Nutrient enrichment off Port Stephens: the role of the East Australian Current

Oke, Peter R.; Middleton, Jason H.

doi:10.1016/s0278-4343(00)00127-8

Cited by 79 publications

(68 citation statements)

References 24 publications

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“…In contrast, waters of similar latitude on the Australian east coast are approximately twice as productive (Jitts 1965) and show a spring phytoplankton bloom with a second bloom in late summer to early autumn (Humphrey 1963, Hallegraeff & Jeffrey 1993. Sporadic increases in primary productivity on the southeast coast are the result of EAC activity that uplifts nutrient-rich slope water onto the shelf and close to the surface (Oke & Middleton 2001), sometimes in association with warm-core (Tranter et al 1986) or cold-core (Gibbs et al 1997) eddy formation, often resulting in coastal diatom blooms (Hallegraeff & Reid 1986 (Table 1). Analysis of silicate concentrations commenced in the 1970s.…”

Section: Methodsmentioning

confidence: 98%

“…The intrusions of deeper water onto the shelf results from 4 different mechanisms: (1) wind-driven upwelling, (2) upwelling due to the EAC intruding onto the shelf, (3) acceleration of the EAC as the shelf narrows and (4) separation of the EAC from the coast (McLeanPadman & Padman 1991, Roughan & Middleton 2002. Frequently, upwelling occurs north of Port Hacking, often at ~31°S (Rochford 1975, Tranter et al 1986, Cresswell 1994, Gibbs et al 1997, Oke & Middleton 2001 and, as shown in the present study, the resulting phytoplankton bloom is subsurface by the time it arrives at Port Hacking (~34°S). These upwelling-favourable conditions are known to have a link with SOI atmospheric (Hsieh & Hamon 1991) and local weather conditions (McLean-Padman & Padman 1991).…”

Section: Port Hackingmentioning

confidence: 99%

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Long-term changes in temperate Australian coastal waters: implications for phytoplankton

Thompson

Baird²,

Ingleton³

et al. 2009

Mar. Ecol. Prog. Ser.

104

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Section: Methodsmentioning

confidence: 98%

Section: Port Hackingmentioning

confidence: 99%

Long-term changes in temperate Australian coastal waters: implications for phytoplankton

Thompson

Baird²,

Ingleton³

et al. 2009

Mar. Ecol. Prog. Ser.

104

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“…First, the unidirectional East Australian Current (EAC) runs north to south along the east coast of Australia, and then weakens and deflects away from the coast at the south-eastern corner of the mainland (Knox 1963, Huyer et al 1988, O'Hara & Poore 2000, Oke & Middleton 2001, Roughan & Middleton 2004. Second, seawater and air temperatures decline with the transition from subtropical to temperate regions with increasing latitude.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Supply-side biogeography: geographic patterns of settlement and early mortality for a barnacle approaching its range limit

Lathlean

Ayre²,

Minchinton³

2010

Mar. Ecol. Prog. Ser.

