scholarly journals High Temporal and Spatial Variability of Atmospheric-Methane Oxidation in Alpine Glacier Forefield Soils

2017 ◽  
Vol 83 (18) ◽  
Author(s):  
Eleonora Chiri ◽  
Philipp A. Nauer ◽  
Edda-Marie Rainer ◽  
Josef Zeyer ◽  
Martin H. Schroth
Keyword(s):  
Community Structure ◽  
Temporal Variability ◽  
Physical Parameters ◽  
Spatial And Temporal Variability ◽  
Alpine Glacier ◽  
Glacier Forefield ◽  
Methane Oxidizing Bacteria ◽  
Uptake Rates ◽  
Soil Age ◽  
Upland Soils

ABSTRACT Glacier forefield soils can provide a substantial sink for atmospheric CH4, facilitated by aerobic methane-oxidizing bacteria (MOB). However, MOB activity, abundance, and community structure may be affected by soil age, MOB location in different forefield landforms, and temporal fluctuations in soil physical parameters. We assessed the spatial and temporal variability of atmospheric-CH4 oxidation in an Alpine glacier forefield during the snow-free season of 2013. We quantified CH4 flux in soils of increasing age and in different landforms (sandhill, terrace, and floodplain forms) by using soil gas profile and static flux chamber methods. To determine MOB abundance and community structure, we employed pmoA gene-based quantitative PCR and targeted amplicon sequencing. Uptake of CH4 increased in magnitude and decreased in variability with increasing soil age. Sandhill soils exhibited CH4 uptake rates ranging from −3.7 to −0.03 mg CH4 m−2 day−1. Floodplain and terrace soils exhibited lower uptake rates and even intermittent CH4 emissions. Linear mixed-effects models indicated that soil age and landform were the dominating factors shaping CH4 flux, followed by cumulative rainfall (weighted sum ≤4 days prior to sampling). Of 31 MOB operational taxonomic units retrieved, ∼30% were potentially novel, and ∼50% were affiliated with upland soil clusters gamma and alpha. The MOB community structures in floodplain and terrace soils were nearly identical but differed significantly from the highly variable sandhill soil communities. We concluded that soil age and landform modulate the soil CH4 sink strength in glacier forefields and that recent rainfall affects its short-term variability. This should be taken into account when including this environment in future CH4 inventories. IMPORTANCE Oxidation of methane (CH4) in well-drained, “upland” soils is an important mechanism for the removal of this potent greenhouse gas from the atmosphere. It is largely mediated by aerobic, methane-oxidizing bacteria (MOB). Whereas there is abundant information on atmospheric-CH4 oxidation in mature upland soils, little is known about this important function in young, developing soils, such as those found in glacier forefields, where new sediments are continuously exposed to the atmosphere as a result of glacial retreat. In this field-based study, we investigated the spatial and temporal variability of atmospheric-CH4 oxidation and associated MOB communities in Alpine glacier forefield soils, aiming at better understanding the factors that shape the sink for atmospheric CH4 in this young soil ecosystem. This study contributes to the knowledge on the dynamics of atmospheric-CH4 oxidation in developing upland soils and represents a further step toward the inclusion of Alpine glacier forefield soils in global CH4 inventories.

scholarly journals SPATIAL AND TEMPORAL VARIABILITY OF FISH COMMUNITY BIOMASS IN COASTAL WATERS OF TANGERANG REGENCY, BANTEN

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Nina Nurmalia Dewi ◽  
M Mukhlis Kamal ◽  
Yusli Wardiatno
Keyword(s):  
Community Structure ◽  
Resource Management ◽  
Coastal Waters ◽  
Temporal Variability ◽  
Fish Community ◽  
Primary Data ◽  
Spatial And Temporal Variability ◽  
Fish Biomass ◽  
High Current ◽  
Swept Area

