Michael Zettler - Academia.edu (original) (raw)

Papers by Michael Zettler

The time series on species composition and biomass or abundance of phyto-and zooplankton as well ... more The time series on species composition and biomass or abundance of phyto-and zooplankton as well as macrozoobenthos in the Belt Sea and the Baltic proper, existing since 1979, was continued in 2003.

Since the beginning of the mussel monitoring programme in 1993 Unio crassus has been observed in ... more Since the beginning of the mussel monitoring programme in 1993 Unio crassus has been observed in 52 watercourses of Mecklenburg-Vorpommern (north-east Germany). Although this number seems to be high, it has to be stressed that in more than half of the waterways this species became extinct and only empty shells indicated former populations. Eighteen brooks or rivers currently harbour U. crassus. The population size varied between hundred and six hundred thousand per river. The populated river length in Mecklenburg-Vorpommern was in most cases less than 10 km. Only three rivers (Nebel, Sude and Warnow) had populated lengths longer than this. Altogether, the length of running waters populated by U. crassus in Mecklenburg-Vorpommern was 134 km. About 1.5 million specimens of U. crassus inhabit these waters. Due to the consideration of U. crassus within the EC Habitats Directive, Mecklenburg-Vorpommern initialised a yearly monitoring scheme starting in 2003. The authors were authorised to perform the monitoring according to previous methods used at the national level. The population dynamics, abundance development and density were shown from different U. crassus locations. One of the main factors conjuncted with the decline of U. crassus was the increased nitrate-nitrogen content caused by eutrophication. Juveniles were recorded only in watercourses with NO 3 -N values around or below 2 mg/l. Furthermore, other causes are stressed. In terms of the EC Habitats Directive a monitoring scheme is needed in Europe so that fast action can be taken to increase protection status to an adequate level.

In 2001-2004 extensive studies of the macrozoobenthos community within the German Arkona Basin we... more In 2001-2004 extensive studies of the macrozoobenthos community within the German Arkona Basin were undertaken. The results with consideration of the habitat conditions prevailing in different depth zones are presented. By multidimensional scaling we dis- tinguished two separate macrozoobenthos communities (global r = 0.758, p = 0.1), one predominant in a habitat with sandy sediment or gravel and stones at

Marine benthic ecosystems are difficult to monitor and assess, which is in contrast to modern eco... more Marine benthic ecosystems are difficult to monitor and assess, which is in contrast to modern ecosystem-based management requiring detailed information at all important ecological and anthropogenic impact levels. Ecosystem management needs to ensure a sustainable exploitation of marine resources as well as the protection of sensitive habitats, taking account of potential multiple-use conflicts and impacts over large spatial scales. The urgent need for large-scale spatial data on benthic species and communities resulted in an increasing application of distribution modelling (DM). The use of DM techniques enables to employ full spatial coverage data of environmental variables to predict benthic spatial distribution patterns. Especially, statistical DMs have opened new possibilities for ecosystem management applications, since they are straightforward and the outputs are easy to interpret and communicate. Mechanistic modelling techniques, targeting the fundamental niche of species, and Bayesian belief networks are the most promising to further improve DM performance in the marine realm. There are many actual and potential management applications of DMs in the marine benthic environment, these are (i) early warning systems for species invasion and pest control, (ii) to assess distribution probabilities of species to be protected, (iii) uses in monitoring design and spatial management frameworks (e.g. MPA designations), and (iv) establishing long-term ecosystem management measures (accounting for future climate-driven changes in the ecosystem). It is important to acknowledge also the limitations associated with DM applications in a marine management context as well as considering new areas for future DM developments. The knowledge of explanatory variables, for example, setting the basis for DM, will continue to be further developed: this includes both the abiotic (natural and anthropogenic) and the more pressing biotic (e.g. species interactions) aspects of the ecosystem.

