An intertidal Zostera pool community at Kawerua, Northland, New Zealand and its foraminiferal microfauna

Latest version published by Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node on 10 November 2023 Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node

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This dataset is from a paper about an unusual occurrence of the sea grass, Zostera capricorni, living in an intertidal pool on the storm-swept west coast of Northland is described. The macrofauna associated with the Zostera is similar to that found associated with it elsewhere in its more normal sheltered subtidal and intertidal sandy mud Hat habitat. The pool has a sandy bottom with rocks scattered throughout. The rocks support a rich macrofauna and flora both over their sides and beneath them and this is briefly described.

Living foraminiferal microfauna were found in the sandy sediments that cover the pool bottom, as well as on Corallina turf, but were not found on the laminae of Zostera or on the brown alga Hormosira banksii. The dominant foraminifera on Corallina turf are Rosalina bradyi and Ammonia beccarii with a number of less numerous species. The bottom sands are dominated by live Florilus parri (27-42%), Ammonia beccarii (7-28%) and Evolvocassidulina orientalis, Quinqueloculina seminulum, Rosalina bradyi, Cassidulina carinata, Elphidium charlottensis and Discorbinella bertheloti (all 3-10%). At suborder level the fauna consists of about 90% Rotalina, 9% Miliolina and less than 1% Textulariina. Counts of stained (live) foraminifera indicate standing crop abundance values of 10,000-16,500 living foraminifera per square metre of pool bottom. The faunas contain an unusually high number of planktonics (13-17% of total) for an intertidal situation, but this is thought to be due to the prevalence of onshore winds that drive oceanic water in close to the west coast of New Zealand.

Data Records

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How to cite

Researchers should cite this work as follows:

Hayward B, Hayward B W (2023). An intertidal Zostera pool community at Kawerua, Northland, New Zealand and its foraminiferal microfauna. Version 1.1. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Occurrence dataset. https://nzobisipt.niwa.co.nz/resource?r=zostrea_pool_nz&v=1.1


Researchers should respect the following rights statement:

The publisher and rights holder of this work is Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.

GBIF Registration

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Occurrence; Observation


B.W. Hayward
  • Originator
  • Point Of Contact
New Zealand Geological Survey
Lower Hutt
B. W. Hayward
  • Metadata Provider
New Zealand Geological Survey
Lower Hutt
Kevin Mackay

Geographic Coverage

Kawerua, Northland, New Zealand

Bounding Coordinates South West [-35.635, 173.439], North East [-35.635, 173.439]

Temporal Coverage

Start Date / End Date 1979-01-01 / 1979-01-15

Project Data

The Auckland University Field Club Scientific Station is situated at Kawerua on the exposed west coast of Northland, 14km south of the mouth of the Hokianga Harbour. Directly in front of the station, the coast consists of a number of basaltic reefs that extend out into the sea for up to 100m. They enclose lagoons and numerous large and small intertidal pools, providing a diversity of habitat types and wealth of marine life available for study. This article describes the macroflora and fauna, and foraminiferal microfauna of only one of the many types of intertidal pool present.

Title Rock pool community near Auckland University research station
Study Area Description The pool studied is situated 50m north of the track which leads down to the beach from the Kawerua Station. It is at approximately mid-tidal level and has no connection with the sea for about 6 hours during every low tide. The pool is protected from the fierce Tasman Sea waves by a solid reef across its western side. It is enclosed by low piles of boulders covering flat rock shelves to the north and south, and by a quartz sand beach on the eastern, shoreward side. The pool itself is approximately 30 x 15m in size and has a water depth of 5-25cm when not submerged. The pool contains numerous rocks (10-30cm diameter) scattered throughout. Much of its floor is covered by a 1-15cm thick layer of shelly, quartz sand, but in places where there is an abundance of rocks, the sediment is fine gravel. Small clumps (up to 30cm diameter) of the sea grass, Zostera capricorni, occur sporadically in parts of the pool and around their roots the sediment is dark muddy sand.

Sampling Methods

Early in January 1979, six samples were collected from the intertidal Zostera pool and preserved in 10% ethanol. The samples consisted of three of plant material — Zostera laminae, Hormosira banksii and Corallina turf, and three of sediment taken from the upper 2 cm.

Study Extent Kawerau rock pool, Northland, New Zealand

Method step description:

  1. On return to the laboratory, the samples were thoroughly washed over a 200-mesh sieve (nominal opening 0.075mm) and left to stand for one hour in a solution of Rose Bengal (a stain for protoplasm, commonly used to identify individuals living at the time of collection). The samples were then washed thoroughly and dried. Despite thorough examination, no foraminifera were found in samples 5 and 6 (on Hormosira or Zostera) and these were discarded.
  2. Samples 1-3 were divided up using a microsplitter until sufficient material was left containing approximately 300 benthic foraminifera. All foraminifera (including planktonics) in these microsplits were picked, mounted, identified and counted and a note made of the number of stained (live) foraminifera. These counts give an estimate of the relative abundance of the different species and the percentage of live foraminifera in the total sample.
  3. In addition, a measured volume (50cc for samples 2 and 3, 100cc for sample 4) of each sediment sample was taken and the foraminiferal tests concentrated by floating off in carbon tetrachloride. The entire float material was then examined under water and the stained foraminiferal tests picked out using a glass capillary tube. They were then mounted, identified and counted. These picks give an estimate of the density of live foraminifera in a given volume of sediment (standing crop) and also the relative abundance of the different species living at the time.
  4. Finally, a further search was made through all four samples and additional species not found in the previous counts were noted as present.

Bibliographic Citations

  1. Hayward, B. W. (1979). An intertidal Zostera pool community at Kawerua, Northland and its foraminiferal microfauna. Tane, 25, 173-186.

Additional Metadata

marine, harvested by iOBIS