Plankton Production Research Articles

Forbs from seasonal managed wetlands boost plankton production more than emergent graminoids by supplying novel labile detritus

Abstract Opportunities to enhance ecosystem functions exist in human‐dominated working landscapes, but understanding of key drivers is often lacking in these novel environments. In Suisun Marsh, California, USA, impounded managed wetlands designed to promote waterfowl incidentally support higher plankton densities—a key resource for imperilled pelagic fishes—than adjacent tidal habitats. Managed wetland operations could produce plankton at critical periods for fish and the aquatic food‐web more broadly, but drivers of plankton production in managed wetlands are poorly understood. We proposed that decaying vegetation resulting from controlled flooding in managed wetlands is important for stimulating plankton blooms, but that the effect varies by plant species and functional type. We conducted a mesocosm experiment to test the effects of different inundated plants on plankton production, including three forb species, three emergent graminoid species and a control treatment without added plant material. Forbs promoted larger phytoplankton blooms and higher zooplankton production—by an order of magnitude—than both emergent graminoids and the control treatment. Emergent graminoids supported larger phytoplankton blooms, but not higher zooplankton production, than the control treatment. Phytoplankton blooms exhibited pulse dynamics in all treatments, with densities increasing initially and crashing by the end of the experiment. Phytoplankton blooms in forb and emergent treatments lasted similar durations, counter to the expectation that emergent graminoids would support diminished production over a relatively prolonged period. Among zooplankton taxa, Daphnia magna and rotifers were strongly associated with all three forbs species while the nonnative cyclopoid copepod Limnothoina tetraspina were associated with cattails (Typha domingensis) and the control. Forbs temporarily depleted dissolved oxygen concentrations during the first week of the experiment, suggesting a tradeoff by which decaying forbs boost plankton production at risk of initial hypoxia. Our results suggest that seasonal drying and flooding operations in managed wetlands are likely to enhance plankton production because dry periods promote forb growth and subsequent flooding introduces labile forb material to the aquatic food web. Results also suggest that seasonal managed‐wetlands act as novel floodplain‐analogues, by which flood pulses drive productivity. Further research is needed to quantify production benefits and tradeoffs to the aquatic ecosystem at the landscape scale and to identify optimal management regimes that will help conserve imperilled species.

The Bonney Coast upwelling: How physical processes shape the feeding behaviour of blue whales

This study employs a fully coupled physical-biological model to explore the oceanic dynamics and phytoplankton production in one of Australia’s most prominent coastal upwelling systems, the Bonney Coast Upwelling, that has barely been studied before. The study focusses on how physical processes provide two different food sources for blue whales (Balaenoptera musculus), namely, krill (treated as nonbuoyant particles) and zooplankton, both feeding on phytoplankton. While plankton grows in the euphotic zone in response to nutrient enrichment on time scales of weeks, krill can only be transported into the region via ambient currents. Findings of this study suggest that phytoplankton blooms appear slowly in the main upwelling plume on timescales of 4-8 weeks. Dynamical influences from incoming coastal Kelvin waves significantly weaken or strengthen this classical upwelling plume and its plankton productivity. On the other hand, the upwelling-favourable wind induces a continuous coastal current that also extends eastward past the Bonney Coast. This current operates to transport and distribute krill (that cannot swim horizontally) westward along the shelf, which explains the apparent conundrum why blue whales also feed on the upstream side of the upwelling plume. The author postulates that the variability of both plankton production and the intensity of the upwelling flow (passing krill swarms along the shelf) control the feeding locations of blue whales and other baleen whales on Australia’s southern shelves.

