scholarly journals Biogeochemical processes in permeable estuarine sediments following benthic community change: implications for system dynamics & Lyngbya majuscula blooms in Deception Bay, Queensland

2015 ◽  
Author(s):  
Peter Hanington
Keyword(s):  
System Dynamics ◽  
Benthic Community ◽  
Community Change ◽  
Estuarine Sediments ◽  
Biogeochemical Processes ◽  
Lyngbya Majuscula

The potential of benthic iron and phosphorus fluxes to support the growth of a bloom forming toxic cyanobacterium Lyngbya majuscula, Moreton Bay, Australia

2016 ◽  
Vol 67 (12) ◽  
pp. 1918 ◽  
Author(s):  
Peter Hanington ◽  
Andrew Rose ◽  
Ron Johnstone
Keyword(s):  
Water Column ◽  
Benthic Community ◽  
Sediment Cores ◽  
Community Change ◽  
Flood Event ◽  
Nutrient Fluxes ◽  
Marine Cyanobacterium ◽  
Lyngbya Majuscula ◽  
Moreton Bay ◽  
Sandy Sediments

Lyngbya majuscula is a bloom-forming toxic marine cyanobacterium. Most research on L. majuscula growth in Moreton Bay has focussed on water column supplies of iron and phosphorus with little consideration of benthic sources and supply. This study investigates the potential for sandy sediments in a shallow, well mixed subtropical embayment (Deception Bay, Moreton Bay, Australia) to supply iron and phosphorus for L. majuscula growth after significant benthic community change following a major flood event. Measurements of benthic oxygen, iron and nutrient fluxes were obtained by incubating intact sediment cores sampled from Deception Bay. Results suggest that post-flood sediment communities are capable of supplying >1300% of daily L. majuscula Fe requirements and up to 9.2% of daily P demands, suggesting that L. majuscula growth in Deception Bay is likely to be P limited. The benthic release of PO43– and FeII only occurred after water column DO became depleted below 3mgL–1. This study suggests that the benthic release of PO43– and FeII could support the initiation and growth of L. majuscula blooms in Deception Bay.

scholarly journals 40 Years of benthic community change on the Caribbean reefs of Curaçao and Bonaire: the rise of slimy cyanobacterial mats

Coral Reefs ◽  
2017 ◽  
Vol 36 (2) ◽  
pp. 355-367 ◽  
Author(s):  
Didier M. de Bakker ◽  
Fleur C. van Duyl ◽  
Rolf P. M. Bak ◽  
Maggy M. Nugues ◽  
Gerard Nieuwland ◽  
...  
Keyword(s):  
Benthic Community ◽  
Community Change ◽  
Cyanobacterial Mats ◽  
The Caribbean

Effects of Lyngbya majuscula (Cyanophycea) blooms on sediment nutrients and meiofaunal assemblages in seagrass beds in Moreton Bay, Australia

2006 ◽  
Vol 57 (2) ◽  
pp. 155 ◽  
Author(s):  
Rosa García ◽  
Ron W. Johnstone
Keyword(s):  
Depth Distribution ◽  
East Coast ◽  
Oxygen Depletion ◽  
Seagrass Beds ◽  
Biogeochemical Processes ◽  
Sediment Depth ◽  
Lyngbya Majuscula ◽  
Moreton Bay ◽  
Bloom Period ◽  
Abundance And Distribution

Blooms of Lyngbya majuscula have been increasingly recorded in the waters of Moreton Bay, on the south-east coast of Queensland, Australia. The influences of these blooms on sediment infauna and the implications for sediment biogeochemical processes was studied. Sediment samples were taken from Moreton Bay banks during and after the bloom season. The deposition of L. majuscula seems to be responsible for the higher total Kjedahl nitrogen (TKN) concentrations measured during the bloom period. Total organic carbon (TOC) concentrations did not change. Lyngbya majuscula blooms had a marked influence on the meiobenthos. Nematodes, copepods and polychaetes were the most abundant groups of meiofauna, and the bloom produced a decrease in the abundance and a change in the sediment depth distribution of these organisms. The distribution of nematodes, copepods and polychaetes in sediment became shallower. Further, the bloom did not affect the abundance and distribution of polychaetes as strongly as it did copepods and nematodes. The changes observed in the distribution of meiofauna in the sediment during the bloom period indicate that L. majuscula produces oxygen depletion in sediments, and that different fauna seem to be affected to different degrees.

