Submarine Geological Study of the Bottom Sediments...

TitleSubmarine Geological Study of the Bottom Sediments of theAdjacent Seas of the Japanese Islands with Special Referenceto the Distribution of Organic Matter in Sediments

Author(s) Shirai, Toru

Citation Memoirs of the Faculty of Science, Kyoto University. Series ofgeology and mineralogy (1968), 34(2): 147-173

Issue Date 1968-03-26

URL http://hdl.handle.net/2433/186545

Right

Type Departmental Bulletin Paper

Textversion publisher

Kyoto University

MEMolRs oF THE FAcuL'ry oF SclENcE, KyoTo UNIvERslTy, SERIEs oF GEoLoGY AND

VoL XXXIV, No. 2, pp. 147-173MINERALOGY,

Submarine Geological Study of the Bottom Sediments of the Adjacent Seas of the Japanese Islands

with Special Reference to the Distribution

of Organic Matter in Sediments*

By

T6ru SHIRAi

(Received Dec, 31, 1967)

Abstract Organic matter content in the marine sedimenbs is related to both the sediment characteristics

and the morphological features of the fioor. Organic matter content is closely related to thegrain size composition of the sediments, and, in the case of the area of slow or too rapid depo-

sition of detrital sediments, it is low in all types of sediments. Thus the organic matter distri-

bution in sediments depends partly upon hydrodynamic situations and partly upon conditionswhich affect the preservation of organic matter.

The concentration and composition of organic acids in the sediments of Lake Biwa varywith the depth from the surface ofsediments. On the other hand, there are some differences incomposition of organic acids in the sediments of each station of the sea off San'in district.

Introduction

Geologically and sedimentologically it is interesting to discuss relationship

between marine environment and the quantity of organic matter that has accumu-

lated on the sea floor under various conditions. From this viewpoint, a knowledge

of the distribution of organic matter in sediments have been studied by a number

of workers (TRAsK, 1932, 1939; REvELLE and SHEpARD, 1939; EMERy andRiTTENBERG, 1952; EMERy, 1960; NiiNo and EMERy, 1961; BoRDovsKiy, 1965).The writer intends to study the distribution of organic matter in the sediments of

the adjacent waters ofJapan. In the present paper, the bottom sediments ofJapan Sea off San'in district, Suruga Bay, Osaka Bay and Tanabe Bay have beenexamined for organic matter content and for other characteristics.

Acknowledgements

The writer is sincerly indebted to Professor Susumu MATsusmTA for his kind

* Contributions from the. Scto Marine Biological Laboratory, No. 461.

148 T6ru SmRAr

instruction and encouragement. Also the writer is sincerely indebted to Professors

Hajime KADoTA and Tadao KAMEi of Kyoto University, and to Assistant Professor

Tsunemasa SHiKi of Kyoto University, and to Assistant Professor Hideo MiyosHiof K6chi University for their guidance and assistance. Appreciation is also ex-

pressed to Professor Fujio UcmNoMi and Assistant Professor Elji HARADA of Kyoto

University, and to Assistant Professor Ryuichi TsucHi of Shizuoka University for

their assistance during the survey. Also, appreciation is expressed to the stuff of

the Tottori Prefectural Fishery Experimental Station and the stuff of the Hydro-

graphic Department ofJapan for their assistance during the survey. The writer is

also grateful to the crew members of the surveying ship Daisen, Kaiy6 and Tan-

.selmaru.

Method

Sampling Japan Sea off San'in district: A number of bottom sediments were collected

from the area off Tottori Prefecture by the writer on board the surveying ship

Daisen of Tottori Prefectural Fishery Experimental Station in September andOctober, 1960. The sediments were collected by a dredge. These samples weredesignated as Series D samples (Fig. 2).

Seven bottom samples (K-l7NK-23) were collected from the area west of OkiIslands by the writer and other workers on board the surveying ship Kaiy6 of

Hydrographic Department ofJapan onJuly 14 and 15, 1962. Two samples (K-17 and K-18) were collected by a dredge and the other by a core sampler. These

samples were stored at low temperature. A number of bottom sediments werecollected from the area off San'in district by member of Hydrographic Department

on board the above ship in June and July, 1962, which were dried and stored at

room temperature. These samples were designated as Series K samples (Fig. 1). In August, 1965, a number of bottom samples were obtained from the YamatoBank, the area near Takeshima Island and several other locations by the surveying

ship Meiy6 of Hydrographic Department. These samples were designated asSeries T and M samples (Fig. 1).

Suruga Bay: The field survey and the sampling ofsediments in Suruga Baywere undertaken by the writer together with other workers on board research ship

Tanseimaru of the Ocean Research Institute, University of T6ky6 during theperiods from March 23 to 30 and fromJune 9 to 11, 1965. A number ofsampleswere collected by a dredge, and designated as Series TSD and TSC-D samples.Sediment core samples were obtained by a gravity corer, and designated as Series

TSC samples. The samples collected by a sledge trawl were designated as Series

TSB samples. The samples for organic matter analysis were stored at -250C.

Submarine Geological Study on the Bottom Sediments of the Adjacent 149 Seas of theJapanese Islands

Tanabe Bay: The sampling ofsediments was undertaken on August 8, 1965by the writer on board the research boat ofMarine Biological Laboratory ofKy6to

University. Eighteen samples from 25 locations were collected by a snappersampler. The samples used for organic matter analysis were stored at low tem-perature. The sampling locations and chart which was given by Seto MarineBiological Laboratory are shown in Fig. 7.

Osaka Bay: The sampling was undertaken by the writer on board thesurveying ship Meiy6 on August 25, 1965. Twenty-two bottom samples by adredge and nine sediment core samples by a gravity corer were obtained (Fig. 8).

The samples used for organic matter analysis were stored at low temperature.

Grain size analysis

Each samples was analyzed mechanically to obtain a curve showing the weight

distribution as a function of the Iogarithm ofparticle size. Sieving techniques and

pippet methods were applied to sand and mud fractions respectively. Cumulative

curve was plotted on graph, and the phi median diameter, phi mean diameter,phi deviation measure and phi skewness measure of each samples were dctermined

by Inman's equations (Inman, 1952). These measurements of Series K sampleswere made using the results of the grain size analysis by Sat6 (Sat6, 1964). For

the samples of Suruga Bay, approximate values obtained from the unpublisheddata of SmKi and the writer are given in present paper.

Chemical analysis

The quantity of organic matter may be estimated in various ways. Analysisof organic carbon by combustion is diMcult and time consuming, and analysis by

titration is subject to error. Nitrogen is a good index of the organic matter con-

tent of the samples, although some workers do not consider nitrogen content as an

adequate measure of organic matter because of the existence of a great spread in

the ratio ofcarbon to nitrogen. In this study, determination ofnitrogen by Kjeldahl

analysis has been used. The amounts of nitrogen are given as mg nitrogen per g

dry weight of sediment. . ' The weight loss by ignition has been measured to estimate the approximate

organic matter content of the bottom sediments. The COD ofsamples has beenalso determined to estimate the quantity of organic matter.

Organic matter in Sediments

JaPan Sea off San'in District

The submarine geology of the sea off San'in district, the southern part of

Japan Sea, has been studied by several workers (NiiNo, 1948; SATo, 1964). Thesubmarine topography of the area is shoivv'n in Fig. 1. There is a series of islands

and banks, and a submarine peninsula spreads northerly for 150 km off Tottori

150 T6ru SHIRAI

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Prefecture. The continental shelfoff San'in district has a deeper edge of200-300

m deep and a wider width of than the ordinary shelves along the Japan Sea coast

of theJapanese Isalnds (SATo, 1964). In the area from Oki Bank to San'inshelf, there is a remarkable deep-sea plain, 900-l700 m deep (SATo, 1964). The

data concerning the bottom sediments are given in Tables 1 ev3.