The year 2010 was the third year of the complex biological monitoring conducted in the German off... more The year 2010 was the third year of the complex biological monitoring conducted in the German off-shore area (mainly the exclusive economical zone) of the North Sea by the Leibniz Institute of Baltic Sea Research Warnemünde (IOW) and commissioned and supported by the Federal Maritime and Hydrographic Agency (BSH). Phytoplankton (incl. chlorophyll a), mesozooplankton and macrozoobenthos were investigated at 12 stations (for benthos exceptionally 13 stations, Fig.1). The plankton was sampled at 5 cruises (Tab. 1) and the zoobenthos at 2 cruises. Macrozoobenthos was investigated during spring and autumn 2010 at 13 stations within the German offshore area (predominantly EEZ) of the North Sea. In both sampling campaigns altogether 286 species were recorded. Between the stations the species number varied from 16 (off Sylt) to 90 (ENTE3). With 121 species (both campaigns added) the station at the central North Sea (ENTE3) was most diverse. With only two exceptions the species richness was ...

Abstract The time series on species composition and biomass or abundance of phyto- and zooplankto... more Abstract The time series on species composition and biomass or abundance of phyto- and zooplankton as well as macrozoobenthos in Kiel Bight, Mecklenburg Bight and the Arkona Sea, existing since 1979, was continued in 2011. The phytoplankton spring bloom developed later than usual after the cold winter; it reached its peak at the end of march/beginning of April 2011 in the western Baltic. At least in the Arkona Sea, it was a classical diatom bloom, but formed by the unusual species Achnanthes taeniata. In Kiel Bight, we found abundant dinoflagellates (Peridiniella danica) and Dictyochophyceae (Verrucophora farcimen). Also these species are rather new and unusual in this area. In the central Baltic, Mesodinium rubrum formed a bloom in May. The cyanobacteria developed already in the first half of July and reached the maximum extent on 12 July 2011. A typical summer diatom bloom could not be found during the cruise in August 2011. In autumn 2011, dinoflagellates were dominating in the w...

ICES Journal of Marine Science, 2014

Marine Pollution Bulletin, 2010

The Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD) are the Eu... more The Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD) are the European umbrella regulations for water systems. It is a challenge for the scientific community to translate the principles of these directives into realistic and accurate approaches. The aim of this paper, conducted by the Benthos Ecology Working Group of ICES, is to describe how the principles have been translated, which were the challenges and best way forward. We have tackled the following principles: the ecosystem-based approach, the development of benthic indicators, the definition of 'pristine' or sustainable conditions, the detection of pressures and the development of monitoring programs. We concluded that testing and integrating the different approaches was facilitated during the WFD process, which led to further insights and improvements, which the MSFD can rely upon. Expert involvement in the entire implementation process proved to be of vital importance.

Marine Pollution Bulletin, 2007

Two biotic indices, ATZI Marine Biotic Index (AMBI) and Benthic Quality Index (BQI) have been rec... more Two biotic indices, ATZI Marine Biotic Index (AMBI) and Benthic Quality Index (BQI) have been recently introduced within the EC Water Framework Directive to assess the quality of marine habitats: both are based on sensitivity/tolerance classification and quantitative information on the composition of soft-bottom macrofauna. Their performance, especially with regard to sampling effort was assessed based on two data sets collected in Southern Baltic and one from the Gulf of Lions Mediterranean. AMBI was not affected by sampling effort but BQI was. Two modifications were proposed for BQI (i.e., BQI) (1) the removal of the scaling term (i.e., BQI W ), and (2) the replacement of the scaling term by different scaling term (i.e., BQI ES ). Both modified BQIs were largely independent of sampling effort. Variability was slightly lower for BQI W than for BQI ES . BQI was highly correlated with BQI W and with BQI ES both in the Southern Baltic and in the Gulf of Lions. However, the proportions of stations, which were not attributed the same ecological quality status (EcoQ) when using BQI and its two modified forms were always high. Differences in ecological classification were mostly due to the scales used to infer EcoQ. Based on this study we recommend to use BQI ES in future studies because it apparently constitutes the best compromise in (1) being independent of sampling effort, (2) limiting the variability in computation in relation with sampling effort, (3) being correlated with BQI and corresponding EcoQ.

