TY  - JOUR
A1  - Perkins, Anita K.
A1  - Ganzert, Lars
A1  - Rojas-Jimenez, Keilor
A1  - Fonvielle, Jeremy Andre
A1  - Hose, Grant C.
A1  - Grossart, Hans-Peter
T1  - Highly diverse fungal communities in carbon-rich aquifers of two contrasting lakes in Northeast Germany
JF  - Fungal ecology
N2  - Fungi are an important component of microbial communities and are well known for their ability to decompose refractory, highly polymeric organic matter. In soils and aquatic systems, fungi play an important role in carbon processing, however, their diversity, community structure and function as well as ecological role, particularly in groundwater, are poorly studied. The aim of this study was to examine the fungal community composition, diversity and function in groundwater from 16 boreholes located in the vicinity of two lakes in NE Germany that are characterized by contrasting trophic status. The analysis of 28S rRNA gene sequences amplified from the groundwater revealed high fungal diversity arid clear differences in community structure between the aquifers. Most sequences were assigned to Ascomycota and Basidiomycota, but members of Chytridiomycota, Cryptomycota, Zygomycota, Blastocladiomycota, Glomeromycota and Neocallimastigomycota were also detected. In addition, 27 species of fungi were successfully isolated from the groundwater samples and tested for their ability to decompose complex organic polymers - the predominant carbon source in the groundwater. Most isolates showed positive activities for at least one of the tested polymer types, with three strains, belonging to the genera Gibberella, Isaria and Cadophora, able to decompose all tested substrates. Our results highlight the high diversity of fungi in groundwater, and point to their important ecological role in breaking down highly polymeric organic matter in these isolated microbial habitats. (C) 2019 Elsevier Ltd and British Mycological Society. All rights reserved.
KW  - Groundwater
KW  - Aquatic fungi
KW  - DOC
KW  - CDOM
KW  - Aquifers
KW  - Humic acids
Y1  - 2019
U6  - https://doi.org/10.1016/j.funeco.2019.04.004
SN  - 1754-5048
SN  - 1878-0083
VL  - 41
SP  - 116
EP  - 125
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Perkins, Anita K.
A1  - Santos, Isaac R.
A1  - Rose, Andrew L.
A1  - Schulz, Kai G.
A1  - Grossart, Hans-Peter
A1  - Eyre, Bradley D.
A1  - Kelaher, Brendan P.
A1  - Oakes, Joanne M.
T1  - Production of dissolved carbon and alkalinity during macroalgal wrack degradation on beaches
BT  - a mesocosm experiment with implications for blue carbon
JF  - Biogeochemistry
N2  - Marine macroalgae are a key primary producer in coastal ecosystems, but are often overlooked in blue carbon inventories. Large quantities of macroalgal detritus deposit on beaches, but the fate of wrack carbon (C) is little understood. If most of the wrack carbon is respired back to CO2, there would be no net carbon sequestration. However, if most of the wrack carbon is converted to bicarbonate (alkalinity) or refractory DOC, wrack deposition would represent net carbon sequestration if at least part of the metabolic products (e.g., reduced Fe and S) are permanently removed (i.e., long-term burial) and the DOC is not remineralised. To investigate the release of macroalgal C via porewater and its potential to contribute to C sequestration (blue carbon), we monitored the degradation of Ecklonia radiata in flow-through mesocosms simulating tidal flushing on sandy beaches. Over 60 days, 81% of added E. radiata organic matter (OM) decomposed. Per 1 mol of detritus C, the degradation produced 0.48 +/- 0.34 mol C of dissolved organic carbon (DOC) (59%) and 0.25 +/- 0.07 mol C of dissolved inorganic carbon (DIC) (31%) in porewater, and a small amount of CO2 (0.3 +/- 0.0 mol C; ca. 3%) which was emitted to the atmosphere. A significant amount of carbonate alkalinity was found in porewater, equating to 33% (0.27 +/- 0.05 mol C) of the total degraded C. The degradation occurred in two phases. In the first phase (days 0-3), 27% of the OM degraded, releasing highly reactive DOC. In the second phase (days 4-60), the labile DOC was converted to DIC. The mechanisms underlying E. radiata degradation were sulphate reduction and ammonification. It is likely that the carbonate alkalinity was primarily produced through sulphate reduction. The formation of carbonate alkalinity and semi-labile or refractory DOC from beach wrack has the potential to play an overlooked role in coastal carbon cycling and contribute to marine carbon sequestration.
KW  - Tidal pumping
KW  - Organic matter degradation
KW  - Carbon cycle
KW  - Mineralisation
KW  - Porewater exchange
KW  - Submarine groundwater discharge
Y1  - 2022
U6  - https://doi.org/10.1007/s10533-022-00946-4
SN  - 0168-2563
SN  - 1573-515X
VL  - 160
IS  - 2
SP  - 159
EP  - 175
PB  - Springer
CY  - Dordrecht
ER  -