The shelfsediments off San'in district are divided into three zones as following.

1) Sediments ofbay offHino River mouth are constituted by well sorted veryfine sand. Sand content constitutes over 80 per cent and clay content only a small

per cent. Organic matter is not abundant. The low content of organic matterin those sediments shows that organic matter is not accompanied with very fine

sand during transportation processes. Organic matter decreases rapidly in thecoarse sediments of the outside area of this zone.

2) Shelfsediments off Tottori Prefecture are composed mainly ofwell sorted

sand which contains only a small amount of organic matter. Low organic mattercontent in the shelves can be ascribed, as is discussed in the following chapter, to

winnowing agency and a very slow rate ofdeposition ofinorganic detrital sediment.

3) The sediments of shelf margin, 100 to 150 m in depth, is characterized

by fine sand. Organic matter content is very low in this zone as well as in the

inside area of this zone. These sediments had been probably accumulated byhydrodynamic action in the past. Low organic matter content can be ascribed tothe absence of finer fractions of the sediments (which incorporate organic matter,)

due to hydrodynamic activity.

In the outside area of this zone organic matter content increases rapidly with

the increase of finer fractions of the sediments. The approximate 200 m depthcan be considered as a transition zone between sandy and muddy areas, or between

Iow and high organic matter content areas.

As described above, the shelf sediments off Tottori Prefecture change, with

the increase of depth and distance from the shore, from coarse sand to mediumsand, fine $and and silt.

Organic matter content increases rapidly in the shelf margin and increases

progressively with the decrease of grain size. Rapid and progressive increase of

organic matter in the zone deeper than 200 m may show accumulation of suspended

matter. The sediments of shelf margin, deeper than 200 m, is characterized bysandy mud or mud, which consists mainly of silt. The sorting becomes poorer in

this zone and sometimes the sediments contain some plant fibers. The organicmatter content tends to increase with the increase of silt content.

Organic matter content in the sediments of shelf margin off Sendai Rivermouth is lower than that of other areas, but the mud content is high. On theother hand, these sediments show frequency curves which are not simple. These

l52 T6ru SHIRAI

features may indicate that the conditions of deposition in the area developed by

these sediments differ from those of other areas.

The bottom sediments off Ky6gamisaki are characterized by very poorly sorted

mud which has high clay content. These sediments contain plant fibers or fragments

that were probably derived from land. Topographically the shelf off Ky6gamisaki

has an edge 400 m deep and 60 km wide (SATo, 1964). In the area deeper than200 m, the sediments, however, show the characteristic of the slope sediment.

Namely, the sediment is characterized by very poorly sorted sandy mud in thezone 200 m deep, and by very poorly sorted mud in the zone deeper than 300 m.Organic matter content in this area is higher than that of other areas off San'in

district. Its content increases with depth, and with the increase of clay content.

In the area west of Oki Islands, the sediments of submarine peninsula consist

of silty mud. In this area organic matter content is high on the slope, especially

on the foot of the slope. It is remarkable that the organic matter content is high

on the submarine peninsula far north of Oki Islands. It may be considered that

this high content of organic matter depends upon the rapid accumulation of sedi-

ments, but such an environment ofdeposition is contradictory with the topographic

condition of this area.

The Oki and Yamato Banks are large submarine banks. According to SATo(1964), the deep continental shelf and the top of these banks were results of sub-

margence since the maximum lowering ofsea level in WUrm Glacial Stage. Thesediments of these banks are characterized by well sorted medium-very fine sands.

Organic matter content is low on the top and sides ofbanks (Fig. 3). This should

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Fig. 3.

Submarine Geological Study on the Bottom Sediments of the Adjacent 153 Seas of the Japanese Islands

be attributed to winnowing agency and oxidation oforganic matter related with very

slow rate of deposi.tion ofinorganic sediments.

The bottom sediments of deep sea plain between Oki Bank and San'in Shelfare characterized by muddy sand or silty mud. Organic matter content is low in

this area. As noted above, the organic matter content is related, usually, to mud

content (Fig. 4). The scarcity of the organic matter in the sediments in this deep-

sea plain may be ascribed to the slow rate of deposition of detrital sediments in

this area. It is considered that only a small quantity of sediments reach there

beyond the shelf and slope.

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The sediments on the topographic mounds near Takeshima Island are charac-

terized by well sorted mediumNfine sands which contain abundant foraminiferal

tests, and are low in organic matter content.

Suruga Bay Suruga Bay is bordered on the east by the Izu Peninsula and on the west byplains and hills. Several large rivers, the Oi, Abe, and Fuji Rivers empty into

the bay from the western and northern direction. The continental shelfdevelops

well except at the inner part of the bay, and its break is about 200 m deep below

sea level. The shelf becomes narrow and its break becomes shallow toward thenorth. Northern Seno Umi and the outer bank rise at the center of the bay toabout 50 m from the surface. A canyon-like .depression runs from north to south

along theIzu Peninsula (Fig. 5). The data concerning thesediments ofSuruga Bay

are given' in Tables 4 and 5. In the core samples from the area off the Oi River mouth, plant fragrnents are

found in the mud uhder sand layers at the depth of30 to 40 cm. The upper 20 cm

of the sediment core off Osesaki also contains plant fragments. The nitrogen

154 T6ru SHIRAI

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content of the sediment decreases to about half of its value within the upper 50 cm

of the sediment core off Osesaki, whereas a slower rate of decrease was observed in

the core off the 'Oi River mouth.

The characteristics of the sediments and the environments of deposition differ

from place to place in the bay. Four distinct sedimentary environments areobserved: the west part of the bay, the easst part of the bay, the banks, and the

inner part of the bay.

1) Banks: The basement of the banks is composed of soft sandy mudstone,which may be reffered to the Neogene Tertiary or Pleistocene. At the east sideof the Seno Umi Bank the rock is exposed, showing that the rate of accumulation is

negligible at this place and probably very slow at other places near this location.

The rock is heavily bored by animals. These materials are covered partly by layer


of mud and partly by gravels embedded in sand and mud. The gravels are com-posed of hard sedimentary rocks, igneous rocks, and the soft sandy mudstone.

The soft mudstones are probably derived from immediately underlying rocks bysubmarine weathering or perhaps by former erosion. Ali gravels are considerably

water-worn and some of them have an organic encrustation. The soft mudstonesare bored heavily by burrowing activity of organisms. .

Organic matter contentis low inthesediments of thebanks. Coarse sediments

of the bank have very low nitrogen content. Mud has relatively high nitrogencontent. This value, however, is considerably lower than that of the mud of other

places in the bay. In the sediments of the east side where the rate of deposition is

presumed to be slow? the organic matter content is low in value, in comparison with

that of the west side of Seno Umi Bank. . • 2) West part of the bay: Nearshore is characterized by well-sorted finesand. This sand develops along the coast as a result of the agency of both the

orbital current and the longshore current under abundant supply of detrital sediment

from river mouth. In this situation, the mud fraction, which contains the organic

matter, is put into suspension and scattered to the zone beyond the limit of•wave

disturbances on the bottom. The low organic matter content in these sediments is

therefore ascribed only to the winnowing agency by current action. In the muddy area ofoffshore, organic matter content is high. On the other

hand, it is low in the transition zone between sandy area and muddy area, where

sedimentation seems rather rapid. In this case, the effect ofdilution may be rather

an adequate explanation.

