EVOLUTION OF THE ANTARCTIC MARINE BENTHIC ALGAL FLORA

There are many logistic difficulties associated with studying Antarctic marine algae and, as a consequence, the taxonomic information available is far from comprehensive and any generalizations should be regarded with caution. The Antarctic marine benthic flora is characterized by a low species richness. Biogeographical characteristics of the flora are outlined. There is a high degree of endemism, possibly around 35–40%. Other major floristic elements are a group of species with a distribution extending to Tierra del Fuego and subantarctic islands, a group spread through temperate regions of the Southern Hemisphere, and a cosmopolitan group. Ecological observations show that ice has a major effect on the occurrence and distribution of algae, and ecophysiological studies indicate that Antarctic macroalgae possess various adaptations to ice, low temperatures, and strongly seasonal light conditions. Possible trends in the evolution of the Antarctic benthic marine flora, including a reduction in species richness and the origins of biogeographical links with subantarctic and temperate regions of the Southern Hemisphere, are discussed in the context of tectonic and climatic changes over the past 100 million years. A comparison is made with studies on the evolution of shallow-water marine fauna.     

STUDIES ON THE MARINE ALGAL FLORA OF VENEZUELA. V. PSEUDOGLOIOPHLOEA HALLIAE1,2

Details of structure and reproduction, particularly pre- and postfertilization development, are given for the first time in Pseudogloiophloea halliae. In general, the author's observations agree with what is known for most species of the genus. Some remarks on the identity of 3 species of Pseudogloiophloea in the tropical and subtropical American Atlantic shores are also included.     

西藏豆科植物一新记录种

作者在从事《青藏高原及其邻近地区植物区系及分布格局研究 (KSCX2 - 1 - 0 6B)》项目研究时 ,对PE所藏青藏高原地区豆科标本进行了全面的整理和鉴定 ,首次发现民和黄芪在西藏有分布 ,本文予以报道并附有该种详细的形态描述     

BOLIDOMONAS: A NEW GENUS WITH TWO SPECIES BELONGING TO A NEW ALGAL CLASS, THE BOLIDOPHYCEAE (HETEROKONTA)

A new algal class, the Bolidophyceae (Heterokonta), is described from one genus, Bolidomonas, gen. nov., and two species, Bolidomonas pacifica, sp. nov and Bolidomonas mediterranea, sp. nov., isolated from the equatorial Pacific Ocean and the Mediterranean Sea, respectively. Both species are approximately 1.2 μm in diameter and have two unequal flagella; the longer flagellum bears tubular hairs, whereas the shorter is smooth. The flagellar basal apparatus is restricted to two basal bodies, and there is no transitional helix. Cells are naked, devoid of walls or siliceous structures. The internal cellular organization is simple with a single plastid containing a ring genophore and a girdle lamella, one mitochondrion with tubular cristae, and one Golgi apparatus close to the basal bodies. The Mediterranean and the Pacific species differ in the insertion angle between their flagella and their pattern of swimming, these differences possibly being linked to each other. Analyses of the SSU rDNA gene place the two strains as a sister group to the diatoms. Moreover, pigment analyses confirm this position, as fucoxanthin is found as the major carotenoid in both lineages. These data strongly suggest that the ancestral heterokont that gave rise to the diatom lineage was probably a biflagellated unicell.     

安徽植物区系新增补

报导了安徽植物地理分布新记录种６种。分别是：麻椰树、膜叶椴、细枝绣线菊、毛花绣线菊、巴东胡颓子、紫斑风铃草。     

中国豆科植物区系新资料

报道了中国豆科一新记录属闭荚藤属和一新记录种滇西围涎树前者分布于我国西藏墨脱雅鲁藏布江峡谷热带山地雨林中,后者见于云南西部盈江亚热带山地常绿阔叶林中。     

A VIDEO SONAR AS A NEW TOOL TO STUDY MARINE MAMMALS IN THE WILD: MEASUREMENTS OF DOLPHIN SWIMMING SPEED

The use of a multibeam sonar for fine-scale studies of the foraging activity of bottlenose dolphins ( Tursiops truncatus ) was tested in a coastal environment where a group of 14 individuals is known to be resident. The sonar was set on a rubber boat and the signals were received continuously as the dolphins were foraging in a pass swept by strong tidal currents. These signals were recorded in HI 8 video standard. The system produced real-time undistorted images of the dolphins and of their movements within the limits of the sonar beam (15° vertical width, 90° horizontal width, range set at 50 m). The average swimming speed relative to the bottom was 1.8 m ·sec⁻¹ but swimming speed relative to the water was 2.2 m-sec⁻¹ when allowance was made for the average 1.2 m·sec⁻¹ tidal current. Maximum swimming speed relative to the water was as high as 4.8 m·sec⁻¹. It is estimated from studies of swimming energetics that continuously foraging in a current vein flowing at 1.2 m·sec¹ would represent only small additional costs compared to foraging out of these currents. However, previous observations of the same pod have shown that these dolphins keep foraging in this site when current speed reaches 2.7 m·sec⁻¹; under such circumstances, the cost of foraging in this site was calculated to increase by 96%. This suggests that foraging efficiency should be dramatically enhanced during rising tide since the dolphins consistently forage in these currents year round.     

