AN INTERTIDAL ZOSTERA POOL COMMUNITY AT KAWERUA, NORTHLAND AND ITS FORAMINIFERAL MICROFAUNA

SUMMARY 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 hot lorn 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 microfaunas 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 domi­ nant 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 consist 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 liv­ ing 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.