3) East part of the bay: Nearshore sediments of the southwest coast of Izu

Peninsula are characterized by well-sorted medium and fine sand. In thesesediments organic matter content is low.

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The area outside nearshore sands is characterized by poorly sorted sand andsilt' or sand and mud. The sediments tend to become finer with the incr6ase of

depth and distance from shore. Organic matter content becomes larger in thesediments of muddy area and increases towrd the bottom of the "canyon" running

156 T6ru SHIRAI

along the west coast of Izu Peninsula. It shows the highest value on the bottom

of the "canyon" except at St. C-12, east of Seno Umi Bank.

The bottom of the "canyon" is floored by poorly sorted muds. The surfacesediments tend to decrease in MdÅë toward the south. Sand content of the sedi-

ment tends to increase toward the south, and silt content to decrease, on the con-

trary. Clay content is almost similar along the "canyon" axis. From severallocations in the mouth of the "canyon", pebbles which consists of water-worn or

angular hard sedimentary rocks and igneous rocks were collected. Organic matter

content clearly decreases down the "canyon" axis, and unusually low value isobserved in the St. C-12.

The decrease of organic matter content of the bottom sediments down the"canyon" axis can be ascribed to several reasons. One is the more abundantaccumulation of detrital sediments which preserve organic matter and of organic

matter itself in the northern part. It should be noticed that abundant plantmaterials were also obtained from the bottom east of Seno Umi Bank. Further-more, the thin layers containing plant fragments intervene in the sediment core of

St. 6 (station in the bottom of the "canyon" northeast ofSeno Umi Bank). Theseindicate that plant materials from land play rather an important role as a source of

organic matter in sediments. The supply of these plant materials, which hadprobably been carried from the north along the bottom ofthe "canyon", is presumed

to be more abundant in the northern part.

The existence of hydrodynamical agency can be suggested as an another factor

determining the distribution of organic matter in the bottom sediments alongthe "canyon" axis. Nitrogen content decreases with the decrease ofsilt content and

with the increase ofsand content, toward the mouth of the "canyon". Conceivably

a part of organic matter is accompanied with mud fraction of the sediments.Accordingly, it can be considered that there is a sort of hydrodynamic agency on

the bottom along the "canyon" axis. As mentioned above, the thin laminaecontaining black coloured fine grains and laminae containing plant debris intervene

in the sediment core ofSt, 6. The sequence ofdifferent types oflaminae is probably

a hydrodynamical result ofintermittent deposition.

The unusually low organic matter content of St. C-12 that is located in the

east of Seno Umi Bank in the bottom of the "canyon", can be ascribed to several

reasons. One is the very slow rate of deposition in this place. In this case it is

natural to consider that there is an agent which tends to keep the floor clear of

sediments. The "canyon" shows V-shape in cross section view there, and itsbottom has a steeper inclination than the upper stream.

In the place immediately southeast of this station (foot of east side slope),

the sediment shows great variety in accordance with the depth ofburial; at surface


jt is composed of poorly sorted mud, and, at about 10 cm below the surface, the

sediment consists ofmud containing pebbles, which consist mainly ofsoft mudstone

similar to the basement of bank. The sediment shows at surface a rather highorganic matter content, which decreases greatly with the depth from the surface

of the sediment (Table 5). The high concentration of organic matter in surface

sediment may indicate a high accumulation of the sediment.

Further down the "canyon" axis, the sediments consist of coarser materials

as previously noted. Sledge trawl operated by Dr. HARADA showed that the area,

which is immediately down the "canyon" from St. C-12, is nearly barren of life,These facts may indicate that the area of mouth of "canyon" is in a unstable state.

4) Inner part ofthe bay: The sediments are characterized by poorly sortedmud. In this part, organic matter content is ofthe highest value. Relatively low

quantity of organic matter content in some sediments of this part is probablyattributed to the coarser size ofsediment.

Tanabe Bal

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158 T6ru SHiRAi Tanabe Bay is a bay existing on the southwest coast of the Kii Peninsula, and

is connected with the Pacific Ocean at the western bay mouth. The bay is quite

shallow and generally does not exceed 30 m. The southern half of the bay isbordered by a complex coast line rich in arms, The sole large river, the Aizu River,

empties into the bay from the north.

The data concerning the bottom sediments are given in Table 6. Content of

nitrogen ranges mostly from 1.3 to 1.7 mg per g dry weight of sediment at theouter part. In the sediment of the central and inner part of the bay, it is usually

between 1.5 and 2.4 mg per g dry weight of sediment. Namely, its content wasfound to be higher in the central and inner part of the bay, to become smaller in

the outer part.

Osaka Bay

Osaka Bay is an ellipsoidal bay with the long axis trending NE-SW, and isconnected with the Pacific Ocean by Kii Strait and with Seto Inland Sea by Akashi

Strait. The bay is shallow and genrally calm. The sole large river, the RiverYodo empties into the bay from the northeast. The northeastern half of the bay

was surveyed.

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The sediments obtained from the surveyed area consisted of mud except forthose from Stations S-15 and S-16 which consisted of gravel and sand. The sedi-


ments from the northern part of the bay were blackish grey or dark greenish grey

in wet condition. The sediments off the southern coast of the surveyed area were

greenish grey in colour. In the central part of the surveyed area, the muds were

bluish grey in colour but had brown oxidizing surface layer. The sediments atStations S-3N7 and S-9 had an offensive odor. The top layer, about 20 cm thick,

of most cores was soft, and that of the sediments at Stations S-1N9 and S-20 was

soupy. The data concerning the nitrogen content are given in Table 7. The nitrogen

content of surface sediment was found at the minimum to be 1.3 mg per g dryweight of sediment in the central part of the bay, and at the maximum to be 8.5

mg per g dry weight of sediment at Station S-9. A higher value was observedin the sediments off Kishiwada, Osaka and K6be City, and a lower value in thoseof the central area.

Vertical distribution of nitrogen content and some other characteristics of the

sediments are given in Table 8. The nitrogen content shows a downward decrease.Within the first 50 cm or so ofeach core, the nitrogen content decreases its value to

about 2 or 2.5 mg per g dry weight of sediment. It seems that nitrogen contentrapidly decreases its value to about 2 or 2.5 mg per g dry weight ofsediment within

the upper 50 cm, and decreases slowly in greater depth.

Consideration on distribution of organic matter in sediments

Based on the data concerning the distribution of organic matter content in

areas of different types of environments, the causes of variations in feature of the

distribution oforganic matter in marine sediments can be considered.

The data concerning the banks show that the organic matter content is low in

all types of bank sediments trated here. It is generally held that production is

greater in areas of banks. It is because around the banks the ascending currents

develop. Nevertheless, organic matter content is remarkably low in the sediments

ofsuch areas. This feature can be ascribed to several reasons. One is that organic

matter is easily winnowed away incorporated with mud by hydrodynamical activity.

However, in the fine sediments of the banks, as in the mud of Seno Umi Bank for

example, organic matter content is rather small in comparison with that of near-

shore fine sediments. Next, the very slow rate of deposition of inorganic sedi-

ments, which protects the organic matter from intensive oxidation by burial and

reduces the destruction by bottom organisms, is considered as another reason.

The low content may also be due to the more active consumption by organismson the banks.

In the nearshore coarse sediments, organic matter content is low in general.

