Pattern of outbreaks of crown-of-thorns starfish (Acanthaster planci L. ) along the Great Barrier Reef since 1966

1992 ◽  
Vol 43 (3) ◽  
pp. 555 ◽  
Author(s):  
PJ Moran ◽  
G De'ath ◽  
VJ Baker ◽  
DK Bass ◽  
CA Christie ◽  
...  

Two series of outbreaks of the crown-of-thorns starfish, Acanthaster planci (L.), have been recorded on the Great Barrier Reef since the early 1960s. Data from scientific surveys and reliable unpublished observations were analysed statistically to quantify the pattern of movement of these outbreaks. Data on outbreak populations were obtained from 84 and 97 reefs for the periods 1966-74 and 1979-91, respectively. Outbreaks during the former period were found to occur further south with time, their rate of movement increasing from 49 km year-1 in 1966 to almost 81 km year-1 by 1974. Two sets of outbreaks were identified during the 1979-91 period, one occurring to the north, and the other to the south, of latitude 16�s. The 'southern drift' in outbreaks was found to be the more dominant of the two, 'travelling faster' for a greater period. Its initial rate of movement was estimated at 77 km year-1 compared with 57 km year -1 for the 'northern drift'. The latter travelled 150 km before it stopped in 1984. In contrast, the 'southern drift' had travelled a distance of 560 km by 1991, although it had also become almost stationary by then. Outbreaks that moved south during 1979-91 followed a path similar to those that occurred in the 1966-74 period. This similarity in the outbreak paths was particularly evident during the first 6 years of each period. In all, 35 reefs were recorded as experiencing both outbreaks, the average time between each being 14.68 years. The origin of the northern and southern patterns in the 1979-91 period was found to coincide, suggesting that the likely epicentre for primary outbreaks is close to latitude 16�s.

1986 ◽  
Vol 37 (5) ◽  
pp. 545 ◽  
Author(s):  
GL Pickard

At Davies Reef, flow over the east reef flat was unidirectional downwind at 10-20 cm s-1 with strong winds and smaller tides but was semi-diurnal tidal reversing at 5-15 cm s-1 with lighter winds and higher tides. The flood direction was to the south-east out of the lagoon and the ebb into the lagoon. Wave overtopping was estimated to contribute at least 40% of the flow over the reef flat-the first estimate of this component of flow over reef flats. Transit times over the reef flat were 30-170 min and flushing times for the east lagoon were estimated as ½ -1 day for strong winds to the north-west but 2-4 days for lighter winds. In the east lagoon, the upper-layer currents were semi-diurnal tidal reversing all the time at speeds up to 20 cm s-1, with longer-term net flow downwind at about 2 cm s-1 with strong winds but upwind at 0.2 cm s-1 with light winds. In the east passage, the strongly tidal currents (up to 60 cm s-1.) had a long-term net flow to the south at about 2 cm s-1 without any clear correlation with the wind.


1985 ◽  
Vol 24 (95) ◽  
pp. 327-340
Author(s):  
Francis Thompson

The Irish land act of 1881, it is generally agreed, was a victory for the Land League and Parnell, and nationalist policy with regard to the act and the attitude of southern tenants towards it have been many times subjected to detailed examination by historians of this period. In these analyses of the events of 1880–81, however, little reference is normally made to the part played by the different parties and interests in the north of the country. It is often assumed, for example, that the Ulster tenants held aloof from the campaign for reform, lending no more than occasional vocal support to the agitational efforts of tenants in the south and west. Indeed, they were later excoriated by William O'Brien, Michael Davitt and others not only for giving no support to the land movement but also for sabotaging Parnell's policy of testing the 1881 act by precipitately rushing into the land courts to take advantage of the new legislation: ‘that hard-fisted body of men, having done nothing themselves to win the act, thought of nothing but turning it to their own immediate use, and repudiating any solidarity with the southern and western rebels to whom they really owed it’. If, however, northern tenants were harshly judged by nationalist politicians in the years after 1881, the part played by the northern political parties in the history of the land bill has been either ignored or misunderstood by historians since that time. The Ulster liberals, for example, are rarely mentioned, the implication being that they made no contribution to the act even though it implemented almost exactly the programme on which they had been campaigning for much of the previous decade. The northern conservatives, on the other hand, are commonly seen as leading opponents of the bill, more intransigent than their party colleagues in the south, ‘quick to denounce any weakening of the opposition’ to reform, and ‘determined to keep the tory party up to the mark in defending the landlord interest’


