- Email: [email protected]
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
Deep-Sea Research, 1960, Vol. 7, pp. 201 to 207.
Pergamon Press Ltd., London.
Printed in Great Britain
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska* SAYED A. EL WARDANI** Department of Oceanography, University of Washington (Received !0 November 1959)
Abstract Total phosphorus was determined on some 170 samples from eleven stations in the Bering Sea, the Aleutian Trench, and the Gulf of Alaska. Samples ranged in depth from the surface to 7000 m. In these samples organic phosphorus, estimated as the difference between total and inorganic phosphorus, bears an inverse relationship to the distribution of inorganic phosphorus. Surfacewaters, generally low in inorganic phosphorus, contain up to 1.0 t~g. at./L organic phosphorus, with a grand average of 0.27 t,g. at./L for the upper 200 m. The amount of organic phosphorus present in surface waters reaches values as high as 47 per cent of the total. On the other hand, waters below about 200 m. have little or no measurable amounts of organic phosphorus. In its vertical distribution, total phosphorus varies at the most by a factor of three and is more or less uniform with depth compared to the inorganic phosphorus. Inferences are drawn concerning the nature of organic matter and the state of organic phosphorus in deep waters. The observed distribution of various forms of phosphorus substantiates the theory that the major part of the phosphorus cycle is enacted in the surface layers. INTRODUCTION PHOSPHORUSis present in sea water in solution and particulate solid state and in both inorganic and organic compounds. Knowledge is limited concerning the quantitative distribution of phosphorus among its various forms in sea water, as well as concerning the nature of the compounds in which it is organically bound. Such information is of interest in connection with the biogeochemical processes involving transfer, accumulation, and partition of phosphorus in the marine environment and in connection with problems of organic production in the sea. The significance of organic phosphorus determinations in oceanographic studies has been discussed by KETCHUM, CORWIN and KEEN (1955) who reported on the results of analysis of nearly 1000 samples from the equatorial Atlantic Ocean. These authors also showed that in waters below 1000 m, phosphorus was essentially present in the inorganic form, while surface waters contained an important fraction of the element in organic form. Voluminous data on the distribution of inorganic phosphorus in Pacific waters are available but only a few analyses on organic phosphorus have been reported and these are primarily from coastal environments. HANSEN and ROBINSON (1953) found 0.36-0.59/~g atom/L of organically-bound phosphorus in Dabob Bay in Puget Sound. More recently TAKEDA (1957) studied the relationship between organic phosphorus and plankton in Pacific surface waters off the eastern shore of northern Honshu. He found inorganic phosphorus uniformly distributed in surface waters during May when the plankton was propagating, wbile total phosphorus varied with *Contribution No. 237 Department of Oceanography, University of Washington, Seattle. This work was supported by funds made available for the International GeophysicalYear programme by the National Science Foundation (NSF Y/9.14/139 and Y/216./323). **Present Address, San Jose State College, San Jose, California. 201
202
SAYED A. EL WARDANI
the propagation of plankton. Total phosphorus decreased with increese of the standing crop of p h y t o p l a n k t o n and vice versa. He gave no estimate, however, of organic phosphorus in the waters investigated. ROCHt:ORD (1958) studied the degree of the conservative character of total phosphorus as a means of identifying East Australian water masses and reported on the particulate phosphorus content of coastal waters. ~,0 ~
180 ~
160 °
% ~'-r
i4U'
+~'
d~
L
I
*'
,~,, ,~,,"
5@~.
