SURFACE OCEAN RADIOCARBON FROM A PORITES CORAL RECORD IN THE GREAT BARRIER REEF: 1945–2017

Radiocarbon ◽  
2021 ◽  
pp. 1-11
Author(s):  
Yang Wu ◽  
Stewart J Fallon ◽  
Neal E Cantin ◽  
Janice M Lough
Keyword(s):  
High Resolution ◽  
Great Barrier Reef ◽  
Ocean Dynamics ◽  
Barrier Reef ◽  
Reference Series ◽  
Surface Ocean ◽  
Porites Coral ◽  
Subsurface Ocean ◽  
Ocean Atmosphere

ABSTRACT We present a high-resolution seawater radiocarbon (Δ14C) record from a Porites coral collected from Masthead Island in the southern Great Barrier Reef (GBR) covering the years 1945–2017. The Δ14C values from 1945–1953 (pre-bomb era) averaged –49‰. As a result of bomb-produced 14C in the atmosphere, Δ14C values started to rise rapidly from 1959, levelled off at ∼131‰ in the late 1970s and gradually decreased to ∼40.3‰ by 2017 due to the decrease in the air-sea 14C gradient and the overturning of the 14C ocean reservoir (i.e., surface ocean to subsurface ocean; atmosphere to surface ocean). The Masthead Island record is in agreement with previous 14C coral records from the southern GBR. A comparison between surface ocean and atmospheric Δ14C suggests that, since 2010, the main reservoir of bomb-derived 14C has shifted from the atmosphere to the surface ocean, potentially resulting in reversed 14C flux in regions where the CO2 gradient is favorable. The high-resolution Masthead coral Δ14C sheds light on long-term variability in air-sea exchange and GBR regional ocean dynamics associated with climate change and in conjunction with the previous records provides a robust seawater 14C reference series to date other carbonate samples.

Water quality in the inshore Great Barrier Reef lagoon: Implications for long-term monitoring and management

2012 ◽  
Vol 65 (4-9) ◽  
pp. 249-260 ◽  
Author(s):  
Britta Schaffelke ◽  
John Carleton ◽  
Michele Skuza ◽  
Irena Zagorskis ◽  
Miles J. Furnas
Keyword(s):  
Water Quality ◽  
Great Barrier Reef ◽  
Barrier Reef ◽  
Reef Lagoon ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Inshore Great Barrier Reef

High-resolution, unstructured meshes for hydrodynamic models of the Great Barrier Reef, Australia

2006 ◽  
Vol 68 (1-2) ◽  
pp. 36-46 ◽  
Author(s):  
Sébastien Legrand ◽  
Eric Deleersnijder ◽  
Emmanuel Hanert ◽  
Vincent Legat ◽  
Eric Wolanski
Keyword(s):  
High Resolution ◽  
Great Barrier Reef ◽  
Unstructured Meshes ◽  
Barrier Reef ◽  
Hydrodynamic Models

Manipulation of fishing effort in Australia's penaeid Prawn Fisheries

1990 ◽  
Vol 41 (1) ◽  
pp. 1 ◽  
Author(s):  
IF Somers
Keyword(s):  
Side Effects ◽  
Great Barrier Reef ◽  
Simulation Model ◽  
Fishing Effort ◽  
Regulatory Mechanisms ◽  
Barrier Reef ◽  
Restrictive Measures ◽  
The Impact ◽  
Term Management

The potentially detrimental side-effects of prawn trawling are coming under increasing scrutiny in Australian waters, particularly in such ecologically sensitive areas as Queensland's Great Barrier Reef, and various restrictive measures are being suggested. Before changes are imposed on the prawning industry, the effects of trawling on the target prawn species and the long-term management of these effects need to be fully understood. Using a simulation model of a simplified prawn fishery, this paper describes the basis for the current regulatory mechanisms for Australian's prawn fisheries, in particular the manipulation of both the level and pattern of fishing effort. It is shown that even in moderately fished stocks, the fishery manager has several options, such as seasonal and nursery area closures, that are consistent with the goal of minimizing the impact of prawn trawling, while in no way penalizing the industry economically. With these in mind, possible ways of resolving or reducing the conflict with groups outside the prawning industry are discussed.

scholarly journals Long‐term dynamics and drivers of coral and macroalgal cover on inshore reefs of the Great Barrier Reef Marine Park

2019 ◽  
Vol 30 (1) ◽  
Author(s):  
Daniela M. Ceccarelli ◽  
Richard D. Evans ◽  
Murray Logan ◽  
Philippa Mantel ◽  
Marji Puotinen ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Barrier Reef ◽  
Macroalgal Cover ◽  
Marine Park

scholarly journals Patterns of fish calling in a nearshore environment in the Great Barrier Reef

