Marine Ecosystem and Environment in the Tokyo Bay

Marine Ecosystem and Environment
in the Tokyo Bay
–Past and Current-
Naho HORIMOTO
Department of Ocean Sciences
Faculty of Marie Science
Tokyo University of Marine Science and Technology

Mooring operation and recovery
Real time measurement of Primary Productivity in Sagami Bay
(SORST - JST)
Depth, Temperature, Salinity, In situ PAR,
Chlorophyll fluorescence,
Primary Productivity by Fast Reputation Rate of Fluorescence
Underwater winch is designed
that Buoy moves up and
down with Kevlar rope in
accordance with a time-table
user programmed.
Profiling Data is send to the
Lab by email

CTD SYSTEM
(Conductivity=salinity, Temperature and Depth)
CTD Cast Winch Control
Steel Wire Armored Cable
Water Sampling
Slip ring
Deck Unit
PC Operation

CTD Sensors
Pressure
(Depth)
Conductivity
(Salinity)
Cradle for
Niskin Bottle
Sampler
Chlorophyll Fluorometer
Temperature
Dissolved Oxygen
light quantum
(Irradiance)
Main Body
Light Attenuation Coefficient
(Turbidimeter)

Pressure (Depth, m)
CTD Vertical Profile in 20th December 2005 at Sagami Bay
Temperature(oC)
Salinity
Temperature
Dissolved Oxygen
Salinity (Practical Salinity Unit)
Dissolved Oxygen (ml/l)
Turbidimeter (%)
In vivo Chlorophyll (ug/l)
light quantum
Chlorophyll
light quantum (uE/m3/s)
Turbidimeter

DIN (µM)
Si(OH) 4 -Si (µM) PO 4 -P (µM)
75
70
65
60
55
50
45
40
35
30
25
1.6
1.4
1.2
1.0
0.8
0.6
0.4
50
40
30
20
10
1989
Result from Mastumura et al. (2001)
F3
F6
1990 1991 1992 1993 1994 1995 1996 1997 1998
Cocks-Start Test
Trends of decrease
(a=0.05)
Changes in surface nutrient concentrations at Sta.F3 and F6

After Kawabe and Kawabe (1997)
(Chemical Oxygen Demand)
Variation of surface COD and DIN, and solar radiation

Chl a (µg/l)
Solar radiation (MJ/m 2 )
DIN (µM)
40
30
20
10
14
13
13
12
12
11
11
75
70
65
60
55
50
45
40
35
30
25
Result from Mastumura et al. (2001)
F3
F6
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Variation of Chl a, solar radiation, and DIN at Sta. F3 and F6
F3
F6

Before 1950s
Ceratium
Occurrence Times
Gonyaulax
Red Tide (a decade AV)
Red Tide
Skeletonema
Prorocentrum
Chaetoceros
Heterosigma
1950-1970s 1980-1990s
Blue Tide
(a decade AV)
Occurrences of red tide and blue tide
Blue Tide

greatly increased amounts of phosphorus or nitrogen
entering an aquatic ecosystem from either sewage
systems or agricultural fertilizers
Sulfur was educed due to
oxidation of hydrogen
sulfide, that color is light
blue and tint smells of
sulfur
P N
Bottom anoxia and extinction of benthos
Red Tide and Blue Tide
Red tide and
End of bloom, phytoplankton accumulate on the sea
bottom and microbes consume large amount of
oxygen to decompose them.
Phytoplankton are microscopic, single-celled plants.
Phytoplankton is a primary producer in the ocean.
Southern wind cause upwelling

size
0.2µm
PICO
2µm
NANO
20µm
MICRO
200µm
Dissolved
organic carbon
Microbial loop
Trophic transfer of carbon
Diagram of a marine food chain
Classic food chain
MACRO

30
Annual mean nitrate at the surface
(source World Ocean Atlas @ NODC)
L
Open Ocean
Small
(µM)
nutrient
s
Chl a
0.1
0.5 1 10
Composite image of chlorophyll
concentration in the ocean
(source SEAWIFS project)
Coastal +
Upwelling area
Large
How does phytoplankton biomass and species composition vary ?
What size dominates within each area?
H
Chl a
(µg L -1 )