EMECS’11 – SEACOASTS XXVI JOINT CONFERENCE Managing risks to coastal regions and communities in a changing world

Jing ZHANG1,2, Osamu INAMURA3, Chihiro URASAWA1 Tomoki OTSUKA1, Natsumi YAMAZAKI1

1 Graduate School of Science & Engineering, Univ. Toyama 2 Northwest Pacific Region Environmental Cooperation Center 3 Uozu Aquarium

August 22-27, 2016, St Petersburg, Russia

Food web characterization using carbon and nitrogen isotope analysis in the Toyama Bay and the Sea of Japan

・ food web from coast to offshore in Toyama Bay, and Sea of Japan ・ Carbon and nitrogen input to coastal area of the Toyama Bay ・ Carbon-nitrogen cycles, and environmental management

Content

Higher recent ventilation than anywhere else in

the Pacific including

the Antarctic. Data source: WOCE and NODC of

Russia (Talley, 06’;

Talley et al., 04’)

A miniature ocean

Japan Sea

Background

t ~100 yrs

similar deep water subduction/ advection

Dissolved Oxygen in 1000 m

Motivation

Toyama Bay

Sea of Japan

World Ave. Hokkaido

Kyusyu・Okinawa area

Kanto Region

southern Japan

0.5

Remarkable seawater temperature rise ↓

1. Scientific questions; 2. social needs: e.g., fish catches

(Japanese Society of Fisheries Economics)

Fish catches decreases from 1985 to 2013 in the Sea of Japan

(Large purse seine)

sardine horse mackerel

mackerel

others ×kt

Sardine decreased sharply

Long term change of surface seawater temperature in Japan (℃/100 yr, JMA)

Toyama Bay is the Natural fish Reservoir ・Rich fisheries resources through the ages

・Fish species: 614 (Toyama Bay) /1396 (Sea of Japan)

Effect of global warming on the marine resources has been concerned in recent years

King of the fishes Yellowtail

1200m

Fish catches dramatically decreased (winter 2015)

Yellowtail

~10%

2014

100m Temp

2015

December January

Best live temperature for Yellowtail: 15～17℃ It existed in the central part of Sea of Japan in the winter, 2015； In January, yellowtail did not enter Toyama Bay due to low seawater temperature

December January

2015 2016

Image of the food web

Carnivorous fish

Primary producers

Herbivores

Secondary consumers

Food web and energy flow from primary producer to fish

→Food web

Other zooplankton

Detritus

Amphipoda Copepod

Phytoplankton

Euphausiacea

Sardine

Squid offshore

Ommastrephes bartramii

Pomfret

Shark in shallow water

Salmon

Cololabis saira Todarodes pacificus

Phytoplankton

Marine snow

Sediment

shallow water Fish

Zooplankton

deep water Fish

●:Fish of deep water

●:Fish of shallow water

●:Zooplankton in Toyama Bay (Deep & shallow)

Zooplankton δ1

5N（

‰）

δ13C（‰）

Chaetognatha

Mysidacea

Copepoda

Amphipoda

Euphausiacea

Buccinum tenuissimum

Lycodes tanakae Bothrocara hollandi

Stephanolepis cirrhifer

Etrumeus teres

Pasiphaea japonica

Berryteuthis magister

Seriola quinqueradiata

Ser. Quin. young

Offshore food web in the Toyama Bay By CN stable isotope ratio analysis

Sinking particle

(marine snow)

Sediment

14

12

10

8

6

4

2

Yellowtail

Metapenaeopsis lata

Yellowtail

Thread-sail filefish

Phytoplankton

-25 -23 -21 -19 -17 -15 -13

δ13C（‰）

Capitulum mitella Hemigrapsus

sanguineus

Shell

Bivalvia

Coast

Round herring

Benthic algae

δ1

5N（

‰）

Food web

TL :２

TL : １

Offshore

Limpet

Food web in coastal area By CN stable isotope ratio analysis

14

12

10

8

6

4

2

-25 -23 -21 -19 -17 -15 -13

δ13C（‰）

カメノテ

Coast

Limpet

・ Coastal species : Supported by the nutrients from the river

＋EOM EOM : Epilithic organic matter

・ EOM : important

δ1

5N（

‰）

Sinking particle

(marine snow)

