Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

Foraminiferal record of ecological impact of deforestation and oyster farms, Mahurangi Harbour, New Zealand

Hugh R. Grenfell A C , Bruce W. Hayward A and Mark Horrocks B

A Geomarine Research, 49 Swainston Rd, St Johns, Auckland 1072, New Zealand.

B Microfossil Research, 31 Mont Le Grand Rd, Mt Eden, Auckland 1024, New Zealand.

C Corresponding author. Email:

Marine and Freshwater Research 58(5) 475-491
Submitted: 31 August 2006  Accepted: 8 March 2007   Published: 22 May 2007


The microfossils in eight short sediment cores in Mahurangi Harbour, northern New Zealand, record major ecological changes since colonisation by Europeans. During the period of catchment deforestation (1850s–1900) these changes include increased sedimentation rates, decline of soft-shore molluscs, increased diatoms and seaward migration of brackish, agglutinate-dominated, foraminiferal associations, inferred to be due to increased freshwater runoff and decreased pH. The interval of most rapid change (1950s–1980s) occurred before and during the establishment of oyster farms, which therefore are not implicated. Comparison of the microfossil content of surface sediment samples taken inside and outside of four oyster farms indicates variable effects dependent on farm location. In less saline sites, the presence of oyster-shell debris in sediment beneath oyster farms appears to have buffered the foraminiferal faunas from some of the impacts of lowered salinity and pH. At more tidally flushed, saline sites, the oyster farms influence a wider surrounding area that has lower relative abundance of three species of Elphidium and other calcareous Foraminifera, attributed to slightly muddier sediment, higher nutrients and consequently lower oxygen. A newly arrived exotic foraminifer, Elphidium vellai, appears to be an indicator species for the enhanced nutrient, carbonate-rich conditions beneath oyster farms.

Additional keywords: benthic Foraminifera, freshwater runoff, pH, salinity.


Angel D. L.Verghese S.Lee J. J.Saleh A. M.Zuber D.Lindell D.Symons A.2000Impact of a net cage fish farm on the distribution of benthic Foraminifera in the northern Gulf of Eilat (Aqaba, Red Sea).Journal of Foraminiferal Research305465doi:10.2113/0300054

Bernhard J. M., and Sen Gupta B. K. (1999). Foraminifera in oxygen-depleted environments. In ‘Modern Foraminifera’. (Ed. B. K. Sen Gupta.) pp. 201–216. (Kluwer Academic Publishers: Dordrecht.)

Buzas M. A.Culver S. J.Jorissen F. J.1993A statistical evaluation of the microhabitats of living (stained) infaunal benthic foraminifera.Marine Micropaleontology20311320doi:10.1016/0377-8398(93)90040-5

Copin-Montégut G. (1996). ‘Chimie de L’Eau de Mer.’ (Institut Océanographique: Paris.)

Cummings V. J., Turner S. J., Funnell G. A., Milburn C. J., and Thrush S.F. (1997). ‘Mahurangi Estuary Ecological Monitoring Programme: Report on Data Collected up to January 1997.’ Client Report prepared for the Auckland Regional Council. Report number ARC60207. (National Institute of Water and Atmospheric Research: Auckland.)

Debenay J.-P.2000Foraminifers of paralic tropical environments.Micropaleontology46(Supplement 1)153160doi:10.2113/46.2.153

De Grave S.Moore S. J.Burnell G.1998Changes in benthic macrofauna associated with intertidal oyster, Crassostrea gigas (Thunberg) culture.Journal of Shellfish Research1711371142

Feeney C. M. (1984). ‘Water and Soil Management Issues in the Mahurangi Catchment, Estuary and Harbour.’ Auckland Regional Water Board Technical Publication No.29. (Auckland Regional Authority: Auckland.)

Forrest B. M. (1991). Oyster farm impacts on the benthic environment: a study in Mahurangi Harbour. M.Sc. Thesis, University of Auckland, Auckland.

