1. CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
Final COAST working group meeting
Lisbon, February 2003
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
Javier Franco, Ángel Borja and Iñigo Muxika
Dept. Oceanography and Marine Environment, AZTI Foundation
Herrera Kaia, Portualdea, z/g – Pasaia, Gipuzkoa (Spain)

2. BACKGROUND: The Water Framework Directive (WFD)
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
BACKGROUND: The Water Framework Directive (WFD)
and the macrobenthic communities
The WFD establishes that the ecological status of surface water bodies must be assessed.
In transitional and coastal waters benthic communities are one of the biological quality elements.
Diversity and abundance of invertebrate taxa, and the presence of disturbance-sensitive taxa and taxa indicative of pollution must be measured.
But, at present, available tools do not fulfill the requirements of the WFD.
“Methods combining composition, abundance and sensitivity may be the most promising” (COAST guidance document)

3. Metrics to be used for macrobenthic communities
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
Metrics to be used for macrobenthic communities
according to the WFD
Diversity: Shannon-Weaver diversity (H´).
Abundance of invertebrate taxa: number of species (taxa) (Species richness, S).
Abundance: number of individuals.
Presence of disturbance-sensitive taxa and taxa indicative of pollution: Biotic indices.
AMBI (Azti Marine Biotic Index;
Previous biotic indices in Europe (Glemarec and Hily, 1981; Hily, 1984; Majeed, 1987; Grall and Glémarec, 1997)
It is based on the sensitivity of benthic fauna to stress gradients. Species are classified in five ecological groups. The distribution of these ecological groups provides a biotic index with eight levels, from 0 to 7.

4. The AMBI Biotic Index development
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
The AMBI Biotic Index development
Based on sensitivity/tolerance to pollution, five ecological groups can be established:
ORGANIC MATTER ENRICHMENT
Abundance
Biomass
Richness
Peak of opportunistic species
PEARSON Y ROSENBERG (1978)
MODEL
Group I - Species very sensitive to organic enrichment
Group II - Species indifferent to organic enrichment
Group III - Species tolerant to excess of organic matter enrichment
Group IV - Second order opportunistic species
Group V - First order opportunistic species

5. The AMBI Biotic Index development
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
The AMBI Biotic Index development
BIOTIC COEFFICIENT 1 2 3 4 5 6
PERCENTAGE OF GROUPS
100 90 80 70 V 60 I
AZOIC SEDIMENT 50
III 40 30 IV 20 II 10 1 2 3 4 5 6 7
BIOTIC INDEX
UNPOLLUTED
SLIGHTLY POLLUTED
MEANLY POLLUTED
HEAVILY `POLLUTED
EXTREM.
POLLUTED
INCREASING POLLUTION

6. The AMBI Biotic Index development
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
The AMBI Biotic Index development BC BI
GROUPS
(taxa) I II
III IV V
0,0 1 2 3 4 5 6 7
UNPOLLUTED
0,2
1,2
SLIGHTLY POLLUTED
sensitive
MEANLY POLLUTED
3,3
4,3
5,0
HEAVILY POLLUTED
5,5
6,0
ESTREMELY POLLUTED
AZOIC
opportunists
Biotic coefficient = {(1,5 * %GII) + (3 * %GIII) +(4,5 * %GIV) + (6 * %GV)}/100
TAXONOMIC
CCOMPOSITION %
GROUPS
BIOTIC
COEFFICIENT
BIOTIC
INDEX

7. The AMBI Biotic Index validation (Mann-Witney test; p=0,003)
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
The AMBI Biotic Index validation
HYPOTHESIS: the biotic index is able to detect differences between control (unpolluted) and contaminated areas (based on abiotic variables).
CONTROL STATIONS
No metal > ER-M (Long et al. 1995), and
O.M. < 3 %, and
D.O. > 4 ml·l-1
DEGRADED STATIONS
Some metals > ER-M (Long et al. 1995), or
O.M. > 9 %, or
D.O. < 3 ml·l-1 ( hypoxia)
Mean BC of control stations: 1,9 (n = 19)
Mean BC of degraded stations: 3,7 (n = 40)
There are significant differences between control and degraded stations
(Mann-Witney test; p=0,003)

8. A CASE STUDY: monitoring of macrobenthic communities
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY: monitoring of macrobenthic communities
in an area affected by a submarine outfall (N. Spain)
In spring 2001, as a transitory solution in the context of the sewerage scheme, the discharges were diverted to a submarine outfall at 1.2 km from the coast and about 47 m depth.
Benthic communities were studied 5 months before, and 4 months and 16 months after the diversion. Benthic communities at two separate stations (in areas at 50 and 160 m depth) were used as a proxy to reference conditions.
Benthos was sampled with a Box-corer grab at 9 sampling sites; 3 replicates were taken at each sampling site.
The general characteristics of the sediments (grain size, organic matter, redox potential) and the heavy metal content were also analysed.
Study made for Diputación Foral de Gipuzkoa and Aguas del Añarbe

9. spatial and temporal distribution of the taxonomic richness
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
spatial and temporal distribution of the taxonomic richness
The reference stations present the highest taxonomic richness.
The stations most affected by the discharges present the lowest taxonomic richness.
TAXONOMIC RICHNESS

10. spatial and temporal distribution of the abundance
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
spatial and temporal distribution of the abundance
The reference stations present the lowest abundances.
The stations most affected by the discharges present the highest abundances.
ABUNDANCE

11. spatial and temporal distribution of the diversity
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
spatial and temporal distribution of the diversity
The reference stations and the non-affected stations present the highest diversities.
The stations most affected by the discharges present the lowest diversities.
DIVERSITY

12. spatial and temporal distribution of the biotic coefficient
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
spatial and temporal distribution of the biotic coefficient
The reference stations and the non-affected stations present low biotic coefficients (unpolluted or slightly polluted).
The stations most affected by the discharges present high biotic coefficients (heavily polluted).
BIOTIC COEFFICIENT

13. relationships among the biological indicator metrics
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
relationships among the biological indicator metrics 1 2 3 4 5 6 7 20 40 60 80
100 8 10
RICHNESS - BC*
RICHNESS - ABUNDANCE (x1000)* 1 2 3 4 5 6 7 8 10 20 40 60 80
100
ABUNDANCE (x1000) - BC**
RICHNESS - DIVERSITY** 1 2 3 4 5 6 7 8 10
DIVERSITY - BC**
ABUNDANCE (x1000) - DIVERSITY**

14. changes in the biotic coefficient
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
changes in the biotic coefficient
BEFORE
AFTER-1
AFTER-2

15. towards an ecological quality ratio (EQR)
CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
A CASE STUDY:
towards an ecological quality ratio (EQR)
Diversity
>4.8 1
Richness
0-15 0
>60 1
Biotic coefficient
7 0

16. CLASSIFICATION TOOLS FOR BENTHIC INVERTEBRATE FAUNA IN COASTAL WATERS
An example from an area affected by a submarine outfall in N. Spain
CONCLUSIONS
The taxonomic richness, the diversity and the biotic coefficient follow a linear relationship with the degree of affection by the discharges.
On the other hand, the abundance shows a more complex relationship to the degree of affection.
The metrics used are able to differentiate non-affected from affected sites, to detect human impacts and to establish temporal changes.
These metrics can be combined in order to give a general index of ecological quality, as established by the WFD.