Quantitative paleoenvironmental studies using freshwater ostracods in northeast Germany [Elektronische Ressource] / Finn Andreas Viehberg, geb. Heinrichs

Informations

• Publié par: ernst-moritz-arndt-universitat_greifswald
• Publié le: 01 janvier 2005
• Nombre de lectures: 65
• Poids de l'ouvrage: 50 Mo

Extrait

Quantitative paleoenvironmental studies
using freshwater ostracods
in northeast Germany







Inauguraldissertation

zur Erlangung des akademischen Grades
doctor rerum naturalium (Dr. rer. nat.)
an der Mathematisch- Naturwissenschaftlichen Fakultät der
ERNST - MORITZ - ARNDT - UNIVERSITÄT GREIFSWALD


vorgelegt von
Finn Andreas Viehberg,
geb. Heinrichs
geboren am 12.01.1975 in Braunschweig
Dersekow, am 25. April 2005















Dekan:

1. Gutachter/in:
2. Gutachter/in:


Tag der Promotion:


















Ostracoda

Muschelkrebse (German)
Seed-Shrimps (English)
Musselkräftors (Swedish)
Mosselkreeftjes (Dutch)
Ma łżoraczki (Polish)
Рак у шковые (Russian)


F. A. Viehberg: Quantitative paleoenvironmental studies using freshwater ostracods in northeast Germany

Table of contents
1. Introduction........................................................................................................................1
1.1. The use of ostracods in quantitative paleoenvironmental studies ....................................... 3
1.2. Main objectives...................................................................................................................... 6
2. Study area..........................................................................................................................7
3. Historical review of ostracod records in Mecklenburg-Vorpommern ........................11
3.1. Checklist of recent and quaternary ostracods (Crustacea) from freshwater, brackish and
marine environments in Mecklenburg-Vorpommern, NE Germany.......................................... 11
4. Material and Methods......................................................................................................39
4.1. A new and easy method for qualitative sampling of meiobenthos-communities ............... 40
5. Paleoenvironmental studies...........................................................................................43
5.1. Paleolimnological study based on ostracods (Crustacea) in late-glacial and Holocene
deposits of Lake Krakower See (Mecklenburg-Vorpommern, NE Germany)........................... 43
5.2. Lateglacial and Holocene ostracod assemblage succession in the southern Baltic Sea
(Germany) .................................................................................................................................. 51
6. Training set......................................................................................................................72
6.1. Freshwater ostracod assemblages and their relationship to environmental variables in
waters from northeast Germany ................................................................................................ 72
7. Summary..........................................................................................................................94
8. Zusammenfassung..........................................................................................................95
9. References.......................................................................................................................96
Appendix ...........................................................................................................................109
A Species...........................................................................................................................109
A 1. Darwinuloidea Brady & Norman, 1889 ........................................................................... 109
A 2. Cypridoidea Baird, 1845.................................................................................................. 109
A 3. Cytheroidea Baird, 1850 ................................................................................................. 113
B Data ...........................................................................................................................115
B 1. Study sites (training set) ................................................................................................. 115
B 2. Training set...................................................................................................................... 117
B 3. Training set (lakes).......................................................................................................... 128
1. Introduction
1. Introduction

Ostracods (Crustacea, Ostracoda) are small bivalved aquatic crustaceans. They are one of
the most diverse groups in the Arthropoda with an excellent fossil record throughout the
entire Phanerozoic (Hinz-Schallreuter & Schallreuter 1999). Their carapace is composed of
two valves, which are hinged dorsally. The single valves are segregated of low-magnesium
(Mg) calcite, which are able to preserve in sediments with non-acidic porewaters. They
inhabit marine, brackish-, and freshwater environments and some species are also described
from semi-terrestrial habitats, inland saline, hot mineral springs, groundwaters, and other
extreme aquatic habitats.
The freshwater ostracods in the present study area are typically 0.5 to 1.5 mm long,
however, some interstitial forms are only 0.2 mm in size, while other species attain 3 mm.
They undergo a postembryonic ontogeny of eight larval stages, each composing a new
carapace, which is discarded during the next moult process. The duration of the whole
lifecycle is species and temperature dependant and lasts between several weeks to a year.
Frequently, it goes along with a stenochrone seasonal phenology of the species.
The present work focuses on extant and subfossil freshwater ostracods. The collected
species of the present work belong to the three podocopid superfamilies, Darwinuloidea
*Brady & Norman, 1889, Cypridoidea Baird, 1845, and Cytheroidea Baird, 1850. Their
representatives are sediment dwellers or fairly good swimmers of the benthos (Figure 1).
They are mainly scavengers or feed on organic detritus, microbial mats, algae and/or aquatic
fungi. Furthermore, some species live in specialized biocoenoses (e.g., pleuston, stygon)
and are well adapted to it.
But despite their potential to colonize a large range of water types, ostracods occur less
frequently in subneutral waters. Moreover, they react sensitive to various other ecological
variables. It is known that salinity, temperature, oxygen saturation, and chemical composition
of the host water influences the occurrence of ostracod species. The composition of ostracod
assemblages are equally influenced by habitat type and stability, water depth and energy
level. The tolerances and especially the preferences of each species are utilized in
environmental studies dealing with ostracods. So, they were successfully applied as indicator
organisms in water and sediment quality assessment (e.g., Namiotko et al. 1993, Mezquita et
al. 1999; Chial et al. 2003).
The knowledge can also be used to reconstruct paleoenvironmental conditions, because
ostracod valves are commonly preserved in Quaternary sediments. It is demonstrated in
various studies that ostracods are valuable indicators for describing changes in lakes
paleohydrology (e.g., Colman et al. 1994, Mourguiart et al. 1998) or trophic status (e.g.,
Scharf 1998). Furthermore, environmental variables are reconstructed, such as temperature
(e.g., Colman et al. 1990; Forester 1991), salinity (e.g., Gell et al. 1994; Boomer et al. 1996),
or ion-composition (e.g., Forester 1991; Smith et al. 1992).
The studies were able to describe distinct changes in the investigated basins, where the
ostracod record mostly co-varies with lithology and other proxy results. Anyway a
quantification of the reconstructed variables is often missing.

* In paleontological literature it is common to use the ending '-acea' for superfamily ranking. The suffix
'-oidea' is used here, according to Article 29 of the International Code of Zoological Nomenclature
(fourth edition, 1999)
-1- 1. Introduction
Geochemical analyses of subfossil ostracod valves focus on trace-element ratio (Sr/Ca and
18 13Mg/Ca) and stable isotope composition ( O and C). Signals in the geochemical record
reflect paleoenvironmental alterations on a more objective level (Holmes & Chivas 2002;
Schwalb 2003) and in some studies it is also possible to quantify the results (e.g., von
Grafenstein et al. 1992). But the knowledge of the ecology of living ostracods is essential to
interpret the geochemical results of the past (De Deckker 2002).
It is the general scope of the present work to refine the indicator ability of freshwater
ostracods and to use their described potential for aspects in Lateglacial and Holocene
paleolimnological research in northeast Germany. An evaluation of the available regional
data from previous paleontological and ecological studies revealed that this group was
already used to some extent in the study area, started already in the middle of the
th19 century (i.e.,