The Photosynthetic Capacity of the Phytoplankton in the Waters of a Coral Reef

1976 ◽  
Vol 3 (1) ◽  
pp. 53 ◽  
Author(s):  
DJ Griffiths

Phytoplankton are relatively scarce in surface waters in a region of the Great Barrier Reef near Lizard Island. The phytoplankton sampled have a high rate of photosynthetic efficiency (1.2 millimoles CO2 fixed per milligram chlorophyll a per hour), although between 30 and 50% of the total carbon fixed may be excreted in soluble form. The rate of photosynthetic CO2 fixation into the particulate fraction is sensitive to varying levels of oxygen, suggesting the existence of a photorespiratory mechanism, a factor which might significantly influence the photosynthetic productivity of the algae in these tropical waters.


1975 ◽  
Vol 10 (1) ◽  
pp. 33-41 ◽  
Author(s):  
J. Butcher ◽  
M. Boyer ◽  
CD. Fowle

Abstract Eleven small ponds, lined with polyethylene, were used to assess the consequences of applications of *DursbanR at 0.004, 0.030, 0.100 and 1.000 ppm and AbateR at 0.025 and 0.100 ppm active ingredient. The treated ponds showed a more pronounced long-term increase in pH and dissolved oxygen and decreasing total and dissolved carbon dioxide in comparison with untreated ponds. Algal blooms were of longer duration in treated ponds than in controls. Total photosynthetic productivity was higher in treated ponds but bacterial numbers did not change significantly. Photosynthetic productivity was estimated by following the changes in total carbon dioxide.



Zootaxa ◽  
2009 ◽  
Vol 2260 (1) ◽  
pp. 927-930
Author(s):  
J. K. LOWRY ◽  
H. E. STODDART

One species of wandinid amphipod is reported from the Great Barrier Reef, Queensland, Australia. Wandin griffini Lowry & Stoddart is known from Lizard Island, One Tree Island and reefs on the Outer Barrier, living among rubble usually at the base of living coral. The species is rare in this habitat.



Zootaxa ◽  
2007 ◽  
Vol 1434 (1) ◽  
pp. 51 ◽  
Author(s):  
ANNA MURRAY ◽  
GREG W. ROUSE

Two new species of Terebrasabella Fitzhugh & Rouse, 1999 are described from eastern Australia. Terebrasabella hutchingsae sp. nov., was found from preserved coral rock debris collected in 1977 on the outer Barrier Reef near Lizard Island, Queensland. Terebrasabella fitzhughi sp. nov., was found alive in burrows in and among spirorbin serpulid tubes on intertidal rocks in Tasmania in 1996. Both species were found in mucoid tubes, and brood their young in a manner similar to the only other described species of Terebrasabella, T. heterouncinata Fitzhugh & Rouse, 1999. Terebrasabella hutchingsae sp. nov., is exceptional as it possesses a type of thoracic neurochaetal uncinus different from the other two species, and which is similar to the notochaetal acicular “palmate hook” seen in Caobangia. Descriptions of both species are given, and the diagnosis for Terebrasabella is emended. Larval and chaetal morphology and relationships among of the three known Terebrasabella spp. are discussed.



Author(s):  
Margaret E. Bindloss

SynopsisPhotosynthetic productivity of phytoplankton in Loch Leven was studied over a 4-year period (1968–71), using the oxygen light and dark bottle technique. Marked seasonal changes in hourly and daily rates of gross photosynthetic productivity are described within the range 0·02 to 1·59 g O2/m2.h and 0·4 to 21·0 g O2/m2.day respectively. Hourly rates are shown to be relatively insensitive to variations in surface light intensity, whereas daily rates are influenced to a considerable extent by the duration of incident radiation (daylength).The phytoplankton itself exerts a dominant influence on underwater light penetration, accounting for ca 75 per cent of light extinction at highest crop densities. This self-shading effect contributes to the poor correlation observed between crop density and areal gross productivity. The chlorophyll a content per unit area in the euphotic zone often approached its estimated theoretical limit of 430 mg/m2.In general, increase in photosynthetic capacity (per unit content of chlorophyll a) accompanied increase in water temperature. During certain periods an inverse relationship between photosynthetic capacity and population density was evident. Reduction in photosynthetic capacity is attributed, in part, to the high pH values (> 9·5) with concomitant CO2-depIetion associated with dense phytoplankton crops.Estimates of net photosynthetic productivity were frequently zero or negative, even over periods when algal populations were increasing and dissolved oxygen and pH values were above their respective air-equilibrium values. Underestimation of gross photosynthesis due to photochemical oxidation, photorespiration or the use of stationary bottles could not account for this apparent anomaly. The most probable sources of error in the estimates of net photosynthetic productivity are discussed.





2007 ◽  
Vol 52 (3) ◽  
Author(s):  
Rodney Bray ◽  
Thomas Cribb ◽  
Andrea Waeschenbach ◽  
D. Littlewood

AbstractA new species of Acanthocolpidae, Stephanostomum adlardi is described from the serranid Plectropomus leopardus from Lizard Island in the northern Great Barrier Reef. It differs from all previously described acanthocolpids in the structure of the oral sucker which is extended into dorsal and ventral lobes each bearing a row of spines. A phylogenetic tree estimated from combined nuclear small and partial large ribosomal RNA gene sequences shows that, despite the unusual oral sucker structure, the species is a true member of the genus Stephanostomum. The molecular results also suggest that Monostephanostomum nolani is derived from within Stephanostomum.





1983 ◽  
Vol 13 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Edward C. Jensen ◽  
James N. Long

Results are presented from an intensive study of crown structure in a 39-year-old codominant Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). The patterns of crown development observed may represent a species adaptation for maximizing photosynthetic efficiency. While branches originating at nodes provide the basic structure of the crown, short-lived nonnodal branches provide much of the photosynthetic capacity. In addition, nonnodal branches support nearly half of the young needles near the top and outside edges of the crown.





2000 ◽  
Vol 51 (3) ◽  
pp. 221 ◽  
Author(s):  
D. C. Zeller ◽  
G. R. Russ

A mark–release–resighting (MRR) technique was used to estimate population size of the coral trout, Plectropomus leopardus, on coral reefs fringing Lizard Island, Great Barrier Reef, Australia. Fish were captured by hook-and-line fishing, and marked with individual freeze-brand numbers in August 1995. An underwater visual census (UVC) technique was used during September and October 1995 both for resighting of marked fish and to make an independent estimate of fish density and thus population size. The study area was 750 966 m2 . The UVC sampled 154 000 m2 (20.5%) of this area. Six different methods of analysis of MRR gave similar population size estimates (e.g. Petersen 12 873; 95% CI 9989–15 754) extrapolated to the 4.5 million-m2 reef area from datum to 20-m depth around Lizard Island. UVC gave a population size estimate (24 182; 95% CI 21 860–26 504) twice that of MRR. The lower estimate derived from MRR may be the result of tag-induced mortality, or of the relative difficulty in discriminating between marked and unmarked trout by UVC. This is only the second estimate of population size of coral trout on an area of the Great Barrier Reef.



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