276
I I JOInt Research Projects
The studies and synthesis of ELA W A T have shown that an evaluation of the results, e.g. on abundances and distributions of benthic organisms, required a comparison with long-term records (Chap. 9). But it became obvious that relatively
few data are available on spatial and temporal distributions and abundances for
many species of the Wadden Sea. Thus, long-term quantitative surveys of speciesand individual densities should be carried out at several locations to assess a reference dynamic and to be able to diagnose and analyse possible changes.
All existing long-term data series of biological parameters and historical comparisons (Michaelis & Reise 1994) are incredibly precious. The relevance of longterm data series grows the longer the record lasts and the more events can be identified over the course of time (Beukema et al. 1998). Existing long-term data series
should definitely be continued and be in a continuous feedback with topical research efforts. Wherever possible, historical archives such as sediment profiles,
biofacies and literature records should be used in addition (cf. Reise 1995).
Are sedimentation and turnover in the Wadden Sea determined by extreme
events?
Weather and security reasons usually restrict research in the Wadden Sea to summertime. In ELA W A T, some investigations were carried out in winter, e.g. during
the ice winter 1995/96, but these results could not be related to other winter situations due to a lack of data. Exchange rates and the turnover of matter and energy
can be fairly easily quantified during calm weather conditions. But what do their
values mean in relation to extreme events, like e.g. storms? Extreme events can
exert a strong intluence on the Wadden Sea (Nehls & Thiel 1993) and should thus
be studied further. Yet, extreme events are often unpredictable and require a
spontaneous research action. This can only be realized by existing institutions
having staff and technical resources at stand-by (see also Sects. 11.1; 11.4).
The results of ELA W AT pose the question for a budget of fine grained sediments in the Wadden Sea. Given the debate about the loss of mudflats and sedimentation areas in the Wadden Sea (Chap. 3.4, Flemming & Nyandwi 1994), the
exchange rates of particulate and dissolved matter should be assessed during storm
events, as these can transfer large amounts of matter. So far methodological difficulties have prevented such investigations. Should these be overcome, the quality
of the matter should be determined simultaneously.
What are the connections between sub- and intertidal areas in the Wadden Sea?
Many benthic species in the Wadden Sea have sub-populations both in the interand subtidal areas. The investigations of ELA W AT indicate that subtidal populations might have a considerable importance for the recruitment and recolonization
of intertidal areas. Over the last decades, research efforts have mainly concentrated on the intertidal of the Wadden Sea which is easily accessible. But the distribution and composition of the benthos in the subtidal realms of the Wadden Sea
is almost unknown. This gap has to be filled with quantitative surveys on species
compositions, population dynamics and abundances of subtidal species and sub-
I I JOInt Research Projects
The studies and synthesis of ELA W A T have shown that an evaluation of the results, e.g. on abundances and distributions of benthic organisms, required a comparison with long-term records (Chap. 9). But it became obvious that relatively
few data are available on spatial and temporal distributions and abundances for
many species of the Wadden Sea. Thus, long-term quantitative surveys of speciesand individual densities should be carried out at several locations to assess a reference dynamic and to be able to diagnose and analyse possible changes.
All existing long-term data series of biological parameters and historical comparisons (Michaelis & Reise 1994) are incredibly precious. The relevance of longterm data series grows the longer the record lasts and the more events can be identified over the course of time (Beukema et al. 1998). Existing long-term data series
should definitely be continued and be in a continuous feedback with topical research efforts. Wherever possible, historical archives such as sediment profiles,
biofacies and literature records should be used in addition (cf. Reise 1995).
Are sedimentation and turnover in the Wadden Sea determined by extreme
events?
Weather and security reasons usually restrict research in the Wadden Sea to summertime. In ELA W A T, some investigations were carried out in winter, e.g. during
the ice winter 1995/96, but these results could not be related to other winter situations due to a lack of data. Exchange rates and the turnover of matter and energy
can be fairly easily quantified during calm weather conditions. But what do their
values mean in relation to extreme events, like e.g. storms? Extreme events can
exert a strong intluence on the Wadden Sea (Nehls & Thiel 1993) and should thus
be studied further. Yet, extreme events are often unpredictable and require a
spontaneous research action. This can only be realized by existing institutions
having staff and technical resources at stand-by (see also Sects. 11.1; 11.4).
The results of ELA W AT pose the question for a budget of fine grained sediments in the Wadden Sea. Given the debate about the loss of mudflats and sedimentation areas in the Wadden Sea (Chap. 3.4, Flemming & Nyandwi 1994), the
exchange rates of particulate and dissolved matter should be assessed during storm
events, as these can transfer large amounts of matter. So far methodological difficulties have prevented such investigations. Should these be overcome, the quality
of the matter should be determined simultaneously.
What are the connections between sub- and intertidal areas in the Wadden Sea?
Many benthic species in the Wadden Sea have sub-populations both in the interand subtidal areas. The investigations of ELA W AT indicate that subtidal populations might have a considerable importance for the recruitment and recolonization
of intertidal areas. Over the last decades, research efforts have mainly concentrated on the intertidal of the Wadden Sea which is easily accessible. But the distribution and composition of the benthos in the subtidal realms of the Wadden Sea
is almost unknown. This gap has to be filled with quantitative surveys on species
compositions, population dynamics and abundances of subtidal species and sub-