~)o,,/
_~
Oceae
160 o
40 ~
~40, °
FIG. 1. Location of stations. The present study was conducted in the summer of 1957 during Brown Bear Cruise 176, as part of the I n t e r n a t i o n a l Geophysical Year programme of the University of Washington. Water samples were collected from eleven stations in the Bering Sea, Aleutian waters and the G u l f of Alaska to investigate the vertical distribution of total, inorganic, and organic phosphorus (FIG. 1). Particular emphasis was placed on deep and bottom waters for which organic phosphorus data are virtually non-existent. ANALYTICAL
PROCEDURE
KETCHUM,CORWINand KEEN (1955) investigated the accuracy and precision of HARVEY'Sautoclave digestion method (HARVEY,1948)for measuring total phosphorus in sea water, and recommended its use in preference to the routine analysis of soluble inorganic phosphorus. Because of the lack of a suitable autoclave this procedure was not used during the present study and the organic matter was digested with perchloric acid, following the procedure described by HANSEN and ROBINSON (1953). Heavy polyethylene bottles (16-oz.) with buttress caps were used for storage of samples (500 c.c.). The bottles were cleaned by scrubbing the walls with a rubber policeman and warm 10~ hydrochloric acid, then rinsing several times with tap water, distilled water and finally the sea water to be analyzed. Prior to analysis, organic matter adhering to the walls was dispersed back into the sample by adding 2 cc. of concentrated hydrochloric acid and scrubbing with a rubber policeman. A 50-cc. aliquot was then transferred with a volumetric pipette into a 125-cc. Vycor Erlenmeyer flask, followed by 3 cc. of 70.7~ perchloric acid. The organic matter was oxidized and arsenic removed, as described by HANSENand ROBINSON(1953). Because oftbe limited number of Vycorflasks available, only twelve digestions were conducted at once, of which two were reagent blanks. After digestion the residue was dissolved in distilled water and transferred to a 50-cc. volumetric flask and the phosphorus content was measured spectrophotometrically, using the method described by WOOSTER and RAKESTRAW 0951). Although the perchloric acid digestion procedure of HANSEN and
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
203
ROBINSON is more laborious and time-consuming than HARVEY'Smethod, it was found to have an accuracy and reproducibility comparable to that of HARVEY'Smethod as reported by KETCHUM, CORWlN and KEEN(1955). Replicate analyses of a standard solution of disodium glycerophosphate (1 and 2 t~g. at./L) gave recoveries within 5 per cent of the original amount taken and the reproducibility determined from eleven calibrations run during the period of analysis was 7 per cent. Inorganic phosphorus was determined aboard ship immediately after sampling, using a Beckman model DU spectrophotometer and the procedure described by WOOSTERand RAKESTRAW0951). Total phosphorus content of the samples was measured in the shore laboratory and the organic fraction was estimated by finding the difference between the total and inorganic phosphorus. Only those differences exceeding 7 per cent of the total were considered significant and are reported in this paper as the organic phosphorus content. In the analysis of total phosphorus, arsenic interference is eliminated by its removal as the trichloride. On the other hand, inorganic phosphorus determination includes the arsenate content of sea water. This may result in erroneously low values for the estimated organic phosphorus; however, the low arsenate content of sea water (GORGY,RAKESTRAWand Fox 1948, give 0'03 to 0'70/zg. at./L) and the relatively high concentration of inorganic phosphorus in the waters investigated make this error insignificant. Phosphorus, 0
I
2
5
0
I
/zg 2
at/L
5
4
0
I
2
5
4
50
I00
20C E
5oc
c] I00C
200C
500C
;O,OOC
FIG. 2. Vertical distribution of total, inorganic and inorganic phosphorus at Stations 1, 15 and 31. Broken line = total phosphorous. Solid line = inorganic phosphorus. Shaded area = organic phosphorus. RESULTS
AND
DISCUSSION
Tables 1 a n d 2 show the result of analyses for total a n d organic phosphorus, respectively, a n d FIG. 2 illustrates the vertical distribution of total, inorganic, a n d organic phosphorus at three stations. The data indicate that total phosphorus has a vertical distribution parallel to that of the inorganic form, being lower at the surface t h a n at greater depth. In the eleven stations investigated, surface water contained up to 1.0/~g at./L of organic phosphorus with a grand average of 0.27 v-g at./L for the
2.84 2.83 2"63 2.57 2"62 2"68
3 "03 3"21 3"30
3"20 3"50
3'51 3"20 2"55 3"40
1 "89 2"05 1"64 3"04 2"96
8 50 ° 55'N 177 ° 23'E
- - Sample was not analyzed
2"71 2"68 2"39 2'54 2"74
3-05
2"86 3"14 2"98 2"71
2000
1"96 1 "83 2"10 2"55 2"93 3"19 3.56 3.14 3"25 3"16 3"33 3.24
Depth (m) 0 l0 30 75 125 200 300 500 700 800 1000 1500
2500 3000 3500 4000 4500 5000 5500 6000 6500 7000
1 50 ° 22'N 177 ° 40'W
Sta. No. /-at. Long.
