Free Radicals and other reactive species in Disease
... Free radicals and other reactive species are constantly
generated in the human body. Some are made by ‘accidents
of chemistry’; for example, leakage of electrons directly on
to O2 from the intermediate electron carriers of the
mitochondrial electron transport chain generates a steady
stream of O2. 2 ...
Biological Formation of Organic Substances from Particulate
... for formation of DOM from plant debris in soils or algal biomass in waters and/or sediments. Note that
rates of superoxide production normalized to the proportion of metabolically active cells is detected to
vary between 0.02 0.02 amol cell−1 hour−1 (mean ± standard error) and 19.4 5.2 amol cell ...
Aerosol pollutants can have long-range effects on ocean oxygen
... ‘oxygen minimum zones’, and organisms that live within them require special adaptations in
order to survive. Some of the world’s biggest oxygen minimum zones are found in the
Pacific Ocean, where oxygen concentrations have decreased considerably in recent years.
These are mostly formed naturally, al ...
Life in the Oceanic Realms - Indian Academy of Sciences
... waters, relatively nutrient-poor open oceanic waters, coral
reef atolls, metal-rich hydrothermal vent fluids with temperatures of 200-350oC, cold-seeps, estuaries, mangrove
swamps, intertidal beaches and rocky shores. Oceans are
home to some of the most diverse and unique life forms. This
article is ...
PICES XV S9-2846 Poster The role of temperature, salinity, light
... ammonium or 20 M urea as the sole nitrogen source. Experiments conducted at high (120 µE·m-2·s-1) and low
(40 µE·m-2·s-1) photosynthetic photon flux densities (PPFDs), demonstrate that P. cuspidata grew significantly
faster at high PPFD, but showed no preference for one nitrogen source over the oth ...
Marine Primary Productivity: Measurements and Variability
... primary producers. Primary producers however, immediately respire some of the organic
matter they make to meet their own energy needs, so it is not available as food to other
organisms. We are more interested, however, in Net primary production, which is the
organic matter that is left over or the c ...
Harmful Algal Blooms in Southern Californian Waters
... food webs, a few are capable of producing substances that are noxious or toxic, resulting in illness
and even death of marine life and occasionally humans who consume contaminated seafood.
When microalgae create these conditions, we refer to them as harmful algal blooms (HABs). An
older term often u ...
Lab/Fieldwork Activity Example
... plants present. The determination the chlorophyll a pigment, using the fluorimetric method, represents
the most common method of assessing the production of phytoplankton in the sea. Color sensors on
satellites also measure chlorophyll concentrations, however only of surface waters, and consecutive
Algae in Fresh Water Ecosystem (PDF Available)
... of phytoplankton. Phosphorus (P) and Nitrogen (N) are often considered as the principal limiting nutrients for aquatic
algal production (Cecilia, 2011 and Hutchinson, 1967). Generally aquatic ecosystems receive excess of this nutrient
through untreated domestic sewage and agriculture runoff (Shinde ...
Fisheries Fact Sheet - Algae
... algae and photosynthetic bacteria. Although they all share
similar habitats, seagrasses are the only true plants found in
the marine environment.
Algae lack the features of true flowering plants such as roots,
stems and vascular tissue. Instead of roots, they anchor
themselves to rocks or other orga ...
reasssement of the photosynthetic quotient
... estimate that errois between 5-15% could commonly
occur between oxygen and the 14C method due to
the uncertainty over whether the 14C technique is
measuring gross or net production and as such would
be insufficient to be the principal cause of the high
observed PQ values. Further support for this co ...
harmful algae news - Woods Hole Oceanographic Institution
... there were many microscopic
organisms but the most abundant was
C. taylorii (Photo 2b). The cells of this
species are peculiar with a really
“unusual” aspect, as already pointed out
[8-9]. The identification was not easy
because this species is typical of coral
reefs and its presence in the
measurements of primary production in coastal sea water using a
... unrealistically high, and undesirable temperature increases usually occur. Furthcrmorc,
no precise “balance” of dissolved oxygen or
carbon dioxide can be readily computed
when there is a large surface area of water in
contact with the atmosphere.
The thin plastic tube experiment proposed
by Margalef ...
