scholarly journals Effects of water-column enrichment on the production dynamics of three seagrass species and their epiphytic algae

1999 ◽  
Vol 179 ◽  
pp. 201-213 ◽  
Author(s):  
DJ Wear ◽  
MJ Sullivan ◽  
AD Moore ◽  
DF Millie
Keyword(s):  
Water Column ◽  
Seagrass Species ◽  
Epiphytic Algae ◽  
Production Dynamics

scholarly journals Water quality, isoscapes and stoichioscapes of seagrasses indicate general P limitation and unique N cycling in shallow water benthos of Bermuda

2015 ◽  
Vol 12 (20) ◽  
pp. 6235-6249 ◽  
Author(s):  
J. W. Fourqurean ◽  
S. A. Manuel ◽  
K. A. Coates ◽  
W. J. Kenworthy ◽  
J. N. Boyer
Keyword(s):  
Water Column ◽  
Spatial Patterns ◽  
Animal Movement ◽  
P Availability ◽  
Seagrass Species ◽  
Δ13c And Δ15n ◽  
Elemental Ratios ◽  
Syringodium Filiforme ◽  
P Limitation ◽  
Near Shore

Abstract. Striking spatial patterns in stable isotope ratios (isoscapes) and elemental ratios (stoichioscapes) of seagrass leaves and the water column nutrients indicate general P-limitation of both water column and benthic primary productivity on the Bermuda Platform, and they highlight the role of the Bermuda Islands as a source of N and P. We found consistent differences among the four seagrass species (Syringodium filiforme, Thalassia testudinum, Halodule sp. and Halophila decipiens) in the N, P, δ13C and δ15N of leaf tissues. The δ15N of seagrass leaves was especially variable, with values from −10.1 to 8.8 ‰, greatly expanding the reported range of values for all seagrass species globally. Spatial patterns from both the water column and the seagrass leaves indicated that P availability was higher near shore, and δ15N values suggest this was likely a result of human waste disposal. Spatially contiguous areas of extremely depleted seagrass 15N suggest unique N sources and cycling compared to other seagrass-dominated environments. Seagrass N : P values were not as far from the stoichiometric balance between N and P availability as in the water column, and there were no strong relationships between the water column N : P and the seagrass N : P. Such isoscapes and stoichioscapes provide valuable ecogeochemical tools to infer ecosystem processes as well as provide information that can inform food web and animal movement studies.

scholarly journals The Biomass and Physiological Responses of Vallisneria natans (Lour.) Hara to Epiphytic Algae and Different Nitrate-N Concentrations in the Water Column

Water ◽  
2017 ◽  
Vol 9 (11) ◽  
pp. 863 ◽  
Author(s):  
Fenli Min ◽  
Jincheng Zuo ◽  
Yi Zhang ◽  
Qingwei Lin ◽  
Biyun Liu ◽  
...  
Keyword(s):  
Water Column ◽  
Physiological Responses ◽  
Epiphytic Algae ◽  
Nitrate N ◽  
Vallisneria Natans

Seasonal production regimes off south-western Australia: influence of the Capes and Leeuwin Currents on phytoplankton dynamics

2005 ◽  
Vol 56 (7) ◽  
pp. 1011 ◽  
Author(s):  
Christine E. Hanson ◽  
Charitha B. Pattiaratchi ◽  
Anya M. Waite
Keyword(s):  
Water Column ◽  
Western Australia ◽  
Light Attenuation ◽  
Light Limitation ◽  
Early Winter ◽  
Leeuwin Current ◽  
Winter Conditions ◽  
Stable Isotope Signatures ◽  
Near Shore ◽  
Production Dynamics

Temporal primary production dynamics were investigated off south-western Australia, where the summer upwelling regime of the Capes Current was compared with early winter conditions characterised by strengthened near-shore Leeuwin Current flow. Seasonal upwelling in this region sourced nitrate levels of ≥1 μm from the nutricline at the base of the Leeuwin Current’s mixed layer, with total water column production reaching a maximum of ~950 mg C m−2 day−1 in the Capes Current. Stable isotope signatures of particulate matter indicated that productivity off south-western Australia was heavily reliant on nitrate as a nitrogen source, with mean δ15N ranging from ~4 to 5 ‰ under both upwelling and non-upwelling (winter) conditions. Unexpectedly, significant nutrient enrichment within the Leeuwin Current (up to 3.1 μm nitrate) occurred during winter, likely as a result of the meandering Leeuwin Current flooding the inner shelf north of the study area and entraining relatively high-nutrient shelf waters in its southwards flow. However, early winter production under these nutrient-replete conditions (mean ± s.d. 310 ± 105 mg C m−2 day−1) was significantly lower than in summer (695 ± 140 mg C m−2 day−1) due to light limitation, both as a result of reduced surface irradiance characteristic of the winter months and significantly higher light attenuation within the water column as compared with summer conditions.

