In the other 90%: phytoplankton responses to enhanced nutrient availability in the Great Barrier Reef lagoon

Furnas, Miles, Mitchell, Alan, Skuza, Michelle, and Brodie, Jon (2005) In the other 90%: phytoplankton responses to enhanced nutrient availability in the Great Barrier Reef lagoon. Marine Pollution Bulletin, 51 (1). pp. 253-265.

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Abstract

Our view of how water quality effects ecosystems of the Great Barrier Reef (GBR) is largely framed by observed or expected responses of large benthic organisms (corals, algae, seagrasses) to enhanced levels of dissolved nutrients, sediments and other pollutants in reef waters. In the case of nutrients, however, benthic organisms and communities are largely responding to materials which have cycled through and been transformed by pelagic communities dominated by micro-algae (phytoplankton), protozoa, flagellates and bacteria. Because GBR waters are characterised by high ambient light intensities and water temperatures, inputs of nutrients from both internal and external sources are rapidly taken up and converted to organic matter in inter-reefal waters. Phytoplankton growth, pelagic grazing and remineralisation rates are very rapid. Dominant phytoplankton species in GBR waters have in situ growth rates which range from not, vert, similar1 to several doublings per day. To a first approximation, phytoplankton communities and their constituent nutrient content turn over on a daily basis. Relative abundances of dissolved nutrient species strongly indicate N limitation of new biomass formation. Direct (15N) and indirect (14C) estimates of N demand by phytoplankton indicate dissolved inorganic N pools have turnover times on the order of hours to days. Turnover times for inorganic phosphorus in the water column range from hours to weeks. Because of the rapid assimilation of nutrients by plankton communities, biological responses in benthic communities to changed water quality are more likely driven (at several ecological levels) by organic matter derived from pelagic primary production than by dissolved nutrient stocks alone.

Item ID: 6857
Item Type: Article (Research - C1)
ISSN: 1879-3363
Keywords: Great Barrier Reef; nutrients; water quality
Date Deposited: 03 Mar 2010 02:38
FoR Codes: 06 BIOLOGICAL SCIENCES > 0607 Plant Biology > 060705 Plant Physiology @ 50%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
SEO Codes: 96 ENVIRONMENT > 9611 Physical and Chemical Conditions of Water > 961104 Physical and Chemical Conditions of Water in Marine Environments @ 100%
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