1956 ◽  
Vol 7 (3) ◽  
pp. 317 ◽  
Author(s):  
R Endean ◽  
W Stephenson ◽  
R Kenny

The species composition and general ecology of intertidal organisms present at Heron Island, a coral cay in the Capricorn Group, are recorded in this paper. It was found that the general zonation picture on this Great Barrier Reef island differed markedly from that found previously at localities on the Queensland mainland (Endean, Kenny, and Stephenson 1956). In particular the mainland upper barnacle (Chthamalus) zone was not represented at Heron I., and the species forming the mainland lower barnacle zone (Tetraclita squamosa (Bruguiere) ) was replaced by a different species (Tetraclita vitiata Darwin). Also the characteristic algal zone of mainland localities was replaced by a lithothamnion-zoanthid-coral zone. In order to investigate the possibility of a gradual transition from the mainland type zonation to that found on the Great Barrier Reef, as exemplified by Heron I. zonation, the species composition and general ecology of intertidal organisms inhabiting a series of continental islands lying off the Queensland coast between lat. 16� and 22� S. were investigated. The fauna of these islands was found to be closely allied to that of the mainland. There was, however, an intrusion of corals and zoanthids on the more exposed of the islands visited which lie between lat. 20� and 22�S., and also on the more northerly of the islands visited. The biogeographical implications of these findings are discussed, and it is noted that the results of the present investigation support the contention of Whitley (1932) that a longitudinal division of the Queensland marine fauna into "Solanderian" and "Banksian" elements is warranted. Accounts are also given of the major environmental factors that might affect specific composition and zonation patterns at the localities investigated. Analyses of these have given much information on the general ecology and distribution of many Queensland intertidal species. Thls information is discussed. Of particular interest was the finding that the Peronian barnacle Tetraclita rosea (Krauss) has extended its range,to the north of the biogeographical boundary situated near lat. 25� S. by colonizing the more exposed of the continental islands.


2000 ◽  
Vol 355 (1401) ◽  
pp. 1257-1261 ◽  
Author(s):  
Ulrike E. Siebeck ◽  
N. Justin Marshall

Wrasses (Labridae) are the second largest family of fishes on the Great Barrier Reef (after the Gobiidae) and, in terms of morphology and lifestyle, one of the most diverse. They occupy all zones of the reef from the very shallow reef flats to deep slopes, feeding on a variety of fauna. Many wrasses also have elaborately patterned bodies and reflect a range of colours from ultraviolet (UV) to far red. As a first step to investigating the visual system of these fishes we measured the transmission properties of the ocular media of 36 species from the Great Barrier Reef, Australia, and Hawaii, California and the Florida Keys, USA. Transmission measurements were made of whole eyes with a window cut into the back, and also of isolated lenses and corneas. Based on the transmission properties of the corneas the species could be split into two distinct groups within which the exact wavelength of the cut–off was variable. One group had visibly yellow corneas, while the corneas of the other group appeared clear to human observers. Five species had ocular media that transmitted wavelengths below 400 nm, making a perception of UV wavelengths for those species possible. Possible functional roles for the different filter types are discussed.


The chief circumstance that induced Capt. Flinders to think his observations Upon the marine barometer were worthy of attention, was the coincidence that took place between the rising and falling of the mercury, and the setting in of winds that blew from the sea and from off the land, to which there seemed to be at least as much reference as to the strength of the wind or the state of the atmosphere. Our author’s examination of the coasts of New Holland and the other parts of the Terra Australis, began at Cape Leuwen, and con­tinued eastward along the south coast. His observations, which, on account of their length, we must pass over, show, that a change of wind from the northern half of the compass to any point in the southern half, caused the mercury to rise; and that a contrary change caused it to fall. Also, that the mercury stood considerably higher When the wind came from the south side of east and west, than when, in similar weather, it came from the north side.