Assessment of water quality and plankton production in managed and unmanaged fresh water ponds in district Hisar, Haryana, India

Managed and unmanaged extensive fisheries culture systems in small village ponds in district Hisar of Haryana, India to correlate the water quality and biological cycles in ponds with fish production were undertaken. The studies revealed that the ponds are in good trophic status. Chlorides, total hardness, calcium, magnesium, biochemical oxygen demand (BOD), phosphates (o-PO4) and ammonia were high whereas dissolved oxygen and fish growth/yield was low in unmanaged ponds in comparison to managed ponds. This may be due to high organic loads.The deterioration of water quality, as indicated by very high ammonia and BOD in unmanaged ponds might have decreased the fish growth and a variety of factors like organic load, ammonia production, nature/quantity of fertilizers may have influenced such correlations. Management of water quality by managing the optimization of waste input in village ponds may help in enhancing the fish production through such small scale aquaculture.. KEYWORDS :Water quality, Physico-chemical characteristics, Fish yield, BOD, Ammonia

A switch in thermal and haline contributions to stratification in the Greenland Sea during the last four decades

Stratification and its thermal and haline contributions are important ocean properties of fundamental climatic influence. Upper-ocean stratification shapes marine ecosystems by regulating nutrient availability and deep-ocean stratification is important for carbon sequestration and ventilating the ocean interior. Here, we first assess the applicability of an ocean reanalysis product in representing stratification in the Nordic Seas and East Greenland Shelf. While the reanalysis performs well in most interior basins, it exhibits significant shortcomings on the East Greenland shelf, raising concerns about the reanalysis product in these areas. We then examine the development in the thermal and haline contributions to summer upper- (100 m) and winter intermediate- (1000 m) ocean stratification in the Greenland Sea from 1980 to 2020. We find that there has been a transition in the controls of winter stratification in the upper 1000 m of the Greenland Sea. The transition was associated with a westward migration of the boundary between salinity- and temperature-stratified waters and eventual switch from haline to thermal control of winter stratification. With that follows a change in the type of forcing that can lead to convection: The Greenland Sea is now less dependent on eroding salinity gradients but rather depends on cooling to overcome stratification. There has been a similar switch in summer stratification in the upper-ocean of the Greenland Sea where surface waters shifted from variable stratification, alternating between salinity and temperature dominance, to a stable temperature-stratified regime. This switch coincided with declining sea-ice concentrations related to the disappearance of the Odden ice tongue after 1997. The high sea-ice conditions previously characteristic of the Greenland Sea are now rare suggesting the transition will persist with potential implications for marine ecology and local sea-ice formation. Our findings reveal differences in how thermal and haline stratification has developed over the last 40 years, which may help explain or predict plankton production and carbon uptake and export.

Study of upwelling and mixing process in the Somali coastal region using satellite and numerical model observations: A Lagrangian approach

During the summer monsoon, the Somali region undergoes a significant upwelling phenomenon that enhances plankton productivity, thereby benefiting fisheries. Wind and coastal dynamics initially drive this upwelling, but eventually, eddy flows influence it. Our study explores the interplay between ocean currents, eddies, and chlorophyll-a concentrations using the backward Finite-Size Lyapunov Exponents (bFSLEs) technique. We also delve into the specific role of Ekman transport in distributing chlorophyll-a across the region. The Great Whirl (GW), an anticyclonic eddy, predominantly causes strong downwelling, interrupting the summer monsoon upwelling along the Somali coast longitudinally. Despite the GW's significant impact on moving upwelled water offshore, the influence of downwelling diminishes northward. As a result, the northern Somali coast, especially around 9°N and 10°N, showcases the most extensive offshore upwelling, reaching as far as 55°E. Our findings highlight a robust connection between chlorophyll-a levels and oceanic dynamics, influenced by both currents and eddies, as evidenced by bFSLEs, and by cross-shore Ekman transport, particularly within chlorophyll-a concentrations ranging from 0.2 to 0.6 mg m−3. The data suggests that Ekman transport-induced upwelling primarily drives coastal phytoplankton biomass. Furthermore, bFSLEs analysis underlines the supportive role of ocean currents and eddies in the offshore distribution of chlorophyll-a, especially near the coast. Further examination of lagged correlations reveals a temporal lag between peak concentrations of chlorophyll-a and Ekman transport; the lag increases offshore and is at least 9 days near the coast.

