Iron limitation of microbial phosphorus acquisition in the tropical North Atlantic

In certain regions of the predominantly nitrogen limited ocean, microbes can become co-limited by phosphorus. Within such regions, a proportion of the dissolved organic phosphorus pool can be accessed by microbes employing a variety of alkaline phosphatase (APase) enzymes. In contrast to the PhoA family of APases that utilize zinc as a cofactor, the recent discovery of iron as a cofactor in the more widespread PhoX and PhoD implies the potential for a biochemically dependant interplay between oceanic zinc, iron and phosphorus cycles. Here we demonstrate enhanced natural community APase activity following iron amendment within the low zinc and moderately low iron Western North Atlantic. In contrast we find no evidence for trace metal limitation of APase activity beneath the Saharan dust plume in the Eastern Atlantic. Such intermittent iron limitation of microbial phosphorus acquisition provides an additional facet in the argument for iron controlling the coupling between oceanic nitrogen and phosphorus cycles

The influence of Arctic Fe and Atlantic fixed N on summertime primary production in Fram Strait, North Greenland Sea

Climate change has led to a ~ 40% reduction in summer Arctic sea-ice cover extent since the 1970s. Resultant increases in light availability may enhance phytoplankton production. Direct evidence for factors currently constraining summertime phytoplankton growth in the Arctic region is however lacking. GEOTRACES cruise GN05 conducted a Fram Strait transect from Svalbard to the NE Greenland Shelf in summer 2016, sampling for bioessential trace metals (Fe, Co, Zn, Mn) and macronutrients (N, Si, P) at ~ 79°N. Five bioassay experiments were conducted to establish phytoplankton responses to additions of Fe, N, Fe + N and volcanic dust. Ambient nutrient concentrations suggested N and Fe were deficient in surface seawater relative to typical phytoplankton requirements. A west-to-east trend in the relative deficiency of N and Fe was apparent, with N becoming more deficient towards Greenland and Fe more deficient towards Svalbard. This aligned with phytoplankton responses in bioassay experiments, which showed greatest chlorophyll-a increases in + N treatment near Greenland and + N + Fe near Svalbard. Collectively these results suggest primary N limitation of phytoplankton growth throughout the study region, with conditions potentially approaching secondary Fe limitation in the eastern Fram Strait. We suggest that the supply of Atlantic-derived N and Arctic-derived Fe exerts a strong control on summertime nutrient stoichiometry and resultant limitation patterns across the Fram Strait region.S.K. was financed by GEOMAR and the German Research Foundation (DFG Award Number AC 217/1-1 to E.P.A). T.J.B. acknowledges funding from a Marie Skłodowska-Curie Postdoctoral European Fellowship (OceanLiNES; Project ID 658035). Open Access funding provided by Projekt DEAL

Positive and negative effects of COVID-19 pandemic on aquatic environment: a review

In December 2019, a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak was reported for the first time in Wuhan, Hubei province, China. This coronavirus has been referred as Coronavirus Disease 2019 or COVID-19 by World Health Organization (WHO). The spread of COVID-19 has become unstoppable, infecting around 93.5 million people worldwide, with the infections and deaths still increasing. Today, the entire planet has changed due to the greatest threat on the planet since the introduction of this lethal disease. This pandemic has left the world in turmoil and various measures have been taken by many countries including movement control order or lockdown, to slow down or mitigate the infection. Since the lockdown has been implemented almost in all affected countries, there has been a significant reduction in anthropogenic activity, including a reduction in industrial operations, vehicle numbers, and marine-related activities. All of these changes have also led to some unexpected environmental consequences. As a result of this lockdown, it had a positive and negative impact on the environment including the aquatic environment. Hence this review will therefore focus on the good and bad perspectives of the lockdown toward the aquatic environment

KOSMOS Bergen 2015 mesocosm study: Environmental data, carbonate chemistry and nutrients

To evaluate the influence of episodic extreme ocean acidification events in coastal regions, we deployed eight pelagic mesocosms for 53 days in Raunefjord, Norway, and enclosed 60 m³ of local seawater containing a natural plankton community under post-bloom conditions. Four mesocosms were manipulated to simulate extreme pCO2 levels of 2069 µatm while the other four served as untreated controls. To monitor the effects of extreme pCO2 conditions, a variety of physical, ecological, and biogeochemical parameters inside and outside the mesocosms were measured over the course of the experiment in regular intervals

Metals contamination using Polymesoda Expansa (Marsh Clam) as bio-indicator in Kelantan river, Malaysia = Pencemaran logam di Sungai Kelantan, Malaysia menggunakan Polymesoda expansa (Lokan) sebagai penunjuk biologi