160 T6ru SmRAi

Several reasons can be considered in explaining the low values. One is hydrody-

namical agency. This is due, naturally, to the fact that plenty oforganic matter

is incorporated with fine grained mineral particles, or that organic detritus behaves

in a manner similar to finer sediment particles owing to similarity in their moving

velocities. Other reasons can also be considered. For example, inorganic detrital

sediments which accumulated under very rapid deposition dilute the organicmatter. On the contrary, too slow rate ofdeposition ofnondecomposable materials

may result in the extensive oxidation and decrease oforganic matter. For example,

in the case of bay sediments off Hino River mouth, too slow rate of deposition can

be hardly cobsidered. Dilution effect seems reasonable to explain the low organic

matter content in these sediments. However, considering the very good sortingand the low content of mud fraction, hydrodynamic agency is more probable as amain reason determining the low values of organic matter content in these sedi-

ments. The low value of organic matter content in the fine sand which developsalong the coast of Suruga Bay offers another good instance to support the hydrody-

namical reason. These sediments occur as a result of separation of mud fromsand due to hydrodynamical activity under abundant supply of detrital sediments

from river mouths. Low organic matter content must be due to scattering ofsuspended materials which acompany the organic matter.

In general, the Iow organic matter content in nearshore well sorted fine or

very fine sand is ascribed firstly to hydrodynamical agency.

Organic matter content increases rapidly in the area of mud beyond the area

of nearshore coarse sediment. This increase can be attributed to the separation

ofmud fraction from coarse materials by hydrodynamic activity. The mud fraction

of the sediment, which accompanies organic matter, is put into suspension andscattered offshore by the water exchange. Thus organic matter content increases

abruptly in the area bepond the limit of wave disturbances on the bottom where

mud fraction ofsediment accumulates. In nearshore area, organic matter contentincreases with distance from shore, and is highest on the slopes. This feature can be

ascribed to several reasons. One is the abundant accumulation of suspendedmatter in the areas ofabundant organic matter content. Another is the optimumrate of accumulation of detrital sediments, which tend to favor the preservation of

organic matter in such areas. Dilution effect of nondecomposable materials on

organic matter must be considered here.

Low organic matter content in the shelf sediments can be ascribed to tworeasons. One is the very slow rate ofdeposition ofdetrital sediments on the shelf.

Another is the hydrodynamical activity. In the shelfoff Tottori Prefecture, it is

held that well-sorted fine sand in the shelf margin had been accumulated by hydro-


dynamical activity in the past. Hence low organic matter content in these sedi-

ments due to both the hydrodynamical activity in the past and to the very slow

rate of deposition. In the zone beyond the shelf margin, organic matter contentincreases progressively seaward in accordance with the increase of mud fraction.

The degree ofsorting also becomes poor with the increase ofmud content. Thesefeatures indicate that the suspended materials, which accompany the organicmatter, make their way across the shelÅí Namely, it is considered that a sort of

hydrodynamical agency like winnowing, is going on on the shelÅí The high mudcontent and the high organic matter content in the shelfsediments off Ky6gamisaki

may indicate the excessive accumulation of suspended materials in this area.

From the foregoing discussion, the following generalization can be made.The organic matter content in bottom sediment depends, primarily, on the supply

of organic matter. The distribution of organic matter produced in the water or

derived from lands is, however, not always projected directly to the sea bottom.

It is largely controlled by environment ofdeposition. Organic matter precipitates

in a combined state with suspended mineral particles, or suspended organic detritus

tends to behave in a manner similar to that of finer fractions of the sediments,

during the processes of transportation and deposition. Therefore, the distribution

of the organic matter is greatly controlled by hydrQdynamic condition, and isclosely related to the particle size distribution of botton sediment. On the other

hand, it is also greatly controlled by conditions which affect the preservation of

organic matter. Namely the relative rate ofdeposition ofnondecomposable detrital

sediment controls partly the distribution of organic matter content in sediment.

There is a greater possibility of preservation of organic matter in deposits which

are accumulated at the optimum rates of deposition. With these points in mind,the causes of some of the differences in distribution of organic matter content in

the sediment can be explained.

Organic acids in sediments

Biochemical oxidation of mumerous organic materials in sediments produces

many metabolic products, including significant amounts of organic acids. Thepresence of organic acids in sediments and their relationship to sediment charac-

teristics are ofinterest. The distribution oforganic acids in sediment may indicate

microbiological and biochemical characteristics of the environments. From this

standpoint, the distribution of organic acids in marine and lake sediments were

examined. Identification and determination of organic acids in sediment samples fromthe sea off San'in district and lake Biwa were carried out by using chromatographic

method (MuELLER et al., 1958; MiyosHi et al., 1962), and the following results

162 T6ru SHIRAI

were obtained.

Lake Biwa: Vertical distribution oforganic acids in bottom sediments ofthe

location off Yanagasaki and off Otsu, and the related data are given in Tables

9Nll. Sediment samples contained acctic, formic, lactic, propionic, butyric andunidentified organic acids, regardless of their depth from the surface of sediment.

In the sediments off Yanagasaki, acetic acid was found in the highest concentration

in the first 1.3 m from the surface of sediment, and formic acid was detected in

the highest concentration below the depth of 1.8 m from the surface of sediment.

The concentration of butyric acid increases with the depth from the surface of

sediment. The percentage of this acid of total organic acids shows a downwardincrease which is slow for the first 2 m or so.

The area west of Oki Islands: The sampling locations are shown in Fig. 1.The data concerning the distribution of organic acids and the related data are

shown in Tables 12 and 13. Sediment samples contained acetic, formic, lactic,propionic, butyric and unidentified organic acid, regardless of their origin. A

lower concentration of butyric acid was found in the sediments of St. 19 and 20.

The ratio of acetic acid to butyric acid was much higher in these sedirnents. It

should be noted that the value of adi in these sediments is large in comparison

with that ofthe sediments ofother stations. In St. 17, a lower percentage ofaceticacid, a higher percentage of formic acid, and the lowest value of the ratio ofacetic

acid to butyric acid were found. A higher percentage of formic acid was detected

in the sediments of St. 22 and 23. From these data, it is considered that there

are some differences in composition of organic acids in the sediments of the various

location, in relation to the sediment characteristics and morphological features of

the floor.

Summary

1) The sea off San'in district: Organic matter content is very Iow in thecoarse sediments on the shelf. From shelfmargin to slope, it increases progressively

with depth, and with the increase ofmud content of the sediment. On the banksand deep sea plain, low organic matter content was found.

Suruga Bay: Organic matter content is low in the coarse sediments of near-

shore, and increases in the muddy area ofoffshore. In the east part of the bay,

the content increases with depth, from the shore to the bottom of the "canyon"

running along the Izu Peninsula, with the increase of mud content of the sedi-

ment. In the sediments of the bottom of the "canyon", the content is high anddecreases towards the bay mouth in accordance with the decrease of mud content.

Tanabe Bay: Organic matter content was found to be high in the centraland inner parts of the bay, and to become smaller in the outer part.


Osaka Bay: A high value of organic matter content was observed in thesediments off large cities, and a lower value in those of the central part.

2) The organic matter content is low in all types of bank sediments. Itscontent is low in nearshore coarse sediment, and increases rapidly in the area of

muddy offshore. Organic matter content in the sediment of each depositionalenvironment is closely related to the particle size distribution of bottom sediment.

The sediment of high mud content contains abundant organic matter, except forthe sediments of banks, of the area far offshore where deposition of detrital sedi-

ment seems to be very slow, and also of the area of too rapid deposition.