Identifying priority sites for whale shark ship collision management globally

The expansion of the world's merchant fleet poses a great threat to the ocean's biodiversity. Collisions between ships and marine megafauna can have population-level consequences for vulnerable species. The Endangered whale shark (Rhincodon typus) shares a circumglobal distribution with this expanding fleet and tracking of movement pathways has shown that large vessel collisions pose a major threat to the species. However, it is not yet known whether they are also at risk within aggregation sites, where up to 400 individuals can gather to feed on seasonal bursts of planktonic productivity. These “constellation” sites are of significant ecological, socio-economic and cultural value. Here, through expert elicitation, we gathered information from most known constellation sites for this species across the world (>50 constellations and >13,000 individual whale sharks). We defined the spatial boundaries of these sites and their overlap with shipping traffic. Sites were then ranked based on relative levels of potential collision danger posed to whale sharks in the area. Our results showed that researchers and resource managers may underestimate the threat posed by large ship collisions due to a lack of direct evidence, such as injuries or witness accounts, which are available for other, sub-lethal threat categories. We found that constellations in the Arabian Sea and adjacent waters, the Gulf of Mexico, the Gulf of California, and Southeast and East Asia, had the greatest level of collision threat. We also identified 39 sites where peaks in shipping activity coincided with peak seasonal occurrences of whale sharks, sometimes across several months. Simulated collision mitigation options estimated potentially minimal impact to industry, as most whale shark core habitat areas were small. Given the threat posed by vessel collisions, a coordinated, multi-national approach to mitigation is needed within priority whale shark habitats to ensure collision protection for the species.

Preserved particulate organic carbon is likely derived from the subsurface sulfidic photic zone of the Proterozoic Ocean: evidence from a modern, oxygen-deficient lake.

Biological processes in the Proterozoic Ocean are often inferred from modern oxygen-deficient environments (MODEs) or from stable isotopes in preserved sediment. To date, few MODE studies have simultaneously quantified carbon fixation genes and attendant stable isotopic signatures. Consequently, how carbon isotope patterns reflect these pathways has not been thoroughly vetted. Addressing this, we profiled planktonic productivity and quantified carbon fixation pathway genes and associated organic carbon isotope values (δ13 CPOC ) of size-fractionated (0.2-2.7 and >2.7 μm) particulate matter from meromictic Fayetteville Green Lake, NY, USA. The high-O2 Calvin-Benson-Bassham (CBB) gene (cbbL) was most abundant in the <2.7 μm size fraction in shallow oxic and deep hypoxic waters, corresponding with cyanobacterial and eukaryote algal populations. The low-O2 CBB gene (cbbM) was most abundant near the lower oxycline boundary in the larger size fraction, coincident with purple sulfur bacteria populations. The reverse citric acid cycle gene (aclB) was equally abundant in both size fractions in the deepest photic zone, coinciding with green sulfur bacteria populations. Methane coenzyme reductase A (mcrA), of anaerobic methane cyclers, was most abundant at the lower oxycline boundary in both size fractions, coinciding with Methanoregula populations. δ13 CPOC values overlapped with the high-O2 CBB fixation range except for two negative excursions near the lower oxycline boundary, likely reflecting assimilation of isotopically-depleted groundwater-derived carbon by autotrophs and sulfate-reducers. Throughout aphotic waters, δ13 CPOC values of the large size fraction became 13 C-enriched, likely reflecting abundant purple sulfur bacterial aggregates. Eukaryote algae- or cyanobacteria-like isotopic signatures corresponded with increases in cbbL, cbbM, and aclB, and enrichment of exopolymer-rich prokaryotic photoautotrophs aggregates. Results suggest that δ13 CPOC values of preserved sediments from areas of the Proterozoic Ocean with sulfidic photic zones may reflect a mixture of alternate carbon-fixing populations exported from the deep photic zone, challenging the paradigm that sedimentary stable carbon isotope values predominantly reflect oxygenic photosynthesis from surface waters.

