Ammonia and Inorganic phosphate excretion by zooplankton from inshore waters of the Great Barrier Reef, Queensland. I. Relationship between excretion rates and body size

1982 ◽  
Vol 33 (1) ◽  
pp. 55 ◽  
Author(s):  
T Ikeda ◽  
E Hing Fay ◽  
SA Hutchinson ◽  
GM Boto
Keyword(s):  
Great Barrier Reef ◽  
Warm Season ◽  
Ammonia Excretion ◽  
Dry Weight ◽  
Cold Season ◽  
Barrier Reef ◽  
Experimental Conditions ◽  
Phosphate Excretion ◽  
Inshore Waters ◽  
Excretion Rates

Ammonia and phosphate excretion rates were measured on various copepods and some ctenophores, siphonophores, decapod larvae, mollusc larvae, polychaete larvae, chaetognaths and appendicularians from inshore waters of the Great Barrier Reef during warm and cold seasons. Regression analyses showed high correlations between the excretion rate and body weight of zooplankton: in the warm season, log yn = 0.518 + 0.525 log x (n = 348. r = 0.612) log yp = -0.174 + 0.429 log x (n=117, r=0.570), and in the cold season, log yn = 0.186 + 0.518 log x (n = 268, r = 0,777) log yp = -1.002 + 0.740 log x (n = 255, r = 0.694), where yn is ammonia excretion (nanograms N per animal per hour), yp is phosphate excretion (nanograms P per animal per hour), x is body dry weight (micrograms per animal); n is the number of measurements, and r is the correlation coefficient. Since the two regression lines for ammonia excretion were parallel a Q10 value of 2.53 was calculated from the results of warm and cold seasons. This calculation was not possible for the phosphate excretion because the regression lines between the seasons were not parallel. The mean ratio of ammonia excretion to phosphate excretion (N:P ratio, by atoms) was 28.56 in the warm season and 24.48 in the cold season. The present results were compared with those of other workers who used zooplankton from different seas, and the effects of experimental conditions, such as injury of specimens, container size, incubation time and feeding on the excretion rates are discussed.

Ammonia and phosphate excretion by zooplankton from the inshore waters of the Great Barrier Reef. II. Their in situ contributions to nutrient regeneration

1982 ◽  
Vol 33 (4) ◽  
pp. 683 ◽  
Author(s):  
T Ikeda ◽  
JH Carleton ◽  
AW Mitchell ◽  
P Dixon
Keyword(s):  
Great Barrier Reef ◽  
Laboratory Data ◽  
Ammonia Excretion ◽  
Barrier Reef ◽  
Nutrient Regeneration ◽  
Bottom Community ◽  
Phosphate Excretion ◽  
Inshore Waters ◽  
Zooplankton Excretion ◽  
Excretion Rates

Zooplankton excretion was estimated by combining biomass data with experimental laboratory data on excretion rates at three stations, characterized by low nutrient levels, in the inshore waters of the Great Barrier Reef. Hourly ammonia excretion (as nitrogen) by net zooplankton (>205 �) was calculated to range from 11.9 to 22.6 � m-3 or from 1.6 to 5.0 g m-2 per year, and hourly phosphate excretion (as phosphorus) from 1.4 to 2.8 � m-3 or from 0.16 to 0.63 g m-2 per year. Hourly excretion of ammonia by microzooplankton ( < 205 �) was calculated to be 2.6 � m-3 (as nitrogen) and of phosphate 0.55 � m-3 (as phosphorus), values that were 15 and 27% of the excretion by net zooplankton, respectively. Combined excretion rates by net zooplankton and microzooplankton could supply only 9.0-29.2% of the nitrogen and 6.6-25.6% of the phosphorus for an assumed yearly primary production of carbon of 100 g m-2 (= 17.6 g m-2 of nitrogen and 2.5 g m-2 of phosphorus). Calculations from an empirical equation relating temperature to oxygen consumption by a bottom community indicated a high potential for benthic nutrient regeneration in reef inshore waters (27.1 g m-2 per year, as nitrogen). The bottom community therefore appears to be the most important source of nutrient regeneration within the area studied.

scholarly journals Coral growth, survivorship and return-on-effort within nurseries at high-value sites on the Great Barrier Reef