3) Since plenty oforganic matter is accompanied with fine grained particles,

its distribution is greatly controlled by hydrodynamic condition. It is also con-

trolled by the depositional conditions which affect the preservation of organic

matter, such as the rate of accumulation of detrital sediment, or the condition on

and in the sediment. Hence, the features ofdistribution oforganic matter in the

sediments above stated, can be expalined with these points in mind.

4) Identification and determination of organic acids in sediment samplesfrom the sea off San'in district and lake Biwa were carried out and the following

results were obtained.

I. Sediment samples contain acetic, formic, lactic, propionic, butyric andunidentified organic acids, regardless of their origin and depth from the surface of

2. The concentration and composition of organic acids in the sediments of

Lake Biwa vary with the depth from the surface of sediment. Among these,butyric acid increases with the depth from the surface of sediment.

3, There are some differences in composition of organic acids in the sedi-

ments of the various locations of the sea off San'in district.

References

BoRDovsKiy, O.K., (1961): Diagenetic changes in bottorn sediments from the central Pacific, Ocean. Abstracts of Symposium, Tenth PaciL, Sci. Congr., 384.BoRDovsKiy, O.K., (1965): Accumulation and transformation of organic substance in marine sediments. Marine Geol., 3, 3-83.EMERy, K.O. and RiTTENBERG, S.C., (19. 52): Early diagenesis of California Basin sediments in relation to origin of oil. Bull. Am. Assoc. Petrol. Geotogists, 36, 735-806.

EMERy, K.O., (1960): The sea off Southern California.John Willey & Sons, New York, .INMAN, D.L., (1952) : Measures for describing the size distribution of sediments. .lour. Sed. Petrol.,

22, 125-145.IwABucm, Y., (1962): The accumulation oforganic matter in bottom sediments. .four. GeoL Soc. .laPan, 68, 585-596.KADoTA, H. and Miyos}ii, H., (1964): The role oforganic matter in the production ofsulfides by sulfate-reducing bacteria in marine and estuarine sediments. Mem. Res. Inst. Feod Sci., Kyoto

Univ., 22, 9-29.

164 T6ru S}IIRAI

KATo, K., (1965): Chemical investigation on marine humus in bottom sediment. Mem. I7ac. Fish. Hokkaido Univ., 40, 91-209.MENARD, H.W., (1964) : Marine geology of the Pacific. McGraw-Hill Book Company, 271 pp.MiRoNov, S.I. and BoRDovsKiy, O.K., (1959): Organic matter in bottom sediments of the Bering Sea. Preprints Inter. Oceanogr. Congr., 1-1022.Miyosm, H. et al., (1962): Identification and determination ol' organic acids in marine and Iake sediments. Butt. JaPanese Soc. Fish., 28, 534-539.

MuELLER, H.F. et al., (1958): Chromatographic identification and determination of organic acids in water. Anal. Chem., 30, 4I-44.

NAsu, N., (1956): Particle size distribution in the vicinity off Sagami River Mouth. Jour. Sci.,

Univ. Tok.7o, 10, Part 1, 65-108.

NAsu, N., (1962): Submarine geology at the entrance of T6kyo Bay. Jour. Oceanogr. Soc. Japan, 20th Anniversary Volume, 98-120.NiiNo, H., (1948,) : Sediments of Oki Bank inJapanese Sea. Jour. Sed. Petrol., 18, 79-85.

NiiNo, H. and EMERy, K.O., (1961): Sediments of shallow portions of East China Sea and South China Sea. Bull. Geol. Soc. America, 50, 731-762.

ORR, W.L. and EMERy, K.O., (1956): Composition of organic matter in marine sediments. Preliminary data on hydrocarbon distribution in basins off Southern California. Bult. Geol.

Soc. America, 67, 1247-1258.

REvELLE, R. and SHEpARD, F.P., (l939): Sediments off the Ca]ifornia coast. Recent marine sediments. Bull. Amer. Assoc. Petrol. Geologists, Tulsa, pp. 245-282.

SATo, T., (1962): Sand and gravel bed cored from the bottom of the Suruga Bay. .Iour. Geol. Soc. IaPan, 68, 609-617.

SATo, T., (1964): The submarine geology off San'in District, Southcrn Japan Sea. Jottr. Geol.

Soc. IaPan, 70, 43tF445.

SHEpARD, F.P., (1963): Submarine geology. Harper & Row Pubiishers, New York, 557 pp.SHiMADA, D., (1960) : Distribution of organic matter constituents in the shelfsediments from the

Japan Sea. Sci. Rep. Tohoku Univ., Sec. 3, 4, 3, 499-5l2.

SvERDRup, P.D. et al., (1942): The Oceans. Prentice-Hall, New York, 1087 pp.TRAsK, P.D., (1932): Origin and Environment of Source sediments of petroleum. Gulf Publish- ing company, Huston. 323 pp.TRAsK, P.D., (1939) : Organic content of recent marine sediments, Recent .Marine sediments. Amer.

Assoc. Petrol. Geologists, Tulsa, pp. 428-453.

VALLENTyNE, J.R., (1957) : The molecular nature of organic matter in lakes and oceans, with lesser reference to sewage and terrestrial soils. Jrour. Fish. Res. Bd. Canada, 14, 33-82.

ZoBELL, C.E., (1946): Marine microbiology. Chronica Botanica Company, Waltham, Mass., 240 pp.

Table 1. Data concerping Series K Samples.

Sample N.number

Lat. E. Depth inLong. meters

Loss onignition(per cent ofdry sediment)

Kjeldahl-N (mg"ta{ihderynt) "Åë

Data concerning Particle Size Distribution*

MdÅë odi ' adi s:/kd sOli?, cOriIO.y Characterof bottom

Kl 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

37e3737373737373736-3636363636se36363536363636363637

8gi8'

;gig

lg:o,

61i3

4,8s:9,

g,9:8

igig

?sig

g36I}

?l[g

2?:5,

gzi?

e3.8

136e136136136136135136135135135135135l35l35.135135132132132132132132132134135

07.8tl5.002.812.815.424.107.754.427.6

,50.317.331.959.656.456.141.64S.743.832.536.737.230.530.0".2OO.5

6oo2805oo210

180 554542520810731676880

85 1'10

en232320

l85930490

105912"1220 317 568

10.16.39.4

3.2 5.5IZ313.76.5

12.011.212.0

5.12.4

12.3 2.912.5IO.412.110.912.311.411.3

2.812.492.19

2.132.013.824.1O2.333.953.063.362.211.851.961.873.982.525.253.784.744.714.591.652.03

5.IO4.754.60

1.884.656.856.874.906.755.456.13

2.03

1.926.085.207.005.556.306575.502.233.08

4.954.102.95

1.253.536.156.673.706.505.936.35

2.20

2.13s.954.336.776.056.306.326.oo2.392.63

2.901.5e2.45

1.882.351.852.142.301.751.751.63

O.68

O.722.132.652.oo2.552.551.271.201.181.18

O.05 O;33 O.67

o.32 O.48 O.38 o.co O.52 O.14-e.24 O.13

-O.25

-O.29 O.M O.33 O.l2-O.20 o.oo O.20 O.42-O.51-O.89

43va65

8562

o IO55

8 18 12

1oo

1OO 17ca

7 24 18 6 13 91 83

414725

1024776735747274

o

oos397159617g779

15

165

le

514232310181014

o

o17152217211510o2

G.S

Sh•MS•G

Sh•caAl

" Calculated from SATO's data (1964).