3"20 3 "03 2"85 2"81 2"81 2"71 2"66 2"65 2"68
2"83 3"18 3"30 3"46
1"49 1 "72 2"26 2"72 3"31 3"46 3"13 3"12
10 51 ° 08'N 174 ° 41'E
3"14 3'02
3"27
l "54 1 "96 2"27 2"63 2"66 3"03 3"59 3"50 3 "42 3"11 3"11
11 51 ° 41'N 178 ° 10'E
2"66 1 "95 2"03 2"50 3 "27 2"70 2"80 3"00 3"10 3"34 3"34
14 53 ° 3YN 179 ° 35'W
3"10 3"00 3"00 2"86 2"70 2"76 2"70 2"68 2"70 2"72 3"60
1 "28 1"40 1 "38 2"43 3"02 3"60 3"21 3"33 3"30 2"80 2"82
15 51 ° 0 2 ' N 171 ° 45"W
1.90 1"74 2"49 2"39 3"00 2"80 2"90 3"02 3"40 3"00 3"00 3"20 3"69 2"96
21 55°00'N 169°40'W
Table 1. Total phophorus, /zg. at./1
2"85 2.60
2"90
3"10
3-00
m
m
E
I
24 53 ° 12'N 162 ° 27'W
3"00 2-70
1 "79 1"50 1"40 2.90 2"42 2"65 2-74 2-60 3"20 3"10
29 56 ° 24'N 151 ° 16'W
2"45 1 "70 1 "85 2"75 3-37 3"00 3"40 3 "62 3"56 3"32 3"52 3"70 3-00 3"20 2"70 3"00
30 51 ° 53'N 150 ° 42'W
3"34 3 "46 3"16 2"82 3"00 3"12 3"00 2"20
I "83 2"08 1 "35 1 "23 2-82 2-18 2-39
31 48 ° 0 Y N 142 ° 50'W
),
r~
>
f/3
t,O
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
0 0 0
0
Z~
Ill
666
66
6
IIllll
66
I
ll[ll[llll
I
III
z~ 0 0 0
~"o
o
0
0 0 0 0 0 0
.z~ ~o
~q
IIIIIIIII
o
z.~ _b, ~ 0 0 0
I
0
"'~ o
o
0 0 0 0 0
~o
g..
66
,6~6l
~ 6
0
I[lll
O0
z~ 66666
z~
6
666
l
205
206
SAYED A. EL WARDANI
upper 200 m. None of the surface samples, however, gave an organic phosphorus concentration higher than the inorganic level as reported in KETCHUM, CORWIN and KEEN (1955). In Table 3 the percentages of total phosphorus present in the organic form in the upper 200 m are given and show that the organic fraction reaches as much as 47 per cent of the total and averages 18 per cent. The waters below about 200 m, however, showed no significant differences between total and inorganic phosphorus concentrations (Table 2) except in a few samples amounting to less than 5 per cent of the total. The present observed distribution of organic phosphorus resembles the distribution found by KETCHUM, CORWIN and KEEN (1955) in the equatorial Atlantic, where 95 per cent of the surface samples contained significant quantities of organic phosphorus, while deeper waters (in this case below 1000 m) had no measurable amounts. Table 3,
i Station No. l --~epth,~
Percentage o f total phosphorus in the organic Jorm upper 200 m
1
(m) I]---0 30.6 10 27.4 30 19.0 75 13"3 125 17.0 2OO
8 10.6 11.7 8.6 11.8
i
10 13.4 18.6 13.3 9.2 12.1
i ~ 11
:
14
I i
15
21
29
30
30
- - .......... !. . . . . . . . 37.6 147-0 26.3 17.8 29.0 4 5 . 5 21.4 12-8 ~ 24.2 15.5 18-6 46.0 13.2 14.8 21.7 12.8 35-0 22-2 12.9 9.7 10.3 13.8 16.7 15.0 13-3 11.9 10.0 7-8 I1.0
Ave.* 21'5 10.7 i 13.3 i 15.8 18.0 i 22.2 17.0 i 15.3 Grand average = 18.1 *Average for samples with organic phosphorus greater than 7 °,o of the total.