Ambivalence of planktonic invaders and transformation of communities

The ambivalence of planktonic invaders has been studied using the example of ecosystem effects of the invasive cladoceran Cercopagis pengoi (Ostroumov, 1891) in the Vistula Lagoon of the Baltic Sea. The influence of the invader on the taxonomic structure and productivity of plankton is studied. It is discovered that, in the long term, the predation pressure of C. pengoi on zooplankton has decreased; the abundance, biomass, and production of the dominant species Rotifera, Cladocera, and Copepoda also declined. The negative impact of C. pengoi on the planktonic community is reflected in a reduction in the food supply of juvenile Baltic herring and other planktivorous fish. The wide ecological niche of Cercopagis contributes to the expansion of its range, which can lead to a reduction in populations of phytophagous crustaceans, increased water blooms, and the further deterioration of the food supply of fish.

Effect of a cyclonic eddy on phytoplankton: A bioassay experiment

AbstractCyclonic eddies often increase the primary productivity of marine ecosystems. However, the study of their influence on the taxonomic structure and productivity of plankton is complex due to the short‐term and mesoscale nature of the action of eddies. In a laboratory bioassay experiment, we simulated two mechanisms of eddy's effect on the deep phytoplankton maximum: an increase in the upward flow of deep nutrients and illumination. Doubling of nutrient additions compared to control increased chlorophyll's specific growth rate (SGR) 1.7‐fold over 12 days while doubling the light intensity increased SGR by 3.5 times. During the first 4 days of the experiment, at the exponential growth stage, SGR of carbon biomass was maximum with the simultaneous doubling of nutrients and light (0.44 day−1). It was statistically significantly higher than at increased nutrients but not light. These results suggest that nutrient deficiencies were less crucial for phytoplankton growth than light. The increase in the phytoplankton biomass was mainly due to the growth of a large‐celled diatom Pseudosolenia calcar‐avis. It showed the highest SGR (1.15–1.28 day−1) at increased nutrients and/or light, resulting in high wet biomass of 2–3 g m−3 over 4 days. The ecological meaning of the obtained results is as follows. First, in the eddy, where the deep phytoplankton maximum is located close to the nutricline, its rise to more illuminated layers results in higher phytoplankton growth than the shortening distance to the nutricline. Second, increases in the upward flow of nutrients and light intensity, separate or simultaneous, stimulate the rapid reproduction of large‐celled diatoms that increase the carbon‐to‐chlorophyll ratio by 2–4 times. Third, exposure to a typical Black Sea mesoscale cyclonic eddy can lead to phytoplankton blooms in the thermocline within a few days.

Recombinant protein production in Pseudoalteromonas haloplanktis TAC125 biofilm

Biofilms have great potential for producing valuable products, and recent research has been performed on biofilms for the production of compounds with biotechnological and industrial relevance. However, the production of recombinant proteins using this system is still limited. The recombinant protein production in microbial hosts is a well-established technology and a variety of expression systems are available. Nevertheless, the production of some recombinant proteins can result in proteolyzed, insoluble, and non-functional forms, therefore it is necessary to start the exploration of non-conventional production systems that, in the future, could be helpful to produce some “difficult” proteins. Non-conventional production systems can be based on the use of alternative hosts and/or on non-conventional ways to grow recombinant cells. In this paper, the use of the Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 grown in biofilm conditions was explored to produce two fluorescent proteins, GFP and mScarlet. The best conditions for the production were identified by working on media composition, and induction conditions, and by building a new expression vector suitable for the biofilm conditions. Results reported demonstrated that the optimized system for the recombinant protein production in biofilm, although it takes longer than planktonic production, has the same potentiality as the classical planktonic approach with additional advantages since it needs a lower concentration of the carbon sources and doesn't require antibiotic addition. Moreover, in the case of mScarlet, the production in biofilm outperforms the planktonic system in terms of a better quality of the recombinant product.