Table 2. Data conberning Series M and T Samples.

RftMmPb'.e,N• LatELong•Elfi:lhilli'ill/iotilitiiilll'll Loss on Kjgldahl-

u,n.i,tto,",(.perNNiEps.

sediment) sediment) Åë5

Data concerningParticle Size Distribution

ipi6 Åë2s Åëso Åë7s ,Åës4 digs s:An'd O/e

Silt o/o

etay

MMMM-TTTTT

1

2341

2345

g6, ;4,lg l3,g

g6, gt,13, i,g5,

g; 18i3 lg3

g7, ??lg ,ig,2

35 56.9 131

zz]52 gnoo

l3ig ;66'

6gl,7 lgg

264I3, g?9,

31.5 6oo

65.6771.9261.9145.95

12.281Loo13.9710.263.426.76

14.8514.59 4.34

5.585.714.533.062.111.854.654.172.11

4.605.174.30

O,78O.3G2.742.47

5.87 5.99 5.64-O.28 1.26 1.31 4.06 3.60 Lll

6.54 8.026.52 7.966.03• 7.421.07 4.37-1.41 1.821.60 1.834.46 4.974.33 5.561.46 2.17

(10.05)(10.50) 9.10 8.05 2.38 2.29 5.78 6.96 2.66

2 4 4 492.74 4.50 932.61 4.10 9tl

6.59 157.75 202.97 4.70 85

4747552643

7466

5

51494125

22

1114.2

Note: The percentage of gravels is not indicated here, because it is easy to calculate it by subtracting from 1ooO/. the percentage of

thesedimentstabelated. ' •

gegg

ggo-pvp:go.N.v:g

ygB.

g

o8o-ou8'su

recegetr.

gy"eo

Bgeg.egut

o.

go>.qgge

M8

166 T6ru SHIRAI

Table 3. Data concerning Series D samples.

Sample

No.

Depth

(M)

Loss on* Kjeldahl-ignition N* (O/6) (mgN/g) Åë5 Åë16 Åë25

Particle

Åë50

slze

Åë75

measures

Åë84Åëgs sgftn'd o/o

Silt o/o

Clay1- 2 3 4 5 6 7 8 9 10 11 13 15 16 18**

19****2- l

2 3 4 5 6 7 8 9 io3- 1 2

3**** 4 5 6 7 8 9 11 12 13 154- 1*** 2*** 3*** 4** 5 6 7 8 9

20 29 40 50 62 68 77 78 841iro

150160154116 44 57 65 78 86 98118141202209209 18 36 43 54 66 72 78 95106174236320458 74 97130154181

214222388382

1.94

9.1O

8.8711.78

3.785.12

6.2211.73

1.481.54

0•"O.53O.41O.47O.37O.42O.472.443.682.982.46O.94O.73O.48

O.43

o."O.46O.521.682.513.593.68O.49

O.46O.40O.37

o."O.43O.481.142.242.071.86O.95t.13

O.901.23

2.193.562.522.642.87

2.90 2.86-O.56-L14-O.54 O.39-1.42-O.95 O.40 1.69 4.56 3.46 3.76 1.21

-1.32-2.30-O.32-O.02-O.12 O.45 O.90 2.32 2.50 3.32 1.57

-1.50-O.42-O.13-O.92-O.04-O.l4

2.484.42O.05

1.632.372.65

2502.893.21

3.20 3.19-O.26-O.34 O.11 O.94 O.14-O.14

1.07

2.255.394.184.361.91

-O.97-O.27

O.21

O.54O.65O.992.182.603.304.571.56

-O.12

O.23O.37O.60O.14O.67O.78o.oo3.054.72O.70

2.462.81

4.072.963.454.00

3.30 3.26-O.06

O.05O.461.23

O.58O.301.32

2.505.744.504.712.39

-- O.68O,22O.49O.881.101.42

2.472.823.924.802.34O.34

O.41

O.70O.85O.51

O.93O.78O.383.304.881.30

2.883.004.473.233.454.38

3.603.51O.51

O.791.182.001.041.181.993.31

6.906.135.503.42

O.071.241.09

1.602.162.282.703.924.885.362.65O.88

O.671.39

1.401.21

1.63l.67

2.363.905.524.50

3.513.51

5.184.054.055.36

3.903.801.101.491.69

2.501.421.82

2.404.598.527.026,954.28

O.99!.971.662.222.402.502.845.856.126.672.871.31

O.891.981.91

1.742.302.392.745.326.635.80

3.864.036.365.105.217.70

4.164.051.361.891.862.701.641.932.565.429.467.997.964.7e

1.37

2.141.892.412.50.2.623.126.706.997.51

2.971.50

1.132.21

2.092.012.552.582.905.927.256.82

3.994.566.976.486.368.55

5.604.941.88

2.902.262.972.46

2.81

8.3011.22

1O.056.s6

*Calculated against dry sediment. **S•Sh ,***ShNote: from 1000/, the total paercentage of the sediments

2.202.502.362.672.772.91

4.49

9.208.683.372.05

1.91

2.642.482.382.902.826.859.20

10.00

4.61

6.709.809.409.10

8083979498999095

1OO67

2 11

867

85919999999991

52268

1OO88

94 99 9995

1OOlOO9053

239

857515

494916

2015

1oo

1ooo

2766737630

****G-Sh

oooo

1 1

9406580

oo

ooo

1oo7

398852

152275424265

o2

ooooooo6

3216l63

ooooooo89

12oo

oooooo3

8109

o3

1099

19

The percentage of gravel is not indicated here, because it is easy to calcuiate it by subtracting

tabulated.

Table4. Data concerning the Sediments of Suruga Bay.

Station

numberN. Lat.

TSC

TSD

TSB

12

3

45

67

910D11

12

14D15161718

1

2

2t3

4567

89

1011

1213141516172

4

34o3434343434343534343434343434353434

34343434343434343434343435353535353434

E. Long.Depth in

meters

Water co-ntent (percent ofwetsediment)

Loss on ig- COD (02nition (per consumedcent of dry mglg, drysediment) sediment)

Kjeldahl-N (mgNlg, drysediment)

Character

44.9t

42.942.8542.849.949.1

54.5OI.643.1

42.442.842.942.835.653.302.538.638.9

43.943.9542.143.230.729.945.544.453.755.055.053.203.1

02.458.004.804.547.347.8

of bottom

13so138138138138138138138138138138138138138138138138138

138138138138138138138138138138138138138138138138138138138

22.ot

l7.715.7

25.226.9538.038.045.443.433.936.441.418.334.834.740.230.4528.7

30.828.236.732.120.223.242.940.330.230.029.030.548.349.632.5tK5.9547.237.837.6

498 52 22 735 91016501565 465 14e15801735 360 1922550 850 920 215 84

68 392 16004oa3oo 52222-180 250 55345a370130-l20 70 270 145 120 190515-486

17iro

46.330.825.248.944.464.362.362.731.655.746.945.246.7

50.0

26.915.0* 3.8*55.646.9

35.242.939.529.723.428.543.927.938.130.662.1

50.9

5.23.9

2.9 6.0 4.96.0

6.010.6 5.56.94.5

8.35.5

6.3

5.04.1*2.2*6.1

5.4

5.49.47.6

4.03.63.45.9

4.87.64.1

9.9

5.0

15.56.6

1.6

11.6

17.423.629.4 6.312.913.514.2

15.1

8.2

6.5* 1.0*17.5 9.0

8.514.413.7 7.3 3.6

5A10.6

6.413.8 9.726.5

12.3

2.371.66

1.05

2.81*2.052.85

3Dl3.321.10

2.071.532.312.77

2.27

1.791.26*O.43*2.732.70

2.051.98*1.22*l.67*1.341.521.87

1.16*1.69*1.75*3.36

2.39

M M f.s

M.GM.S

M M M f.s

M M MM.S

c.S

M c.S

G MM•S•G

S.G

MM

RS.G

MM.SM.SM.GM

Åís

MM.GM.GM.GMM

*Fraction finer than -1Åë was examined.