16.6 i 30"9
The insignificance (analytically) of organic phosphorus in the deep waters raises the question as to the processes involved in depriving deep waters of measurable concentrations of this fraction of phosphorus. ZOBELL (1946) discussed the regeneration of phosphorus in sea water and referred to a number of earlier investigators who suggested the rapidity with which phosphorus is regenerated from organic matter by bacterial decay. GOLDSCHMIEDT,METTENLEITER and BORCHARDT (1958) identified alkaline phosphatase as one of the principal enzymes in sea water and from serial investigations these authors showed that the concentration of the enzyme increased with the depth of the water and with distance from land. Phosphatases, enzymes which catalyze the breakdown of phosphate-containing substrates, release phosphorus from organic combination and may account for the absence of significant concentrations of organic phosphorus in deep waters. The present investigation substantiates the theory that, at least in oceanic environments with great depths of water, the major part o f the phosphorus cycle in the ocean takes place in the euphotic zone. There are indications that oceanic deep waters contain organic matter, but information on its nature and composition is insufficient to permit predictions as to the state of organically-bound phosphorus. PLUNKETT and RAKESTRAW (1955) measured the dissolved orgamc carbon in a number of deep-water samples from six stations off the California coast and in the Northwestern Pacific. They found 0.59-2.82 mg/L of dissolved organic carbon in waters deeper than 500 m. GAST and T~oMPsor~ (1958) considered that the difference between observed total and free boron in sea
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
207"
water was due to the presence of polyhydroxy organic compounds which complex with part of the boron. They estimated that as much as 0.015 millimoles of organic polyhydroxy compounds may be present in water deeper than 500 m in the Northeast Pacific. Until the present methods of measuring total and inorganic phosphorus in sea water are materially improved, the presence or absence of organic phosphorus compounds and the concentration or organic phosphorus in deep waters will remain uncertain. Acknowledgement--The author wishes to thank Mr. M. SHAFIZADEHfor assisting with the analysis of the samples. REFERENCES GAST, J. A. and THOMPSON,T. G. (1958) Determination of the alkalinity and borate concentration of sea water. AnaL Chem. 39, 1549-1551. GOLDSCHMIEOT, H., METT~NLErrER, M. W. and BORCHAROT, P. R. (1958) Presence and function of alkaline phosphatas¢ in sea water. Turtox News, 36, (11), 269. GORGY, SAMY., RAKESTRAW,N. W. and Fox, D. L. (1948) Arsenic in sea water. J. Mar. Res., 7, 22-32. HANSEN, A. A. and ROBINSON,R. J. (1953) The determination of organic phosphorus with perchloric acid oxidation. J. Mar. Res., 12, 31-42. HARVEY, H. W. (1948) The estimation of phosphate and of total phosphorus in sea water. J. Mar. Biol. Assoc., U.K. 27, 337-359. KETCHUM,B. H., CORWIN,N. and KEEN,D. J. (1955) The significance of organic phosphorus determinations in ocean waters. Deep-Sea Res., 2, 172-181. PLUNKETT, M. A. and RAKESTRAW,N. W. (1955) Dissolved organic matter in the sea. Deep-Sea Res., Suppl. to Vol. 3, 12-14. ROCHFORD, D. 0958) Total phosphorus as a means of identifying East Australian water masses. Deep-Sea Res., 5, 89-110. TAKEDA,ITSURO(1957) Organic phosphorus in Pacific waters offthe eastern shore of northern Honshu. J. Chem. Soc., Japan 78, 491-494. WOOSTER, W. S. and RAKESTRAW, N. W. (1951) The estimation of dissolved phosphate in sea water. J. Mar. Res. 10, 91-100. ZOBELL, CLAUDEE. (1946) Marine microbiology. Chronica Botanica Co., Waltham, Mass, 168 pp.