scholarly journals Water quality, isoscapes and stoichioscapes of seagrasses indicate general P limitation and unique N cycling in shallow water benthos of Bermuda

2015 ◽  
Vol 12 (13) ◽  
pp. 9751-9791 ◽  
Author(s):  
J. W. Fourqurean ◽  
S. A. Manuel ◽  
K. A. Coates ◽  
W. J. Kenworthy ◽  
J. N. Boyer
Keyword(s):  
Water Column ◽  
Spatial Patterns ◽  
Animal Movement ◽  
P Availability ◽  
Seagrass Species ◽  
Δ13c And Δ15n ◽  
Elemental Ratios ◽  
Syringodium Filiforme ◽  
P Limitation ◽  
Near Shore

Abstract. Striking spatial patterns in stable isotope ratios (isoscapes) and elemental ratios (stoichioscapes) of seagrass leaves and the water column nutrients indicate general P-limitation of both water column and benthic primary productivity on the Bermuda Platform, and they highlight the role of the Bermuda Islands as a source of N and P. We found consistent differences among the four seagrass species (Syringodium filiforme, Thalassia testudinum, Halodule sp. and Halophila decipiens) in the N, P, δ13C and δ15N of leaf tissues. The δ15N of seagrass leaves was especially variable, with values from −10.1 to 8.8‰, greatly expanding the reported range of values for all seagrass species globally. Spatial patterns from both the water column and the seagrass leaves indicated that P availability was higher near shore, and δ15N values suggest this was likely a result of human waste disposal. Spatially-contiguous areas of extremely depleted seagrass δ15N suggest unique N sources and cycling compared to other seagrass-dominated environments. Seagrass N : P values were not as far from the stoichiometric balance between N and P availability as in the water column, and there were no strong relationships between the water column N : P and the seagrass N : P. Such isoscapes and stoichioscapes provide valuable ecogeochemical tools to infer ecosystem processes as well as provide information that can inform food web and animal movement studies.

scholarly journals Seagrass Ecosystems of India as Bioindicators of Trace Elements

2020 ◽  
Author(s):  
Amrit Kumar Mishra ◽  
Rajalaxmi Sahoo ◽  
Saumya Samantaray ◽  
Deepak Apte
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Water Column ◽  
Tamil Nadu ◽  
Gulf Of Mannar ◽  
Seagrass Species ◽  
High Concentration ◽  
Palk Bay ◽  
Trace Element Contamination ◽  
Lakshadweep Islands

Seagrasses are considered as efficient bioindicators of coastal trace element contamination. This chapter provides an overview on the trace element accumulation, tolerance and biomonitoring capacity of the various seagrass species distributed along the coast of India. A total of 10 trace elements are reported in seagrasses, 11 in sediment and nine in the water column from India. From the 11 seagrass species studied, 60% of research have focused on Syringodium isoetifolium, Cymodocea serrulata, Cymodocea rotundata and Halophila ovalis. 78% of seagrass trace element research in India is from Palk bay and Gulf of Mannar (GOM), Tamil Nadu and 16% from Lakshadweep Islands. Out of the 10 trace elements, Cd, Cu, Pb and Zn are the most studied in seagrass, Fe, Mn, Ni and Pb in sediment and Cu, Fe, Mg, Ni and Zn in the water column. Accumulation capacity of various trace elements in seagrass were species-specific. S. isoetifolium have the highest concentration of Cd and Mg at Palk bay and Lakshadweep Islands respectively. The concentration of Cu was higher in C. serrulata at GOM. Halodule uninervis and Halophila decipens have the highest concentration of Co, and Cr, Ni, Pb and Zn from Lakshadweep Islands. The highest concentration of Fe and Mn were highest in Halophila beccarii and H. ovalis from the coast of Goa and Palk bay respectively. Threshold levels (>10 mg L-1) of Cd, Cu, Pb and Zn were observed for C. serrulata, H. ovalis, H. uninervis and T. hemprichii, that can affect the Photo System -II of these seagrasses and exert cellular stress leading to seagrass loss and die-off. High concentration of these elements can exert negative impacts on seagrass associated trophic assemblages and ecosystem functioning. Seagrasses of India can be utilized as bioindicators of coastal trace element contamination but the associated toxicity and human health risks needs further investigation.

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