<p><em>Coastal waters of Tangerang Regency </em><em>ha</em><em>s abundant</em><em> in</em><em> fish resource includ</em><em>ing</em><em> pelagic, demersal, and reef fish. This study was conducted to assess </em><em>fish </em><em>biomass varia</em><em>bility and</em><em> of fish</em><em> community structure</em><em> in </em><em>c</em><em>oastal waters of Tangerang Regency which can be used as a basis in determining alternatives for sustainable fish resource management. This research was conducted in June and August 2013 in three </em><em>locations i.e.,</em><em> Kronjo, Cituis, and Tanjung Pasir. Primary data collected </em><em>were </em><em>fish </em><em>weight </em><em>per species. Fish biomass from each locations </em><em>was</em><em> obtained using swept area method</em><em> </em><em>using </em><em>trawl. The results showed that Kronjo </em><em>region contained</em><em> </em><em>the </em><em>highe</em><em>st</em><em> total </em><em>average </em><em>biomass of fish</em><em>.</em><em> </em><em>T</em><em>emporal</em><em>ly</em><em>, total </em><em>ave-rage </em><em>biomass</em><em> </em><em>of fish </em><em>i</em><em>n August was higher than </em><em>in </em><em>June for Kronjo and Cituis</em><em>. M</em><em>eanwhile</em><em>, the con-trary</em><em> </em><em>occurred in</em><em> Tanjung Pasir</em>.<em> This </em><em>conditions occurred </em><em>due to the high current and </em><em>high </em><em>wave in August than </em><em>in </em><em>June. </em><em>In general, b</em><em>iomass of planktivorous was dominant during the study indicating overfishing lead to fishing down the food web in the Coastal waters of Tangerang Regency.</em></p><p><em> </em><strong><em>Keywords: </em></strong><em>biomass, coastal waters of Tangerang Regency, spatial and temporal variability, </em><em>swept area, over fishing.</em></p>

scholarly journals Modeling characterization of the vertical and temporal variability of environmental DNA in the mesopelagic ocean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elizabeth Andruszkiewicz Allan ◽  
Michelle H. DiBenedetto ◽  
Andone C. Lavery ◽  
Annette F. Govindarajan ◽  
Weifeng G. Zhang
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Temporal Variability ◽  
Mechanistic Model ◽  
Temporal Distribution ◽  
Environmental Dna ◽  
Vertical Displacement ◽  
Physical Parameters ◽  
Spatial And Temporal Variability ◽  
The Impact

AbstractIncreasingly, researchers are using innovative methods to census marine life, including identification of environmental DNA (eDNA) left behind by organisms in the water column. However, little is understood about how eDNA is distributed in the ocean, given that organisms are mobile and that physical and biological processes can transport eDNA after release from a host. Particularly in the vast mesopelagic ocean where many species vertically migrate hundreds of meters diurnally, it is important to link the location at which eDNA was shed by a host organism to the location at which eDNA was collected in a water sample. Here, we present a one-dimensional mechanistic model to simulate the eDNA vertical distribution after its release and to compare the impact of key biological and physical parameters on the eDNA vertical and temporal distribution. The modeled vertical eDNA profiles allow us to quantify spatial and temporal variability in eDNA concentration and to identify the most important parameters to consider when interpreting eDNA signals. We find that the vertical displacement by advection, dispersion, and settling has limited influence on the eDNA distribution, and the depth at which eDNA is found is generally within tens of meters of the depth at which the eDNA was originally shed from the organism. Thus, using information about representative vertical migration patterns, eDNA concentration variability can be used to answer ecological questions about migrating organisms such as what depths species can be found in the daytime and nighttime and what percentage of individuals within a species diurnally migrate. These findings are critical both to advance the understanding of the vertical distribution of eDNA in the water column and to link eDNA detection to organism presence in the mesopelagic ocean as well as other aquatic environments.

scholarly journals The Influences of Nutrients and Snow on the Spatial and Temporal Variability of Sea Ice Algae

2021 ◽  
Author(s):  
◽  
Francisca A.H. Vermeulen
Keyword(s):  
Community Structure ◽  
Southern Ocean ◽  
Sea Ice ◽  
Temporal Variability ◽  
Ross Sea ◽  
Pulse Amplitude ◽  
Integrated Approach ◽  
Algal Community ◽  
Spatial And Temporal Variability ◽  
Algal Groups