Pergamon Press Ltd., London.
Printed in Great Britain
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska* SAYED A. EL WARDANI** Department of Oceanography, University of Washington (Received !0 November 1959)
Abstract Total phosphorus was determined on some 170 samples from eleven stations in the Bering Sea, the Aleutian Trench, and the Gulf of Alaska. Samples ranged in depth from the surface to 7000 m. In these samples organic phosphorus, estimated as the difference between total and inorganic phosphorus, bears an inverse relationship to the distribution of inorganic phosphorus. Surfacewaters, generally low in inorganic phosphorus, contain up to 1.0 t~g. at./L organic phosphorus, with a grand average of 0.27 t,g. at./L for the upper 200 m. The amount of organic phosphorus present in surface waters reaches values as high as 47 per cent of the total. On the other hand, waters below about 200 m. have little or no measurable amounts of organic phosphorus. In its vertical distribution, total phosphorus varies at the most by a factor of three and is more or less uniform with depth compared to the inorganic phosphorus. Inferences are drawn concerning the nature of organic matter and the state of organic phosphorus in deep waters. The observed distribution of various forms of phosphorus substantiates the theory that the major part of the phosphorus cycle is enacted in the surface layers. INTRODUCTION PHOSPHORUSis present in sea water in solution and particulate solid state and in both inorganic and organic compounds. Knowledge is limited concerning the quantitative distribution of phosphorus among its various forms in sea water, as well as concerning the nature of the compounds in which it is organically bound. Such information is of interest in connection with the biogeochemical processes involving transfer, accumulation, and partition of phosphorus in the marine environment and in connection with problems of organic production in the sea. The significance of organic phosphorus determinations in oceanographic studies has been discussed by KETCHUM, CORWIN and KEEN (1955) who reported on the results of analysis of nearly 1000 samples from the equatorial Atlantic Ocean. These authors also showed that in waters below 1000 m, phosphorus was essentially present in the inorganic form, while surface waters contained an important fraction of the element in organic form. Voluminous data on the distribution of inorganic phosphorus in Pacific waters are available but only a few analyses on organic phosphorus have been reported and these are primarily from coastal environments. HANSEN and ROBINSON (1953) found 0.36-0.59/~g atom/L of organically-bound phosphorus in Dabob Bay in Puget Sound. More recently TAKEDA (1957) studied the relationship between organic phosphorus and plankton in Pacific surface waters off the eastern shore of northern Honshu. He found inorganic phosphorus uniformly distributed in surface waters during May when the plankton was propagating, wbile total phosphorus varied with *Contribution No. 237 Department of Oceanography, University of Washington, Seattle. This work was supported by funds made available for the International GeophysicalYear programme by the National Science Foundation (NSF Y/9.14/139 and Y/216./323). **Present Address, San Jose State College, San Jose, California. 201
202
SAYED A. EL WARDANI
the propagation of plankton. Total phosphorus decreased with increese of the standing crop of p h y t o p l a n k t o n and vice versa. He gave no estimate, however, of organic phosphorus in the waters investigated. ROCHt:ORD (1958) studied the degree of the conservative character of total phosphorus as a means of identifying East Australian water masses and reported on the particulate phosphorus content of coastal waters. ~,0 ~
180 ~
160 °
% ~'-r
i4U'
+~'
d~
L
I
*'
,~,, ,~,,"
5@~.
