scholarly journals Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and contribution to primary production

2006 ◽  
Vol 3 (4) ◽  
pp. 895-959 ◽  
Author(s):  
J.-P. Gattuso ◽  
B. Gentili ◽  
C. M. Duarte ◽  
J. A. Kleypas ◽  
J. J. Middelburg ◽  
...  

Abstract. One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS) data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface of the coastal zone receiving an irradiance greater than Ez: PaNon-polar=28.80−16.69 log10(Ez)+0.84 log102(Ez)+0.83 log103(Ez) PaArctic=16.01−15.67 log10(Ez)+2.03 log102(Ez)+1.00 log103(Ez) Data on the constraint of light availability on the major benthic primary producers and net primary production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m). The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1) light does not limit the distribution of primary producers and (2) net community production (NCP, the balance between gross primary production and respiration) is positive. Positive benthic NCP can occur over 37% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, and the relatively limited biological information available, are discussed.

2006 ◽  
Vol 3 (4) ◽  
pp. 489-513 ◽  
Author(s):  
J.-P. Gattuso ◽  
B. Gentili ◽  
C. M. Duarte ◽  
J. A. Kleypas ◽  
J. J. Middelburg ◽  
...  

Abstract. One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS) data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface (S) of the coastal zone receiving an irradiance greater than Ez (in mol photons m−2 d−1): SNon-polar = 29.61 − 17.92 log10(Ez) + 0.72 log102(Ez) + 0.90 log103(Ez) SArctic = 15.99 − 13.56 log10(Ez) + 1.49 log102(Ez) + 0.70 log103(Ez) Data on the constraint of light availability on the major benthic primary producers and net community production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m). The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1) light does not limit the distribution of primary producers and (2) net community production (NCP, the balance between gross primary production and community respiration) is positive. Positive benthic NCP can occur over 33% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, the lack of global information on the benthic nepheloid layer, and the relatively limited biological information available, are discussed.


1983 ◽  
Vol 40 (S1) ◽  
pp. s229-s243 ◽  
Author(s):  
B. T. Hargrave ◽  
N. J. Prouse ◽  
G. A. Phillips ◽  
P. A. Neame

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


Author(s):  
Artem Lapenkov ◽  
Artem Lapenkov ◽  
Yury Zuyev ◽  
Yury Zuyev ◽  
Nadezhda Zuyeva ◽  
...  

Coastal zones have great diversity of resources. The shallow water zones contain the most of plant and benthic communities. A description of relief and type of ground is needed for the rigorous monitoring of biota and environmental condition of coastal zone. Generally, on the basis of these data the investigation methods of the coastal zone are selected. The shallows research strategy has been developed by us for northern part of the Lake Ladoga. If the coastal areas are characterized by great depth and flat topography, then sonar’s can be used to describe them and samples of ground can be taken by bottom grabs. In the Lake Ladoga these methods don’t operate correctly by reason of the compound bottom relief and the fact that a sizeable part of the bottom is occupied by hard ground. Therefore, our investigations base on the diving transect method of Golikov and Skarlato (1965). A diver moves along transects. He registers the depth, length to coastline, water temperature, relief and ground, edificators and records video. In the laboratory all these data are decoded and used for mapping of bays. Studies of plant communities have been performed and strategy for research of benthic communities in complex relief and hard ground conditions has been developed based on the descriptions of shallow waters. Description of the Malay Nikonovskia Bay bottom has given an opportunity to estimate changes in the bottom of the bay under the influence of the trout farm.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ulrike Braeckman ◽  
Francesca Pasotti ◽  
Ralf Hoffmann ◽  
Susana Vázquez ◽  
Angela Wulff ◽  
...  

AbstractClimate change-induced glacial melt affects benthic ecosystems along the West Antarctic Peninsula, but current understanding of the effects on benthic primary production and respiration is limited. Here we demonstrate with a series of in situ community metabolism measurements that climate-related glacial melt disturbance shifts benthic communities from net autotrophy to heterotrophy. With little glacial melt disturbance (during cold El Niño spring 2015), clear waters enabled high benthic microalgal production, resulting in net autotrophic benthic communities. In contrast, water column turbidity caused by increased glacial melt run-off (summer 2015 and warm La Niña spring 2016) limited benthic microalgal production and turned the benthic communities net heterotrophic. Ongoing accelerations in glacial melt and run-off may steer shallow Antarctic seafloor ecosystems towards net heterotrophy, altering the metabolic balance of benthic communities and potentially impacting the carbon balance and food webs at the Antarctic seafloor.


Database ◽  
2019 ◽  
Vol 2019 ◽  
Author(s):  
Pim Bongaerts ◽  
Gonzalo Perez-Rosales ◽  
Veronica Z Radice ◽  
Gal Eyal ◽  
Andrea Gori ◽  
...  

Abstract Mesophotic coral ecosystems (MCEs) and temperate mesophotic ecosystems (TMEs) occur at depths of roughly 30–150 m depth and are characterized by the presence of photosynthetic organisms despite reduced light availability. Exploration of these ecosystems dates back several decades, but our knowledge remained extremely limited until about a decade ago, when a renewed interest resulted in the establishment of a rapidly growing research community. Here, we present the ‘mesophotic.org’ database, a comprehensive and curated repository of scientific literature on mesophotic ecosystems. Through both manually curated and automatically extracted metadata, the repository facilitates rapid retrieval of available information about particular topics (e.g. taxa or geographic regions), exploration of spatial/temporal trends in research and identification of knowledge gaps. The repository can be queried to comprehensively obtain available data to address large-scale questions and guide future research directions. Overall, the ‘mesophotic.org’ repository provides an independent and open-source platform for the ever-growing research community working on MCEs and TMEs to collate and expedite our understanding of the occurrence, composition and functioning of these ecosystems. Database URL: http://mesophotic.org/


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