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Species range limits are often associated with reduced adult densities, and this may reflect the failure of a particular life-history stage. For benthic marine invertebrates, settlement is a time of great mortality that strongly influences adult population structure, at least at local spatial scales. In south-eastern Australia we determined that adult abundance of the intertidal barnacle Tesseropora rosea declines over a 450 km region of rocky shore from the middle to the southern limit of its range, and we tested the hypothesis that this biogeographic pattern reflects variations in the production, settlement, or early post-settlement mortality of larvae or adult mortality. Sampling at 2 sites on 11 rocky shores in this region over 2 yr revealed that none of the life-history stages or demographic processes displayed a latitudinal gradient or a clear decline towards the south, and settlement and adult mortality were highly variable among locations. Indeed local variation in early lifehistory processes and adult mortality appears to dictate regional variability and observed latitudinal patterns of adult abundance of T. rosea, but longer term studies spanning at least a decade may determine if storage from one strong year in recruitment can set patterns of adult abundance.KEY WORDS: Abundant-centre hypothesis · Early post-settlement mortality · Tesseropora rosea · Adult mortality · Geographic distribution · Latitudinal gradient Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 412: [141][142][143][144][145][146][147][148][149][150] 2010 although these supply-side processes are often highly variable in space and time (see Underwood & Fairweather 1989, Caley et al. 1996, Hunt & Scheibling 1997, they sometimes reflect latitudinal gradients of temperature, currents, wave exposure and nutrient availability in the ocean (Connolly & Roughgarden 1998, Connolly et al. 2001, Zacherl et al. 2003, Sanford et al. 2006. Consequently, the geographic distribution of benthic marine invertebrates, particularly as a species approaches its range limit, may be strongly influenced by latitudinal gradients in the supply and early life history of larvae. Alternatively, processes operating at more local scales in the post-recruitment environment (e.g. storm events, habitat, microclimates, predation) could override larger scale patterns of recruitment that might determine geographic patterns in adult abundance (Helmuth 1998). Measuring settlement and early post-settlement mortality of benthic marine invertebrates is often difficult, however, because larvae are small and often die soon after settlement. Few studies have measured these early lifehistory processes simultaneously across large geographic scales (but see Caffey 1985, Connolly et al. 2001, Hughes et al. 2002, but such studies can yield important insights into the processes setting the range limits of species.Along the linear coastline of south-eastern Australia, there is great potential for the population size of sessile...

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“…2b), and Port Stephens (PS, Fig. 2c), were chosen due to their predisposition to coastal upwelling (Rochford 1975;Hallegraeff and Jeffrey 1993;Oke and Middleton 2001), which is the dominant natural nutrient-enrichment process along the coast of NSW. There are no sewage outfalls within the immediate vicinity of the entrance of the estuaries in these regions.…”

Section: Methodsmentioning

confidence: 99%

“…Satellite images of sea surface temperature (SST) and sea surface Chl a (SeaWiFS) were obtained from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) marine laboratories in Hobart. The general direction of flow of the East Australian Current was inferred from the SST images (Parslow et al 2000;Oke and Middleton 2001). However, current speed and direction along the coast were also measured 4 d after the November sampling run aboard the CSIRO research vessel, Franklin.…”

mentioning

confidence: 99%

Population growth and transport of the red tide dinoflagellate, Noctiluca scintillans, in the coastal waters off Sydney Australia, using cell diameter as a tracer

Dela-Cruz

Middleton

Suthers

2003

Limnology & Oceanography

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Spatial abundance patterns of the heterotrophic dinoflagellate, Noctiluca scintillans, were investigated along the southeast coast of Australia to address the hypothesis that population growth of Noctiluca is driven by anthropogenic eutrophication. Abundance patterns were related to the immediate physical flow field and not the conditions conducive to growth. Noctiluca cells were advected southward with the East Australian Current, which was the dominant transport vector for the cells in this region. Areas of population growth of Noctiluca were identified by variations in cell-size distributions. Small cells (Ͻ525 m) were considered to be capable of population growth, in contrast to red tide cells, which are known to be large (Ͼ600 m), senescent, and the end result of a long series of biological and physical processes occurring in temporally and spatially distant water masses. Small cells were therefore considered to be located closer to the region in which growth was stimulated. The proportion of small cells in the samples was significantly correlated with relatively high concentrations of chlorophyll a. Consequently, this relationship was used to show that population growth of Noctiluca may be stimulated by an increase in chlorophyll a due to sewage discharge, although the prevailing hydrological conditions determine the likelihood of such impacts. High chlorophyll a concentrations within estuaries were also found to sustain a stable but low standing stock of Noctiluca, which may seed oceanic stocks. Thus, by examining cell size rather than abundance distributions, we identified and interpreted the variance in the spatial abundance patterns of Noctiluca within a dynamic hydrological environment.

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Nutrient enrichment off Port Stephens: the role of the East Australian Current

Cited by 79 publications

References 24 publications

Long-term changes in temperate Australian coastal waters: implications for phytoplankton

Long-term changes in temperate Australian coastal waters: implications for phytoplankton

Supply-side biogeography: geographic patterns of settlement and early mortality for a barnacle approaching its range limit

Population growth and transport of the red tide dinoflagellate, Noctiluca scintillans, in the coastal waters off Sydney Australia, using cell diameter as a tracer

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