Investigation of benthic community change over a century-wide scale in the western English Channel

2009 ◽  
Vol 90 (6) ◽  
pp. 1161-1172 ◽  
Author(s):  
E. Capasso ◽  
S.R. Jenkins ◽  
M. Frost ◽  
H. Hinz
Keyword(s):  
Benthic Community ◽  
Sea Urchins ◽  
Anthropogenic Activities ◽  
Community Analysis ◽  
Community Change ◽  
Large Species ◽  
English Channel ◽  
Benthic Environment ◽  
Marthasterias Glacialis ◽  
The Impact

Since the early part of the 20th Century the impact of a range of anthropogenic activities in our coastal seas has steadily increased. The effect of such activities is a major cause for concern but in the benthic environment few studies exist that date back more than a few decades. Hence understanding long term changes is a challenge. Within this study we utilized a historic benthic dataset and resurveyed an area west of Eddystone reef in the English Channel previously investigated 112 years ago. The aim of the present work was to describe the current benthic community structure and investigate potential differences between 1895 and 2007. For each of the four major phyla investigated (Polychaeta, Crustacea, Mollusca and Echinodermata), multivariate community analysis showed significant differences between the historic and contemporary surveys. Echinoderm diversity showed a clear reduction between 1895 and 2007. The sea urchins Echinus esculentus, Spatangus purpureus, and Psammechinus miliaris and large star-fish Marthasterias glacialis showed reductions in abundance, in some cases being entirely absent from the survey area in 2007. Polychaetes showed a shift from tubiculous species to small errant and predatory species such as Glycera, Nephtys, and Lumbrineris spp. Within the group Mollusca large species such as Pecten maximus and Laevicardium crassum decreased in abundance while small species increased. Crustaceans in 1895 were dominated by crab species which were present in similar abundances in 2007, but, the order Amphipoda appeared to show a significant increase. While some of the differences observed could stem from differences in methodologies between the surveys, in particular increases of small cryptic species, the loss of large conspicuous species was judged to be genuine. The study area is an important beam trawling and scallop dredging ground; the differences observed are concomitant with changes generally associated with disturbance from demersal fishing activities such as these.

scholarly journals The Interplay of Macrofauna Functional Groups Shapes Nitrogen Cycling in Oligotrophic Estuarine Sediments

2021 ◽  
Author(s):  
Mindaugas Zilius ◽  
Darius Daunys ◽  
Marco Bartoli ◽  
Ugo Marzocchi ◽  
Stefano Bonaglia ◽  
...  
Keyword(s):  
Functional Groups ◽  
N Cycling ◽  
Interactive Effects ◽  
Estuarine Sediments ◽  
Biogeochemical Processes ◽  
N Transformations ◽  
Benthic Metabolism ◽  
Solute Fluxes ◽  
The Baltic ◽  
Local Dominance

Abstract The effects of single macrofauna species on benthic nitrogen (N) cycling has been extensively studied, whereas the effect of macrofauna communities on N-related processes remains poorly explored. In this study, we characterized benthic N-cycling in bioturbated sediments of an oligotrophic northern Baltic waters (Öre estuary). Solute fluxes and N transformations (N2 fixation, denitrification and DNRA) were measured in sediments and in macrofauna-bacteria holobionts to partition the role of three dominant macrofauna taxa (Limnecola balthica, Marenzelleria sp. and Monoporeia affinis) in shaping N-cycling, and to disentangle the contribution of different functional groups within the community. In the studied area, benthic macrofauna comprised a low diversity community with extremely high local dominance of three macrofauna taxa, which are widespread and dominant in the Baltic. The biomass of these three taxa in the benthic community explained up to 30% of variation in measured biogeochemical processes, confirming their role in ecosystem functioning. The results also show that these taxa significantly contributed to the benthic metabolism and N-cycling (direct effect) as well as reworked sediments with positive feedback to dissimilative nitrate reduction (indirect effect). Taken together, these functions promoted a re-use of nutrient at the benthic level, limiting net losses (e.g. denitrification) and effluxes to bottom water. Finally, the detection of multiple N transformations in dominating macrofauna holobionts suggested a community-associated active and versatile microbiome, which alternatively contributes to the biogeochemical processes. The present study highlights hidden and interactive effects among microbes and macrofauna, which should be considered in analysing benthic functioning.

Intertidal clam harvesting: benthic community change and recovery

1998 ◽  
Vol 29 (6) ◽  
pp. 429-437 ◽  
Author(s):  
B E Spencer ◽  
M J Kaiser ◽  
D B Edwards
Keyword(s):  
Benthic Community ◽  
Community Change
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