Forrest B. M.Creese R. C.2006Benthic impacts of intertidal oyster culture, with consideration of taxonomic sufficiency.Environmental Monitoring and Assessment112159176

Geslin E.Debenay J.-P.Duleba W.Bonetti C.2002Morphological abnormalities of foraminiferal tests in Brazilian environments: comparison between polluted and non-polluted areas.Marine Micropaleontology45151168doi:10.1016/S0377-8398(01)00042-1

Green M. A.Aller R. C.Aller J. Y.1993Carbonate dissolution and temporal abundances of Foraminifera in Long Island Sound sediments.Limnology and Oceanography38331345

Green M. A.Aller R. C.Aller J. Y.1998Influence of carbonate dissolution on survival of shell-bearing meiobenthos in nearshore sediments.Limnology and Oceanography4311828

Harris T. F. W. (1993). ‘The Mahurangi System.’ (Environment and Planning Division, Auckland Regional Council: Auckland.)

Hayward B. W.Hollis C. J.1994Brackish Foraminifera in New Zealand: a taxonomic and ecologic review.Micropaleontology40185222

Hayward B. W.Grenfell H. R.Pullin A. D.Reid C.Hollis C. J.1997aForaminiferal associations in the upper Waitemata Harbour, Auckland, New Zealand.Journal of the Royal Society of New Zealand272151

Hayward B. W.Hollis C. J.Grenfell H. R.1997bRecent Elphidiidae (Foraminiferida) of the South-west Pacific and fossil Elphidiidae of New Zealand.New Zealand Geological Survey Paleontological Bulletin72170pp

Hayward B. W., Grenfell H. R., Reid C. M., and Hayward K. A. (1999). Recent New Zealand shallow-water benthic foraminifera: taxonomy, ecologic distribution, biogeography, and use in paleoenvironmental assessment. Monograph 21, Institute of Geological and Nuclear Sciences, Avalon.

Hayward B. W.Scott G. H.Grenfell H. R.Carter R.Lipps J. H.2004Techniques for estimation of tidal elevation and confinement (~salinity) histories of sheltered harbours and estuaries using benthic Foraminifera: Examples from New Zealand.The Holocene14218232

Hayward B. W.Grenfell H. R.Sabaa A.Morley M. S.Horrocks M.2006Impact and timing of increased freshwater runoff into sheltered harbour environments around Auckland City, New Zealand.Estuaries and Coasts29165182

Johnston R. M. S. (1984). Sediments and sedimentary processes in Mahurangi Harbour. M.Sc. Thesis, University of Waikato, Waikato.

Jorissen F. J. (1999). Benthic foraminiferal microhabitats below the sediment–water interface. In ‘Modern Foraminifera’. (Ed. B. K. Sen Gupta.) pp. 161–179. (Kluwer Academic Publishers: Dordrecht.)

Kaiser M. J.Laing I.Utting D.Burnell G. M.1998Environmental impacts of bivalve mariculture.Journal of Shellfish Research175966

Karlsen A. W.Cronin T. M.Ishman S. E.Willard D. A.Kerhin R.Holmes C. W.Marot M.2000Historical trends in Chesapeake Bay dissolved oxygen based on benthic Foraminifera from sediment cores.Estuaries23488508

Kaspar H. F.Gillespie P. A.Boyer I. C.Mackenzie A. L.1985Effects of mussel aquaculture on the nitrogen cycle and benthic communities in Kenepuru Sound, Marlborough Sounds, New Zealand.Marine Biology85127136doi:10.1007/BF00397431

Koretsky C. M.van Cappellen P.DiChristina T. J.Kostka J. E.Lowe K. L.Moore C. M.Roychoudhury A. N.Viollier E.2005Salt marsh pore water geochemistry does not correlate with microbial community structure.Estuarine, Coastal and Shelf Science62233251doi:10.1016/J.ECSS.2004.09.001

Kovach W. L. (1993). MVSP shareware, multivariate statistics package. Kovach Computing Services, Pentraeth, Wales.

Le Cadre V.Debenay J.-P.Lesourd M.2003Low pH effects on Ammonia beccarii test deformation: implications for using test deformations as a pollution indicator.Journal of Foraminiferal Research3319doi:10.2113/0330001

McGlone M. S. (1994). Unpublished report on the pollen analysis of cores from the Mahurangi Estuary. Landcare Research, Lincoln.

