Phytoplankton succession and the formation of a deep chlorophyll maximum in a hypertrophic volcanic lake

作者：Simmonds Bernard^*; Wood Susanna A; Oezkundakci Deniz; Hamilton David P

来源：Hydrobiologia, 2015, 745(1): 297-312.

DOI：10.1007/s10750-014-2114-z

• Deep chlorophyll maximum
• Cyanobacteria
• Dinoflagellates
• Eutrophication
• Succession

Deep chlorophyll maxima (DCM) are a common feature of poorly mixed, low-productivity lakes, but are less commonly observed in eutrophic systems. This study investigates the transition from a late-spring surface chlorophyll maximum (SCM) to an early summer DCM in a hypertrophic lake, identifying the phenology and mechanisms responsible for the transition and how the DCM was maintained in this hypertrophic system. Data and samples were collected weekly during summer and monthly in winter at five sampling stations in monomictic Lake AOEkaro, North Island, New Zealand. Additional samples were collected on two occasions at c. 3-5 h intervals over 24 h at a single station, corresponding to periods with a SCM and DCM, respectively. The mean DCM depth was correlated with mean thermocline depth, and euphotic depth (z (eu)) continuously exceeded the depths of both the DCM and thermocline. The decline in the SCM and the transition to a DCM population were coincident with a gradual depletion of dissolved inorganic nutrients in surface waters and increased light penetration into the nutrient-rich hypolimnion. This study demonstrated that there are similarities between DCMs in lakes of high and low productivity, relating to the interplay between light, nutrients and thermal stratification.

• 出版日期2015-2