~)o,,/
_~
Oceae
160 o
40 ~
~40, °
FIG. 1. Location of stations. The present study was conducted in the summer of 1957 during Brown Bear Cruise 176, as part of the I n t e r n a t i o n a l Geophysical Year programme of the University of Washington. Water samples were collected from eleven stations in the Bering Sea, Aleutian waters and the G u l f of Alaska to investigate the vertical distribution of total, inorganic, and organic phosphorus (FIG. 1). Particular emphasis was placed on deep and bottom waters for which organic phosphorus data are virtually non-existent. ANALYTICAL
PROCEDURE
KETCHUM,CORWINand KEEN (1955) investigated the accuracy and precision of HARVEY'Sautoclave digestion method (HARVEY,1948)for measuring total phosphorus in sea water, and recommended its use in preference to the routine analysis of soluble inorganic phosphorus. Because of the lack of a suitable autoclave this procedure was not used during the present study and the organic matter was digested with perchloric acid, following the procedure described by HANSEN and ROBINSON (1953). Heavy polyethylene bottles (16-oz.) with buttress caps were used for storage of samples (500 c.c.). The bottles were cleaned by scrubbing the walls with a rubber policeman and warm 10~ hydrochloric acid, then rinsing several times with tap water, distilled water and finally the sea water to be analyzed. Prior to analysis, organic matter adhering to the walls was dispersed back into the sample by adding 2 cc. of concentrated hydrochloric acid and scrubbing with a rubber policeman. A 50-cc. aliquot was then transferred with a volumetric pipette into a 125-cc. Vycor Erlenmeyer flask, followed by 3 cc. of 70.7~ perchloric acid. The organic matter was oxidized and arsenic removed, as described by HANSENand ROBINSON(1953). Because oftbe limited number of Vycorflasks available, only twelve digestions were conducted at once, of which two were reagent blanks. After digestion the residue was dissolved in distilled water and transferred to a 50-cc. volumetric flask and the phosphorus content was measured spectrophotometrically, using the method described by WOOSTER and RAKESTRAW 0951). Although the perchloric acid digestion procedure of HANSEN and
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
203
ROBINSON is more laborious and time-consuming than HARVEY'Smethod, it was found to have an accuracy and reproducibility comparable to that of HARVEY'Smethod as reported by KETCHUM, CORWlN and KEEN(1955). Replicate analyses of a standard solution of disodium glycerophosphate (1 and 2 t~g. at./L) gave recoveries within 5 per cent of the original amount taken and the reproducibility determined from eleven calibrations run during the period of analysis was 7 per cent. Inorganic phosphorus was determined aboard ship immediately after sampling, using a Beckman model DU spectrophotometer and the procedure described by WOOSTERand RAKESTRAW0951). Total phosphorus content of the samples was measured in the shore laboratory and the organic fraction was estimated by finding the difference between the total and inorganic phosphorus. Only those differences exceeding 7 per cent of the total were considered significant and are reported in this paper as the organic phosphorus content. In the analysis of total phosphorus, arsenic interference is eliminated by its removal as the trichloride. On the other hand, inorganic phosphorus determination includes the arsenate content of sea water. This may result in erroneously low values for the estimated organic phosphorus; however, the low arsenate content of sea water (GORGY,RAKESTRAWand Fox 1948, give 0'03 to 0'70/zg. at./L) and the relatively high concentration of inorganic phosphorus in the waters investigated make this error insignificant. Phosphorus, 0
I
2
5
0
I
/zg 2
at/L
5
4
0
I
2
5
4
50
I00
20C E
5oc
c] I00C
200C
500C
;O,OOC
FIG. 2. Vertical distribution of total, inorganic and inorganic phosphorus at Stations 1, 15 and 31. Broken line = total phosphorous. Solid line = inorganic phosphorus. Shaded area = organic phosphorus. RESULTS
AND
DISCUSSION
Tables 1 a n d 2 show the result of analyses for total a n d organic phosphorus, respectively, a n d FIG. 2 illustrates the vertical distribution of total, inorganic, a n d organic phosphorus at three stations. The data indicate that total phosphorus has a vertical distribution parallel to that of the inorganic form, being lower at the surface t h a n at greater depth. In the eleven stations investigated, surface water contained up to 1.0/~g at./L of organic phosphorus with a grand average of 0.27 v-g at./L for the
2.84 2.83 2"63 2.57 2"62 2"68
3 "03 3"21 3"30
3"20 3"50
3'51 3"20 2"55 3"40
1 "89 2"05 1"64 3"04 2"96
8 50 ° 55'N 177 ° 23'E
- - Sample was not analyzed
2"71 2"68 2"39 2'54 2"74
3-05
2"86 3"14 2"98 2"71
2000
1"96 1 "83 2"10 2"55 2"93 3"19 3.56 3.14 3"25 3"16 3"33 3.24
Depth (m) 0 l0 30 75 125 200 300 500 700 800 1000 1500
2500 3000 3500 4000 4500 5000 5500 6000 6500 7000
1 50 ° 22'N 177 ° 40'W
Sta. No. /-at. Long.