Bivalve, such as marsh clam (Polymesoda expansa) feed by filtering most of the suspended particle in water that surrounding them. Lots of elements being trap into their body via this feeding habit including pollutant such as trace metals. Unfortunately, these marsh clams were taken directly by human as their daily diet. Due to its ability to filter water, marsh clam was used to monitor the level of trace metals in aquatic system in significant place such as industrial area. Therefore, this study was carried out at Kelantan River near to the industrial area in Pengkalan Chepa, Kelantan, Malaysia. A total of 80 marsh clams were collected from 4 different sites to represent a different environmental condition. The in-toto of the marsh clam were dissected and digest with suprapur nitric acid by using Teflon Bomb method. Six metals were determined by using Inductively Coupled Plasma Mass Spectrometry including chromium, iron, copper, cadmium, lead and zinc. The highest mean concentration of all metals studied (Cr 45.03 μg/g dry weight; Fe 1.28 μg/g dry weight; Cu 21.8 μg/g dry weight; Cd 1.15 μg/g dry weight; Pb 2.31 μg/g dry weight; Zn 898 μg/g dry weight) in the marsh clam tissue was recorded at station 4 which is near to the industrial area discharge. Whereas, those concentration were lower at Station 1 and Station 2, which located at the upstream and far from the industrial area discharge. On the other hand, the size of marsh clam does not significantly correlate to the concentration of selected trace metals. Level of selected metals in some the samples were exceeded the permissible limit provide by Malaysia Food Safety and Food Regulation 1985 especially marsh clam collected from station near to industrial area. Therefore, marsh clam collected for consumption near to industrial area need to be continuously monitor to prevent any acute effect on human health risk

Iron limitation of microbial phosphorus acquisition from METEOR cruise M116

Here we demonstrate enhanced natural community APase activity following iron amendment within the low zinc and moderately low iron Western North Atlantic. In contrast we find no evidence for trace metal limitation of APase activity beneath the Saharan dust plume in the Eastern Atlantic. Such intermittent iron limitation of microbial phosphorus acquisition provides an additional facet in the argument for iron controlling the coupling between oceanic nitrogen and phosphorus cycles

Dissolved trace elements (Fe, Mn, Co, Ni, Cu, Zn, Cd and Pb) measured on water bottle samples from ultra clean CTD/Water sampler-system during POLARSTERN cruise PS100 / GN05 (ARK-XXX/2)

This dataset contains measured dissolved trace element concentrations (Fe, Mn, Co, Ni, Cu, Zn, Cd and Pb) of station depth profiles sampled in Fram Strait (North Greenland Sea) during GEOTRACES expedition GN05 (PS100) between 21 July and 1 September 2016. Samples were collected strictly following GEOTRACES guidelines (Cutter et al., 2017; https://www.geotraces.org) and analysed exactly as per Rapp et al., 2017 ( Anal. Chim. Acta; doi:10.1016/j.aca.2017.05.008). Concentrations were intercalibrated with GEOTRACES reference materials SAFe S and GSC (Bruland Research Lab), with exception of dissolved Cd data. Information on the analytical procedure including reference materials and limits of detection can be found in related published manuscripts, the PhD thesis of Stephan Krisch (Christian-Albrechts-Universität zu Kiel) or can be obtained from the authors upon request. Table caption: Measured concentrations of dissolved trace elements in Fram Strait sampled during GEOTRACES expedition GN05 (PS100) between 21 July-1 September 2006. Uncertainty is calculated as one standard deviation (1σ, STD) to replicate measurements via ICP-MS. ND = no data. Use of quality flags (QF) according to GEOTRACES policy (https://www.geotraces.org/geotraces-quality-flag-policy/). Plesae note, dissolved Cd data is not quality controlled. Somes samples were pooled (indicated in column "Bottle") from different bottles at one depth; the concentrations reflects the mean and the corresponding uncertainty is calculated as the standard deviation to replicate measurements. Trace metal concentrations at station 24 may show larger variations between different bottles at one specific depth. Because station 24 is located at Dijmphna Sund entrance sill, we associate these discrepancies to the water column's strong lateral and vertical turbulence (see ucCTD physical oceanography data) (e.g. Mortensen et al. 2011, 2013, Carroll et al. 2017) that goes in hand with localized TM aggregation-dissolution and sediment resuspension processes, thus affecting TM fractionation (e.g. Homoky et al. 2012)

Long-term mesocosm study in Gullmar Fjord Sweden in 2013

The present biogeochemical parameters were measured or calculated in 2013 during a long-term mesocosm CO2 perturbation study in Gullmar Fjord (Sweden). The natural plankton community was enclosed in ten pelagic mesocosms following the natural winter-to-summer plankton succession. Five of the mesocosms were enriched with CO2 to simulate end-of the century ocean acidification (760 µatm) while the others served as controls. The data set was used for mass balance calculations to investigate the impact of realistic end-of-the-century CO2 concentrations on the development and partitioning of the carbon, nitrogen, phosphorus, and silica pools in a coastal pelagic ecosystem