Sampling date

March

March

March

March

MarchJuneJuneJuneMarch

March

June

June

June

March

23,)e

et

el

24,)e

)"

25,e}

29,s7

)1

30,

9,1O,

11,

23,e:

1)

30,)1

9,e)

))

1)

1O,71

se

71

1)

le

11,}J

cc

28,

March 29,

1965

1965

1965

1965

19651965196519651965

1965

1965

1965

1965

l965

1965

m8g-•+,

o"

c5'-

g3o--

'g

tn

ygg.

g

o8o'

tp.

8Sg1pxco9sBgee.

ggat

oth"tro>

.g.

gg"

-ctN

168

Table 5.

T6ru SHIRAI

Vertical distribution of water content, loss onand MdÅë in bottom sediments of Suruga Bay.

ignition, Kjeldahl-N

Water content* (o/o)Core depth (cm) TSC 1 TSC 6

Station numberTSC 9 ' TSC11 TSC 12 TSD 5

O- 5 5- 7 7- 9 9-13•1O-1520-2530-3555-60

46.3

46.739.934.2

64.3

58.963.0

62.7

53.7

55.754.959.151.8

46.940.2

46.9

41.6

*Calculated against wet sediment.

Loss on ignition* (o/o)Core depth (cm) TSC 1 TSC 6

Station number

TSC9 TSC II TSC 12 TSD 5

C5 5- 7 7- 9 9-131O-1520-2530-3555-60

5.2

5.05.14.6

6.0

6.86.8

10.6

g.L.

6.95.86.76.7

4.55.4

5.4

5.3

*Calculated against dry sediment.

Kjeldahl-N' (mg N/g)Core depth (cm) TSC 1 TSC 6

Station number

TSC9 TSC II TSC 12 O- 5 5- 7 7- 9 9-11 5-1010-1515-1717-2020-2530-3555-60

2.37

2.23

2.181.93

2.85

2.802.972.632.593.872.20

9.203.32

1.47

2.072.283.012.29

1.531.87

TSD 5 2.70

1.77

*Calculated against dry sediment.

Md"Core depth (cm) TSC6

Station number TSC 11 TSC 12 TSD 5

C5 5- 7 7- 9 9-11 5-101O-1515-2020-2525-30

7.28

6.787.707.417.766.90

5.486.506.026.90

5.106.53

6.074.654.95

Table 6. Data concerning the Sediments of Tanabe Bay (August, 1965).

Station

number

Depth

(M)

Water co- Loss on ig-ntent <per nitSon <percent of wet cent of drysediment) sedimnet)

Kjeldahl-N <mgNlg, drysediment)

di5 Åë16 di25

Data concerning

ÅëSO Åë75 di84 Åë95

Particle Size Distribution

MÅë aÅë adi o/o

Sando/o

Silt

o/o

Clay

TB 1

2

4

5

6

7

8

9

12

15*

16*

17

l8

19

20*

21**22

23

24

25

43

33

16

22

15

13

ll

11

2641

33

24

15

15

47

11

20

26

8

26.15

35.34

40.97

41.22

45.79

44.39

43.47

32.59

30.14

14.05

26.14

30.41

28.21

26.71

27.09

25.48

27.95

28.12

30.72

5.09

6.06

7.60

7.74

7.78

7.66

6.26

6.69

6.72

4.40

3.00

6.86

8.55

5.73

2.86

4.71

5.03

7.64

3.33

1.38

1.61

2.35

1.23

2.33

2.38

2.!1

1.69

1.68

O.51

O.55

O.71

O.69

1.29

O.02

1.26

1.47

1.50

L17

1.00

1.41

3.50

3.52

3.30

4.08

3.07

2.47

-O.03 1.85

O.50

O.69

3.21

-O.58 1.53

1.95

2.20

4.40

4.44

4.45

5.18

4.10

3.69

1.60

l.43

2.78

2.70

2.40

3.70

O.97

2.3

2.34

2.52

4.76

4.84

4.90

5.85

4.60

4.05

2.12

2.21

3.12

3.00

3.10

3.90

1.58

2.52

3.07

3.20

6.00

6.16

6.15

7.10

6.00

4.74

3.21

3.85

3.66

3.45

3.65

4.31

3.11

2.80

3.65

3.88

8.08

8.80

7.86

10.62

8.05

6.53

4.78

5.56

4.04

3.90

4.26

4.92

4.59

3.20

4.17

6.00

9.40

9.17

8.70

12.87

9.72

7.96

6.40

7.10

4.58

4.30

4.98

5.87

6.09

3.50

7.50

9.19

3.06

4.10

- 6.90- 6.81- 6.58- 9.03- 6.91- 5.83- 4.00

8.72

6.50

8.31

9.83

4.27

4.27

8.68

3.50

3.69

4.79

3.53

2.90

l.11

1.90

2.50

2.37

2.13

3.85

2.81

2.14

2.40

2.84

O.90

O.80

1.29

1.09

2.56

O.60

-O.Ol

O.47

O.36 O.27

O.20

O.50 O.32

O.51

O.32

O.15 O.02 O.06.

O.03

O.44

O.16

O.17

82

77

8

9

10

4

15

24

66

53

7476

70

28

68

93

14

16

67

66

67

57

60

60

25

36

19

18

23

63

24

6

4

7

25

34

23

39

25

16

9

11

7

4

6

9

8

1

Note: The percentage of gravel the sediments tabulated.

* sand** gravel

is not indicated here, because it is easy to calculate it by subtracting from loo o/. the total percentage of

caopoan

oh"trogpt

vpt

:grc

-.--

m---,po:qca

mpt

ergee

:t.

oQ8o-

tg.

8ag

's

kgzeo:za

ethfftro>gc-.pt

aoR

Hao

170 T6ru SHIRAI

Table 7. Data concerning the sediments of Osaka Bay (August, 1965).

Station

numberN. Lat. E. Long.

Depth

meters

in Water co-ntent (percent ofwetsediment)

Loss on ig-nition (percent of drysediment)

NKj?lidlgahl' character

gy,aE•ihd,'.Yt) of bottom

Sl 2 3 tl

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

34o343434343434343434343434343434343434343434

36.48t37.5438.3539.0340.2738.3636.8635.6234.3133.6432.9230.2228.0729.5531.4531.5827.2725.4227.2528.5030.8531.85

13so135135135135l35135134134134134134134134134134134134134134134134

12.sot14.2715.4516.5818.3218.4018.4617.3015.77l5.0013.7812.3410.0008.2006.4206.0513.1314.3016.2118.1119.4720.90

17161614.61314.616171819202531363233 ,211818161514.6

63.281.960.972.572.471.874.467.284.460.960.259.163.029.8

57.058.163.466.966.770.7

9.710.1 9.61Ll12.612.51LOro.710.010.3 9.8 9. .9

9.810.1

9.010.7 9.210.011.811.9

3.217.092.973.893.143.904.333.778.542.952.843.473.791.25

2.793.003.844.104.184.28

mudmudmudmudmudmudmudmudmudmudmudmudmudmud

gravelgravelmudmudmudmudmudmud

Table 9. Vertical distribution of org anic acids in bottom sediments in Lake B iwa.

