52 
PACIFIC SCIENCE, Vol. XIII, January 1959 
welling, in water masses surrounding small 
islands, and it may be of considerable value 
in the study of patchiness in the distribution 
of organisms, e.g., of aggregation in the sta- 
tistical sense. There is little doubt that a 
comparable technique may be used to de- 
termine the effects on organisms of other 
pairs of environmental factors and in this 
connection the use by Moore (1950, 1952) 
and Moore, Owre, Jones, and Dow (1953) of 
the light and temperature relationships of 
euphausiids and other zooplankton should 
not be overlooked. Last, a convenient, three- 
dimensional picture of the distribution of a 
species would be presented if a T-S-P dia- 
gram, constructed from data from vertical 
series of samples, were allied with the geo- 
graphical distribution of the species. 
SUMMARY 
1. Two principles concerning plankton dis- 
tribution have been established by earlier 
workers. First, bodies of water with distinct 
properties possess distinctive planktonic fau- 
nas. Second, when one of these bodies of 
water mixes with another, the faunas are 
mixed. In this present study, species have 
been selected as indicators of the constituent 
waters of an area about southern New Zea- 
land where waters of subtropical and sub- 
antarctic origins are mixing together, and 
with coastal water. The surface waters entering 
the area are identified by their temperature- 
salinity relationships. 
2. All occurrences of a number of selected 
species of the plankton have been superim- 
posed on the T-S diagram of surface waters in 
the area to produce the temperature-salinity- 
plankton (T-S-P) diagram. It is found that 
the distribution of each of the several waters 
coincides with the distribution of its indi- 
genous species. Further, where one of the 
waters penetrates into, and mixes with 
another, it is demonstrated that the species of 
the one are transported into the other and a 
mixed fauna results. 
3. Examples are discussed in which stations 
(isolated geographically and in time) aggre- 
gate in the T-S diagram. The similar environ- 
mental conditions which exist at these stations 
are the result of several intrusions at different 
localities of subantarctic into coastal water. 
The individual intrusions have been demon- 
strated by considering the geographic distri- 
bution of water properties in near-synoptic 
series of stations. The close affinity between 
the stations of each aggregate is demonstrated 
in the T-S-P diagram by means of the simi- 
larity of the plankton captured at the stations. 
4. Plankton distribution in the T-S-P dia- 
gram, allied with that shown by the geo- 
graphical distribution of the species, has 
demonstrated a southward migration of the 
subtropical convergence during the summer. 
5. Temperature and salinity tolerances of 
species and the reactions of species, or groups 
of species, to changes in temperature and 
salinity, are readily observable in the T-S-P 
diagram. 
6. The T-S-P diagram is potentially useful 
in studies of distribution about convergences, 
small islands, near areas of upwelling, and for 
studying patchiness of plankton. 
REFERENCES 
Barnard, K. H. 1930. Crustacea Part XI. 
Amphipoda. Brit. Antarctic {Terra Nova) 
Exped. 1910, Brit. Mas. Nat. Hist., Zool. 
Rpt. 8(4): 307-454. 
Bary, B. M. 1956. Notes on ecology, syste- 
matics, and development of some Mysi- 
dacea and Euphausiacea (Crustacea), from 
New Zealand. Pacific Sci. 10(4): 431-467. 
Boden, B. P. 1954. The euphausiid crusta- 
ceans of southern South African waters. 
Roy. Soc. So. Africa, Cape Town, Trans. 
34(1): 181-243. 
Brady, G. S. 1918. Copepoda. Australasian 
Antarctic Exped. 1911-14, Sci. Rpts., Ser. C. 
Zool. and Bot. 5(3): 1-48. 
David, P. M. 1955. The distribution of 
Sagitta gazellae Ritter-Zahony. " Discovery' ' 
Rpts. 27: 235-278. 
