Phytoplankton biomass and primary production in semi-enclosed reef lagoons of the central Great Barrier Reef, Australia

Coral Reefs ◽  
1990 ◽  
Vol 9 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Miles J. Furnas ◽  
Alan W. Mitchell ◽  
Malvern Gilmartin ◽  
Noelia Revelante
Keyword(s):  
Primary Production ◽  
Great Barrier Reef ◽  
Phytoplankton Biomass ◽  
Barrier Reef

A Bayesian network model linking nutrient management actions in the Tully catchment (northern Queensland) with Great Barrier Reef condition

2010 ◽  
Vol 61 (5) ◽  
pp. 587 ◽  
Author(s):  
Will Shenton ◽  
Barry T. Hart ◽  
Jon Brodie
Keyword(s):  
Bayesian Network ◽  
Great Barrier Reef ◽  
Phytoplankton Biomass ◽  
Nutrient Management ◽  
Nitrogen Management ◽  
Catchment Management ◽  
Barrier Reef ◽  
Nitrogen Fertiliser ◽  
Management Actions ◽  
Reef Condition

Correlating catchment management actions with improvements in the ecological condition of downstream coastal regions is challenging. We describe a Bayesian network (BN) model that predicts the effects of nitrogen-fertiliser management strategies in the Tully River catchment (northern Queensland) on the condition of inshore reefs of the Great Barrier Reef (GBR). The model consists of three linked submodels that relate sugarcane nitrogen management with runoff into the Tully River and nitrate concentration in the GBR lagoon, predicts phytoplankton biomass in the GBR lagoon from the nitrate inputs, and links the phytoplankton biomass with three marine influences to predict the probability of the reefs being dominated by coral (good) or macro-algae (bad). Four scenarios were modelled – current and the ‘six easy steps’ nitrogen management, and active and depleted algal grazing (herbivory) of the reef. The model predicts an increased probability of the reef being coral-dominated with current fertiliser practice and with active reef herbivory, with increased algal-dominance if reef herbivory is decreased. Introduction of a better nitrogen-fertiliser management with active herbivory resulted in an increased probability of coral dominance. This comparative-scenario analysis highlights the importance of both agricultural nutrient management practices and marine processes in predicting reef condition.

Plankton of the central Great Barrier Reef: abundance, production and trophodynamic roles

2010 ◽  
Vol 90 (6) ◽  
pp. 1173-1187 ◽  
Author(s):  
Yu.I. Sorokin ◽  
P.Yu. Sorokin
Keyword(s):  
Great Barrier Reef ◽  
Phytoplankton Biomass ◽  
Trophic Status ◽  
Benthic Communities ◽  
Barrier Reef ◽  
Pelagic Ecosystem ◽  
Estuarine Area ◽  
Mesozooplankton Biomass ◽  
Zooplankton Density ◽  
Plankton Production

The abundance, composition and metabolic activity of plankton were assessed in the Tribulation zone of the central Great Barrier Reef (16°–17°S). Wet phytoplankton biomass ranged in shallow reef waters from 30 to 70 mg m−3, and from 60 to 270 mg m−3in the deep lagoon and in the estuarine areas which are dominated by pico- and nano-algae. Wet bacterioplankton biomass varied from 70 to 290 mg m−3. Wet meroplankton biomass was less than 10 mg m−3. Wet daytime mesozooplankton biomass ranged from 100 to 300 mg m−3in the deep lagoon. In the estuarine area, it reached 400 to 1300 mg m−3and in the shallow inner lagoon of the Low Isles ring reef it varied from 10 to 30 mg m−3. Zooplankton density increased at night and was 3 to 5 fold greater in the deep lagoon, for about 2 orders of magnitude greater over the reef shallows and up to 3 orders of magnitude greater in mangrove habitats, due to the emergence of demersal components from the benthos. The biomass of zooplankton hidden in the benthic substrates during the day reached 10 to 40 g m−2. Pelagic primary production in the deep lagoon varied between 0.2 and 0.5 g C m−2 d−1. A calculation of the energy balance suggests that the basic energy source for heterotrophic plankton production in the deep lagoon is the organic matter exported from surrounding reef benthic communities and from mangroves. The trophic status of coral reef pelagic ecosystem might range from mesotrophic to eutrophic.

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