Growth and carbon turnover of Piaractus mesopotamicus Holmberg, 1887 (Osteicthyes: Characidae): contribution of extruded feed and natural food.

Piaractus mesopotamicus, is a fish usually farmed in semi-intensive systems with access to natural food and supplementary feed. This study evaluates effects of feed allowance on the productive performance, carbon turnover and proportions of nutrient (carbon) contribution of feed and natural food for the growth of pacu. Juvenile fish were stocked in fiberglass tanks and fed to 100, 75, 50, 25, 0% apparent satiety (ApS), with a practical, extruded (C4 photosynthetic pathway) feed in a randomized design trial (n=3); plankton production for simulated semi-intensive farming system condition was induced by chemical fertilization. A control treatment was set up in tanks devoid of natural food. Data on muscle stable carbon isotope ratios were used to study carbon turnover using a relative growth-based model. Low variation of the δ13C impaired fitting a turnover model curve for the 0 and 25 % ApS treatments. Fish of the 100% and 75% ApS treatments reached circa 95% and 82.85% of the carbon turnover, respectively. Extruded feed was the main nutrient source for the growth of pacu in the semi-intensive, simulated farming condition. The current study contributes to the knowledge of the relationship between feeding rates and carbon turnover rates in the pacu muscle.

Primary Production of Plankton in the Volga Reservoirs

Primary Production of Plankton in the Volga Reservoirs

Determination of Primary Plankton Production in Reservoirs of the Volga River

Determination of Primary Plankton Production in Reservoirs of the Volga River

Retrospective analysis of the pelagic ecosystem of the Western Mediterranean Sea: Drivers, changes and effects

In the Western Mediterranean Sea, forage fishes have changed in abundance, body condition, growth, reproduction, and distribution in the last decades. Different hypotheses have been proposed to explain these changes, including increase in fishing mortality; changes in environmental conditions affecting species fitness, and planktonic productivity and quality; recovery of top predators; and increase in competitors. We investigated the main drivers and changes of the pelagic ecosystem and their effects using an ecosystem-based modelling approach. Specifically, we (1) quantified the potential historical contribution of various drivers of change, (2) investigated changes in temporal trends and spatial distributions of main ecosystem components, and (3) identified ecological consequences of these changes in top predator and competitors, their fisheries and ecosystem traits during 2000–2020. We updated an established Ecopath food-web model representing the Spanish and French Mediterranean sub-areas (GSA06 and GSA07) in 2000 with recent available data. We applied the temporal dynamic Ecosim module, and tested historical time series of fishing effort, fishing mortality and environmental factors as potential drivers. Observed biomass and landings of key species were used to validate model projections. A spatial-temporal Ecospace model was developed to project species distribution changes. Results showed historical biomass and catch changes driven by a combination of high fishing pressure and environmental change (i.e. increase in temperature and salinity, and decline in primary productivity). Small pelagic fish showed significant temporal changes and predicted shifts in their distributions, following a latitudinal gradient. Predators and competitors showed changes as well, displaying heterogeneous spatial patterns, while fisheries landings declined. Overall, results matched observations (e.g., decline of sardine, fluctuations of anchovy and increases in bluefin tuna) and illustrated the need to complement traditional assessments with integrative frameworks to move towards an ecosystem-based approach in the Mediterranean. They also highlighted important knowledge gaps to guide future research in the region.

