Contribution of benthic microalgae to ice covered coastal ecosystems in northern Hokkaido, Japan

2005 ◽  
Vol 85 (2) ◽  
pp. 283-289 ◽  
Author(s):  
A. McMinn ◽  
T. Hirawake ◽  
T. Hamaoka ◽  
H. Hattori ◽  
M. Fukuchi
Keyword(s):  
Primary Production ◽  
Photosynthetic Activity ◽  
Benthic Communities ◽  
Pulse Amplitude ◽  
Benthic Microalgae ◽  
Pulse Amplitude Modulation ◽  
Ice Algae ◽  
Pam Fluorometry ◽  
Sea Ice Algae ◽  
Shallow Seas

Benthic microalgal communities usually make a major contribution to the primary production of estuaries and shallow seas. Pulse amplitude modulation (PAM) fluorometry was used to investigate the contribution of benthic microalgae to the primary production of the Okhotsk Sea coast and Saroma Ko Lagoon in northern Hokkaido. In general the benthic communities had a relatively high biomass but low photosynthetic activity. This led to estimates of 29·2% and 64·5% for the benthic contributions for the 9 m and 3 m depth sites at Mombetsu and 13·1% for Saroma Ko. Sea ice algae provided the greatest contribution at Saroma Ko.

scholarly journals Depth alone is an inappropriate proxy for physiological change in the mesophotic coralAgaricia lamarcki

2019 ◽  
Vol 99 (7) ◽  
pp. 1535-1546 ◽  
Author(s):  
Jack H. Laverick ◽  
Tamara K. Green ◽  
Heidi L. Burdett ◽  
Jason Newton ◽  
Alex D. Rogers
Keyword(s):  
Photosynthetic Activity ◽  
Single Species ◽  
Pulse Amplitude ◽  
Pulse Amplitude Modulation ◽  
Depth Range ◽  
Site Variation ◽  
Depth Ranges ◽  
Response To Environmental Change ◽  
Pulse Amplitude Modulation Fluorometry ◽  
Isotope Analyses

AbstractThe physiology of mesophotic Scleractinia varies with depth in response to environmental change. Previous research has documented trends in heterotrophy and photosynthesis with depth, but has not addressed between-site variation for a single species. Environmental differences between sites at a local scale and heterogeneous microhabitats, because of irradiance and food availability, are likely important factors when explaining the occurrence and physiology of Scleractinia. Here, 108 colonies ofAgaricia lamarckiwere sampled from two locations off the coast of Utila, Honduras, distributed evenly down the observed 50 m depth range of the species. We found that depth alone was not sufficient to fully explain physiological variation. Pulse Amplitude-Modulation fluorometry and stable isotope analyses revealed that trends in photochemical and heterotrophic activity with depth varied markedly between sites. Our isotope analyses do not support an obligate link between photosynthetic activity and heterotrophic subsidy with increasing depth. We found thatA. lamarckicolonies at the bottom of the species depth range can be physiologically similar to those nearer the surface. As a potential explanation, we hypothesize sites with high topographical complexity, and therefore varied microhabitats, may provide more physiological niches distributed across a larger depth range. Varied microhabitats with depth may reduce the dominance of depth as a physiological determinant. Thus,A. lamarckimay ‘avoid’ changes in environment with depth, by instead existing in a subset of favourable niches. Our observations correlate with site-specific depth ranges, advocating for linking physiology and abiotic profiles when defining the distribution of mesophotic taxa.

Primary Production and Respiration in Pelagic and Benthic Communities at Two Intertidal Sites in the Upper Bay of Fundy

1983 ◽  
Vol 40 (S1) ◽  
pp. s229-s243 ◽  
Author(s):  
B. T. Hargrave ◽  
N. J. Prouse ◽  
G. A. Phillips ◽  
P. A. Neame
Keyword(s):  
Primary Production ◽  
Benthic Communities ◽  
Late Summer ◽  
Benthic Microalgae ◽  
Phytoplankton Production ◽  
Bay Of Fundy ◽  
Intertidal Sediments ◽  
Benthic Primary Production ◽  
Benthic Respiration ◽  
Undisturbed Sediments

Primary production by microalgae on intertidal sediments during ebb tide at two sites in Cumberland and Minas Basin, Bay of Fundy, amounted to 47–83 g C∙m−2∙yr−1 Phytoplankton production measured during flood tide over intertidal sediments in Cumberland Basin varied from 4–10 g C∙m−2∙yr−1 with respiration in the water column between 6 and 12 g∙C∙m−2∙yr−1 depending on concentrations of suspended matter. Respiration by undisturbed sediments (47–62 g C∙m−2∙yr−1) was measured at both locations to estimate aerobic metabolic consumption of organic matter.Maximum rates of benthic primary production occurred during early and late summer at both locations but Values at the Cumberland Basin sites were two to three times greater than those observed in Minas Basin; Chlorophyll a in surface sediments was also lower at the stations in Minas Basin where coarser grained deposits reflect extensive sediment transport. Annual benthic respiration at the two stations in Cumberland Basin, however, was only slightly greater than that at four stations in Minas Basin. Spartina marshes, phytoplankton, and benthic microalgae may provide supplies of organic matter for aerobic consumption in these intertidal sediments which are more similar than are measures of benthic primary production.Key words: benthic microalgae, primary production, intertidal community metabolism, Bay of Fundy

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