2000 ◽  
Vol 355 (1401) ◽  
pp. 1289-1293 ◽  
Author(s):  
Robert D. McCauley ◽  
Douglas H. Cato
Keyword(s):  
Great Barrier Reef ◽  
Sound Production ◽  
Local Environment ◽  
Spatial Separation ◽  
Activity Levels ◽  
Barrier Reef ◽  
Call Type ◽  
Calling Patterns ◽  
Noise Statistics

Long–term sea–noise statistics have been obtained from a region of the central section of the Great Barrier Reef. Fish calling was a major contributor to sea–noise levels. Calling was either in choruses, where groups of fishes called en masse , or as isolated calls repeated ad nauseam . Four calling types predominated, with each displaying unique call characteristics and calling patterns through time and space. Analysis of call types offered information on the fish's calling physiology, behaviour and, through the call's interaction with the local environment, on the location of the caller. Call types ranged from less than 10 ms to several seconds long, and were comprised from one to nearly 40 pulses. The structure of each pulse was related to swim–bladder mechanics; normally swim–bladders were lightly damped. Fish calling was most common during the Australian summer with one call type also displaying lunar trends. All calls had daily patterns of sound production with highest activity levels generally at night. There was some spatial separation of zones of highest call rates, but sources avoided competition for the ‘sound space’ primarily by offsetting the time of chorus or maximum call rate. On some occasions, a call type attributed to nocturnal planktivorous fishes may have ensonified much of the Great Barrier Reef.

scholarly journals Combining contemporary and long-term erosion rates to target erosion hot-spots in the Great Barrier Reef, Australia

Anthropocene ◽  
2015 ◽  
Vol 10 ◽  
pp. 1-12 ◽  
Author(s):  
Rebecca Bartley ◽  
Jacky Croke ◽  
Zoe T. Bainbridge ◽  
Jenet M. Austin ◽  
Petra M. Kuhnert
Keyword(s):  
Great Barrier Reef ◽  
Hot Spots ◽  
Barrier Reef ◽  
Erosion Rates

scholarly journals High-resolution simulations of interactions between surface ocean dynamics and frazil ice

2020 ◽  
Vol 14 (11) ◽  
pp. 3707-3729
Author(s):  
Agnieszka Herman ◽  
Maciej Dojczman ◽  
Kamila Świszcz
Keyword(s):  
High Resolution ◽  
Vertical Velocity ◽  
Volume Fraction ◽  
Ocean Dynamics ◽  
Computational Domain ◽  
Water Mixture ◽  
Strong Wind ◽  
Surrounding Water ◽  
Frazil Ice ◽  
Ocean Atmosphere

Abstract. Frazil and grease ice forms in the ocean mixed layer (OML) during highly turbulent conditions (strong wind, large waves) accompanied by intense heat loss to the atmosphere. Three main velocity scales that shape the complex, three-dimensional (3D) OML dynamics under those conditions are the friction velocity u* at the ocean–atmosphere interface, the vertical velocity w* associated with convective motion, and the vertical velocity w*,L associated with Langmuir turbulence. The fate of buoyant particles, e.g., frazil crystals, in that dynamic environment depends primarily on their floatability, i.e., the ratio of their rising velocity wt to the characteristic vertical velocity, which is dependent on w* and w*,L. In this work, the dynamics of frazil ice is investigated numerically with the high-resolution, non-hydrostatic hydrodynamic model CROCO (Coastal and Regional Ocean COmmunity Model), extended to account for frazil transport and its interactions with surrounding water. An idealized model setup is used (a square computational domain with periodic lateral boundaries, spatially uniform atmospheric and wave forcing). The model reproduces the main features of buoyancy- and wave-forced OML circulation, including the preferential concentration of frazil particles in elongated patches at the sea surface. Two spatial patterns are identified in the distribution of frazil volume fraction at the surface: one related to individual surface convergence zones, very narrow, and oriented approximately parallel to the wind/wave direction and one in the form of wide streaks with a separation distance of a few hundred meters, oriented obliquely to the direction of the forcing. Several series of simulations are performed, differing in terms of the level of coupling between the frazil and hydrodynamic processes, from a situation when frazil has no influence on hydrodynamics (as in most models of material transport in the OML) to a situation in which frazil modifies the net density, effective viscosity, and transfer coefficients at the ocean–atmosphere interface and exerts a net drag force on the surrounding water. The role of each of those effects in shaping the bulk OML characteristics and frazil transport is assessed, and the density of the ice–water mixture is found to have the strongest influence on those characteristics.

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