2001 ◽  
Author(s):  
Mordechai Cogan

Beginning with the death of David and the rise of Solomon, 1 Kings charts the history of Israel through the divided monarchy, when Ahab reigned in the north and Jehoshaphat reigned in the south. This new translation, with introduction and commentary by biblical scholar Mordechai Cogan, is part of the Anchor Bible Commentary series, viewed by many as the definitive commentaries for use in both Christian and Jewish scholarship and worship. Cogan's translation brings new immediacy to well-known passages, such as Solomon's famously wise judgment when asked by two prostitutes to decide their dispute regarding motherhood of a child: "Cut the live son in two! And give half to one and half to the other." With a bibliography that runs to almost a thousand articles and books, Cogan's commentary demonstrates his mastery of the political history described by 1 Kings, as well as the themes of moral and religious failure that eventually led to Israel's defeat and exile.


Author(s):  
Peter Thomson

The Barguzin River flows out of the Barguzin Mountains, through the town of Barguzin and then the coastal community of Ust-Barguzin before it finally loses itself in a broad cove of Baikal known as Barguzin Bay. The only way across the river for miles upstream from the lake is a ramshackle little wooden ferry with a tiny, corrugated steel shed with a wood stove in it and room on its deck for about half a dozen cars. The ferry slips noiselessly away from the end of the road on the south bank, and looking west toward the lake, two ghostly, rusting timber loading cranes loom on the horizon while the river spills over into a grassy marsh on its north bank. Turning back to the east, there’s a small motorboat laboring to get upstream—laboring because it’s attached to a tow rope, which is attached to the ferry. The ferry, it turns out, is just a hapless little barge, at the mercy of the river without the guidance of the motorboat pilot on the other end of the towline. Our crossing takes less than five minutes, and connected to it by nothing but that single strand, the pilot directs the barge into place perfectly on the far side. But the deckhand fails to secure it, the ferry swings wide in the current, spins ninety degrees, and slams butt-end into the dock. The pilot scowls as he turns the motorboat around and uses its blunt bow, covered in a tractor tire, to push the barge back into place, where the deckhand finally lashes it to the dock. The Barguzin is Baikal’s third largest tributary, after the Selenga to the south of here and the Upper Angara to the north. It carries about six percent of the water flowing into the lake, along with migratory fish like omul and sturgeon, born in the shallow gravel beds upriver before wandering downstream to spend most of their lives in the lake. And even though it flows through only two towns between its headwaters and the lake, the Barguzin carries a significant pollution load into Baikal, as well, especially organic chemicals from timber operations.


Author(s):  
Ben McFarland

The process of scientific discovery is something like a walk near Freswick Castle. I assume you’ve never been there. (Neither have I, but a friend has.) Freswick Castle stands at the end of Scotland’s northeast end, at the mouth of the Burn of Freswick in the district of Caithness. As of this writing, it is unlisted in Google Maps, and I had to manually scan the coast to find it. Outside the castle is a simple, unlabeled structure that doubles as a biochemical parable. The castle itself is narrow and three stories tall, with orange shingles and gray stone, set on an arc of narrow beach between hills to the north and cliffs to the south. The building is approximately the cruciform shape of a shrunken cathedral, with the rightward wing moved to the top of the structure so it resembles a lowercase f. If you wander the grounds near Freswick Castle, you will discover a stone wall in the wind-blown waves of yellow- green grass, worn but still standing firm like Hadrian’s Wall. From above, it is a period preceding the castle’s f. Let’s approach this as a scientist, with measurement. From the castle side, this structure resembles the circular stump of a roofless tower, eight feet tall and twice that wide. The stones are ancient sand, compacted and weathered, stained different shades of red from iron deposited millions of years ago, but the mortar is new. But inspection is not enough—we should go in. Walk around to the other side, and an opening appears, as shown in Figure 2.1. The structure is not a closed circle, but it is a spiral wall open to the sea, and to you. Inside, a small stone bench invites you to sit. A window slit next to the bench is an eye to the outside. Surrounded by a jigsaw of rocks, you can hear the echo of waves all around and watch the blue-gray sky above. If the spiral’s opening is a mouth, then you are Jonah in the whale. You are both inside and outside at once.


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