Morrisey D. J.1993Environmental impact assessment – a review of its aims and recent developments.Marine Pollution Bulletin26540545doi:10.1016/0025-326X(93)90403-7

Murray J. W. (1991). Ecology and distribution of benthic Foraminifera. In ‘Biology of Foraminifera’. (Eds J. J. Lee and O. R. Anderson.) pp. 221–253. (Academic Press: London.)

Murray J. W.2000The enigma of the continued use of total assemblages in ecological studies of benthic foraminifera.Journal of Foraminiferal Research30244245doi:10.2113/0300244

Nugues M. M.Kaiser M. J.Spencer B. E.Edwards D. B.1996Benthic community changes associated with intertidal oyster cultivation.Aquaculture and Research27913924doi:10.1046/J.1365-2109.1996.T01-1-00821.X

Oldman J. W., and Black K. P. (1997). ‘Mahurangi Estuary Numerical Modelling. Client Report prepared for ARC Environment. Report number ARC60208/1.’ (National Institute of Water and Atmospheric Research: Auckland.)

Orr J. C.Fabry V. J.Aumont O.Bopp L.Doney S. C.Felly R. A.Gnanadesikan A.Gruber N.Ishida A.Joos al.2005Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms.Nature437681686doi:10.1038/NATURE04095

Patterson R. T.Fishbein E.1989Re-examination of the statistical methods used to determine the number of point counts needed for Micropaleontological quantative research.Journal of Paleontology63245248

Read P.Fernandes T.2003Management of environmental impacts of marine aquaculture in Europe.Aquaculture226139163

Schafer C. T.2000Monitoring nearshore marine environments using benthic foraminifera: some protocols and pitfalls.Micropaleontology46(Supplement 1)161169

Schafer C. T.Winters G. V.Scott D. B.Pocklington P.Cole F. E.Honig C.1995Survey of living Foraminifera and polychaete populations at some Canadian aquaculture sites: potential for impact mapping and monitoring.Journal of Foraminiferal Research25236259

Scott D. B.Schafer C. T.Honig C.Younger D. C.1995Temporal variations of benthic foraminiferal assemblages under or near aquaculture operations: documentation of impact history.Journal of Foraminiferal Research25224235

Scott D. B.Collins E. S.Duggan J.Asioli A.Saito T.Hasegawa S.1996Pacific Rim marsh foraminiferal distributions: implications for sea-level studies.Journal of Coastal Research12850861

Sen Gupta B. K.Turner R. E.Rabalais N. N.1996Seasonal oxygen depletion in continental-shell waters of Louisiana – historical record of benthic foraminifers.Geology24227230

Sen Gupta B. K. (1999). Foraminifera in marginal marine environments. In ‘Modern Foraminifera’. (Ed. B. K. Sen Gupta.) pp. 141–159. (Kluwer Academic Publishers: Dordrecht.)

Stroud M. J., and Cooper A. B. (1997). ‘Modelling Sediment Loads to the Mahurangi. Client Report prepared for ARC Environment. Report number ARC60211.’ (National Institute of Water and Atmospheric Research: Auckland.)

Swales A., Hume T. M., Oldman J. W., and Green M. O. (1997). ‘Mahurangi Estuary: Sedimentation History and Recent Human Impacts. Client Report. Report number ARC60201.’ (National Institute of Water and Atmospheric Research: Auckland.)

Swales A., Hume T. M., McGlone M. S., Pilvio R., Ovenden R., Zviguina N., Hatton S., Nicholls P., Budd R., Hewitt J., Pickmere S., and Costley K. (2002). ‘Evidence for the physical effects of catchment sediment runoff preserved in estuarine sediments: Phase II (field study).’ Auckland Regional Council Technical Publication 221.

Trotter S. A. (1990). Estuarine sedimentation and land cover history: the case of the Mahurangi. M.Sc. Thesis, University of Auckland.

Wang P. (1992). Distribution of Foraminifera in estuarine deposits: a comparison between Asia, Europe and Australia. In ‘Centenary of Japanese Micropaleontology’. (Eds K. Ishizaki and T. Saito.) pp. 71–83. (Terra Scientific Publishing: Tokyo.)

Wildish D. J.Hargrave B. T.Pohle G.2001Cost-effective monitoring of organic enrichment resulting from salmon mariculture.ICES Journal of Marine Science58469476doi:10.1006/JMSC.2000.1030

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