3"20 3 "03 2"85 2"81 2"81 2"71 2"66 2"65 2"68
2"83 3"18 3"30 3"46
1"49 1 "72 2"26 2"72 3"31 3"46 3"13 3"12
10 51 ° 08'N 174 ° 41'E
3"14 3'02
3"27
l "54 1 "96 2"27 2"63 2"66 3"03 3"59 3"50 3 "42 3"11 3"11
11 51 ° 41'N 178 ° 10'E
2"66 1 "95 2"03 2"50 3 "27 2"70 2"80 3"00 3"10 3"34 3"34
14 53 ° 3YN 179 ° 35'W
3"10 3"00 3"00 2"86 2"70 2"76 2"70 2"68 2"70 2"72 3"60
1 "28 1"40 1 "38 2"43 3"02 3"60 3"21 3"33 3"30 2"80 2"82
15 51 ° 0 2 ' N 171 ° 45"W
1.90 1"74 2"49 2"39 3"00 2"80 2"90 3"02 3"40 3"00 3"00 3"20 3"69 2"96
21 55°00'N 169°40'W
Table 1. Total phophorus, /zg. at./1
2"85 2.60
2"90
3"10
3-00
m
m
E
I
24 53 ° 12'N 162 ° 27'W
3"00 2-70
1 "79 1"50 1"40 2.90 2"42 2"65 2-74 2-60 3"20 3"10
29 56 ° 24'N 151 ° 16'W
2"45 1 "70 1 "85 2"75 3-37 3"00 3"40 3 "62 3"56 3"32 3"52 3"70 3-00 3"20 2"70 3"00
30 51 ° 53'N 150 ° 42'W
3"34 3 "46 3"16 2"82 3"00 3"12 3"00 2"20
I "83 2"08 1 "35 1 "23 2-82 2-18 2-39
31 48 ° 0 Y N 142 ° 50'W
),
r~
>
f/3
t,O
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
0 0 0
0
Z~
Ill
666
66
6
IIllll
66
I
ll[ll[llll
I
III
z~ 0 0 0
~"o
o
0
0 0 0 0 0 0
.z~ ~o
~q
IIIIIIIII
o
z.~ _b, ~ 0 0 0
I
0
"'~ o
o
0 0 0 0 0
~o
g..
66
,6~6l
~ 6
0
I[lll
O0
z~ 66666
z~
6
666
l
205
206
SAYED A. EL WARDANI
upper 200 m. None of the surface samples, however, gave an organic phosphorus concentration higher than the inorganic level as reported in KETCHUM, CORWIN and KEEN (1955). In Table 3 the percentages of total phosphorus present in the organic form in the upper 200 m are given and show that the organic fraction reaches as much as 47 per cent of the total and averages 18 per cent. The waters below about 200 m, however, showed no significant differences between total and inorganic phosphorus concentrations (Table 2) except in a few samples amounting to less than 5 per cent of the total. The present observed distribution of organic phosphorus resembles the distribution found by KETCHUM, CORWIN and KEEN (1955) in the equatorial Atlantic, where 95 per cent of the surface samples contained significant quantities of organic phosphorus, while deeper waters (in this case below 1000 m) had no measurable amounts. Table 3,
i Station No. l --~epth,~
Percentage o f total phosphorus in the organic Jorm upper 200 m
1
(m) I]---0 30.6 10 27.4 30 19.0 75 13"3 125 17.0 2OO
8 10.6 11.7 8.6 11.8
i
10 13.4 18.6 13.3 9.2 12.1
i ~ 11
:
14
I i
15
21
29
30
30
- - .......... !. . . . . . . . 37.6 147-0 26.3 17.8 29.0 4 5 . 5 21.4 12-8 ~ 24.2 15.5 18-6 46.0 13.2 14.8 21.7 12.8 35-0 22-2 12.9 9.7 10.3 13.8 16.7 15.0 13-3 11.9 10.0 7-8 I1.0
Ave.* 21'5 10.7 i 13.3 i 15.8 18.0 i 22.2 17.0 i 15.3 Grand average = 18.1 *Average for samples with organic phosphorus greater than 7 °,o of the total.