Marine Ecology Progress Series, 2009

Latitudinal clines in species diversity in limnic and terrestrial habitats have been noted for we... more Latitudinal clines in species diversity in limnic and terrestrial habitats have been noted for well over a century and are consistent across many taxonomic groups. However, studies in marine systems over the past 2 to 3 decades have yielded equivocal results. We conducted initial analyses of the MarBEF (EU Network of Excellence for Marine Biodiversity and Ecosystem Function) database to test for trends in local and regional diversity over the latitudinal extent of European continental-shelf waters (36°to 81°N). Soft-sediment benthic macrofauna exhibit little evidence of a latitudinal cline in local (α-) diversity measures. Relationships with water depth were relatively strong and complex. Statistically significant latitudinal trends were small and positive, suggesting a modest increase in diversity with latitude once water-depth covariates were removed. These results are consistent regardless of whether subsets of the database were used, replicates were pooled, or component taxonomical groups were evaluated separately. Local and regional diversity measures were significantly and positively correlated. Scientific cooperation through data-sharing is a powerful tool with which to address fundamental ecological and evolutionary questions relating to large-scale patterns and processes.

Marine Ecology Progress Series, 2009

This study examines whether or not biogeographical and/or managerial divisions across the Europea... more This study examines whether or not biogeographical and/or managerial divisions across the European seas can be validated using soft-bottom macrobenthic community data. The faunal groups used were: all macrobenthos groups, polychaetes, molluscs, crustaceans, echinoderms, sipunculans and the last 5 groups combined. In order to test the discriminating power of these groups, 3 criteria were used: (1) proximity, which refers to the expected closer faunal resemblance of adjacent areas relative to more distant ones; (2) randomness, which in the present context is a measure of the degree to which the inventories of the various sectors, provinces or regions may in each case be considered as a random sample of the inventory of the next largest province or region in a hierarchy of geographic scales; and (3) differentiation, which provides a measure of the uniqueness of the pattern. Results show that only polychaetes fulfill all 3 criteria and that the only marine biogeographic system supported by the analyses is the one proposed by Longhurst (1998). Energy fluxes and other interactions between the planktonic and benthic domains, acting over evolutionary time scales, can be associated with the multivariate pattern derived from the macrobenthos datasets. Third-stage multidimensional scaling ordination reveals that polychaetes produce a unique pattern when all systems are under consideration. Average island distance from the nearest coast, number of islands and the island surface area were the geographic variables best correlated with the community patterns produced by polychaetes. Biogeographic patterns suggest a vicariance model dominating over the founder-dispersal model except for the semi-closed regional seas, where a model substantially modified from the second option could be supported. KEY WORDS: Marine biodiversity · Biogeography · Macrobenthos · Polychaetes · Europe Resale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESS Contribution to the Theme Section 'Large-scale studies of the European benthos: the MacroBen database'

Marine Ecology Progress Series, 2009

The pan-European MacroBen database was used to compare the AZTI Marine Biotic Index (AMBI) and th... more The pan-European MacroBen database was used to compare the AZTI Marine Biotic Index (AMBI) and the Benthic Quality Index (BQI ES ), 2 biotic indices which rely on 2 distinct assessments of species sensitivity/tolerance (i.e. AMBI EG and BQI E[S 50 ] 0.05 ) and which up to now have only been compared on restricted data sets. A total of 12 409 stations were selected from the database. This subset (indicator database) was later divided into 4 marine and 1 estuarine subareas. We computed E(S 50 ) 0.05 in 643 taxa, which accounted for 91.8% of the total abundances in the whole marine indicator database. AMBI EG and E(S 50 ) 0.05 correlated poorly. Marked heterogeneities in E(S 50 ) 0.05 between the marine and estuarine North Sea and between the 4 marine subareas suggest that sensitivity/tolerance levels vary among geographical areas. High values of AMBI were always associated with low values of BQI ES , which underlines the coherence of these 2 indices in identifying stations with a bad ecological status (ES). Conversely, low values of AMBI were sometimes associated with low values of BQI ES resulting in the attribution of a good ES by AMBI and a bad ES by BQI ES . This was caused by the dominance of species classified as sensitive by AMBI and tolerant by BQI ES . Some of these species are known to be sensitive to natural disturbance, which highlights the tendency of BQI ES to automatically classify dominant species as tolerant. Both indices thus present weaknesses in their way of assessing sensitivity/tolerance levels (i.e. existence of a single sensitivity/tolerance list for AMBI and the tight relationship between dominance and tolerance for BQI ES ). Future studies should focus on the (1) clarification of the sensitivity/tolerance levels of the species identified as problematic, and (2) assessment of the relationships between AMBI EG and E(S 50 ) 0.05 within and between combinations of geographical areas and habitats. KEY WORDS: AZTI Marine Biotic Index · Benthic Quality Index · Macrozoobenthos · Water framework directive Resale or republication not permitted without written consent of the publisher Contribution to the Theme Section 'Large-scale studies of the European benthos: the MacroBen database' OPEN PEN ACCESS CCESS