Organic

acid 29-31

Sediments off Yanagasaki (July, 1963)

Core depth (cm)

129-131 179-181 239-241

Sediments off Otsu (Nov., 1963)*

Core depth (cm)

289-291 469-471 559-561ButyricPropionicAceticPyruvicFormicLactic

O.02O.695.50o3.61O.16

O.04O.234.09o

2.16O.65

O.08O.875.45o7.681.17

O.20O.663,75o4.57O.78

O.311.424.19O.055.131.32

O.02O.123.35oO.70

O.06O.292.06oO.94O.20

Results are expressed as pe/g dry sediment.*Results are expressed as pe/g wet sediment.Depth of overlying water: 5 m.

Table 10. Data concerning the bottom sediments ofLake B Sediments off Yanagasaki (water depth: 5 m)

iwa (Sept. 1962).

Coredepth(cm)

Watercontent* (o/o)

COD**(mg 02consumed/g)

Kjeldahl-N**(mg Nlg)

Loss onlgmtlon (o/o)

29- 31129-131179-181239-241289-291

53.938.452.036.235.6

32.525.I74.746.327.4

3.182.204.222.472.19

Aci** ferric iron* (mglg)

1.10 1.45 O.90 1.15 1.22

d Soluble

9.1 6.514.2 9.38.3

Acid solubletotal iron* (mglg)

23.50 18.75 15.00 18.75 17.50

o/o

Sand

24 22 9 19.

1

9!o

Silt

6069514549

o/o

Caly

16 9 40 36 so

* Calculated against wet sediment.**Calculated against dry sediment.

'

Submarine Geological Study on the Ifottom Sediments of the Adajcent

Seas of theJapanese Islands

Table 8. Vertical distribution of water contcnt, loss on ignition, and Kjeldahl-N in

bottom sediments of Osaka Bay (August, 1965).

171

sw'ater content* (o/o)

Core depth

(cm) Sl S3 S5 Station number

S7 SIO S13 S l8 S 20 S 22

O- 5 5- IO 40- 45 45- 50 50- 55 70- 75 80- 85 85- 90 90- 951OO-105120-125185-190

63.2

41.9

60.9

45.4

72.4

53.353.3

74.4

52.1

50.3

43.2

60.9

48.3

63.0

47.7

45.2

41.7

58.1

51.2

50.4

51.6

66.952.5

50.8

52.1

70.754.4

52.7

52.5

50.150,8

* Calculated against wet sediment.

Loss on ignition* (o/o)

Core depth


S7 SIO S13 S 18 S 20 S 22

O- 5 5- 10 40- 45 45- 50 50- 55 70- 75 80- 85 85- 90 90- 951OO-105120-125185-190

9.7

7.6

9.6

5.9

12.6

7.89.6

11.0

6.0

8.1

7.5

IO.3

7.1

9.8

7.0

5.3

8.4

10.7

8.5

8.1

8.9

10.09.0

8.2

7.9

1L98.4

8.1

8.1

8.7IO.2

* Calculated against dry sediment.

Kjeldahl-N" (mg'N/g)Core depth


S7 SIO SI3 S 18 S 20 S 22

C5 5- 10 40- 4545- 50

50- 5570 7580- 8585- 90

90- 951OO-105120-125185-190

3.21

1.89

2.09

2.97

2.15

3.14

2.512.69

4.33

2.36

2.59

1.60

2.95

2.21

2.79

2.35

2.53

1.92

3.00

2.78

224

2.45

4.102.6S

225

2.59

4.282.75

2.61

2.34

2.452.77

* Calculated against dry sediment.

172 T6ru SHIRAI

Table 11. Vertical distribution of water content and Kjeldahl-N in

bottom sediments' of Lake Biwa (Sept., 1963).

Core depth

(cm)

Water content**

(o/o)

Kjeldahl-N**'

' (mg Nlg)

Sediment type

10 20 30 40 50 60 70 80 901OO

110

120

130

1tro

150

160

170

180

190

200

210220

230

240

250

260

270

280

290

300

310

54.2

55.5

53.9

49.4

47.8

46.9

17.4

26.1

27.7

27.9

29.1

37.5

38.4

52.9

24.5

56.9

58.4

52.0

26.5

25.1

54.8

43.1

35.3

36.2

25.0

27.2

20.6

20.3

35.6

27.0

21.4

3.19

3.54

3.18

3.18

2.93

3.26

1.14

1.15

1.62

1.63

1.80

2.64

2.20

4.68

1.36

5.27

5.80

4.22

1.62

1.68

4.75

3.0!

2.46

2.47

1.91

1.77

1.54

1.53

2.19

l.82

1.50

mudmudmudmudmudmudmuddy sandmedium sandfinesand -medium sandmuddy sandsilt

silt

mudfine sand

mudmudmudmuddy sandmuddy sand

mudmudmudmudmudmudsandv mudsandy mud

mudmudsandy mud

* Sediments offYanagasaki (depth ofoverlyin ** Calculated against wet sediment.

*** Calculated against dry sediment.

g water: 5 m).

Table 12. Amounts* oforganic acids in bottom se diments off San'in District (July, 1962).

Sample No.

Depth (m)

BUtyric Propionic Acetic Pyruvic Formic Lactic

K-17 91

20 21 22 23

320

930

490

1059

1244

1220

O.47

O.11

O.07

O.74

O.56

O.65

1.20

O.94

O.73

2.71

O.62

1.50

7.39

10.69

8."16.87

10.45

18.54

O.47

o

O.l6

O.28

O.17

o

10.07

6.09

4.32

11.08

3.97

6.86

O.45

O.73

O.67

1.49

1.21

1.09

* Expressed as "e/g dry sediment.

The sampling locations are shown in Fig.

Table 13. Distribution ofwater content,

1, and listed in Table 13.'

COD and Kjeldahl-N in bottom sediments off San'in District (July, 1962)•.

Sample No. N. Lat. E. DepthLong. (M)

Watercontent* (o/o)

COD**(mg 02consumed/g)

Kjeldahl-N"" (mg N/g)

Loss onignition** (o/o)

MdÅë odi o/o

Sando/o

Silt o/o

Clay

mopmo.eso-pt

vpt

:nopo-ca

'ppaop

K-17

18 l9 20 21 22 23

36o

35

36

36

36

36

36

53.1'

56.7

21.5

11.6

35.5

41.3

27.5

132o

132

132

132

132

132

132

43.7'

43.8

32.5

36.7

37.2

30.5

30.0

320

185

930

490

1059

12"1220

55.5

45.0

62.5

53.1

53.8

61.8

61.4

31.9

15.5

42.1

35.4

37.6

46.6

40.9

3.98

2.52

5.25

3.78

4.74

4.71

4.59

12.5

1O.4

12.1

10.9

12.3

l2.3

11.3

7.50

4.33

8.84

7.38

8.3I

8.80

8.47

1.41

2.65

2.47

3.07

1.92

1.69

1.81

IO

ca2

18

1

1

2

4439

34

ro

"32

39

45

15

64

42

55

67

59

m:crBsu

5'oQ8o-

ng.

8x•

g12g'

ge

gBgs)

"•ggat

o'etro>-ggge

* Calculated against wet sediment.

** Ca}culated against dry sediment.-"co

Submarine Geological Study of the Bottom Sediments...

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