234
B. BABENERD, R. BOlE,]. KREY, and V. MONTECINO:
I. Material and Methods
The observations used in this study are based on sections III - IX and XI - XVI of
the "Meteor" cruise (Fig. 1). The African sections were made in December and January,
the Indian sections in February and March.
The physical and chemical data were published by DIETRICH et al. (1966), the
planktological data by KREY et al. (1971).
Water samples from the upper 50 m were taken at 10, 20, 30, 40 and 50 m (sometimes in addition a sample from 2 m is available), and water was filtered for collection
of particulate material. Microbiomass was measured as the protein content of particulate
matter filtered on paper filters. The procedure used was the Biuret method according
to KREY, BANSE and HAGMEIER (1957). All results are given as albumen equivalents.
The weight of particulate matter (seston) was determined prior to the measurement
of protein, using the same filters and a weighing method described by KREY (1950).
From these data detritus was calculated by subtracting the dry weight of microbiomass
from seston. According to HAGMEIER (1961) albumen data can be converted into dry
weight of living material by multiplying with a factor of 4. At some locations of the
area investigated the concentration of the properties measured was near the limit of
detection of the methods used. Therefore, we felt it appropriate to integrate values for
stations and to put the results into only three ranges of concentrations for graphic
presentation.
ll. Results
1. Microbiomass
Microbiomass is highest at some distance from the African coast near the Equator,
in the northern part of the waters at the Indian coast and in the region of Goa (Fig. 2).
The total numbers of phytoplankton show a similar distribution with the exception
of the area off Goa, where low numbers of phytoplankton are found (Fig. 3). It seems
reasonable to assume that most of what is measured as microbiomass in the upper layer
of the ocean represents phytoplankton. Therefore, a good correlation between microbiomass and phytoplankton can be expected.
2. Detritus
The shallow waters of the shelf exert a strong influence on the amount of detritus
(Fig. 4). This is most obvious near the broad continental shelf of India, but is also
indicated along the African coast. There is about the same quantity of detritus and microbiomass present (if calculated as dry weight) but no clear relationship between them
can be seen. Probably the differences in turbidity between coastal and offshore waters
determine the amount of detritus.
3. Nutrients
As an example of nutrients, the distribution of PO~- -P is given (Fig. 5). All values are
the means of observations at 2 m, 25 m and 50 m. The regions off the Indian coast
where higher values of microbiomass occur, show higher concentrations of po3--p,
B. BABENERD, R. BOlE,]. KREY, and V. MONTECINO:
I. Material and Methods
The observations used in this study are based on sections III - IX and XI - XVI of
the "Meteor" cruise (Fig. 1). The African sections were made in December and January,
the Indian sections in February and March.
The physical and chemical data were published by DIETRICH et al. (1966), the
planktological data by KREY et al. (1971).
Water samples from the upper 50 m were taken at 10, 20, 30, 40 and 50 m (sometimes in addition a sample from 2 m is available), and water was filtered for collection
of particulate material. Microbiomass was measured as the protein content of particulate
matter filtered on paper filters. The procedure used was the Biuret method according
to KREY, BANSE and HAGMEIER (1957). All results are given as albumen equivalents.
The weight of particulate matter (seston) was determined prior to the measurement
of protein, using the same filters and a weighing method described by KREY (1950).
From these data detritus was calculated by subtracting the dry weight of microbiomass
from seston. According to HAGMEIER (1961) albumen data can be converted into dry
weight of living material by multiplying with a factor of 4. At some locations of the
area investigated the concentration of the properties measured was near the limit of
detection of the methods used. Therefore, we felt it appropriate to integrate values for
stations and to put the results into only three ranges of concentrations for graphic
presentation.
ll. Results
1. Microbiomass
Microbiomass is highest at some distance from the African coast near the Equator,
in the northern part of the waters at the Indian coast and in the region of Goa (Fig. 2).
The total numbers of phytoplankton show a similar distribution with the exception
of the area off Goa, where low numbers of phytoplankton are found (Fig. 3). It seems
reasonable to assume that most of what is measured as microbiomass in the upper layer
of the ocean represents phytoplankton. Therefore, a good correlation between microbiomass and phytoplankton can be expected.
2. Detritus
The shallow waters of the shelf exert a strong influence on the amount of detritus
(Fig. 4). This is most obvious near the broad continental shelf of India, but is also
indicated along the African coast. There is about the same quantity of detritus and microbiomass present (if calculated as dry weight) but no clear relationship between them
can be seen. Probably the differences in turbidity between coastal and offshore waters
determine the amount of detritus.
3. Nutrients
As an example of nutrients, the distribution of PO~- -P is given (Fig. 5). All values are
the means of observations at 2 m, 25 m and 50 m. The regions off the Indian coast
where higher values of microbiomass occur, show higher concentrations of po3--p,