Marine sediment

Phytoplankton

Yellowtail

Yellowtail Metapenaeopsis lata

Round herring

Thread-sail filefish

Hemigrapsus sanguineus

Bivalvia

Shell

Capitulum mitella

Benthic algae

“Ecological pyramid” of Toyama Bay By CN stable isotope ratio analysis

Offshore

-2

0

2

4

6

8

10

12

-28 -26 -24 -22 -20 -18 -16 -14 -12

δ1

5N（‰

）

Phytoplankton ＋

EOM (Epilithic organic matter)

δ13C of coastal species:

Comparison with

Phytoplankton

δ13C ＝High

Phytoplankton

EOM

C:N=1：3.4

Carbon source

δ13C（‰） B:Bivalvia（n=27）

G:Limpet（n=37）

F:Fish （n=27)

P:Polychaeta (n=1）

T:Shell（n=5）

C: Mitella（n=7）

H:Crab（n=3）

Carbon source of coastal species

Contribution ratio of EOM (Epilithic organic matter) （%） ＝100-(100×(S×CC－S×E2C－CN＋E2N)/ (S×E1C－S×E2C－E1N＋E2N))

S＝15N fractionation / 13C fractionation

CC：δ13C in subject creature CN：δ15N in subject creature E1C δ13C in POM

E1N：δ15N in POM E2C：δ13C in EOM E2N：δ15N in EOM （Yokoyama and Ishii, 2007; Doi et al., 2011）

E1＝POM E2＝EOM Shell S=2（‰）/1（‰）others S=3.4（‰）/1（‰）

Subject Organism

Contribution ratio of EOM （%）

Bivalvia n=17

37±4（32～44）

Conch n=2

35

Polychaetan=1

49

Subject Organism

Contribution ratio of EOM （%）

Hemigrapsus

sanguineus n=3 47 （38～58）

Fish n=15 45±11（24～70）

Two carbon source contributions

Contribution ratio of EOM： 30~60%

→Important carbon source

Carbon source of coastal species and their contributions

：River ：Human activity

terrestrial input

：Estuary

West East

0.2

－4.7

－0.7

－3.0 －3.1

－1.4

4.5

0.6

4.2

4.2

River water in Toyama

Estuary：－5～0‰

Other areas Downstream river δ15N NO3

－：4～6‰ (Nagata et al., 2010)

NO3－ derived from a river:

δ15N is low

δ15N NO3－ in terrestrial water and sea water

：River ：Human activity ：Estuary

West East Submarine Groundwater Discharge

・Important nutrient source ・It supplies 1.5-fold N compared with riverine contribution（Nakaguchi et al.，2005）

δ15N NO3－＝－2.2‰（Zhang, 2014）

Land provides low δ15N

δ15N NO3－ of terrestrial water

δ15N NO3－ in terrestrial water and sea water

Contribution ratio of river water =(１－(1st consymaerδ15N－ 15N fractionation ー Riverδ15N NO3