PATTERNS OF ALGAL SUCCESSION IN A PERTURBATED MARINE INTERTIDAL COMMUNITY1

Patterns of algal succession for a sewage-polluted and an unpolluted habitat near Wilson Cove, San Clemente Island, California, were studied from December 1974 to June 1977. Resident populations were analyzed for 56 fully denuded and 34 undisturbed control quadrats during 11 assessment periods. The denuded quadrats in the perturbated (polluted) habitat showed recovery within 1.0 mo as determined by cover, percent similarity and species diversity comparisons with control plots. The short recovery times of the algal populations dominating the perturbated habitat indicate that these species maintain relatively constant overall abundances due to their potential for rapid recruitment and growth. Denuded quadrats in the unpolluted habitat did not show recovery even after 30.0 mo. These quadrats were dominated during the first 1.3 mo by algae characteristic of the perturbated area, including filamentous Ectocarpaceae, colonial diatoms and bluegreen algae. Petalonia fascia (Müll.) Kuntze (1.3–3.0 mo), and Scytosiphon lomentaria (Lyngb.)J. Ag. and Colpomenia sinuosa (Roth) Derb. & Sol. (1.3–5.0 mo) were abundant shortly following plot denudation and provided thick growths that may have excluded other algae. The similarity between the species occupying the sterilized plots during the first few months and those that provide the majority of cover in the perturbated area supports the hypothesis that the dominant algae of the upper and midintertidal regions of this habitat consist largely of early successional or opportunistic species with high capacities for growth and reproduction. Additionally, these experiments suggest that algal populations described for other perturbated epilithic systems also represent resilient subclimax associations.     

河南省藓类植物新报

报道了最近在河南省宝天曼自然保护区所采１４号藓类植物标本中,经研究,其中包括１个新变种,即：苏氏牛舌藓河南变种Ａｎｏｍｏｄｏｎ ｓｏｌｏｖｊｏｖｉｉ Ｌａｚａｒｅｎｋｏ ｖａｒ．ｈｅｎａｎｅｎｓｉｓ Ｔａｎ,Ｂｏｕｆｆｏｒｄ ｅｆ Ｙｉｎｇ,ｖａｒ．ｎｏｖ．另外有８种为河南省新纪录。     

INTRACELLULAR PHOTOSYNTHATE ALLOCATION AND THE CONTROL OF ARCTIC MARINE ICE ALGAL PRODUCTION1

Ice algae are a case study in photo-autotrophic growth and metabolism under chronically low temperature and irradiance. We measured the allocation of ¹⁴C-labelled photosynthate among major classes of intracellular carbon (low molecular weight compounds, or LMW; lipid; protein; and polysaccharide) and found light-dependent changes in allocation broadly similar to photo-adaptive responses known in phytoplankton at higher temperatures; average relative allocation to protein varied inversely (10–37%) and allocation to lipids and polysaccharides directly (10–23%, and 16–21%, respectively) with the sub-inhibiting irradiance levels we employed (3.5–33.0 μE·M⁻²·s⁻¹). Unlike many observations at higher temperatures, ours indicated (on average) a large and light-insensitive allocation to LMW (ca. 40%) and a greater light-sensitivity in lipid than in polysaccharide allocation. At the higher incubation irradiances, resembling in situ levels typical of areas with little (0–5 cm) snow cover, allocation to protein was often low (10–13%) compared to many observations of nutrient-sufficient or light-limited phytoplankton. Allocation to protein increased substantially (to ca. 40%) during a period of intensified tidal mixing, and assimilation numbers also attained a maximum at about the same time. Suck dynamics show that the ice algae are not constrained to their often protein-poor allocation by the constantly low ambient temperature. Rather, they display marked shifts in metabolism consistent with major changes in light and inorganic nutrient supply, driven in part by the physical process of tidal mixing.     

INTRACELLULAR PHOTOSYNTHATE ALLOCATION AND THE CONTROL OF ARCTIC MARINE ICE ALGAL PRODUCTION1

Ice algae are a case study in photo-autotrophic growth and metabolism under chronically low temperature and irradiance. We measured the allocation of ¹⁴C-labelled photosynthate among major classes of intracellular carbon (low molecular weight compounds, or LMW; lipid; protein; and polysaccharide) and found light-dependent changes in allocation broadly similar to photo-adaptive responses known in phytoplankton at higher temperatures; average relative allocation to protein varied inversely (10–37%) and allocation to lipids and polysaccharides directly (10–23%, and 16–21%, respectively) with the sub-inhibiting irradiance levels we employed (3.5–33.0 μE.M⁻². s⁻¹). Unlike many observations at higher temperatures, ours indicated (on average) a large and light-insensitive allocation to LMW (ca. 40%) and a greater light-sensitivity in lipid than in polysaccharide allocation. At the higher incubation irradiances, resembling in situ levels typical of areas with little (0–5 cm) snow cover, allocation to protein was often low (10–13%) compared to many observations of nutrient-sufficient or light-limited phytoplankton. Allocation to protein increased substantially (to ca. 40%) during a period of intensified tidal mixing, and assimilation numbers also attained a maximum at about the same time. Such dynamics show that the ice algae are not constrained to their often protein-poor allocation by the constantly low ambient temperature. Rather, they display marked shifts in metabolism consistent with major changes in light and inorganic nutrient supply, driven in part by the physical process of tidal mixing.     

A NEW MODE OF LIFE HISTORY IN THE FRESHWATER RED ALGAL GENUS BATRACHOSPERMUM

In a new type of Batrachospermum life history, the Batrachospermum phase does not originate from the erect filaments of a Pseudochantransia but directly from a prostrate crustose growth, the prothalle of Sirodot. It is probable that the few lowermost segments of those Batrachospermum cladomes are diploid, the remainder due to an interposed “somatic” meiosis are haploid.