Evolution and environment of Caribbean coastal ecosystems

Isolation of the Caribbean Sea from the tropical Eastern Pacific by uplift of the Isthmus of Panama in the late Pliocene was associated with major, taxonomically variable, shifts in Caribbean biotic composition, and extinction, but inferred causes of these biological changes have remained elusive. We addressed this through falsifiable hypotheses about how independently determined historical changes in oceanographic conditions may have been responsible. The most striking environmental change was a sharp decline in upwelling intensity as measured from decreases in intra-annual fluctuations in temperature and consequently in planktonic productivity. We then hypothesized three general categories of biological response based upon observed differences in natural history between the oceans today. These include changes in feeding ecology, life histories, and habitats. As expected, suspension feeders and predators became rarer as upwelling declined. However, predicted increases in benthic productivity by reef corals, and benthic algae were drawn out over more than 1 Myr as seagrass and coral reef habitats proliferated; a shift that was itself driven by declining upwelling. Similar time lags occurred for predicted shifts in reproductive life history characteristics of bivalves, gastropods, and bryozoans. Examination of the spatial variability of biotic change helps to understand the time lags. Many older species characteristic of times before environmental conditions had changed tended to hang on in progressively smaller proportions of locations until they became extinct as expected from metapopulation theory and the concept of extinction debt. Faunal turnover may not occur until a million or more years after the environmental changes ultimately responsible.

Plankton community structure in response to hydrothermal iron inputs along the Tonga-Kermadec arc

The Western Tropical South Pacific (WTSP) basin has been identified as a hotspot of atmospheric dinitrogen fixation due to the high dissolved iron ([DFe]) concentrations (up to 66 nM) in the photic layer linked with the release of shallow hydrothermal fluids along the Tonga-Kermadec arc. Yet, the effect of such hydrothermal fluids in structuring the plankton community remains poorly studied. During the TONGA cruise (November-December 2019), we collected micro- (20-200 μm) and meso-plankton (&amp;gt;200 μm) samples in the photic layer (0-200 m) along a west to east zonal transect crossing the Tonga volcanic arc, in particular two volcanoes associated with shallow hydrothermal vents (&amp;lt; 500 m) in the Lau Basin, and both sides of the arc represented by Melanesian waters and the South Pacific Gyre. Samples were analyzed by quantitative imaging (FlowCam and ZooScan) and then coupled with acoustic observations, allowing us to study the potential transfer of phytoplankton blooms to higher planktonic trophic levels. We show that micro- and meso-plankton exhibit high abundances and biomasses in the Lau Basin and, to some extent, in Melanesian waters, suggesting that shallow hydrothermal inputs sustain the planktonic food web, creating productive waters in this otherwise oligotrophic region. In terms of planktonic community structure, we identified major changes with high [DFe] inputs, promoting the development of a low diversity planktonic community dominated by diazotrophic cyanobacteria. Furthermore, in order to quantify the effect of the shallow hydrothermal vents on chlorophyll a concentrations, we used Lagrangian dispersal models. We show that chlorophyll a concentrations were significantly higher inside the Lagrangian plume, which came into contact with the two hydrothermal sites, confirming the profound impact of shallow hydrothermal vents on plankton production.

Physico-chemical Features of Water and Soil in Rural Fish Ponds and its Relationship with Pond Productivity

Samples of water and soil were collected at. monthly and bimonthly intervals, respectively from four different rural fish ponds of Bhadrak District, Orissa for three years (1994-1997) and were subjected to analysis for different physicochemical parameters. The values obtained for different parameters were subjected to analysis of variance and multiple correlation to establish the interrelationship of some important hydrobiological parameters. The parameters like pH, dissolved oxygen, nitrate-nitrogen, phosphate-phosphorus and organic carbon were positively correlated to the plankton production which influences the productivity of the fish ponds.