<p>Polar marine regions are dominated by sea ice, where large gradients in temperature, salinity, nutrients and light occur. Despite this, a rich community exists within the sea ice, consisting of prokaryotic organisms, several algal groups and small zooplankton. Prokaryotes are present in the largest abundance in the sea ice; however, diatoms dominate in biomass. Diatoms are the main primary producers within the ice and they form a vital food source for many organisms. However, factors determining species composition, abundance, spatial and temporal variability and nutrient requirement are relatively poorly understood. In order to increase understanding of these processes, an integrated approach was used in this thesis to provide an insight into the potential changes to the ecology of the Southern Ocean in relation to predicted climate change. In this thesis, I studied ice algal community structure, diversity and nutrient requirements at several locations in the sea ice of the Ross Sea, Antarctica. Though many previous studies have focussed on these organisms, this is the first study to I) integrate recent and historical data collected over 30 years and to compare spatial and temporal differences in sea ice communities, II) use the near real time nutrient induced fluorescence transient (NIFT) method to study nutrient limitation in sea ice and further develop this method for use with the imaging pulse amplitude modulator (I-PAM), III) show that Antarctic diatoms may be more susceptible to silica limitation than previously thought, despite the fact that the silica concentration in the Southern Ocean are relatively high. Results from these studies provide important new information on community structure and how it is influenced by and responds to the environment ...</p>

scholarly journals The Influences of Nutrients and Snow on the Spatial and Temporal Variability of Sea Ice Algae

2021 ◽  
Author(s):  
◽  
Francisca A.H. Vermeulen
Keyword(s):  
Community Structure ◽  
Southern Ocean ◽  
Sea Ice ◽  
Temporal Variability ◽  
Ross Sea ◽  
Pulse Amplitude ◽  
Integrated Approach ◽  
Algal Community ◽  
Spatial And Temporal Variability ◽  
Algal Groups

<p>Polar marine regions are dominated by sea ice, where large gradients in temperature, salinity, nutrients and light occur. Despite this, a rich community exists within the sea ice, consisting of prokaryotic organisms, several algal groups and small zooplankton. Prokaryotes are present in the largest abundance in the sea ice; however, diatoms dominate in biomass. Diatoms are the main primary producers within the ice and they form a vital food source for many organisms. However, factors determining species composition, abundance, spatial and temporal variability and nutrient requirement are relatively poorly understood. In order to increase understanding of these processes, an integrated approach was used in this thesis to provide an insight into the potential changes to the ecology of the Southern Ocean in relation to predicted climate change. In this thesis, I studied ice algal community structure, diversity and nutrient requirements at several locations in the sea ice of the Ross Sea, Antarctica. Though many previous studies have focussed on these organisms, this is the first study to I) integrate recent and historical data collected over 30 years and to compare spatial and temporal differences in sea ice communities, II) use the near real time nutrient induced fluorescence transient (NIFT) method to study nutrient limitation in sea ice and further develop this method for use with the imaging pulse amplitude modulator (I-PAM), III) show that Antarctic diatoms may be more susceptible to silica limitation than previously thought, despite the fact that the silica concentration in the Southern Ocean are relatively high. Results from these studies provide important new information on community structure and how it is influenced by and responds to the environment ...</p>

Long-term trends in fish community composition across coastal bays and lakes in the Lavaca–Colorado Estuary

2016 ◽  
Vol 94 (12) ◽  
pp. 871-884 ◽  
Author(s):  
Philip Matich ◽  
William B. Godwin ◽  
Mark Fisher
Keyword(s):  
Community Structure ◽  
Community Composition ◽  
Temporal Variability ◽  
Human Impacts ◽  
Fish Communities ◽  
Spatial And Temporal Variability ◽  
Important Species ◽  
Coastal Bays ◽  
Long Term Trends

Human impacts continue to alter community structure, emphasizing the need to understand how spatial and temporal variability in disturbance and conservation affect ecological communities to optimize management strategies. Here, we quantify fish species richness, diversity, and community structure across five coastal bays and lakes in the Lavaca–Colorado Estuary, Texas, over 30 years to investigate spatial and temporal variability in species assemblages, and the potential effects of resource management. Results suggest that fish communities varied both spatially and temporally from 1976 to 2008, with greater temporal shifts in habitats more proximate to the Gulf of Mexico and removed from human residential areas — diversity increased in Powderhorn Lake and spotted seatrout (Cynoscion nebulosus (Cuvier, 1830)) and red drum (Sciaenops ocellatus (L., 1766)) abundances increased in Oyster Lake following changes in fishing regulations. Natural fluctuations in environmental conditions coupled with limited access to lakes by geographic restraints may have led to more pronounced changes in community structure. However, the effects of fishing management on fish communities within small lakes and bays within the Lavaca–Colorado Estuary is likely habitat- and context-specific, and continued monitoring, especially among ecologically and economically important species, will provide insight into how environmental change and anthropogenic disturbance may affect long-term trends in coastal community composition.

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