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244961
Author(s):  
Lorna Howlett ◽  
Emma F. Camp ◽  
John Edmondson ◽  
Nicola Henderson ◽  
David J. Suggett
Keyword(s):  
Great Barrier Reef ◽  
Growth Rates ◽  
Water Channel ◽  
Warm Season ◽  
Tourism Industry ◽  
Barrier Reef ◽  
Management Tools ◽  
Trade Offs ◽  
Acropora Hyacinthus ◽  
Relative Return

Coral reefs are deteriorating worldwide prompting reef managers and stakeholders to increasingly explore new management tools. Following back-to-back bleaching in 2016/2017, multi-taxa coral nurseries were established in 2018 for the first time on the Great Barrier Reef (GBR) to aid reef maintenance and restoration at a “high-value” location–Opal Reef–frequented by the tourism industry. Various coral species (n = 11) were propagated within shallow water (ca. 4-7m) platforms installed across two sites characterised by differing environmental exposure–one adjacent to a deep-water channel (Blue Lagoon) and one that was relatively sheltered (RayBan). Growth rates of coral fragments placed onto nurseries were highly variable across taxa but generally higher at Blue Lagoon (2.1–10.8 cm2 month-1 over 12 months) compared to RayBan (0.6–6.6 cm2 month-1 over 9 months). Growth at Blue Lagoon was largely independent of season, except for Acropora tenuis and Acropora hyacinthus, where growth rates were 15–20% higher for December 2018-July 2019 (“warm season”) compared to August-December 2018 (“cool season”). Survivorship across all 2,536 nursery fragments was ca. 80–100%, with some species exhibiting higher survivorship at Blue Lagoon (Acropora loripes, Porites cylindrica) and others at RayBan (A. hyacinthus, Montipora hispida). Parallel measurements of growth and survivorship were used to determine relative return-on-effort (RRE) scores as an integrated metric of “success” accounting for life history trade-offs, complementing the mutually exclusive assessment of growth or survivorship. RRE scores within sites (across species) were largely driven by growth, whereas RRE scores between sites were largely driven by survivorship. The initial nursery phase of coral propagation therefore appears useful to supplement coral material naturally available for stewardship of frequently visited Great Barrier Reef tourism (high-value) sites, but further assessment is needed to evaluate how well the growth rates and survival for nursery grown corals translate once material is outplanted.

Spatial and temporal patterns of near-surface chlorophyll a in the Great Barrier Reef lagoon

2007 ◽  
Vol 58 (4) ◽  
pp. 342 ◽  
Author(s):  
J. Brodie ◽  
G. De'ath ◽  
M. Devlin ◽  
M. Furnas ◽  
M. Wright
Keyword(s):  
Great Barrier Reef ◽  
Chlorophyll A ◽  
Agricultural Development ◽  
Monitoring Program ◽  
Barrier Reef ◽  
Spatial And Temporal Patterns ◽  
Wet Season ◽  
Near Surface ◽  
Nutrient Delivery ◽  
Inshore Waters

Surface chlorophyll a concentrations in the Great Barrier Reef (GBR) lagoon were monitored at individual stations for periods of 6 to 12 years. The monitoring program was established to detect spatial and temporal changes in water quality resulting from increased loads of nutrients exported from the catchments adjoining the GBR. Sampling occurred monthly at up to 86 sites that were located in transects across the width of the continental shelf. In the central and southern GBR (16–21°S), there was a persistent cross-shelf chlorophyll a gradient, with higher concentrations near the coast. No cross-shelf gradient was observed in the far northern GBR (12–15°S). Mean chlorophyll a concentrations in the far northern GBR (0.23 µg L–1) were less than half those in the south and central GBR (0.54 µg L–1). Chlorophyll a varied seasonally within regions, with mean summer-wet season (December–April) concentrations ~50% greater than those in the winter-dry season (May–November). Sub-annual, inter-annual and event-related variations in chlorophyll a concentrations were observed in several zones. Multi-year patterns in concentrations suggest that relatively short (5–8 years) time series may give spurious estimates of secular trends. Higher chlorophyll a concentrations in inshore waters south of 16°S were most likely related to the levels of river nutrient delivery associated with agricultural development on adjacent catchments.

scholarly journals The importance of excretion by Chironomus larvae on the internal loads of nitrogen and phosphorus in a small eutrophic urban reservoir

2008 ◽  
Vol 68 (2) ◽  
pp. 349-357 ◽  
Author(s):  
R. Henry ◽  
CM. Santos
Keyword(s):  
Linear Relation ◽  
Dry Weight ◽  
Ammonium Excretion ◽  
Lake Area ◽  
Nitrogen And Phosphorus ◽  
Phosphate Excretion ◽  
Total Length ◽  
The Mean ◽  
Excretion Rates ◽  
External Loads