Water Hyacinth, an Invasive Species in Africa: A Literature Review

Water hyacinth is without a doubt the water invader that causes the most harm to water bodies. Water hyacinths originated from Eastern Mediterranean, West Asia, and Central Asia; they are cultivated and loved worldwide. According to reports, water hyacinth has anti-inflammatory, antifungal, and antibacterial properties. The plant extracts can also be used to treat cholera, sore throats, and snake bites, as well as to scent hair. Water hyacinth Pontederia crassipes (Eichhornia crassipes) has proliferated rapidly in African inland waters, posing numerous threats to fisheries by reducing the existence of some species; water quality by lowering levels of dissolved oxygen; human health and the environment by introducing various disease-causing pathogens and harbouring dangerous animals. The hyacinths further impact human activities by blocking waterways for fishing and destroying habitat for some fish to bread properly. Tourism and navigation are also affected by limiting access to recreational areas, especially for boat cruising. Fishing; effects on fishing activities and effect on plankton production, which is the main food. Different control methods have been utilised and others suggested in Africa, although it has not been fully controlled as it is highly reproductive and still a menace in African inland waters. The most commonly used control measures are biological and physical controls. As a recommendation, all methods should be used in water bodies to reduce its spread as quickly as possible although with caution on chemical methods. In relation to water hyacinth and its effects on terrestrial animals, there is still a need for much research to still be done; however, it is an aquatic plant that is not wanted in many places does not mean it should be eradicated. Its use to produce biogas could be helpful in reducing the challenges that come with it

Diverse nature of the seasonally coastal eutrophication dominated by oceanic nutrients: An eco-system based analysis characterized by salmon migration and aquaculture

Previously, studies of coastal eutrophication have usually focused on the nutrients input from adjacent land sectors, such as rivers, submarine-ground discharges, and atmospheric depositions. Here we report two examples of well-managed seasonal eutrophication phenomena in coastal marine environments, where nutrients come predominantly from offshore: one by humans and the other by nature (higher trophic animals). In the Sanggou Bay of North China, the total amount of incoming nutrients from the open Yellow Sea is taken up by seaweeds. Seaweed, in turn, supports bivalves culture activities and absorbs nutrients emitted by finfish. In the Academy Bay of Russian Far East, a relatively high plankton primary production sustains throughout the salmon-returning season when nutrients are released from the massive carcasses of dead fish after return from the ocean to their natal streams to spawn and die. This high plankton productivity, in turn, fuels higher trophic ecosystem constituents, including whale populations of global importance. In the future, dominance of nutrients from marine sources needs to be seriously considered in studies of coastal eutrophication.

Land-sea linkages on the Algerian Margin over the last 14 kyrs BP: Climate variability at orbital to centennial timescales

Past and present environmental conditions over the Holocene along the Algerian coast involve complex atmosphere-hydrosphere-biosphere interactions and anthropogenic activities on adjacent watersheds. Atlantic Ocean surface waters entering the western Mediterranean Sea at the Gibraltar Strait create the Algerian Current, which flows along the North African coast in a succession of strong and large-scale eddies. Deep-water upwelling plumes are other recurrent hydrological features of the Algerian margin affecting regional environmental features. However, vegetation and paleohydrological changes that have occurred over the Holocene have not yet been described. To bridge this gap, a suite of paleoclimate proxies was analysed in marine core MD04–2801 (2067 m water depth) at a secular-scale resolution over the last 14 kyrs BP. Terrestrial (pollen grains) and marine (dinoflagellate cysts or dinocysts) palynological assemblages, as well as sedimentological (grain-size analysis and XRD-based quantitative analysis of clay minerals) and biomarkers (alkenones and n-alkanes), were determined to explore the links between past sea surface hydrological conditions and regional environmental changes on nearby watersheds.The over-representation of heterotrophic dinocyst taxa (Brigantedinium spp.) indicates strong planktonic productivity in the study area. Results shows that the links between dryness on land and surface hydrological conditions are expressed by: (i) recurrent upwelling cells during the relatively dry climate conditions of the Younger Dryas (12.7 to 11.7 ka BP), the Early Holocene (11.7 to 8.2 ka BP) and from 6 ka BP onwards, (ii) enhanced fluvial discharges between 8.2 and 6 ka BP during the African Humid Period concomitant with the colonization of coastal lands by Mediterranean forest. Middle to Late Holocene transition around 4.2 ka BP characterizes by the intense event reffered to here as the Algerian Mega Drought (4.3 to 3.9 ka BP).