scholarly journals Trophic state of sediments from two deep continental margins off Iberia: a biomimetic approach

2012 ◽  
Vol 9 (12) ◽  
pp. 17619-17650 ◽  
Author(s):  
A. Dell'Anno ◽  
A. Pusceddu ◽  
C. Corinaldesi ◽  
M. Canals ◽  
S. Heussner ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Depth ◽  
Surface Waters ◽  
Deep Sea ◽  
Nutritional Value ◽  
Trophic State ◽  
Continental Margins ◽  
Organic Detritus ◽  
Deep Sea Sediments ◽  
Biomimetic Approach

Abstract. The trophic state of benthic deep-sea ecosystems can greatly influence key ecological processes (e.g. biomass production and nutrient cycling). Thus, assessing the trophic state of the sediment at different spatial and temporal scales is crucial for a better understanding of deep-sea ecosystem functioning. Here, using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools, we assess the bioavailability of organic detritus and its nutritional value in the uppermost layer of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in primary productivity of surface waters reported for the two regions. Similarly, sediments of the Catalan margin were characterized by significantly higher food quantity and quality in spring, when higher primary production processes occur in surface waters, than in summer and autumn. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Differences in the benthic trophic state of canyons against open slopes were more evident in the Portuguese than in the Catalan margin. Overall our findings indicate that deep-sea sediments are characterized by relatively high amounts of bioavailable organic matter. We suggest that the interactions between biological-related processes in surface waters and particle transport and deposition dynamics can play a crucial role in shaping the quantity and distribution of bioavailable organic detritus and its nutritional value along deep continental margins.

scholarly journals Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

2013 ◽  
Vol 10 (5) ◽  
pp. 2945-2957 ◽  
Author(s):  
A. Dell'Anno ◽  
A. Pusceddu ◽  
C. Corinaldesi ◽  
M. Canals ◽  
S. Heussner ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Depth ◽  
Surface Waters ◽  
Deep Sea ◽  
Nutritional Value ◽  
Trophic State ◽  
Phytoplankton Bloom ◽  
Continental Margins ◽  
Organic C ◽  
Deep Sea Sediments

Abstract. The bioavailability of organic matter in benthic deep-sea ecosystems, commonly used to define their trophic state, can greatly influence key ecological processes such as biomass production and nutrient cycling. Here, we assess the trophic state of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively, by using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Two out of the three sampling periods occurred a few months after dense shelf water cascading events. The benthic deep-sea ecosystems investigated in this study were characterized by high amounts of bioavailable organic matter when compared to other deep-sea sediments. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in primary productivity of surface waters reported for the two regions. Similarly, sediments of the Catalan margin were characterized by significantly higher food quantity and quality in spring, when the phytoplankton bloom occurs in surface waters, than in summer and autumn. Differences in the benthic trophic state of canyons against open slopes were more evident in the Portuguese than in the Catalan margin. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Overall, our findings suggest that the intensity of primary production processes along with the lateral transfer of organic particles, even amplified by episodic events, can have a role in controlling the quantity and distribution of bioavailable organic detritus and its nutritional value along these continental margin ecosystems.

Regional study of microplastics in surface waters and deep sea sediments south of the Algarve Coast

2020 ◽  
Vol 40 ◽  
pp. 101488
Author(s):  
Simone Lechthaler ◽  
Jan Schwarzbauer ◽  
Klaus Reicherter ◽  
Georg Stauch ◽  
Holger Schüttrumpf
Keyword(s):  
Surface Waters ◽  
Deep Sea ◽  
Regional Study ◽  
Deep Sea Sediments

Two new species of Paramphimonhystrella (Nematoda, Monhysterida, Xyalidae) from the deep-sea sediments in the Western Pacific Ocean and adjacent shelf seafloor

Zootaxa ◽  
2017 ◽  
Vol 4344 (2) ◽  
pp. 308
Author(s):  
BENZE SHI ◽  
TINGTING YU ◽  
KUIDONG XU
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Water Depth ◽  
Deep Sea ◽  
Western Pacific ◽  
Valid Species ◽  
Western Pacific Ocean ◽  
Dichotomous Key ◽  
Two New Species ◽  
Deep Sea Sediments

Two new species of marine nematodes, Paramphimonhystrella longispicula sp. n. in the deep-sea sediments from the Philippine Sea in the tropical Western Pacific Ocean with the water depth of 3920–5176 m and P. eurystoma sp. n. in the shelf seafloor from the East China Sea with the water depth of 55–64 m, are described. Both species possess long and slender spicules, which are present only in the congener P. barbula, a species discovered from the continental slope of New Zealand. Paramphimonhystrella longispicula sp. n. can be easily distinguished from P. barbula by the relatively broader buccal cavity, the unequally long cervical setae and a higher number of terminal setae. Paramphimonhystrella eurystoma sp. n. is unique in having a peculiar gubernaculum with two proximal capitula and a peculiar hammer-shaped cuticularized piece posterior to vulva, by which it can be distinguished from P. longispicula sp. n. and P. barbula as well as other congeners. Paramphimonhystrella longispicula sp. n. differs from P. eurystoma sp. n. also by the number of terminal setae (4 vs. 2). A dichotomous key to nine valid species of Paramphimonhystrella is provided. 

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