Sampaga 1 A Comparison Between Megafaunal Presence and
... The deep sea is home to a variety of geological features such as abyssal plains,
mid-ocean ridges, trenches, and submarine canyons. Barkley Canyon is a submarine
canyon located off of the west continental margin of Vancouver Island, British Columbia.
Submarine canyons can be formed via different pr ...
Accumulation of Th, Pb, U, and Ra in marine phytoplankton and its
... nuclides out of the euphotic zone would be
dominated by zooplanklon and larger phytoplankton and hence would not be representative of the preponderance of marine
phytoplankton. However, collection of sufficient quantities of pure phytoplankton
from natural waters for radiochemical analysis is diffic ...
primary production methods - Center for Microbial Oceanography
... ed as CH2 O. Carbon dioxide in sea water is found
in several chemical forms which exchange quickly
enough to be considered in aggregate as total CO2
(TCO2 ). In principle, photosynthesis can be quantiRed by measuring any of three light-dependent processes: (1) the increase in organic carbon; (2) the ...
Case Study 6 Monitoring Phytoplankton Productivity from
... downwelling irradiance. The objective of this exercise is to estimate the light flux
received by a unit volume of water from all directions, the so-called scalar irradiance,
which is the quantity useful for photosynthesis.
Conceptual models for the biogeochemical role of the photic zone
... (1997) to suggest that the difference between phytoplankton and bacterial affinity
may not be as clear as hitherto assumed. We can estimate the specific affinity in
natural populations from experimental data following the procedure suggested in
Table 2. Using typical values from Villefranche Bay (no ...
Summary and Conclusion
... zooplankton. Among the copepods, harpacticoid copepod Macrosetella
gracilis forms the dominant one. Adults and larvae of this species were
found attached to the Trichodesmium filaments. Among fish eggs and
larvae in the zooplankton samples, eggs were more abundant than larvae.
Presence of fish eggs ...
Canini N. D., Metillo E. B., 2017 Temporal changes in the
... study, net phytoplankton was recorded in decreasing order of abundance: diatoms >
dinoflagellates > cyanobacteria. Diatom cells appeared as chain-forming, centric, zigzag
colonies, elongated and solitary or united in a chain by spines. Some species were
common in estuarine, marine, typical of tropic ...
A quantitative analysis of the direct and indirect costs of nitrogen
... rate increased with oxygen concentration. The
sensitivity to oxygen manifests largely as a 'maintenance' effect, increasing overall carbohydrate
consumption (Figure 1a) because the cell must be
equally clear of oxygen even at very low growth and
nitrogen fixation rates. Azotobacter encodes and
University of Groningen von Liebig`s Law of the Minimum and
... misinterpreted by his successors. BRAt,rOT(1899) took this one law out of its context and proposed that
limitation by nitrogen is a dominant factor in plankton ecology, far beyond its original application
to agriculture. This was opposed by NAmANSOrn~(1908) who suggested instead a dynamic balance of ...
Reactive oxygen species production in marine microalgae
All living cells produce reactive oxygen species (ROS) as a byproduct of metabolism. ROS are reduced oxygen intermediates that include the superoxide radical (O2−) and the hydroxyl radical (OH•), as well as the non-radical species hydrogen peroxide (H2O2). These ROS are important in the normal functioning of cells, playing a role in signal transduction and the expression of transcription factors. However, when present in excess, ROS can cause damage to proteins, lipids and DNA by reacting with these biomolecules to modify or destroy their intended function. As an example, the occurrence of ROS have been linked to the aging process in humans, as well as several other diseases including Alzheimer's, rheumatoid arthritis, Parkinson's, and some cancers. Their potential for damage also makes reactive oxygen species useful in direct protection from invading pathogens, as a defense response to physical injury, and as a mechanism for stopping the spread of bacteria and viruses by inducing programmed cell death.Reactive oxygen species are present in low concentrations in seawater and produced primarily through the photolysis of organic and inorganic matter. However, the biological production of ROS, generated through algal photosynthesis and subsequently 'leaked' to the environment, can contribute significantly to concentrations in the water column. Although there is very little information on the biological generation of ROS in marine surface waters, several species of marine phytoplankton have recently been shown to release significant amounts of ROS into the environment. This ROS has the potential to harm nearby organisms, and, in fact, has been implicated as the cause of massive fish, bacteria, and protist mortalities.