Gradients of nutrients, dissolved oxygen and sulfide in wave-protected and unsheltered stands of Phragmites australis

✍ Scribed by Hardy Rolletschek

• Book ID: 102870201
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 714 KB
• Volume: 82
• Category: Article
• ISSN: 1434-2944
• DOI: 10.1002/iroh.19970820305

✦ Synopsis

The horizontal and vertical distribution of TN, TP, TC, and TIC in littoral sediments and O2 and total soluble sulfide (I:S'-) in the overlying water was determined to assess characteristic patterns and the extent of littoral accumulation in Lake Muggelsee. Wave extinction by helophytes allows the formation of deposition zones at the landwater-interface and inside the reed bed. Organogenic sediments (LO1 >60% dm, TP >1.2 mg Plg dm, TN >2% dm) declined non-linear towards open water. Additionally, irregular periods of anaerobiosis and increased I: S'concentrations (1.3 16 big S ' I ) were measured.

Wave breakers, which were built in front of mechanically damaged reed significantly promote littoral accumulation and protect deposition zones from erosion. However, embankment with fagots produces a fine-grained organogenic mud towards open water. These sediments revealed significantly increased 0, consumption rates (610 mg O,h' . d) and steeper gradients of NO;, SO:and CH., indicating intensified anaerobic reduction processes when compared with unsheltered sites. The nutrient gradients differed from those of 'natural' accumulation zones and caused diminished O2 saturation (by 30%) specially in summer months. I: S2concentration was positively correlated to TC content of sediments and temperature and negatively to distance from shore. The annual mean concentration ranged among 10 and 51 pg S ' I and was not affected by wave breakers.