Marine Ecology Progress Series, 2009

We describe an integrated database on European macrobenthic fauna, developed within the framework... more We describe an integrated database on European macrobenthic fauna, developed within the framework of the European Network of Excellence MarBEF, and the data and data integration exercise that provided its content. A total of 44 datasets including 465 354 distribution records from soft-bottom macrobenthic species were uploaded into the relational MacroBen database, corresponding to 22 897 sampled stations from all European seas, and 7203 valid taxa. All taxonomic names were linked to the European Register of Marine Species, which was used as the taxonomic reference to standardise spelling and harmonise synonymy. An interface was created, allowing the user to explore, subselect, export and analyse the data by calculating different indices. Although the sampling techniques and intended use of the datasets varied tremendously, the integrated database proved to be robust, and an important tool for studying and understanding large-scale long-term distributions and abundances of marine benthic life. Crucial in the process was the willingness and the positive data-sharing attitude of the different data contributors. Development of a data policy that is highly aware of sensitivities and ownership issues of data providers was essential in the creation of this goodwill.

Hydrobiologia, 2010

The general aim of setting up a central database on benthos and plankton was to integrate long-, ... more The general aim of setting up a central database on benthos and plankton was to integrate long-, medium-and short-term datasets on marine biodiversity. Such a database makes it possible to analyse species assemblages and their changes on spatial and temporal scales across Europe. Data collation lasted from early 2007 until August 2008, during which 67 datasets were collected covering three divergent habitats (rocky shores, soft bottoms and the pelagic environment). The database contains a total of 4,525 distinct taxa, 17,117 unique sampling locations and over 45,500 collected samples, representing almost 542,000 distribution records. The database geographically covers the North Sea (221,452 distribution records), the North-East Atlantic (98,796 distribution records) and furthermore the Baltic Sea, the Arctic and the Mediterranean. Data from 1858 to 2008 are presented in the database, with the longest time-series from the Baltic Sea soft bottom benthos. Each delivered dataset was subjected to certain quality control procedures, especially on Electronic supplementary material The online version of this article (

Helgoland Marine Research, 2014

In the Helsinki Commission Red List project 2009-2012, taxonomic and distributional data of benth... more In the Helsinki Commission Red List project 2009-2012, taxonomic and distributional data of benthic (macro) invertebrates were compiled by the present authors in a comprehensive checklist of the Baltic Sea fauna. Based on the most recent and comprehensive data, this paper presents the diversity patterns observed among benthic invertebrates in the Baltic Sea. As expected, the total number of species per sub-region generally declined along the salinity gradient from the Danish Straits to the northern Baltic Sea. This relationship is well known from the Baltic Sea and has resulted in a general assumption of an exponentially positive relationship between species richness and salinity for marine species, and a negative relationship for freshwater species. In 1934, Remane produced a diagram to describe the hypothetical distribution of benthic invertebrate diversity along a marine-freshwater salinity gradient. Our results clearly indicated the validity of this theory for the macrozoobenthic diversity pattern within the Baltic Sea. Categorisation of sub-regions according to species composition showed both separation and grouping of some sub-regions and a strong alignment of similarity patterns of zoobenthic species composition along the salinity gradient.

ICES Journal of Marine Science, 2014

Marine Pollution Bulletin, 2010

Marine Pollution Bulletin, 2007

Marine Ecology Progress Series, 2009

Hydrobiologia, 2010

Helgoland Marine Research, 2014