－)/ （Deep sea waterδ15N NO3 －riverδ15N NO3

－ ））×100 ※Primary producers:δ15N＝ δ15N NO3

－

St3 RCR（％）

Bivalvia n=12 35±5（25～43）

Cellana mazatlandica

n=10

23±7（9～32）

St1 RCR（％）

Bivalvia n=5 36±4（33～41）

Cellana mazatlandica

n=5

23±6（14～28）

Contribution ratio of δ15N NO3－ derived from the land to the coastal species

20～40％

Nitrate input from land and contribution

-10

0

10

20

30

40

50

60

70

-10 -5 0 5 10 15 20 25 30

δ1

8O

δ15N

片貝川

早月川

神通川

庄川

小矢部川

Precipitation

Nitrate fertilizer

Nitrification

Human waste, Livestock waste, and compost

Kendall, 1998

δ18O：－0.6～3.8‰ （Average：1.6‰）

Fertilizer of nitrate nitrogen : Lower than precipitation

δ15N of the river water ・NH4

＋ in the fertilizer ・NH4

＋in the soil ・Derived from nitrification of bacteria

NO3- of δ15N・δ18O

Measure δ15N and δ18O of NO3-

→ It can estimate

the origin of NO3－

Oyabe

Shogawa

Jinzu

Katakaigawa

Hayatsukigawa

Origin estimate of δ15N NO3－ in the river water

Nitrification: NO3－

Future work ・seasonal changes, event → ecosystem model

→ → ・ global warming, human activities…

(precipitation, eutrophication, land use)

→ → ・ integrated management, adaptation

Phytoplankton

Food web δ13C=H δ15N＝L δ15N NO3

－ ＝Low

Epilithic organic matter

From land 20～40％

C-①

N

River & SGD Input

Land → Coast → Food web; Energy Flow

C-①

Summary

5

6

7

8

9

10

11

-23 -22 -21 -20 -19

δ1

5N

富山湾_深層_カイアシ小 (5)

富山湾_深層_カイアシ大 (5)

富山湾_深層_オキアミ (4)

富山湾_深層_端脚 (4)

富山湾_深層_アミ (3)

富山湾_深層_ヤムシ (4)

大和海盆_深層_カイアシ小（2）

大和海盆_深層_カイアシ大（2）

大和海盆_深層_オキアミ（2）

大和海盆_深層_端脚（2）

大和海盆_深層_アミ（2）

大和海盆_深層_ヤムシ（2）

Comparison with the same species

δ1

5N（

‰）

δ13C（‰）

Isotope ratio of zooplankton (Toyama Bay and Yamato basin)

Copepoda of Toyama Bay_small (5)

Copepoda of Toyama Bay_large (5)

Euphausiacea of Toyama Bay (4)

Amphipoda of Toyama Bay (4)

Mysidacea of Toyama Bay (3)

Chaetognatha of Toyama Bay (4)

Copepoda of Yamato Basin_small (2)

Copepoda of Yamato Basin_large (2)

Euphausiacea of Yamato Basin (2)

Amphipoda of Yamato Basin (2)

Mysidacea of Yamato Basin (2)

Chaetognatha of Yamato Basin (2)

May 2015

Carbon isotope ratio of the zooplankton： Toyama Bay＞Yamato Basin

Zooplankton : Comparison between Toyama Bay and Sea of Japan

Carbon isotope ratio of the zooplankton：Toyama Bay＞Yamato Basin →Reflecting the growth rate of phytoplankton Growth rate is fast ： carbon isotope ratio → High （Takahashi et al, 1991）

●:Toyama Bay ●:Yamato Basin

Toyama Bay

Yamato Basin

Carbon：High

May 2015

Comparison of the shallow water and deep water

phytoplankton biomass

(chlorophyll concentration µ/l)

De

pth

(m

)

Toyama Bay has fast grow rate and enriched in biomass relative to Yamato Basin

Characteristic

Subdivision of

phyto/zoo plankton Expected outcome

Mechanism of

nutrient

environment impact

on lower-order

ecosystem

Characteristic

Simplification of

phyto/zoo plankton

Data assimilation

Expected outcome

High resolution

prediction of long-term

change

Characteristic transport of eggs and larvae

Reproduction of debris by

environment and baits

conditions

Lower-order ecosystem

linked with zooplankton

Expected outcome Efficient configurations of

Marine Protected Areas

Sakurai 2014

Konishi et

al. 2011

Particle tracking/ Growth/Survival model Ecosystem models

Integrated management of Japanese coastal areas Ecosystem response mechanism

22

Nutrients supplied from East China Sea,

Sea of Japan deep water, and the land.

Primary Producer

Primary Consumer

Secondary

Consumer

Tertiary

Consumer

d13C (‰)

Ecosystem structure in the Sea of Japan

Red snow Crab

Firefly squid

d1

5N

(‰

)