Measurements of ammonium and phosphate excretion by the Chironomus larvae were conducted in order to evaluate the importance of these chironomids for the internal loads of a small eutrophic urban reservoir. Ammonium and phosphate excretion rates by Chironomus larvae of small size (6-10 mm total length) were significantly higher than those of the Chironomids having medium (9-11 mm) and large (11-16 mm) sizes. A dependence in relation to temperature was recorded for the ammonium and phosphate excretions that was significantly higher at 25 °C than at 20 and 15 °C. Through a linear relation between biomass (dry weight) and total length and, between excretion and biomass and, data on chironomids densities, after an intense sampling in 33 sites distributed all along the reservoir bottom, the mean phosphate and ammonium excretion rates corresponded to 2,014 ± 5,134 µg.m-2/day and 1,643 ± 3,974 µg.m-2/day, respectively. Considering the mean biomass (34 mg.m-2) of Chironomus, the lake area (88,156 m²) and the mean excretion rates, the contribution of benthic chironomids to the internal loads would be 181 KgP and 147 KgN. for the sampling months (October-November 1998). These values showed that the internal loads by excretion from Chironomus larvae correspond to approximately 33% of the external loads of phosphorus in the lake and, in the case of nitrogen, to only 5%.

Oxygen consumption, nitrogenous excretion, and filtration rates of Dreissena polymorpha at acclimation temperatures between 20 and 32 °C

1995 ◽  
Vol 52 (8) ◽  
pp. 1761-1767 ◽  
Author(s):  
David W. Aldridge ◽  
Barry S. Payne ◽  
Andrew C. Miller
Keyword(s):  
Oxygen Consumption ◽  
Dreissena Polymorpha ◽  
Ammonia Excretion ◽  
Dry Weight ◽  
Protein Catabolism ◽  
Feeding Rates ◽  
Energy Expenditures ◽  
Consumption Rates ◽  
Metabolic Expenditure ◽  
Excretion Rates

Mussels were acclimated to each of four experimental temperatures (20, 24, 28, and 32 °C) for 30 days. Mussels averaged 10.29 mg tissue dry weight. Oxygen consumption rates at 32 °C were 3.65 times larger than consumption rates at 20 °C (p < 0.01). Ammonia excretion rates at 32 °C were 4.9 times greater than those at 20 °C (p < 0.01). O:N ratios were >60 at 20 and 24 °C but declined (p < 0.01) at 28 and 32 °C to <40. Filtration rates, an estimate of feeding rates, were not significantly different at 20 and 24 °C (p > 0.50) but declined at 28 and 32 °C (p < 0.01). Filtration rates at 32 °C were only 27% of the rates at 20 °C. These results indicate that (i) the metabolic expenditure of Dreissena polymorpha rose 265% as the temperature rose from 20 to 32 °C, (ii) metabolism relied more heavily on lipids and carbohydrates at 20 and 24 °C while protein catabolism increased at 28 and 32 °C, and (iii) the potential feeding rates of D. polymorpha declined by 73% as temperature rose from 20 to 32 °C. Above 28 °C D. polymorpha was unable to match energy expenditures with concurrent food intake and forced to rely on stored fuels.

Management of Water Quality in the Great Barrier Reef Marine Park

1989 ◽  
Vol 21 (2) ◽  
pp. 31-38 ◽  
Author(s):  
Simon Woodley
Keyword(s):  
Water Quality ◽  
Coral Reef ◽  
Great Barrier Reef ◽  
Barrier Reef ◽  
Management Issue ◽  
Reef System ◽  
Marine Park ◽  
World Heritage List ◽  
The World ◽  
Coral Reef System

The Great Barrier Reef is the largest coral reef system in the world. It is recognised and appreciated worldwide as a unique environment and for this reason has been inscribed on the World Heritage List. The Reef is economically-important to Queensland and Australia, supporting substantial tourism and fishing industries. Management of the Great Barrier Reef to ensure conservation of its natural qualities in perpetuity is achieved through the establishment of the Great Barrier Reef Marine Park. The maintenance of water quality to protect the reef and the industries which depend on it is becoming an increasingly important management issue requiring better knowledge and possibly new standards of treatment and discharge.

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