16.6 i 30"9
The insignificance (analytically) of organic phosphorus in the deep waters raises the question as to the processes involved in depriving deep waters of measurable concentrations of this fraction of phosphorus. ZOBELL (1946) discussed the regeneration of phosphorus in sea water and referred to a number of earlier investigators who suggested the rapidity with which phosphorus is regenerated from organic matter by bacterial decay. GOLDSCHMIEDT,METTENLEITER and BORCHARDT (1958) identified alkaline phosphatase as one of the principal enzymes in sea water and from serial investigations these authors showed that the concentration of the enzyme increased with the depth of the water and with distance from land. Phosphatases, enzymes which catalyze the breakdown of phosphate-containing substrates, release phosphorus from organic combination and may account for the absence of significant concentrations of organic phosphorus in deep waters. The present investigation substantiates the theory that, at least in oceanic environments with great depths of water, the major part o f the phosphorus cycle in the ocean takes place in the euphotic zone. There are indications that oceanic deep waters contain organic matter, but information on its nature and composition is insufficient to permit predictions as to the state of organically-bound phosphorus. PLUNKETT and RAKESTRAW (1955) measured the dissolved orgamc carbon in a number of deep-water samples from six stations off the California coast and in the Northwestern Pacific. They found 0.59-2.82 mg/L of dissolved organic carbon in waters deeper than 500 m. GAST and T~oMPsor~ (1958) considered that the difference between observed total and free boron in sea
Total and organic phosphorus in waters of the Bering Sea, Aleutian Trench and Gulf of Alaska
207"
water was due to the presence of polyhydroxy organic compounds which complex with part of the boron. They estimated that as much as 0.015 millimoles of organic polyhydroxy compounds may be present in water deeper than 500 m in the Northeast Pacific. Until the present methods of measuring total and inorganic phosphorus in sea water are materially improved, the presence or absence of organic phosphorus compounds and the concentration or organic phosphorus in deep waters will remain uncertain. Acknowledgement--The author wishes to thank Mr. M. SHAFIZADEHfor assisting with the analysis of the samples. REFERENCES GAST, J. A. and THOMPSON,T. G. (1958) Determination of the alkalinity and borate concentration of sea water. AnaL Chem. 39, 1549-1551. GOLDSCHMIEOT, H., METT~NLErrER, M. W. and BORCHAROT, P. R. (1958) Presence and function of alkaline phosphatas¢ in sea water. Turtox News, 36, (11), 269. GORGY, SAMY., RAKESTRAW,N. W. and Fox, D. L. (1948) Arsenic in sea water. J. Mar. Res., 7, 22-32. HANSEN, A. A. and ROBINSON,R. J. (1953) The determination of organic phosphorus with perchloric acid oxidation. J. Mar. Res., 12, 31-42. HARVEY, H. W. (1948) The estimation of phosphate and of total phosphorus in sea water. J. Mar. Biol. Assoc., U.K. 27, 337-359. KETCHUM,B. H., CORWIN,N. and KEEN,D. J. (1955) The significance of organic phosphorus determinations in ocean waters. Deep-Sea Res., 2, 172-181. PLUNKETT, M. A. and RAKESTRAW,N. W. (1955) Dissolved organic matter in the sea. Deep-Sea Res., Suppl. to Vol. 3, 12-14. ROCHFORD, D. 0958) Total phosphorus as a means of identifying East Australian water masses. Deep-Sea Res., 5, 89-110. TAKEDA,ITSURO(1957) Organic phosphorus in Pacific waters offthe eastern shore of northern Honshu. J. Chem. Soc., Japan 78, 491-494. WOOSTER, W. S. and RAKESTRAW, N. W. (1951) The estimation of dissolved phosphate in sea water. J. Mar. Res. 10, 91-100. ZOBELL, CLAUDEE. (1946) Marine microbiology. Chronica Botanica Co., Waltham, Mass, 168 pp.