。结果表明,CO2浓度由360μmol/mol当前空气中CO2浓度)提高到1000μmol/mol培养73d后,叉节藻的生长下降了40.01%,而刚毛藻却增加了40.08%,UVR对叉节藻的光华学效率造成的抑制率增加了77.76%,对刚毛藻的抑制率增加了17.02%,这说明高CO2引起的海水酸化加剧了UVR对藻体的负面效应,且对具有钙化能力的叉节藻影响更显著。而叉节藻和刚毛藻之间的差异体现了藻体对海水酸化和UVR响应的种间特异性。